37th International Symposium on Intensive Care and Emergency Medicine (part 1 of 3)

P1 Inhibition of jak/stat3 signaling pathway by small molecule r548 prevents inflammation in experimental murine lung injury model

V. Karavana¹, I. Smith², G. Kanellis³, I. Sigala¹, T. Kinsella², S. Zakynthinos¹

¹George P. Livanos and Marianthi Simou Laboratories, Athens, Greece; ²Rigel Pharmaceuticals, Inc, South San Francisco, CA, USA; ³Evangelismos Hospital, Athens, Greece

Introduction: Aberrant inflammation is a hallmark of acute respiratory distress syndrome (ARDS) pathophysiology. JAK/STAT3 pathway is critical for macrophages and neutrophils activation and persistent inflammation. This study aims to investigate the therapeutic potential of inhibiting JAK1/3 activity using the small-molecule R548 inhibitor in LPS induce lung injury model.

Methods: Lung injury was induced in adult male C57BL/6 mice, by intratracheal LPS administration followed by post subcutaneous injection of R548 inhibitor R548 inhibitor, prodrug for the active compound, R507 (Rigel Pharmaceuticals Inc.). Mice sacrificed at 6 h and 24 h after LPS administration. Lung inflammation was examined by protein content, number and type of inflammatory cells in bronchoalveolar lavage fluid (BALF). Protein expression levels of JAK1, p-STAT3, ERK1/2 were analysed by Western blotting.

Results: LPS administration increased BALF cellularity, total protein content, and neutrophils cells number at both 6 h and 24 h. Elevated levels of JAK1, p-STAT3 and ERK1/2 protein expression were observed. In addition, post LPS treatment with the JAK 1/3 inhibitor significantly reduces BALF protein content (P < 0.05), total cells number (P < 0.01), neutrophils cells number (P < 0.01) as early as 6 h. Moreover, R548 treatment decreased JAK1 protein expression by 2 fold (P < 0.01) and p-STAT3 levels by 2.7 fold (P < 0.001) below the LPS group.

Conclusions: These data suggest the JAK/STAT3 signaling pathway plays a critical role in ARDS mediated lung inflammation and injury. Additional studies are warranted to further investigate JAK/STAT3 inhibition as a therapeutic treatment for this serious and life threatening disease.

P2 Stable genetic alterations of CXCR7 regulate the CXCL12/CXCR7 axis, a new "passport" ± for the homing of mscs

L. Liu, J. Chen, X. Zhang, A. Liu, F. Guo, S. Liu, Y. Yang, H. Qiu

Department of Critical Care Medicine, Nanjing Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China

Introduction: Mesenchymal stem cells (MSCs) have several properties that make them attractive therapeutic candidates for treatment of acute disease, but in vivo homing, MSCs does not appear to be highly efficient. CXCL12/CXCR7 axis not only improves the motility of stem cells, but also regulates many essential biological processes. The aim of this study is to evaluate the effects of overexpressing or suppressing CXCR7 on proliferation and migration abilities of mice mesenchymal stem cells.

Methods: The lentivirus vector overexpressing and suppressing the murine CXCR7 gene was transducted into mMSCs. The transfection efficiency of LV in passage 20 transduced-mMSCs was identified using fluorescence microscopy, and the percentage of ZsGreen positive cells was determined by flow cytometry analysis (FCM). CXCR7 mRNA expression in mMSCs was verified by quantitative real-time PCR, and CXCR7 protein expression was analyzed by FCM. The effect of CXCR7 on the migration of mMSCs was evaluated using the scratch assay and the transwell migration assay. In transwell assay, 50 ng/ml CXCL12 was added in two groups to simulation inflammation microenvironments. The ELISA assay was used to detect the concentration of VCAM-1, CXCL12 the supernatant.

Results: The efficiencies of the lentiviral vector transduction of MSC-OE-CXCR7 (overexpression of CXCR7), MSC-OENC-CXCR7 (normal control of overexpression of CXCR7), MSC-Sh-CXCR7 (suppression of CXCR7) and MSC-ShNC-CXCR7 (normal control of suppression of CXCR7) after 20 passages in mMSCs were 91.29%, 91.39%, 91.69% and 91.28% respectively. The CXCR7 mRNA and protein expression were significantly higher in the MSC-OE-CXCR7 cells than in the MSC-OENC-CXCR7 cells, and were significantly lower in the MSC-Sh-CXCR7 when compared with the MSC-ShNC-CXCR7. Moreover, CXCR7 gene overexpression promoted mMSCs migration. In contrast, the suppression of CXCR7 inhibited mMSCs migration when compared with the MSC-ShNC-CXCR7 group. Overexpression CXCR7 increased MSC-secreted CXCL12 and VCAM-1, which contributed to the improvement of mMSCs homing.

Conclusions: Overexpression CXCR7 improved the homing abilities of mMSCs, which might attribute mainly to increasement of CXCL12 and VCAM-1 secreted by mMSCs.

Fig. 1 (abstract P2).

Legend 1: Figure 1 Long-term transgene expression efficiency in mMSCs after lentiviral vector transduction

Fig. 2 (abstract P2).

Legend 2: Figure 2 The effect of CXCR7 on the migration of mMSCs. The concentration of VCAM-1 and CXCL12 in the supernatant of Transwell Chambers was examined using ELISA assay.

P3 Withdrawn

P4 Spectrum study severe hypoxemia: prevalence, treatment and outcome in 2016

D. G. Grimaldi¹, SR The SRLF Trial Group²

¹Hôpital Erasme, Brussels, Belgium; ²SRLF, Paris, France

Introduction: Limited information exists about the prevalence, subsequent management, and outcomes of hypoxemia among ICU patients.

The aim of the study was to assess the prevalence of hypoxemia among ICU patients and to stratify them according to the severity of hypoxemia (PaO2/FIO2 between 300 and 201 in mild, between 200 and 101 in moderate, and <101 mm Hg in severe). Management and outcomes of hypoxemic patients and the proportion of them who met the criteria for acute respiratory distress syndrome (ARDS) were analyzed

Methods: This study was an international, multicenter, 1-day point prevalence study conducted in 117 units during the spring of 2016. All patients already hospitalized or newly admitted the day of the study were susceptible to be enrolled.

Hypoxemia was defined as a P/F ratio of 300 mmHg or less

Results: Of 1604 patients included, 859 (54%) were hypoxemic, 440 (51%) were mildly, 345 (40%) moderately and 74 (9%) severely hypoxemic. Among hypoxemic patients, 183 (21%) had ARDS (37% mild, 46% moderate and 16% severe). Characteristics of patients according to hypoxemia severity are reported in the Table 1. Pneumonia was the main cause of hypoxemia (53%) and of ARDS (79%). Modalities of oxygen treatment vari.

Among hypoxemic patients under invasive mechanical ventilation, 77% received a tidal volume of 8 mL/kg or less of predicted body weight with a median PEEP level of 6 [5–10] cmH2O. Among ARDS patients, 145 (83%) received a tidal volume of 8 mL/kg or less with a median PEEP of 8 [6–12] cmH2O and a median plateau pressure of 23 [19–27] cmH2O.

In the whole population, median ICU length of stay was 12 days [5–28] and the ICU mortality was 20%. In the hypoxemic population, median ICU length of stay appeared to be higher (16 [7–32] days) and further increased in ARDS patients (20 [11–38] days, P < 0.001). ICU mortality was 27% in hypoxemic patients (21% in mild hypoxemic patients, 26% in moderate hypoxemic patients, and 50% in severe hypoxemic patients, P < 0.001)

Conclusions: Hypoxemia affected more than half of the patients in ICU, whereas only 21% of hypoxemic patients met ARDS criteria. Mortality was significantly associated with severity of hypoxemia.

Table 1 (abstract P4). See text for description

P5 Correlation of horowitz ratio with oxygen saturation index in ARDS

E. Kaya, O. Acicbe, I. Kayaalp, S. Asar, M. Dogan, G. Eren, O. Hergunsel

Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey

Introduction: In definition of ARDS PaO2 and PaO2/FiO2 (Horowitz) ratio are the most reliable parameters used. In this study it is aimed to investigate the correlation of Horowitz ratio with oxygenation saturation index (OSI) derived from SpO2 instead of PaO2.

Methods: Demographical data of 307 patients treated with mechanical ventilation in our ICU between 01.01.2014–31.12.2015 due to respiratory failure were revised from iMDsoft (Metavision) system together with FiO2, SpO2, PaO2, Paw parameters. Oxygenation saturation index was calculated with the formula using [FiO2 x Paw]/SpO2. ROC (receiver operator characteristic) analysis was used to search for the relation of Horowitz ratio and OSI.

Results: The median age of the patients were 58,5 years (IQR 18–96). For the patients with Horowitz ratio < 100 cut-off value for OSI was found to be 7,0768 (sensitivity 94.4% and specificity 86.9%). OSI cut-off value was 3,7178 for Horowitz ratio < 200 (sensitivity 90.2% and specificity 79%). For those with Horowitz ratio < 300, OSI cut-off value was calculated as 2,561 (sensitivity 83.3% and specificity 72%).

Conclusions: OSI was defined for ARDS diagnosis in pediatric population which includes the parameter of mean airway pressure in its formula rendering this index a more objective parameter for ventilatory support instead of PaO2/FiO2 ratio. It was a big controversy before Berlin definition that ARDS definition was relying on cirteria which do not directly consider the extent of ventiatory support on oxygenation, however there is still a debate that Berlin definition did not bring a solution in that aspect. Therefore, we think that this study, which we aim to reveal the OSI values that correlate with Horowitz values of mild, moderate and severe ARDS, should be supplemented with other studies and validated by further prospective studies, considering OSI as a reflection of positive pressure changes affecting oxygenation in ARDS.

References

1. Thomas NJ, et al. Pediatr Crit Care Med. 2010; 11(1): 12–17

2. Rotta AT, et al. Rev Bras Ter Intensiva. 2015;27(3):266–273

P6 Ards features of the severe burn patients from colective tragedy

D. Pavelescu, I. Grintescu, L. Mirea

Emergency Hospital Floreasca, Bucharest, Romania

Introduction: ARDS is an independent risk factor for death in burn patients, with appreciable mortality of 26–58%. More than 30% of thermal injured patients have a concomitant smoke inhalation injury

Methods: A retrospective observational study which include 14 young patients 21–36 y.o. with severe burns to the face, neck, chest, extremities, admitted in the ICU of level I trauma Center after a deadly fire in Bucharest in an enclosed space with air temperature in 60 seconds between 900–1500 degrees C, in which 64 people were killed and 147 severely injured.

All of them had signs and symptoms of acute hypoxia requiring mechanical ventilation.

We asses the incidence of smoke inhalation injury, the CO toxicity, the etiology, the development time, the relation between severity of ARDS and % of BSA, the mortality

Results: All of them have smoke inhalation injury and CO toxicity, the etiology was multifactorial (trauma, multiple transfusion, sepsis, smoke injury, resuscitated cardio-respiratory arrest), there was a strong correlation between the severity of ARDS and the % of Burn Surface Area, the mortality was extremely high

Conclusions: The severity of burn associated with inhalatory injury dramatically increase the incidence of ARDS and despite new promising therapeutic interventions, ARDS still remain a devastating disease in severe burn patients.

Fig. 3: (abstract P6).

See text for description

P7 Relationship between energy load and lung regional inflation status in ARDS patients: a CT scan study

M. Guanziroli¹, M. Gotti², A. Marino¹, M. Cressoni¹, G. Vergani¹, C. Chiurazzi³, D. Chiumello¹, L. Gattinoni⁴

¹Università degli Studi di Milano, Milano, Italy; ²ASST Santi Paolo e Carlo, Milano, Italy; ³Humanitas, Rozzano, Italy; ⁴University of Gottingen, Gottingen, Germany

Introduction: Tidal volume, pressure and flow are components of the energy load (EL). We investigated the relationship between intra-tidal lung inflation status variation and EL in mechanically ventilated ARDS patients.

Methods: Twenty-eight ARDS patients underwent end-inspiratory and end-expiratory low dose CT scans at PEEP 5 and 15 cmH2O, maintaining the same tidal volume 7 ± 1.8 mL/kg and respiratory rate 15 ± 4.2 breaths/min. Quantitative CT scan analysis was performed to obtain the amount of not, poorly, well and over inflated tissue (g). EL was computed as the area between the inspiratory limb of pressure-volume curve and the y axis, summed to the energy needed to inflate the PEEP volume. EL at PEEP 5 and 15 cmH2O was then normalized by the End-Expiratory Lung Volume at 5 cmH2O (EELV5).

Results: EL/EELV5 (mJ/mL) is lower at PEEP 5 than 15 cmH2O (1.3 ± 0.73 and 2.4 ± 0.95, p < 0.001). Higher EL/EELV5, respectively for PEEP 5 and 15 cmH2O, is associated with a decrease in not inflated tissue (Δ not inflated tissue = −22.87–61.38*EL/EELV5, r2 = 0.28, p < 0.0001 and Δ not inflated tissue = −4.35–24.59*EL/EELV5, r2 = 0.15, p < 0.01) and with an increase in well inflated tissue (Δ well inflated tissue = 67.72 + 55.91*EL/EELV5, r2 = 0.27, p < 0.0001 and Δ well inflated tissue = −25.13 + 51.91*EL/EELV5, r2 = 0.46, p < 0.0001) at the end of inspiration (Fig. 4). No relationships were found between poorly or over inflated tissue and total energy load.

Conclusions: Higher PEEP is associated to higher EL. Higher EL, increasing lung stress and intra-tidal opening and closing, could be unprotective.

Fig. 4 (abstract P7).

a and b: PEEP 5 cmh₂O; c and d 15 cmh₂O

P8 Relationship between total or lung superimposed pressure and absolute esophageal pressure in ARDS: a CT scan study

M. Guanziroli¹, M. Gotti², G. Vergani¹, M. Cressoni¹, C. Chiurazzi³, A. Marino¹, S. Spano¹, D. Chiumello¹, L Gattinoni⁴

¹Università degli Studi di Milano, Milano, Italy; ²ASST Santi Paolo e Carlo, Milano, Italy; ³Humanitas, Rozzano, Italy; ⁴University of Gottingen, Gottingen, Germany

Introduction: In ARDS patients lung collapse is due to lung superimposed pressure (SP) [1].

SP seems to change as a function of pleural pressure, and both these pressures change as a function of the sterno-vertebral level [2].

Absolute esophageal pressure (Pes) reflects mid-lung pleural pressure, according to the level where the esophageal balloon is placed [1]. However, Pes is unrelated to all morphological indexes of disease severity (not inflated tissue, lung weight, functional residual capacity) and is unrelated to maximal SP [1].

Our aim is to verify if Pes is related to the total and/or the lung SP at the esophageal catheter balloon level.

Methods: Ninety-two ARDS patients underwent an end-expiratory CT scan at PEEP 5 cmH2O. Quantitative CT scan analysis was performed to compute the total and the lung SP at the esophageal catheter balloon level in the slice above the diaphragm.

Pes was recorded at PEEP 5 cmH2O.

Results: The total and the lung SP and Pes at PEEP 5 cmH2O are weakly related, respectively (Fig. 5):

• - total SP (cmH2O) = 11.97 + 0.17 * Pes (cmH2O), r2 = 0.08, p < 0.01

• - lung SP (cmH2O) = 3.47 + 0.13 * Pes (cmH2O), r2 = 0.07, p = 0.01

As shown, Pes is greater than either the total and the lung SP at the level of the esophageal balloon.

Conclusions: If the increased total or lung SP is the main mechanism for lung collapse in ARDS patients and PEEP keeps the lung open mainly by counter-balancing the SP, Pes could not be used to select the best PEEP.

References

[1] Pelosi P. Am J Respir Crit Care Med 2001; 164:122–130

[2] Bottino N. Crit Care 2000; 4:P115

Fig. 5 (abstract P8).

See text for description

P9 Relationship between energy load and lung inhomogeneity in ARDS patients: a CT scan study

M. Guanziroli¹, M. Gotti², G. Vergani¹, A. Marino¹, M. Cressoni¹, C. Chiurazzi³, D. Chiumello¹, L. Gattinoni⁴

¹Università degli Studi di Milano, Milano, Italy; ²ASST Santi Paolo e Carlo, Milano, Italy; ³Humanitas, Rozzano, Italy; ⁴University of Gottingen, Gottingen, Germany

Introduction: In ARDS patients, lung is inhomogeneous [1]. Energy load (EL) describes the interaction between the ventilator and the respiratory system [2]. We investigated the relationship between intra-tidal lung inhomogeneity variation and EL in ARDS patients.

Methods: Twenty-eight ARDS patients underwent a series of end-inspiratory and end-expiratory low dose CT scans at 2 different levels of PEEP, 5 and 15 cmH2O, maintaining the same tidal volume 7 ± 1.8 mL/kg and respiratory rate 15 ± 4.2 breaths/min.

Lung inhomogeneity extent is defined as the fraction of lung volume presenting an inflation ratio greater than 1.61 (95th percentile of homogeneous lungs) [1].

The airway pressure-volume curve at the 2 ventilatory settings was obtained. EL was computed as the area between the inspiratory limb of that curve and the volume axis, summed to the energy needed to inflate the PEEP volume [2].

Results: At both PEEP levels, lung inhomogeneity variation (end inspiration - end expiration) is related to total EL (Fig. 6):

• PEEP 5: Δ inhomogeneity(%) = 4.38–0.01*EL(mJ), r2 = 0.31, p < 0.001

• PEEP 15: Δ inhomogeneity(%) = 2.78–0.002*EL(mJ), r2 = 0.26, p < 0.0001.

Conclusions: During mechanical ventilation, the EL applied to the respiratory system is spent to increase homogeneity of the lung parenchyma. We could speculated that EL is spent at the interfaces between regions with different inflation status.

References

[1] Cressoni M. Am J Respir Crit Care Med 2014; 189:149

[2] Gattinoni L. Intensive Care Med 2016; 42:1567

Fig. 6 (abstract P9).

a PEEP 5 cmH₂O; a PEEP 15 cmH₂O

P10 Does galunisertib reduce edema in experimental ARDS? An exploratory study

F. Massaro¹, A. Moustakas², S. Johansson², A. Larsson³, G. Perchiazzi³

¹Policlinico di Bari, Bari, Italy; ²Uppsala University Biomedical Center, Uppsala, Sweden; ³Akademiska Sjukhuset, Uppsala University, Uppsala, Sweden

Introduction: The transforming growth factor β (TGF-β) pathway is activated in experimental ARDS and is associated with increased pulmonary edema (1) because it reduces transepithelial sodium transport by inducing endocytosis of ENaC (the epithelial sodium channel). In this way TGF-β decreases the osmotic gradient for re-absorption of water from the alveolar and interstitial spaces (2). We hypothesized that blocking TGF-β signaling with Galunisertib (LY2157299 monohydrate, a TGFβ R1 kinase inhibitor) would reduce edema and tested this in a porcine model of ARDS using aerosolized Galunisertib.

Methods: Five piglets (25–30 kg) were randomized to receive (n = 3) or not (n = 2) Galunisertib 50 μM by aerosol. The animals were anesthetized, tracheotomized and ventilated in volume controlled mode (VT: 8 ml/kg, FiO2: 70%, RR:30, PEEP:5 cmH2O, I:E = 1:2). Cardiac output and extravascular lung water (EVLW) were continuously measured (PiCCO, Pulsion Medical System). We measured pressure/volume curves and arterial pH, paO2, paCO2, HCO3- at baseline, immediately after induction of ARDS and then hourly for 6 h. ARDS was induced by repeated lung lavages and injurious ventilation. After the establishment of the ARDS model, Galunisertib was administered and the experiment was continued for 6 h, after which the animals were sacrificed. Histological samples from lungs, heart, kidney and liver were taken. Activation of the TGF-β pathway was immunohistochemically evaluated using an antibody against phosphorylated Smad2 (Small Mother Against Decapentaplegic) and activation of mechanical signaling in the lungs was evaluated using an antibody against phosphorylated FAK (Focal Adhesion Kinase). Moreover, we measured the wet/dry weight ratio of the lung samples.

Results: Two animals did not survive the experiment. The sample size is too small to draw any strong conclusion. However, we could not find any major difference in EVLW, wet/dry ratio, blood gas parameters or in lung mechanics between the two groups during the tested time period. However, the lung samples from the treated group showed a lower degree of TGF-β pathway activation, while the control samples from liver or heart showed no influence by Galunisertib.

Conclusions: We cannot prove or disprove that TGF-β blockade reduces pulmonary edema associated with experimental ARDS. However, the TGF-β blocker seemed to reach its target as indicated by reduced activation of the TGF-β pathway in the lungs, suggesting that aerosol administration is feasible.

References

1. Acta Anaesthesiol Scand. 2016;60(1):79–92,

2. Proc Natl Acad Sci USA. 2014;111(3):E374-83

P11 Stable over expression of p130 and E2F4 makes a difference on multipotential differentiation in bone marrow derived MSCs

X. W. Zhang, F. M. Guo, J. X. Chen, M. Xue, Y. Yang, H. B. Qiu

Department of Critical Care Medicine, Nanjing Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China

Introduction: Bone marrow derived mesenchymal stem cells (BMSCs) are proved to have potential therapeutic effects in ARDS models. However, the mechanism of differentiation in MSCs is still unknown. There is growing evidence suggesting p130 or E2F4 plays an important role in regulating cellular differentiation. Our aim is to evaluate the role of p130/E2F4 in regulating the differentiation of mouse MSCs (mMSCs).

Methods: mMSCs with p130 or E2F4 overexpression were constructed using lentiviral vectors. The transfection efficiency of mMSCs was identified using fluorescence microscopy, and the percentage of GFP positive cells was determined by flow cytometry analysis. The mRNA and protein levels in MSC-p130 (overexpressing p130) and MSC-E2F4 (overexpressing E2F4) were detected by qRT-PCR and Western blotting assay, respectively. The effect of p130/E2F4 on the multipotential differentiation abilities of mMSCs were evaluated by adipogenesis, osteoblastic and chondrogenic differentiation medium respectively. The expression of the osteogenic gene OSX, adipogenisis gene PPAR-¦Ã and chondrogenic gene Sox9 measured by qRT-PCR were used to evaluate the differentiation of each group of mMSCs treated with differentiation induction media.

Results: The transduction efficiencies mediated by the lentiviral vectors were 80.3–84.4% and were maintained over 20 passages of mMSCs. The p130 or E2F4 mRNA expression was significantly higher in the MSC-p130 and MSC-E2F4 cells than in the MSC-NC cells. Similar results for p130 or E2F4 protein expression were also observed in Western blotting. Moreover, p130/E2F4 gene overexpression promoted the differentiation of mMSCs into osteoblasts, while inhibiting adipogenesis and chondrogenic differentiation of mMSCs.

Conclusions: The successful construction of stable and long-term mMSCs lines with overexpressing p130/E2F4 change the multipotential differentiation of mMSCs.

References

1. Liu AR et al.: J Cell Physiol 2013; 228: 1270.

Fig. 7 (abstract P11).

Legend 1: Long-term transgene expression efficiency in mMSCs

Fig. 8 (abstract P11).

Legend 2: The effect of p130 or E2F4 on multipotential differentiation of mMSCs

P12 The homing and protective effects of mesenchymal stem cells overexpressing CXCR7 in LPS-induced acute respiratory distress syndrome mice

J. X. Chen, L. Liu, L. Yang, X. W. Zhang, F. M. Guo, Y. Yang, H. B. Qiu

Department of Critical Care Medicine, Nanjing Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China

Introduction: The low efficiency of homing to injured organ in mesenchymal stem cells (MSCs) has become the bottleneck for the treatment of acute respiratory distress syndrome (ARDS). In a previous in vitro study, the results showed that the CXCL12/CXCR7 axis promoted the migration of MSCs. It is hypothesized that MSCs overexpressing CXCR7 could further benefits LPS-induced ARDS mice.

Methods: mMSCs were transfected with CXCR7 by a lentiviral vector and were transplanted into mice following LPS-induced intratracheal lung injury. Histopathology with haematoxylin and eosin staining and lung injury scoring was performed to evaluate lung tissue injury. Homing of mMSCs were assayed by NIR815 fluorescence imaging and immunofluorescent staining.

Results: The administration of MSC, MSC-GFP and MSC-CXCR7 all improved both lung histopathology (Fig. 9) and lung injury score. Moreover, the MSC-CXCR7 showed lower lung/body weight and lung injury score especially at 24 h compared with MSC-GFP. NIR fluorescence imaging and immunofluorescent staining showed that overexpressing CXCR7 significantly increased the accumulation of mMSCs in the lung especially at 24 h compared to MSC (Fig. 10).

Conclusion: It is demonstrated that overexpressing CXCR7 in mMSCs could further promote their homing to injured lung and improve the pathological damage in ARDS mice.

Fig. 9 (abstract P12).

Legend: Histopathology of the effects of MSC-GFP or MSC-CXCR7 in LPS-induced lung injury

Fig. 10 (abstract P12).

Legend: Effect of overexpressing CXCR7 on the retention of mMSC in the lung after LPS change.

P13 Independent lung ventilation (ilv) in ICU-forgotten, neglected or useless?

M. Fister, R. Knafelj

Rihard Knafelj, Ljubljana, Slovenia

Introduction: ILV remains valuable rescue therapy for refractory hypoxemia in patients with predominantly single sided lung injury (contusion, aspiration, hemorrhage, bronchopleural fistula) especially in centers with no extracorporeal membrane oxygenation (ECMO). Special intubation technique, double lumen endotracehal tube and 2 ventilators are needed.

Methods: Single center prospective observational study. Characteristics of consecutive patients assigned to ILV from 2010–2016 are reported.

Results: Total 8 patients underwent ILV during observed period (0,9% of all ventilated patients). All patients had paO2/FiO2 < 200, all were ventilated in pressure modes (P-AC, BiLEVEL), ventilators were not synchronized - PEEP, RR, FiO2 and Vt were set individually for each ventilator following blood gas results. Recruitment manuvers and NO were used at physician discretion. In 5 patients oxygenation improved significantly within 2 hours of ILV. 2 patients were upgraded to V-V ECMO (Wegener’s, pneumonia), in 4 contraindication to ECMO was present. 3 patients died (lung carcinoma, emphysema, Wegener’s). All tube placements were confirmed radiologically, 1 intubation with double lumen tube was performed via bougie and proper placement confirmed bronhcoscopically. In all patients left sided double lumen tubes were used only. In one patient carinal decubitus was observed due to double lumen tube’s hook. Patients underwent ILV for median 4 days (range 2–10 days).

Conclusions: In severe single sided lung injury necessitating MV, ILV should be considered as it represents valuable adjunct in treating refractory hypoxemia. With lung separation both lungs can be ventilated according to protective ventilation strategy. Special care is needed to prevent tube dislocation, cuffs overinflation and trauma to larynx, trachea and bronchi. Since tubes’ lumens are narrower special attention to possible tube blockage must be paid. Daily reevaluation and conventional tube placement is warranted as soon as possible.

Fig. 11 (abstract P13).

See text for description

P14 Initiation of mechanical ventilation with the lower threshold of tidal volume in ARDS

M. A. Suzer¹, M. E. Kavlak², H. K. Atalan³, B. Gucyetmez⁴, N. Cakar⁴

¹Cankaya Hospital, Ankara, Turkey; ²Atasehir Memorial Hospital, Istanbul, Turkey; ³Acibadem Fulya Hospital, Istanbul, Turkey; ⁴Acibadem University School of Medicine, Istanbul, Turkey

Introduction: We hypothesized that in patients with ARDS, a pH level >7.20 can be achieved by using a tidal volume (TV) of 6 ml/kg. It was demonstrated that low TV (6–8 ml/kg) strategy was related with decreased volutrauma in patients with ARDS (1–3). According to ARDSNet (ARMA) trial, the initial mechanical ventilation (MV) settings should be 8 ml/kg TV, 7–9 L/min minute volume and a respiratory rate up to 35/min to provide pH > 7.20 and it is suggested to reduce the TV to 7 ml/kg and then gradually to 6 ml/kg (4).

Methods: The present study was designed in 2015 as prospective observesional. Patients with ARDS who were >18 years old were included in this study. The initial MV was set with TV:6 ml/kg, MV:7–9 L/min as recommended by ARDSNet (ARMA) trial. Blood gas samples were taken at the 1st and 2nd hours of MV. In patients with pH < 7.20, TV was increased by 1 ml/kg. Demographic data, 1st and 2nd hours blood gas values and ventilation parameters were recorded.

Results: One hundred and ten patients were included in this study. At the 1st hour, pH values in 86.4% (95) of all patients were above 7.20. In patients with pH < 7.20, while pH-corrected-APACHE II and lactate values were significantly higher; HCO3 and SBE were significantly lower than patients with pH > =7.20 (P = 0.006 and P < 0.001 for others). In patients with pH < 7.20, pH values were increased above 7.20 by increasing TV to 7 ml/kg.

Conclusions: In a significant percentage of patients with ARDS, targeted pH value can be achieved by using the lower threshold of recommended initial TV value. In patients with severe hyperlactatemic acidosis, higher initial TV values may be required.

References

1. Petrucci N et al. Cochrane Database Syst Rev 2004; 2:CD003844

2. Petrucci N et al. Cochrane Database Syst Rev 2013; 28:CD003844

3. Needham DM et al. Am J Crit Care Med 2015; 191:177–85

4. ARDSNet Study I, ARMA trial 1998.

P15 Lung protective ventilation: what is the effect of education on tidal volume and p0.1 values?

D. Weller, A. F. Grootendorst, A. Dijkstra, T. M. Kuijper, B. I. Cleffken

Maasstad Hospital, Rotterdam, Netherlands

Introduction: Lung protective ventilation may improve patient outcome on ICU’s and clear guidelines are available for ventilator settings. It is unknown whether nurses and doctors adhere to these guidelines. The purpose of this study was to determine the effect of predefined lung-protective ventilation regime in pressure support ventilation (PS) introduced via an educational programme on tidal volumes and airway occlusion pressure.

Methods: The study was a case control single-center study. For the intervention group, an education programme was integrated consisting of eight clinical lessons of ±30 min, bed side teaching, four times written instruction by email and twice a dissemination of an educational presentation to the entire ICU team, in the period from May to June 2016. This program set guidelines for mechanical ventilation, with the specific instructions to ventilate patients with a tidal volume of 6–8 ml/kg/ideal body weight (IBW) and airway occlusion pressure (P0.1) of 2.8 to 6.0 cmH2O. Prior to ventilation instruction a control group was obtained from the general ICU population.

Inclusion criteria were: mechanical ventilation (PS) within 7 days after presentation on the ICU, exclusion criteria were: any neurological diagnosis, re-intubation and delirium.

Results: In total 14 patients were included in the intervention group versus 17 in the control group (baseline, Table 3).

Thirteen parameters were monitored during the study, primary endpoints where tidal volume ml/kg/IBW and the P0.1. In the intervention group (Table 3) finale tidal volumes were 1.2 ml/kg/IBW lower (p = 0.04). The P0.1 shows no difference between the two groups (p =0.75).

Conclusions: Conclusion: Adherence to lung-protective ventilation is increased with education and improves ventilation practice on ICU’s. An educational program on specific guidelines of mechanical ventilation decreases tidal volumes to optimal values between 6–8- ml/kg/IBW. P0.1 values could not be optimized by this regimen. It seems likely that higher pressure support levels lead to lower inspiratory work of breathing.

Table 2 (abstract P15). See text for description

Table 3 (abstract P15). See text for description

P16 Intra-abdominal pressure adjusted positive end-expiriatory pressure – a pilot study

A. Regli¹, B. De Keulenaer¹, P. Van Heerden²

¹Fiona Stanley Hospital, Perth, Australia; ²Hadassah University Hospital, Jerusalem, Israel

Introduction: Intra-abdominal hypertension (IAH) is associated with increased morbidity and mortality. IAH reduces lung volumes and oxygenation and increases airway pressures. The optimal level of positive end-expiratory pressure (PEEP) to be applied in such patients remains unknown.

Animal data suggests that high PEEP adjusted for intra-abdominal pressure (IAP) may counteract IAH-induced lung volume and arterial oxygen level reductions.

In this pilot trial, our primary aim was to assess whether high and PEEP, adjusted for IAP, can be safely applied in patients with IAH requiring mechanical ventilation. Our secondary aim was to assess the effect of such PEEP levels on oxygenation.

Methods: Prior to enrolment, the patients next of kin were asked for written informed consent. Patients were excluded if deemed unsuitable or if predefined severe cardiovascular dysfunction or severe hypoxemia were present.

Ventilation was standardized. Following a recruitment manoeuvre, the following PEEP levels in cmH2O were randomly applied: 5 (baseline), PEEP = 50% of IAP, and PEEP = 100% of IAP. At each measurement step, we allowed 30 min for equilibration before measuring arterial blood gases and respiratory parameters. For the safety of our patients, predefined stopping criteria were applied.

Results: 15 patients were enrolled. The protocol was stopped in one patient (excluded from analysis) due to an unexpected hypertensive episode (drug error unrelated to protocol). Three patients did not tolerate PEEP = 100% IAP due to hypoxemia, hypotension, or ETT cuff leak in one patient each. PaO2/FiO2 ratios (maen and SD) were 234 (68), 271 (99), and 329 (107) at each PEEP level respectively. The difference was significant (p = 0.009) only between baseline and PEEP = 100% IAP.

Conclusions: PEEP = 100% was commonly not tolerated and only marginally improved oxygenation in ventilated patients with IAH. Such high PEEP pressures can therefore not be recommended for routine clinical practice.

P17 Withdrawn

P18 Withdrawn

P19 Neurally adjusted ventilatory assist versus pressure support in prolonged mechanical ventilation: a randomised feasibility study

D. Hadfield¹, P. A. Hopkins², B. Penhaligon², F. Reid¹, N. Hart³, G. F. Rafferty¹

¹King’s College London, London, UK; ²King’s College Hospital, London, UK; ³Guy’s and St Thomas’ Hospital, London, UK

Introduction: Neurally adjusted ventilatory assist (NAVA) is a complex intervention involving diaphragmatic monitoring and a proportional, neurally triggered ventilation mode [1]. Clinical effectiveness has not been demonstrated and feasibility data are required prior to larger definitive randomised controlled trials (RCTs). Although there is no agreement on minimum levels in clinical trials, low protocol compliance will impact on statistical power and interpretation of results in a definitive study [2]. The aim of this trial is to assess feasibility by measuring protocol compliance in the setting of a pragmatic RCT.

Methods: A feasibility RCT in 76 ventilated adult ICU patients, currently being conducted in a central London hospital. Patients at high risk of prolonged ventilation are randomly assigned to NAVA or Pressure Support (PSV) in the weaning phase. Feasibility end-points include protocol compliance (time in the NAVA mode), recruitment rate and acceptability. Secondary outcomes include ventilator free days and sedation load. The data from the first 48 patients (n = 25 and 23 in the NAVA and PSV groups respectively) are presented.

Results: At 14/11/2016 480 patients had been screened and 55 recruited with a mean recruitment rate of 1.8 patients per month. 71 patients were approached for inclusion with 16 patients (22.5%) excluded due to personal or professional consultee refusal. 68.2% of patients in the intervention group were compliant [CI 47.3–83.6] with a median adherence to the NAVA mode of 87.5% [38.9, 99]. Ventilator free days to day 28 were 18 [8, 24] days in the NAVA group vs. 19 [0, 23] days in the PSV group. There were no adverse events related to the intervention.

Conclusions: These data suggest an acceptable protocol compliance of > 65%. Further analysis of the reasons for non-compliance will be conducted; initial data suggest that a mix of technological, clinical and human factors underlie reduced adherence and protocol compliance. This is the first trial to compare NAVA to PSV in prolonged ventilation in the context of a pragmatic RCT. The results will provide guidance for the design of future trials.

References

1. Sinderby, C., et al., Neural control of mechanical ventilation in respiratory failure. Nature medicine, 1999. 5(12): p. 1433–6.

2. Chan, A.-W., et al., SPIRIT 2013 Statement: Defining Standard Protocol Items for Clinical Trials. Annals of Internal Medicine, 2013. 158(3): p. 200–207.

Table 4 (abstract P19). See text for description

P20 Effects of prone position and recruitment manoeuvres on gas exchange and regional respiratory mechanics

G. Grasselli¹, T. Mauri², M. Lazzeri³, E. Carlesso², B. Cambiaghi⁴, N. Eronia⁴, E. Maffezzini⁴, A. Bronco⁴, C. Abbruzzese¹, N. Rossi¹, G. Foti⁴, G. Bellani⁴, A. Pesenti²

¹Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy; ²University of Milan, Milan, Italy; ³University of Ferrara, Ferrara, Italy; ⁴University of Milan-Bicocca, Monza, Italy

Introduction: Prone position (PP) improves survival and delays the risk of ventilation-induced lung injury in severe ARDS [1]. PP may exploit its benefits in the presence of optimized alveolar recruitment. Thus, we performed prone positioning in combination with recruitment manoeuvres (RMs) to assess the effects on aeration and oxygenation.

Methods: Eleven intubated, volume-controlled, ARDS patients (1 severe, 8 moderate, 2 mild) were studied in supine and PP before and after RMs (40 cmH2O airway pressure for 10 breaths). In each phase electrical impedance tomography (EIT) was recorded for 15 minutes to assess global and regional (dependent and non-dependent) respiratory system compliance (Crs), tidal volume (VT) distribution, end-expiratory lung volume changes (ΔEELV). Gas exchange and respiratory mechanics were monitored at the end of each phase.

Results: PaO[sub]2[/sub]/FiO[sub]2[/sub] was 159 ± 71 mmHg. Clinical PEEP (13 ± 3 cmH[sub]2[/sub]O), VT (6.6 ± 1.2 ml/kg IBW), RR (25 ± 5 bpm) and FiO[sub]2[/sub] (0.6 ± 0.2) were left unchanged. PaO[sub]2[/sub]/FiO[sub]2[/sub] improved after RMs (p = 0.054) and by interaction between PP and RMs (p = 0.046). ΔEELV significantly increased after RM performed in supine (p = 0.032; 40 ± 53 ml vs. pre-RM), in PP (p = 0.002; 95 ± 78 ml vs. pre-RM) but by similar magnitude (p = 0.089) post-RM supine vs. prone. PP didn’t modify Crs, but dependent Crs significantly improved (p = 0.006) and non-dependent Crs (p = 0.009) decreased. VT distribution was more homogenous during PP and lung homogeneity index improved, albeit non-significantly. Neither regional Crs nor homogeneity were affected by RMs.

Conclusions: PP improves regional mechanics and homogeneity; RM performed after proning seems efficacious and might increase PP protective effects.

References

1. Valenza F. et al. Crit Care Med. 2005;33:361–7

Table 5 (abstract P20). See text for description

P21 Feasibility of the lateral-trendelenburg vs semi recumbent body position – the GRAVITY-VAP TRIAL

G. Li Bassi¹, M. Panigada², O. Ranzani¹, T. Kolobow³, A. Zanella ², M. Cressoni⁴, L. Berra⁵, V. Parrini⁶, H. Kandil⁷, G. Salati⁸, S. Livigni⁹, S. Livigni¹⁰, A. Amatu¹⁰, M. Girardis¹¹, M. Barbagallo¹², G. Moise¹³, G. Mercurio¹⁴, A. Costa ¹², A. Vezzani¹², S. Lindau¹⁵, J. Babel¹⁶, M. Cavana¹⁷, A. Torres¹

¹Hospital Clinic, Barcelona, Spain; ²Policlinico di Milano, Milan, Italy; ³National Institutes of Health, Bethesda, USA; ⁴Ospedale San Paolo, Milan, Italy; ⁵Massachusetts General Hospital, Boston, USA; ⁶Ospedale Nuovo del Mugello, Borgo San Lorenzo, Italy; ⁷Gruppo Ospedaliero San Donato, San Donato Milanese, Italy; ⁸Arcispedale S. Maria Nuova, Reggio Emilia, Italy; ⁹Ospedale San Giovanni Bosco, Torino, Italy; ¹⁰Policlinico San Matteo, Pavia, Italy; ¹¹Policlinico di Modena, Modena, Italy; ¹²Azienda Ospedaliero-Universitaria di Parma, Parma, Italy; ¹³Ospedale Citta di Sesto San Giovanni, Sesto San Giovanni, Italy; ¹⁴Policlinico Gemelli, Roma, Italy; ¹⁵University Hospital Frankfurt, Frankfurt, Germany; ¹⁶University Hospital Zagreb, Zagreb, Croatia; ¹⁷Ospedale Santa Chiara, Trento, Italy

Introduction: We recently completed a large randomized clinical trial in critically ill patients to test the LTP vs. SRP in the prevention of ventilator-associated pneumonia (VAP). Here we focus on the feasibility of the study interventions.

Methods: We randomized 194 and 201 critically ill patients into LTP and SRP group, respectively. Patients in LTP were placed in semi-lateral (60°) - Trendelenburg position and turned from one side to the other every 6 hours. LTP was encouraged specifically during the first days of mechanical ventilation, in compliance with the patient’s wish. In the SRP group, patients were kept with the head of the bed elevated > = 30°. We assessed interventions feasibility, and nursing feasibility/workload

Results: Patients in the LTP and SRP group were kept in the randomized position for 38% and 90% of the study time, respectively (p = 0.001). Median fraction of time in LTP reached up to 51.8% (interquartile range 20.7–79.2) during the first 2 days; yet, it progressively decreased in subsequent days and was inversely related to the level of sedation. Median lorazepam equivalents was 46.7 mg/day (interquartile range, 20.8–120.0) and 58.0 (28.0–124.2) in the SRP and LTP groups, respectively (p = 0.37); propofol dose was 1393 mg/day (627–2345) and 1661 (826–2700) (p = 0.13). Finally, morphine equivalents were 112 mg/day (30–217) in the SRP and 119 (31–234) in the LTP (p = 0.56). Nurses reported greater difficulties in positioning the patient in LTP and higher workload (p < 0.001) vs SRP. However, approximately 50% of the LTP patients were easily or very easily positioned. Finally, these nursing challenges slightly ameliorated through practice, as more patients were enrolled in each center.

Conclusions: The LTP was specifically applied during the first days of MV. Of note, higher level of sedation/analgesia was not needed to keep the patient in LTP. At times, the nurses encountered difficulties in executing the LTP.

P22 Lateral-trendelenburg vs. semi recumbent body position for the prevention of ventilator-associated pneumonia – the GRAVITY-VAP TRIAL

M. Panigada¹, G. Li Bassi², O. T. Ranzani², T. Kolobow³, A. Zanella¹, M. Cressoni⁴, L. Berra⁵, V. Parrini⁶, H. Kandil⁷, G. Salati⁸, S. Livigni⁹, A. Amatu¹⁰, M. Girardis¹¹, M. Barbagallo¹², G. Moise¹³, G. Mercurio¹⁴, A. Costa¹², A. Vezzani¹², S. Lindau¹⁵, J. Babel¹⁶, M. Cavana¹⁷, A. Torres²

¹Policlinico di Milano, Milan, Italy; ²Hospital Clinic, Barcelona, Spain; ³National Institutes of Health, Bethesda, USA; ⁴Ospedale San Paolo, Milan, Italy; ⁵Massachussets General Hospital, Boston, USA; ⁶Ospedale Nuovo del Mugello, Borgo San Lorenzo, Italy; ⁷Gruppo Ospedaliero San Donato, San Donato Milanese, Italy; ⁸Arcispedale S. Maria Nuova, Reggio Emilia, Italy; ⁹Ospedale San Giovanni Bosco, Torino, Italy; ¹⁰Policlinico San Matteo, Pavia, Italy; ¹¹Policlinico di Modena, Modena, Italy; ¹²Azienda Ospedaliero-Universitaria di Parma, Parma, Italy; ¹³Ospedale di Sesto San Giovanni, Sesto San Giovanni, Italy; ¹⁴Policlinico Gemelli, Rome, Italy; ¹⁵University Hospital Frankfurt, Frankfurt, Germany; ¹⁶University Hospital Center Zagreb, Zagreb, Croatia; ¹⁷Ospedale Santa Chiara, Trento, Italy

Introduction: The semi-recumbent position (SRP) could increase risk of gravity-driven pulmonary aspiration and ventilator-associated pneumonia (VAP) (1–2). We investigated whether the lateral-Trendelenburg position (LTP) vs. the SRP would prevent microbiologically confirmed VAP.

Methods: 194 patients were randomized into the LTP group and 201 in SRP, and analyzed in an intention to treat approach. Patients in LTP were turned from one side to the other every 6 hours. Whereas, in the SRP group, patients were kept with the head of the bed elevated > = 30°. Primary outcome was VAP incidence rate, based on quantitative bronchoalveolar lavage fluid culture. Secondary outcomes were duration of mechanical ventilation, intensive care unit (ICU) and hospital stays, and ICU/hospital/28-day mortality.

Results: The data safety monitoring board recommended stopping the study at the second interim analysis for low incidence of VAP in the control group, lack of benefits in any major secondary outcome and adverse events in the LTP group. Microbiologically confirmed VAP was 0.5% (1/194 patients) in patients positioned in LTP, and 4.0% (8/201 patients) in patients in SRP, risk ratio (RR) between groups 0.13, 95% confidence interval (CI) 0.02–1.03, p = 0.04. Microbiologically confirmed VAP per 1000 ventilator days was 7.19, 95%CI 3.60–14.37 and 0.88, 95%CI 0.12–6.25 in the LTP and SRP, respectively, RR 0.12, 95%CI 0.01–0.91, p = 0.02. Competing risk analysis, which accounted for the concomitant risk of death and discontinuation of MV on VAP, confirmed lower cumulative probability of VAP in the LTP (cause-specific hazard ratio 0.13, 95% CI 0.02–1.00, p = 0.05). No statistically significant between-group differences were observed in secondary outcomes.

Conclusions: Critically ill patients positioned in the LTP had a statistically significant reduction in the incidence of VAP, in comparison with the SRP. Yet, further clinical examinations are mandatory to corroborate our findings, specifically in populations at high risk of VAP.

References

1) Li Bassi G et al. Crit Care Med 2014; 42: e620–7

2) Panigada M et al. Crit Care Med 2003; 31: 729–37

P23 Effects of lateral position and open chest on partitioned respiratory mechanics during thoracic surgery

M. Umbrello, M. Taverna, P. Formenti, G. Mistraletti, F. Vetrone, A. Marino, G. Vergani, A. Baisi, D. Chiumello

Ospedale San Paolo, Università degli Studi di Milano, Milano, Italy

Introduction: Airway pressure (Paw) based respiratory mechanics is used to guide ventilation. As an altered chest wall may influence the interpretation of Paw, aim of the study was to investigate the behavior of lung and chest wall during different phases of thoracic surgery

Methods: 20 patients undergoing pulmonary resection were enrolled. Double-lung ventilation (DLV) setting: PEEP 8 cmH2O, tidal volume (TV) 8 ml/kg; in one-lung ventilation (OLV) TV was reduced to 5 ml/kg and respiratory rate increased accordingly. Esophageal pressure (Pes) was measured and used to assess partitioned respiratory mechanics (ie. elastance of the respiratory system - Ers, chest wall - Ecw and lung - El). Respiratory mechanics was assessed during DLV in supine and lateral decubitus, OLV in lateral decubitus during closed and open chest

Results: Supine Ers (cmH2O/L) in DLV was 15.8 ± 4.6; no change in lateral position and DLV (19.3 ± 4.4, p > 0.05); significant increase in lateral position with OLV, with no difference between closed and open chest (31.2 ± 9.6 vs. 27.2 ± 8.9, p > 0.05). Figure 12 shows changes of El and Ecw: Ecw increased in lateral position and decreased when chest was opened. El was unchanged in lateral position but significantly increased during OLV.

Conclusions: Paw-based monitoring of respiratory mechanics did not allow to differentiate the cause of an alteration. Partitioned respiratory mechanics gives a deeper insight into the behavior of lung and chest wall.

Fig. 12 (abstract P23).

See text for description

P24 Manual versus closed loop control of oxygenation parameters during invasive ventilation: effects on hyperoxemia

A. G. Garnero¹, D. N. Novotni², J. A. Arnal¹

¹Hôpital Sainte Musse, Toulon, France; ²Hamilton medical, Bonaduz, Switzerland

Introduction: Hyperoxemia occurs up to 50% of mechanical ventilation days in the ICU [1] and is associated with increased mortality as compared to patients ventilated in normoxemia [2]. INTELLiVENT-ASV is a full closed loop ventilation mode adjusting automatically oxygenation parameters according to SpO2 for passive and spontaneously breathing mechanically ventilated patients. This post-hoc analysis of a monocentric randomized controlled parallel group study compared hyperoxemia (PaO2 > 120 mm Hg or SpO2 > 96%) and hypoxemia (PaO2 < 60 mm Hg or SpO2 < 90%) between INTELLiVENT-ASV and conventional ventilation mode in mechanically ventilated ICU patients.

Methods: This randomized controlled trial was performed in the general ICU of Hôpital Sainte Musse, Toulon, France. Eligible participants: adult invasively ventilated for less than 24 h at the time of inclusion with an expected duration of mechanical ventilation of more than 48 h. Exclusion criteria: broncho-pleural fistula, ventilation drive disorder, moribund patients. Patients were allocated to INTELLiVENT-ASV group or to conventional ventilation group (volume assist control and pressure support) using blocked randomization. The post-hoc analysis was performed by the comparison of all arterial blood gases (ABG) performed during the study period: the number of ABG with hyperoxemia and hypoxemia, the median PaO2 and SpO2 for these ABG and FiO2 associated were compared.

Results: 60 patients were included, 30 patients in each group.

Conclusions: The closed loop control of oxygenation settings provided by INTELLiVENT-ASV decreases significantly the number of blood gas with hyperoxemia as compared to manual oxygenation setting without increasing the risk of hypoxemia.

References

[1] Suzuki et al. J Crit Care 28(5):647–654, 2013.

[2] Girardis et al. JAMA 316(15) :1583–1589, 2016.

Fig. 13 (abstract P24).

Legend 1: Demographic results

Fig. 14 (abstract P24).

Legend 2: Blood gas results

P25 Withdrawn

P26 Predicting the presence of spontaneous breathing in mechanically ventilated patients

M. Urner, E. Fan, M. Dres, S. Vorona, L. Brochard, N. D. Ferguson, E. C. Goligher

University of Toronto, Toronto, Canada

Introduction: Databases from large trials are more frequently used to test new hypotheses about the impact of mechanical ventilation. In absence of direct measurement of respiratory effort, it is challenging to know if patients are breathing spontaneously. We sought to establish if the presence of spontaneous breathing can be predicted from readily available clinical variables.

Methods: Logistic regression, extreme gradient boosting, and random forest models were built from clinical variables to predict a diaphragm thickening fraction > 0.2 (mean value in healthy subjects breathing at rest [1]) as reference standard for inspiratory effort. Data from 195 patients was randomly split into a training (75%) and a test dataset (25%). The models were derived from the training dataset by cross-validation and validated on the test dataset. All models were implemented in R using the caret package.

Results: The AUROC for the logistic regression, extreme gradient boosting, and random forest models was 0.65 (0.59 to 0.70), 0.69 (0.63 to 0.72) and 0.68 (0.61 to 0.78). Diaphragm thickening fraction was most closely related to tidal volume, SAPS II score, and minute ventilation (Fig. 15).

Conclusions: We present an approach to detect spontaneous breathing during mechanical ventilation. Our models may be useful to identify spontaneously breathing patient subsets in cohort studies, but predictive accuracy is insufficient to replace direct monitoring of individual patients.

References

[1] Harper CJ et al., J Orthop Sports Phys Ther. 2013; 43(12):927–31

Fig. 15 (abstract P26).

Legend 1: Relative variable importance according to random forest analysis

P27 Mechanical ventilation training using flipped-classroom with a one-hour face-to-face tutorial

C. Leung, G. Joynt, W. Wong, A. Lee, C. Gomersall

Chinese University of Hong Kong, Sha Tin NT, Hong Kong

Introduction: We studied the effectiveness of a flipped classroom approach using e-learning and a one-hour face-to-face (FTF) practical training in teaching medical students to manage basic mechanical ventilation (MV). Teaching MV is challenging due to teacher time limitations.

Methods: We performed a prospective cohort evaluation of the level of MV competence of final year medical students who participated in this optional training. The courseware consisted of an e-chapter (to introduce basic MV settings and physiology); online interactive cases and practice tests with a MV simulator (to facilitate scenario-based practice); a one-hour FTF tutorial (1 teacher to 6 students).

Two critical care educators, informed only of the syllabus outline, created the knowledge and skills assessments at a level expected of interns. Knowledge was assessed by pre- and post-course multiple choice questions (MCQs) testing 10 domains of MV. For each student, two MCQs of equal difficulty per domain were randomized to pre- and post-course tests. The two educators conducted 10-minute post-course skills testing of students’ practical competence in setting the correct MV mode, FiO2, tidal volume, respiratory rate (RR), PEEP in a case scenario; performing appropriate action in response to desaturation, pressure or RR alarms; reassessing after setting or adjusting MV. Students’ feedback on the course’s usefulness was surveyed.

Results: 179(81%) students consented to participate. Mean MCQ score pre-course was 29% and post-course was 53% - with a mean increment (95% CI) of 32.6(28.7–36.6) in students who completed the course including FTF, 7.0(0.8–13.1) when courseware was used without FTF, and 7.7(−1.6–17.1) in those who did not attempt the course (p < 0.001). MCQ score improved in every domain (McNemar’s test, P-values varied from <0.001 to <0.03) and for all domains combined (McNemar’s test P <0.001). 23 randomly selected students participated in the skills test - median score was 8/10(IQR 6.75–8.5). Students reported the course useful for improving their MV competence. Median score of individual course components was 4–5(IQR 4–5); 4 = agree, 5 = strongly agree.

Conclusions: The course is a time-efficient and effective approach to improve students’ MV knowledge and skills. Although FTF appeared to be necessary, we believe that it must be preceded by e-learning as one-hour FTF is insufficient to provide the background and practice skills teaching. Students showed motivation to participate and found the training useful. The courseware is freely available to other educators and therefore only requires clinical teachers to provide one-hour FTF sessions.

P28 Predictors of prolonged mechanical ventilation after lung transplants: a retrospective cohort study

S. Poels, M. Casaer, M. Schetz, G. Van den Berghe, G. Meyfroidt

UZ Leuven, Leuven, Belgium

Introduction: The objective of our study was to identify predictors for prolonged mechanical ventilation (PMV) in patients after lung transplantation (ssLTx).

Methods: We performed a retrospective analysis of 36 patients admitted to our ICU after ssLTx, between 2011 and 2014. Baseline characteristics are summarized in Table 6. Cox proportional Hazard model was used to assess the risk of PMV.

Results: Of the preoperative risk factors (listed in Table 6), the indication pulmonary hypertension (PHT) was a statistical significant predictor, compared with COPD (P 0.04) and other pathology (P 0,0079) but not compared to pulmonary fibrosis (P 0,0927) when corrected for age, APACHE II >20, BMI < 20, dexmedetomidine or conventional sedation.

After transplantation, the only significant predictor of PMV (P 0,0238) was extracorporeal membrane oxygenation (ECMO), corrected for age, APACHE II > 20, BMI <20, Dexdor or conventional sedation and reperfusion edema.

Limitations of this study are the retrospective and single-center design, and the low sample size.

Conclusions: PMV after ssLTx is mainly explained by the indication for lung transplantation (PHT) and the postoperative need for ECMO.

Table 6 (abstract P28). See text for description

Fig. 16 (abstract P28).

Legend 1: Kaplan Meier Cluster diagnosis

P29 The effect of hypoxaemia on cognitive outcome in adult patients with severe acute respiratory failure treated with conventional mechanical ventilation or extracorporeal membrane oxygenation: a systematic review of the literature

B. Holzgraefe¹, L. B. Von Kobyletzki², A. Larsson³

¹Karolinska Institutet, Stockholm, Sweden; ²Lund University, Karlstad University, Lund, Sweden; ³Uppsala University, Uppsala, Sweden

Introduction: Treatment with extracorporeal membrane oxygenation (ECMO) and/or hypoxaemia in patients with acute respiratory failure (ARF) has been suggested to cause short and long-term cognitive impairment. To explore the evidence for this, we performed a systematic review.

Methods: We searched the databases Medline, PsycInfo, Cochrane Library, and Embase to identify publications, i.e. randomised controlled trials, nested case–control studies and cohort studies, reporting the possible association between hypoxaemia and cognitive impairment in patients treated for ARF with or without ECMO.

Results: We identified 2606 citations. After eliminating duplicates, two reviewers screened 1825 publications for eligibility and read 30 full text papers. No study fulfilled the inclusion criteria. We identified six studies, mainly case series, which dealt with the study question. One case series reported a correlation between hypoxaemia (haemoglobin oxygen saturation < 90%) and cognitive dysfunction at discharge but not at 1 and 2-year follow-up. In another study which concerned cognitive impairment after ECMO treatment for all causes, no direct correlation was found between ECMO and cognitive impairment. Cognitive impairment was more common after veno-arterial ECMO, which is rarely used in ARF. Mikkelsen et al. reported that a lower PaO2 was significantly associated with cognitive impairment at 12 months follow-up.

Conclusions: The evidence is sparse that that ECMO treatment for ARF or hypoxaemia during the course of ARF leads to long-term cognitive impairment. Therefore, any estimation of the actual risk of cognitive impairment as a result of using ECMO or employing hypoxaemia, permissively or inadvertently, in ARF cannot be made. More, high quality studies are needed to explore these clinically important questions.

References

Mikkelsen ME et al. American journal of respiratory and critical care medicine 2012; 185(12): 1307–15.

Risnes I et al. The Annals of thoracic surgery 2006; 81(4): 1401–6.

Hopkins RO et al. American journal of respiratory and critical care medicine 1999; 160(1): 50–6.

P30 Patterns of morpho-functional pulmonary recovery after total structural consolidation

G. Cianchi¹, F. Becherucci¹, S. Batacchi¹, M. Cozzolino¹, F. Franchi², S. Di Valvasone¹, M. C. Ferraro¹, A. Peris¹

¹Careggi Teaching Hospital, Florence, Italy; ²University of Siena, Siena, Italy

Introduction: Extracorporeal membrane oxygenation (ECMO) can be used in patients with ARDS and life-threatening hypoxia, also to reduce VILI. We described 4 patients requiring ECMO treatment with massive lung consolidation and impaired lung ventilation.

Methods: Patient 1, a 63 years old woman, was admitted for ARDS in S. pneumoniae pneumonia with massive bilateral consolidations requiring ECMO treatment; for 4 days she was minimally ventilated (2 mL/kg); after ECMO weaning, protective ventilation was applied for other 5 days. After 16 days she was discharged; CT scan showed residual minimal consolidation of the right lung. She had a good recovery after 6 months. Patient 2, a 50 years old woman, was admitted from another ICU for ARDS in bilateral P. aeuriginosa pneumonia. After 7 days of ECMO and 5 more days of protective ventilation, minimal bilateral consolidation with cystic areas were seen at CT scans; at discharge, after 18 days, she had a good recovery of respiratory function. Patient 3, a 49 years old woman, was admitted for A(H1N1) influenza virus pneumonia evolved in ARDS. Massive lung bleeding and complete pulmonary consolidation occurred; ECMO and minimal ventilation lasted 66 days, mechanical ventilation continued for 10 days after ECMO weaning. She was discharged after 81 days spontaneously breathing, with a reduction of bilateral consolidation at CT. She had a good recovery after 6 months. Patient 4, a 54 years old woman, arrived from another ICU for severe ARDS due to viral pneumonia and massive bilateral consolidations. ECMO treatment was started and for 30 days she was not ventilated for massive bilateral consolidations; weaning from ECMO was not possible for bacterial infection and evolution in pulmonary fibrosis. The patient died in ICU for multi organ failure after 300 days.

Results: Massive pulmonary consolidation is not a terminal event in ECMO patients. Pulmonary consolidation can be related to an infection or may depend on massive intra-alveolar bleeding. In our series of 4 ECMO patients, pulmonary consolidation were caused in one case by bleeding, in the others by infectious diseases.

Conclusions: We experienced that massive pulmonary consolidation can resolve, provided that patients is kept alive and VILI is minimized by ECMO support. In our series, outcome and long term sequelae seems mainly related to the underling disease, rather than to the extension of pulmonary consolidation. Periods of limited or absent ventilation do not seem to prevent recovery of alveolar function. Bleeding does not seem to exclude a full lung recovery, while infections may cause abscesses and pulmonary disruption with possible long term sequelae and residual lung dysfunction. The authors confirm that written consent for publication had been obtained.

P31 Initial ECMO experience in a Thai tertiary hospital

H. Phiphitthanaban, P. Wacharasint, V. Wongsrichanalai, A. Lertamornpong, O. Pengpinij, A. Wattanathum, N. Oer-areemitr

Phramonkutklao hospital, Bangkok, Thailand

Introduction: Extracorporeal membrane oxygenation (ECMO) may be a lifesaving procedure in patients with severe respiratory and/or circulatory failure (1,2). We present the first 19 adult patients treated with ECMO at medical intensive care unit (MICU) of Phramongkutklao Hospital, a Thai tertiary referral hospital.

Methods: A descriptive observational study was performed in 19 patients who received ECMO as a rescue therapy. Initial patient’s characteristics, technical aspects, and ECMO-related complications were described.

Results: Our adult ECMO program was started in August 2014. Since then we supported seventeen respiratory failure patients on veno-venous (VV) ECMO, one electrical shock patient on veno-arterial (VA) ECMO, and one cardiac arrest patient on VA ECMO-assisted extracorporeal cardiopulmonary resuscitation (E-CPR). Ultrasound-guided femero-jugular cannulation was percutaneously done, by intensivist, in all VV ECMO patients, while femoro-femoral cannulation was done by cardiothoracic surgeon using open technique in both cases of VA ECMO. The most frequent indication was severe pneumonia with acute respiratory distress syndrome (n = 10). Mean duration on mechanical ventilation before ECMO was 6 days. Before ECMO was initiated, mean Murray score was 3.4, respiratory compliance was 18 mL/cmH2O, PaO2/FiO2 was 102.5, and blood lactate was 5.7 mmol/L. Mean duration of ECMO was 10 days, average length of MICU and hospital stay were 18 and 21 days, respectively. Eight out of nineteen (42%) were decannulated after improvements, while remaining eleven cases who developed multiorgan failure resulting in death while on ECMO. ECMO-related complications were found in eleven cases (58%), which the most complication was active bleeding at the cannulation site.

Conclusions: Team organization and meticulous care during ECMO are crucial for minimizing ECMO-related complication. Even number of patients treated with ECMO in Thailand is increasing, a higher ECMO case volume may be required to increase the experience and improve quality of care.

References

1. Peek GJ, Mugford M, Tiruvoipati R, Wilson A, Allen E, Thalanany MM, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomized controlled trial. Lancet 2009;374:1351–63.

2. Noah MA, Peek GJ, Finney SJ, Griffiths MJ, Harrison DA, Grieve R, et al. Referral to an extracorporeal membrane oxygenation center and mortality among patients with severe 2009 influenza A (H1N1). JAMA 2011;306:1659–68.

P32 Cannula-related deep vein thrombosis during extracorporeal membrane oxygenation (ECMO) treatment do not affect mortality and length of stay in intensive care unit

M. Boddi, G. Cianchi, E. Cappellini, M. Ciapetti, S. Batacchi, G. Di Lascio, M. Bonizzoli, M. Cozzolino, A. Peris

Careggi Teaching Hospital, Florence, Italy

Introduction: Deep vein thrombosis (DVT) continues to be a serious complication in (intensive care unit) ICU patients despite the extensive use of pharmacological and mechanical prophylaxis. During extracorporeal membrane oxygenation (ECMO) treatment, the risk of cannula-related DVT is markedly increased, because the large calipter of cannulas causes endothelium damage and significantly decreases venous flow around the cannula. In this perspective it is possible to assume that during ECMO treatment cannula-related DVT could represent an additional risk of mortality and morbidity for ICU patients. We studied the incidence of cannula-related and not related DVTs in ECMO patients and their potential impact on the mortality and length of stay in this high risk subgroup of ICU patients.

Methods: This is a retrospective study on 116 patients, 53 + 19 years old, with ARDS unresponsive to conventional treatments, who fulfilled the criteria for ECMO positioning set by the the Italian Ministry of Health. ECMO configuration included 78 (67.2%) patients with bicaval dual lumen mono-cannulation (J-ECMO), 21 (18.1%) with jugular-femoral cannulation (JF-ECMO) and 17 cases (14.6%) with femoro-femoral cannulation (FF-ECMO). Ultrasound exams for DVT diagnosis at the jugular-subclavian-axillary and the femoral-popliteal and sottopopliteal venous axes were performed within the first 48 hours after ECMO placement, once a week during ECMO treatment and within 48 hours after cannulas removal. During ECMO treatment the heparin infusion was adjusted to maintain aPTT target between 50 and 80 seconds.

Results: We diagnosed 45 cannula-related DVT: 39 DVTs were located at the jugular vein and 8 at femoral veins. We found 36 (56.25%) not cannula-related DVTs; 9 cases were central venous catheter (CVC)-related DVTs. No DVT was symptomatic and all were diagnosed by scheduled ultrasound sourvellaince; asymptomatic pulmonary embolism was diagnosed in 5 cases, 3 of which in not cannula-related DVT. In our study, the overall incidence of cannula-related DVT was independent of vascular configuration of ECMO (J; FF; JF). The diagnosis of cannula related DVT was not associated with a higher ICU mortality or longer ICU length of stay; on the contrary Not cannula-related DVT significantly increased ICU mortality and ICU length of stay (p < 0.005).

Conclusions: In our ECMO population only DVTs occurring in veins not involved in cannulation were significantly associated with increased mortality and ICU length of stay. These data strongly suggest that different pathophysiologic mechanisms are involved in the occurrence of cannula-related and not related DVT.

P33 Survival of septic patients with refractory ARDS requiring veno-venous ECMO

C. Lazzeri, G. Cianchi, M. Bonizzoli, G. Di Lascio, M. Cozzolino, A. Peris

Careggi Teaching Hospital, Florence, Italy

Introduction: The role of extracorporeal membrane oxygenation (ECMO) remains controversial in adult patients with septic shock and data are so far scare and not univocal. We investigated the outcome of 26 patients with refractory ARDS and septic shock, consecutively admitted to our Intensive Care Unit (which is an ECMO referral center) from January 2013 to December 2015 and treated with venous-venous ECMO (VV-ECMO).

Methods: According to our center protocol, all patients were submitted to an echocardiography (transthoracic and/or transesofageal) before VV-ECMO implantation. Mortality during ICU stay was the primary outcome.

Results: During the study period, 74 patients with refractory ARDS were consecutively treated with VV-ECMO at our center, among whom 16 patients had concomitant septic shock (35.1%). When compared to patients without septic shock, septic patients showed higher values of SOFA (sepsis: 13.1 ± 3 vs no sepsis: 10.2 ± 2, p < 0.001), lactate values (sepsis: 6.12 ± 5.90 vs no sepsis: 3.09 ± 5.65, p = 0.07) and procalcitonin (sepsis: 76.85 ± 95.37 vs no sepsis: 12.05 ± 30.15, p < 0.01). At echocardiography, no differences was observed between the two subgroups in the incidence of left ventricular dysfunction (chi-square: p = 0.657), right ventricle dilation (chi-square: p = 0.347) and right ventricle dysfunction (chi-square: p = 0.688). The overall mortality rate was 44% (33/74) but it did not differ between patients with and without septic shock (chi-square: p = 0.218).

Conclusions: In patients with refractory ARDS requiring VV ECMO, septic shock is quite common. The use of VV-ECMO in these patients is associated with a comparable survival rate when compared to nonseptic patients. According to our data, VV ECMO is not contraindicated in patients with refractory ARDS and septic shock.

P34 Rescue ecmo therapy in h1n1 induced ARDS – successful experience from Belarus

M. L. Katsin, M. Y. Hurava, A. M. Dzyadzko

Republican Scientific and Practical Center for Organ and Tissue Transplantation, Minsk, Belarus

Introduction: The H1N1 strain of Influenza A is associated with a number of complications including acute respiratory distress syndrome (ARDS). Invasive mechanical ventilation (IMV) does not always provide an optimal solution. Extracorporeal membrane oxygenation (ECMO) has been shown to be a rescue treatment of severe H1N1-induced ARDS.

Methods: Here we describe first series of successful application of ECMO in these settings in Belarus.

Results: From January to April 2016 three patients with positive serodiagnostics of H1N1 requiring IMV for severe ARDS were admitted in different urban hospitals. Despite ARDS-Net recommended approach to IMV, it was not possible to achieve PaO2 > 60 mmHg, SpO2 > 54%. Ad-hoc veno-veinous ECMO with femoral and internal jugular cannulation was initiated shortly. IMV parameters were adjusted as follow: tidal volume reduced to 3–4 ml/kg PBW; PEEP 12–16 cmH2O, FiO2 40–50%. Patients were further transferred to the ICU of our tertiary care center. No adverse effects of transportation were noted. Median time of transfer was less than 60 min. Ultraprotective IMV was applied using APRW mode with Pinsp 20–22 cmH2O, PEEP 12–16 cmH2O, and FiO2 35–45%. Target tidal volume was 3–4 ml/kg PBW, and inspiration/expiration ratio was 1.5:1–2.5:1. Two patients required myoplegia. After 1 to 4 days of IMV an APRW mode was changed to IntelliVent-ASV™. ECMO settings were as following: flow 3–4 l/min (60–80% of minute volume); fresh gas flow 1.5–2.5 (max 9.7) l/min depending on PaCO2; and oxygen fraction 60–100% to achieve SpO2 92–94%.

The durations of ECMO were 9, 11 and 42 days. All patients received transcutaneous tracheostomy on 3–5 day of IMV, ventilator-associated pneumonia prevention bundle. We followed standard ECMO weaning procedure protocol after stabilization of respiratory function and achieving control of SIRS. Spontaneous breathing test was successful in two patients on day two after ECMO weaning. One patient with the longest duration of ECMO developed nosocomial septic shock with lung abscess complicated by hemopneumothorax, hemorrhagic shock and further left lung inferior lobectomy. He required additional 10 days of IMV following ECMO weaning, with successful return to natural airway breathing at day 67 after hospitalization. All patients survived hospitalization.

Conclusions: We successfully used ECMO as a rescue therapy in three patients with severe H1N1 induced ARDS that allowed weaning of IMV and recovery.

P35 Long-term ecmo without anticoagulation in patients with severe thrombocytopenia

A. Hermann, P. Schellongowski, A. Bojic, K. Riss, O. Robak, W. Lamm, W. Sperr, T. Staudinger

Medical University of Vienna, Vienna, Austria

Introduction: Severe thrombocytopenia yields a high risk for bleeding thus representing a relative contraindication for anticoagulation and therefore ECMO. We herein report on a series of haematological patients with severe thrombocytopenia undergoing long-term ECMO without anticoagulation.

Methods: Retrospective analysis of patient charts undergoing veno-venous gas exchange between 2012 and 2016. Data were extracted from charts and the local ECMO registry. Six patients fulfilling the criteria of severe thrombocytopenia < 50 G/L without anticoagulation for more than 3 days were identified.

Results: Patients suffered from acute myelogenous leukemia (n = 3), multiple myeloma (1) and acute lymphoblastic leukemia and consecutive stem cell transplantation (n = 2), respectively. ECMO was performed due to ARDS (n = 4) and graft versus host disease involving the lungs (n = 2). All ECMO systems used were heparin coated. Platelet count was 21 G/L (median, range 1–138), ECMO duration was 31 days (6–262), and ECMO was run without any anticoagulation for 17 days (7–262). Altogether, three clotting events were seen leading to oxygenator changes. Bleeding was common, leading to one fatal intracerebral bleeding, a minor subarachnoidal bleeding, a temporary gastric bleeding and persistent haematuria. Altogether, 27 packed red blood cells per patient (median, range 4–280) or 0,78 per day (0.57–1.25) and 22 platelet concentrates per patient (range 7–207) or 0.8 per day (0.57–1.26) were administered. Three of six patients could be weaned from ECMO, one patient survived ICU.

Conclusions: In patients with severe thrombocytopenia, ECMO can be run without anticoagulation even for longer periods. Nevertheless, bleeding is common while clotting events seem to be rare. Given the high mortality rate in this population, however, the indication for ECMO should be scrutinized rigorously.

P36 Long-term quality of life after extracorporeal membrane oxygenation in ards patients: an Italian tertiary centre experience

L. Tadini Buoninsegni, M. Bonizzoli, M. Cozzolino, J. Parodo, A. Ottaviano, L. Cecci, E. Corsi, V. Ricca, A. Peris

Careggi Teaching Hospital, Florence, Italy

Introduction: Patients who develop acute respiratory distress syndrome (ARDS) have high mortality and morbidity rates and survivors could have clinically significant physical and psychological disabilities. Several studies have reported that extracorporeal membran oxygenation(ECMO) may improve survival in severe ARDS but there have been only few studies evaluating long-term outcomes in ECMO-treated ARDS survivors (1). The purpose of the study was to assess intensive care unit (ICU) outcomes and long term outcome and quality of life of patients with ARDS receiving ECMO for refractory hypoxemia.

Methods: We conducted a retrospective observational study in adult ARDS patients who had veno-venous-ECMO in a tertiary centre from January 2014 until April 2016. We collected demographic factors, Simplified acute physiology score (SAPS II) at admission, diagnosis, mechanical ventilation and ECMO duration, ICU outcome. We contacted telephonically all ICU-survivors and organized, when possible, a follow-up visits on average 6 months after discharge from ICU. The primary outcome variable was ICU survival and health related quality of life (HRQoL) measured with the Short-Form 36 (SF-36). Long-term quality of life assessment were assessed and compared to normative individual age- matched Italian population.

Results: Sixty-four patients (mean age 50.4 ± 14.7 years, 62% males) were studied; 44 patients (69%) were retrieved from external intensive care units (ICUs) by a dedicated ECMO retrieval team. SAPS II at admission was 42.0 ± 15.1 (mean ± DS). Infectious disease were the leading causes of ARDS: 46% bacterial and 21% A(H1N1) influenza pneumonias. Mean duration of vv-ECMO support was 18.8 ± 27.5 days (median of 11 days). 38 patients (59%) survived to ICU discharge; 15 were discharged to other hospitals. Of the 38 ICU-survivors, 25 patients (65.7%) had a follow-up visit after 6 months from ICU discharge. 5 patient died within 6 months and 8 patients were lost/unable to come to visit. HRQoL was evaluated for 21 patients: compared with age-matched controls, our ARDS survivors had significantly lower (p < 0.005) SF-36 physical function and physical role functioning; vitality, bodily pain, general health perceptions, emotional role functioning, social role functioning and mental health were comparable with those of general population.

Conclusions: In this ARDS cohort treated with ECMO the ICU-survival and six months after ICU discharge survival rate was similar to other findings (1). Long term survivors had reduced physical health but their psychological domain scores were comparable with those of the general population.

References

1. Schmidt M et al.: Intensive Care Med 2013;39:1704–13

P37 Advance Organ Support (ADVOS) based on albumin dialysis, a new method for CO2 removal and pH stabilization

A. Perez Ruiz de Garibay, B. Ende-Schneider, C. Schreiber, B. Kreymann

Hepa Wash GmbH, Munich, Germany

Introduction: Our group has recently developed an Advance Organ Support (ADVOS) system based on albumin dialysis to provide intensive care treatment for patients suffering multiple organ failure including liver, kidney and lung impairments. The system has already shown improved survival in two different animal models as well as safety and efficacy to eliminate water and protein-bound toxins in humans with liver failure [1, 2]. In the present work, the ability of the ADVOS procedure to eliminate CO2 and stabilize blood pH together with the reduction of bilirubin and urea levels has been determined. Results were compared to a conventional renal dialysis machine (NIKKISO DBB-03).

Methods: For this purpose an ex vivo model for respiratory acidosis was developed continuously infusing 110 ml/min CO2 into 5 liters swine blood. In addition, liver and kidney detoxification were simulated supplementing blood with bilirubin (275 mg/dl) and urea (30 mg/dl), respectively. Blood was subjected to hemodialysis in the ADVOS system for 4 hours through two dialyzers (2 × 1.9 m²) using a blood flow (BF) of 400 ml/min and a dialysate pH of 10. The NIKKISO machine was run through a dialyzer (2.5 m²) with a BF of 350 ml/min and a dialysate pH of 8. CO2, pH, bilirubin and urea levels were analyzed pre- and post-dialyzer. Blood was checked for hemolysis at the beginning and the end of the experiments.

Results: During the whole hemodialysis time using the ADVOS procedure, an average CO2 removal of 108 ± 4 ml/min was achieved. The ADVOS system was able to maintain pH stable between 7.35 and 7.45 during the experiments, while with the NIKKISO machine pH decreased to 6.60 after one hour of treatment, being thereafter continuously out of the measuring range (hence no further calculations were possible) In the ADVOS system the main fraction was excreted as HCO3- (85%), while 15% was eliminated as dissolved CO2. In addition, post-dialyzer blood pH remained in both systems below 8. Urea was efficiently cleared with both machines (97% removal). Moreover, the ADVOS system reduced bilirubin levels about 3 times as much as conventional hemodialysis (59% vs. 21%). No signs for hemolysis were observed.

Conclusions: The ADVOS system, in contrast to normal hemodialysis, was able to efficiently remove CO2, bilirubin and urea while maintaining pH in physiological levels in an ex vivo model for respiratory acidosis simulating additional kidney and liver failure.

References

1. Al-Chalabi A et al. BMC Gastroenterol 13: 83, 2013.

2. Henschel B et al. Crit Care 19 (Suppl 1):P383, 2015.

P38 ECCO2 removal with a membrane oxygenator (Prismalung ®) integrated in a CRRT plataform (prismaflex ®): a feasibility study

F. Turani ¹, M. Resta², D. Niro², P. Castaldi³, G. Boscolo⁴, G. Gonsales⁵, S. Martini¹, A. Belli¹, L. Zamidei⁵, M. Falco¹

¹Aurelia and European Hospital, Rome, Italy; ²Istituti clinici S Donato MI, Milan, Italy; ³Marino Hospital, Cagliari, Italy; ⁴Ospedale dell’ Angelo, Mestre, Italy; ⁵Santo Stefano Hospital, Prato, Italy

Introduction: Extracorporeal CO2 removal is used in COPD/moderate ARDS patients to avoid barotrauma and VILI. When renal failure coexists, a combined ECCO2 removal with RRT may be useful to improve CO2 clearance and kidney function in a single treatment.

The aim of this study is to evaluate 1- the clinical feasibility of a CO2 removal device integrated in a CRRT platform.2 - The clinical safety of the system. 3 - The changes of main respiratory and metabolic indices

Methods: Ten patients have been enrolled into the study. All patients had renal failure, were hypercapnic and mechanically ventilated, but one.

The patients were connected to a low -flow CO2 removal device (Prismalung ®) integrated into a conventional RRT platform (Prismaflex) by a two single lumen catheters inserted in jugular and femoral vein or by a bilumen catheter in a femoral vein. Pump blood flow was started at 300 ml/min and progressively increased to 400 ml/min. RRT was delivered in a CVHDF mode with an effluent flow of 45 ml/kg/hour. Heparin or citrate infusion (three cases) was used to anti coagulate the circuit. ACT and thromboelastography were used to monitoring the coagulation parameters.

At basal time (T 0), 12 th (T 1), 24 th (T2) hours, the main respiratory parameters and the renal indices were evaluated. Bleeding complications, hemofilter clottings, catheter malfunctions were recorded. All data are expressed as Mean ± SD… ANOVA TEST one way with Bonferroni correction was used to compare the changes of the parameters in the time. P < 0.05 was considered statistically significant.

Results: At Table 7 are reported the main results of this study. All patients, but one, survived to the treatment and 4/10 were weaned from the ventilator at the end of ECCO2R. The duration of the treatments was 60 ± 30 hours. There was a clotting of the circuit and two cases of catheter malfunction. No major bleeding episodes were observed.

Conclusions: This study confirms previous study of Prismalung on animals.(1) ECCO2 removal with a membrane oxygenator integrated in a CRRT platform is clinically feasible and devoid of major complications. It allows clearance of CO2, with improvement of respiratory acidosis and control of renal failure.

References

1) Anaesth Crit Care Pain Med (2015) http://dx.doi.org/10.1016/j.accpm.2014.08.006

Table 7 (abstract P38). See text for description

P39 Ultra-low blood flow veno-venous extracorporeal CO2 removal (ECCO2R) with acidification and regional anticoagulation together with hemodiafiltration

T. Lamas¹, J. Mendes²

¹Egas Moniz Hosp., Lisboa, Portugal; ²Fernando da Fonseca Hosp., Lisboa, Portugal

Introduction: The aim of this study was to assess safety and performance of the new ECCO2R device, i.e. Prismaflex® + Prismalung® (Baxter), with citric acid as regional anticoagulant by calcium chelating effect and acidification to displace the dissolved CO2 from HCO3- and removing it through a membrane lung (Prismalung®, PL) with a blood flow (Qb) of 250 ml/min.

Methods: This study was conducted on 6 male pigs (68 ± 4.5 kg) separated in two groups, 2 pigs in the control group (Group A) and 4 pigs in the intervention group (Group B). Both groups were submitted to Phase I consisting of 4 hours with citrate anticoagulation (3.3 mmol/L) no CO2 removal (circuit bypass). In Phase II, for 8 hours both groups were submitted to ECCO2R with a FiO2 100% sweep gas flow of 15 L/min; Group A was submitted to the same citrate anticoagulation system as in Phase I while Group B was switched to citric acid anticoagulation (2.7 mmol/L) and acidification (2.0 mEq/min). All pigs were sedated and paralysed and connected to a ventilator (Servoi®, Maquet). The ventilator parameters were fixed mean tidal volume (7.11 ± 0.48 ml/kg) with PEEP 5cmH2O, FiO2 40%, V/min 8.1 ± 1.5 L/min (respiratory rate 18–20).

Results: CO2 content pre and post PL and CO2 removal is depicted in Fig. 17. The systemic pH and pCO2 did not differ statistically between the two groups. The systemic ionized calcium was stable in both groups. During the study no major critical events were recorded (death, cardiac arrest, arrhythmias, etc.). PL CO2 removal in intervention group (51.8 ± 7.8 ml/min) was significantly higher than in control group (35.2 ± 6.9 ml/min).

Conclusions: Using citric acid as a regional anticoagulant and acidification during ECCO2R is safe and more effective to remove the CO2 comparing standard ECCO2R.

Fig. 17 (abstract P39).

Total blood CO₂ evolution between pre and post PrismaLung (PL). *PLQb (Group A) = Qb + Citrate; PLQb (Group B) Qb + Citric_acid

P40 Effect of flow and temperature on comfort during high flow nasal cannula

A. Galazzi¹, T. Mauri¹, B. Benco¹, F. Binda¹, L. Masciopinto¹, M. Lazzeri², E. Carlesso¹, A. Lissoni¹, G. Grasselli¹, I. Adamini¹, A. Pesenti¹

¹Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, Milano, Italy; ²Sant’Anna Hospital, University of Ferrara, Ferrara, Italy

Introduction: Over the last few years, high flow nasal cannula (HFNC) is increasingly adopted as first line treatment of acute hypoxemic respiratory failure (AHRF) patients [1]. One of the key features of HFNC efficacy seems to be elevated patients comfort, which might critically depend from set temperature and flow. Aim of the study is to assess the comfort of patients undergoing HFNC at different temperatures and flows.

Methods: We conducted a prospective, randomized, cross-over study on 18 AHRF patients, admitted to the intensive care unit (ICU) and receiving respiratory support by HFNC as per clinical indication. We randomly applied 2 flows (HFNC 60 l/min and 30 l/min) and 2 temperatures (31 °C and 37 °C) for 15 minutes (four steps per patient). Clinical FiO2 was left unchanged during all steps. We investigated during the last minutes of each step: comfort by numerical scale from 0 (extreme discomfort) to 5 (very comfortable); dyspnea by modified Borg scale form 0 (none) to 10 (unbearable); physiologic respiratory parameters. Data of each step were compared using linear mixed-effects model analysis (parametric or non-parametric, as appropriate) for repeated measures with Bonferroni or Tukey post-hoc test.

Results: We enrolled 18 patients, aged 51 ± 14 year-old, 6 females. At enrollment, SpO2 was 97 ± 2% with FiO2 43 ± 13%, the etiology of AHRF was various. Main study results are reported in Table 8. Patient comfort level was significantly higher during HFNC at lower flow and temperature (p = 0.015 and p < 0.001 respectively), but interaction was not significant. Peripheral saturation was significantly increased by higher flow rate (p = 0.026). Interestingly, in this convenience sample, higher HFNC support didn’t modify the respiratory rate likely indicating clinical stability.

Conclusions: Lower flow and temperature grant improved patient comfort. Titration of HFNC setting to obtain best comfort might be relevant to exploit clinical efficacy.

References

1. Roca O et al. Crit Care 28;20(1):109, 2016

Table 8 (abstract P40). See text for description

P41 High flow nasal cannula prevent reintubation in post-extubated critically ill patients: a systematic review and meta-analysis

T. Thamjamrassri, J. Watcharotayangul, P. Numthavaj, S. Kongsareepong

Mahidol university, Bangkok, Thailand

Introduction: Extubation failure and reintubation after planned extubation are associated with high mortality [1]. Multiple factors including impair secretion drainage, hypoxemia or hypercarbia are possible causes of extubation failure [2]. Therefore, giving appropriate oxygen therapy and respiratory care after extubation in critically ill patients should decrease incidence of reintubation. Recently, high flow nasal cannula (HFNC) has been used increasingly in critically ill patients because it has many advantages over conventional oxygen therapy (COT). HFNC provides higher flow rate and more humidity which facilitated secretion drainage. Moreover, PEEP causing from HFNC decreases work of breathing [3]. Previous study shown that HFNC decreased incidence of reintubation in post-extubated critically ill patients [4]. Although there is a meta-analysis compared HFNC with other methods of oxygen therapy, patients who failed extubation criteria were included in the study [5]. Therefore, we conduct a meta-analysis comparing HFNC with other methods of oxygen therapy in preventing reintubation in planned extubated critically ill patients.

Methods: MEDLINE, OVID and the Cochrane Library databases were searched. RCTs and cohorts studies comparing HFNC with other methods of oxygen therapy in post-extubated critically ill patients were included. The primary outcome was re-intubation rate. The secondary outcomes were ICU mortality, length of stays (LOS) in ICU and post-extubated respiratory failure.

Results: 6 studies were analyzed in the meta-analysis. HFNC significantly reduced re-intubation rate (RR = 0.4, 95% CI 0.26–0.61) and post-extubated respiratory failure (RR = 0.51, 95% CI 0.35–0.73) comparing to COT. However, there were no significant difference in ICU mortality (RR = 0.93, 95% CI 0.47–1.83) and LOS (PMD = −0.14, 95% CI −0.65–0.36)

Conclusions: HFNC reduced re-intubation rate and post-extubated respiratory failure compared to COT. There were no difference in ICU mortality and LOS.

References

1. Thille AW, et al. Am J Respir Crit Care Med 187:1294–302, 2013

2. Kulkarni AP, et al. Indian J Crit Care Med 12: 1–9, 2008

3. Spoletini G, et al. Chest 148:253–61, 2015

4. Hernández G, et al. JAMA 315:1354–61, 2016

5. Monro-Somerville T, et al. Crit Care Med. 2016 Sep 8. [Epub ahead of print]

P42 The role of high flow nasal cannula oxygen therapy in the intensive care unit

J. Higuera, D. Cabestrero, L. Rey, G. Narváez, A. Blandino, M. Aroca, S. Saéz, R. De Pablo

Ramón y Cajal University Hospital, Madrid, Spain

Introduction: The goal of the study is to analyze the impact and the results of the application of high flow nasal cannula in an intensive care unit of a tertiary, university hospital.

Methods: We perform a retrospective study with all patients who have been treated with high flow nasal cannula (HFNC) for their respiratory failure between May 2013 and April 2016.

Results: 174 patients were included. Average age: 57.81 ± 15.5 (18–88), male (58.6%). Severity index: SOFA 8.17 ± 4.29 (1–19), APACHE II 19.43 ± 8.3 (3–44) and SAPS II 48.66, average stay 14 days and mortality rate of 22.4%

For a better categorization of patients, diagnostics were tabulated in the following groups. Respiratory 52.3% Haematological 20.7%, Septic 16.1%, Neurological 4.6%, Cardiologic 3.4%, Digestive 0.6%, Oncologic 0.6%

The origin of respiratory failure was primarily: Respiratory (72.4%), Septic (21.3%), and miscellaneous (6.3%)

Patients required high flow nasal cannula therapy for hypoxemic decompensation in 77.6% of the cases. In the 1.7% of the cases the cause were mixed and was hypercapnia in the 20.1% of the cases.

56.9% (99/174) of the patients, required mechanical ventilation. 43.1% of the patients (75/174) didn’t require mechanical ventilation. In 31 up to the 99 patients who require mechanical ventilation, HFNC was used as a support for the scheduled extubation. In 68 up to 99 patients, mechanical ventilation was required after HFNC failure.

The group of patients which needed mechanical ventilation had higher mortality (p < 0.0001).

The mortality rate is considerable higher due to retardation of the intubation, after the high flow oxygen therapy has failed. The patients intubated the first 48 hours after the high flow oxygen therapy failure have a mortality of 44% vs the 61% after 72 hours.

There are significant differences in the mortality rate regarding the type of patient. Is very probable that the most benefit group by HFNC is the one with severe respiratory failure with exclusive respiratory cause and hypoxic decompensation.

Conclusions: The use of high flow oxygen therapy has changed the attitude towards the patients with insufficiency respiratory failure and may avoid in some cases the use of mechanical ventilation. The delay in the orotracheal intubation after high flow therapy has failed, increases the rate of mortality. Further controlled studies are needed to display which other patients can be beneficed by the high flow oxygen therapy.

P43 High flow nasal cannula in immunocompromised patients with acute respiratory failure: a systematic review and meta-analysis

A. Mohamed, M. Sklar, L. Munshi

Sinai Health System, Toronto, Canada

Introduction: Our study objectives were to evaluate the impact of high flow nasal cannula (HFNC) in immunocompromised (IC) patients with acute hypoxemia respiratory failure. The role of HFNC compared to conventional oxygen therapy remains controversial in this population.

Methods: We performed a systematic review and meta-analysis to evaluate the application of HFNC in an adult IC patients with acute respiratory failure (to August 2016). We included any randomized controlled trials (RCTs) or observational studies and meta-analyzed results where HFNC was compared to face mask oxygen or non-invasive ventilation (NIV). Our primary outcome was the need for mechanical ventilation. A series of secondary outcomes were analyzed.

Results: Of 3099 citations screened, 6 fulfilled our inclusion criteria (3 RCTs, 3 observational studies). Across 428 patients, the definition of IC included patients with pharmacologic IC states or IC due to one’s underlying disease. Of the two trials evaluating the application of HFNC vs face mask, there was no decrease in the rates of mechanical ventilation (RR 1.03, 95% confidence interval (CI) 0.41–2.61, p = 0.95) Fig. 18. Contrary to this, HFNC vs NIV was associated with a decrease in need for invasive mechanical (RR 0.58, 95% CI 0.41–0.83, p = 0.003).

Conclusions: Evidence to date is limited on the application of HFNC in this population; therefore, a larger number of high quality studies are needed to corroborate these preliminary findings.

Fig. 18 (abstract P43).

Primary Outcome (Mechanical Ventilation)

P44 Setting high flow nasal cannula to maximize physiologic benefits

T. Mauri¹, M. Lazzeri², L. Alban², C. Turrini², M. Panigada³, P. Taccone³, E. Carlesso¹, C. Marenghi³, S. Spadaro², G. Grasselli³, C. Volta ², A. Pesenti¹

¹University of Milan, Milan, Italy; ²University of Ferrara, Ferrara, Italy; ³Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy

Introduction: High-flow nasal cannula (HFNC) is a non-invasive respiratory support associated to several physiologic advantages in acute hypoxemic respiratory failure (AHRF) patients [1]. Previous studies showed that these effects depend on set flow. Aim of the study was to identify the flow at which gas exchange, end-expiratory lung volume (ΔEELV), respiratory rate (RR), inspiratory effort and corrected minute ventilation (MVcorr = MV*PaCO[sub]2[/sub]/40) result in highest improvement.

Methods: We performed a prospective, randomized, cross-over study, divided in 4 phases, on AHRF patients (PaO[sub]2[/sub]/FiO[sub]2[/sub] < =300) admitted to intensive care unit. We randomly applied standard facial mask (12 l/min) vs HFNC set at 30, 45 and 60 l/min, each step lasting 20 minutes. Clinical FiO[sub]2[/sub] was left unchanged. We collected gas exchange, lung volumes by electrical impedance tomography, patient’s inspiratory effort by esophageal pressure (Pes) and respiratory rate.

Results: We enrolled 17 patients (9 females), aged 62 ± 10 year-old. At enrolment the PaO[sub]2[/sub]/FiO[sub]2[/sub] was 151 ± 60 mmHg. The highest PaO2 value in 71% of patients was reached at HFNC 60 l/min (p = 0.0047). The highest lung volume was obtained for 59% of patients at HFNC 60 l/min (p = 0.0094). The lowest respiratory rate (bpm) in 77% of patients was at HFNC 60 l/min (p = 0.0007) and the lowest value in ΔPes was obtained for 57% of patients at HFNC 60 l/min (p = 0.0464). On the contrary, the percentage of patients with minimum value of MVcorr was equally distributed among the 3 HFNC flows (p = 0.662). Figure 19 shows flows distribution.

Conclusions: Our results show that HFNC 60 l/min might be regarded as the optimal flow for most parameters. However, 30–40% of patients obtained best results at lower flows and with absence of “optimum” flow for corrected minute ventilation.

References

1. Roca O. et al. Crit Care 28;20:109, 2016

Fig. 19 (abstract P44).

Legend 1: Flow distribution optimizing variables. p chi-squared test among flows

P45 The role of high flow nasal cannula oxygen therapy in hematological patients with severe respiratory failure

J. Higuera, D. Cabestrero Alonso, A. Blandino, G. Narváez, L. Rey González, M. Aroca, S. Saéz, R. De Pablo

Ramón y Cajal University Hospital, Madrid, Spain

Introduction: Our goal is to analyze the impact and the results of the application of high flow oxygen therapy (HFNC) in hematological patients with respiratory failure

Methods: We performed a retrospective study.

All hematological patients who were treated with HFNC between May 2013 and April 2016 were included (n = 36)

Results: Average age: 51. 67 ± 15. 77 (23–80); 50% male; mean SOFA: 9. 09 ± 5. 15 (2–19), and APACHE II: 22. 61 ± 8. 86 (3–40). The etiology of respiratory failure was hypoxemic in 91. 66% (n = 33) and mixed in 8. 33% (n = 3) of cases.

HFNC avoided intubation and therefore mechanical ventilation (MV) in 38. 9% (n = 14) of the patients. 19 patients required MV after HFNC failure and in the other 3 HFNC was used after extubation. (Fig. 20)

The mortality rate in the study was 44.4% (n = 16). In the group of patients who avoided MV was 14.28% (2/14). In the ones who required mechanical ventilation after HFNC failure the mortality rate was 68.42% (13/19). 3 Patients required HFNC after extubation, 1/3 died. (Fig. 21)

The group of patients, who need mechanical ventilation, had higher mortality. (p <0.0001) However, the mortality rate was higher in this group due to delay of intubation. The average delay in the patients who died (n = 13) was 2.28 days vs. 1.83 days in the survivors group (n = 6)

Conclusions: HFNC oxygen therapy appears to be a safety therapeutic option for the treatment of severe respiratory failure in patients with haematological malignancies. Intubation was avoided in a substantial proportion of patients. Also was related a lower mortality rate in this subgroup of patients. However, the delayed of intubation due to HFNC failure was related to higher mortality.

Fig. 20 (abstract P45).

Legend 1: Graphic 1

Fig. 21 (abstract P45).

Legend 2: Graphic 2

P46 Withdrawn

P47 The advanced airway management in the out-of-hospital setting: a comparison between endotracheal intubation and extra-glottic devices in terms of mortality and outcome

A. Franci, G. Stocchi, G. Cappuccini, F. Socci, M. Cozzolino, C. Guetti, P. Rastrelli, A. Peris

Careggi Teaching Hospital, Florence, Italy

Introduction: The study aims to compare endotracheal tube (ETT) and extraglottic devices (EGD) in the out-of-hospital setting, in terms of consequences and outcome. Secondary endpoints were evaluation of parameters that could correlate with survival and neurological outcome and evaluation of the influence of a mechanical ventilation (MV) vs bag valve mask ventilation (BVM) during the transport from the field to the hospital.

Methods: This retrospective study examined 404 patients with a out-of-hospital airway management between January 2013 and June 2016. 187 of them were transferred to the Intensive Care Unit (154 managed with ETT and 33 with EGD); they were analyzed for demographic, infective, radiologic and neurologic parameters. Patients with ETT were subsequently divided in 2 subgroups, the ones who received a MV during the transport to the hospital and the ones who were manually ventilated.

Results: Our results show that there was no correlation between the use of ETT or EGD and mortality rates 48 hours after the admittance to ICU, but there was a significant difference in survival after 7 days. There was no significant difference between ETT and EGD in terms of neurological and pulmonary outcome when patients were dismissed from ICU. The ventilation technique during the transport revealed to be an accurate parameter of survival after 48 hours, as the MV reduced patients’ mortality when compared to the BVM.

Conclusions: The study confirmed the importance of advanced airway management in the out-of-hospital setting, regardless of the device used. Evidence shows that ETT is recommended whenever possible, and most of all the use of MV because this seems to reduce mortality rate, probably reducing pulmonary damage deriving from the impossible titration of volumes and pressures administered to the lung during BVM.

Table 9 (abstract P47). See text for description

P48 Arterial oxygenation and hemodynamics during extrathoracic negative pressure in a porcine model of lung injury

A. Nestorowicz¹, J. Glapinski², A. Fijalkowska-Nestorowicz³, J. Wosko⁴

¹Medical Univesity, Lublin, Poland; ²Wroclaw University of Technology, Wroclaw, Poland; ³Medical University, Lublin, Poland; ⁴SPSK No4, Lublin, Poland

Introduction: Recruitment maneuvers have been advocated recently, however their routine use is still under debate [1]. This study attempts to evaluate the impact of extrathoracic negative pressure (eNP) on arterial oxygenation and hemodynamics in pigs with acute lung injury.

Methods: The study involved 10 adult Large White pigs weighting 48–60 kg. Under general anaesthesia animals were intubated and ventilated in a volume-controlled mode (Puritan-Bennett 840) with F[sub]I[/sub]O[sub]2[/sub]-1.0, I:E ratio-1:2. Vt −8–10 ml/kg and RR-14–18/min were used to maintain PaCO[sub]2[/sub]- 35–45 mmHg. An infusion of lactate Ringers solution was given iv at a rate of 5–8 ml/kg/h.

Lung injury was induced with bronchoalveolar lavage by warm 0.9% NaCl (30 ml/kg) until PaO[sub]2[/sub]/F[sub]I[/sub]O[sub]2[/sub] remain below 100. Thereafter, using a whole body close-chamber, the eNP was commenced in combination with IPPV.

Heart rate (HR), mean arterial pressure (MAP), mean pulmonary arterial (MPAP) and pulmonary capillary wedge (PCWP) pressures, cardiac output (CO) (Swan-Ganz catheter) as well as arterial oxygen tension (PaO[sub]2[/sub]) were recorded before and after lung injury: at 0 (baseline), −4, −8, −12, −16 cmH[sub]2[/sub]O.

Results: Significant improvement in PaO[sub]2[/sub] was observed during the eNP when compared with baseline. There were no significant changes in hemodynamic parameters when the negative pressures of −4, −8 and −12 cmH[sub]2[/sub]O were applied (fig. 22).

Conclusions: This study demonstrates effectiveness of extrathoracic negative pressure during recruitment of injured lung tissue in terms of arterial oxygenation and hemodynamic stability.

References

1. Lovas A. et al.: Biomed Res Int 2015; 2015: 478970.

Fig. 22 (abstract P48).

Legend 1: *P < 0.05 vs baseline

P49 Influence of extrathoracic negative pressure on mechanics of atelectatic lung during IPPV

A. Fijalkowska-Nestorowicz¹, J. Glapinski², J. Wosko³

¹Medical University, Lublin, Poland; ²Wroc³aw University of Technology, Wroclaw, Poland; ³SPSK No4, Lublin, Poland

Introduction: Respiratory mechanics are regularly impaired when atelectasis occurs. There are many different procedures that can be used in order to reopen collapsed lung tissue. The aim of our study was to determine the effects of extrathoracic negative pressure (eNP) on respiratory mechanics of atelectatic lungs.

Methods: Ten Large White pigs weighting 52 ± 5 kg were included in the study. Under general anaesthesia all animals were tracheotomized (tube size 8.5–9 mm) and ventilated in a volume-controlled mode (P-B 840) at RR–18/min, with VT– 8–10 ml/kg, I:E ratio −1:2 and F[sub]I[/sub]O[sub]2[/sub]–1.0. Lungs injury was induced by repetitive lavages with 1.5–1.8 l warm 0.9% NaCl until PaO[sub]2[/sub]/F[sub]I[/sub]O[sub]2[/sub] remain stable below 100. After lungs injury was produced, the eNP, using a whole body size-box, was commenced in combination with IPPV. Peak airway pressure (P[sub]a[/sub][sub]w[/sub]peak), airway resistance (R) and dynamic compliance (Cdyn) were recorded, using ventilator software, before lungs injury and after – at 0 (baseline), −4, −8, −12 and −16 cmH[sub]2[/sub]O negative pressures.

Results: There were significant differences in P[sub]a[/sub][sub]w[/sub]peak and R but no in Cdyn at negative pressure −8, −12, and −16 cmH[sub]2[/sub]O compared to baseline (tab).

Conclusions: Extrathoracic negative pressure constitutes a positive profile of respiratory mechanics of atelectatic lungs and improves blood oxygenation.

Table 10 (abstract P49). See text for description

P50 Inspiratory negative pressure in simulated spontaneous breathing with a bag valve mask: a bench study

F. Duprez¹, T. Bonus¹, G. Cuvelier², S. Mashayekhi¹, S. Ollieuz¹, G. Reychler³

¹Epicura, Hornu, Belgium; ²Condorcet, Tournai, Belgium; ³UCL, Bruxelles, Belgium

Introduction: In emergency care, oxygen therapy can be administered directly with bag valve mask (BVM). In some cases, this method is applied to patient with a spontaneous breathing. The purpose of this study was to evaluate inspiratory negative pressure (INP) during spontaneous breathing through three different bag valve masks.

Methods: Three BVM (Ambu®Oval, MR100®, Ambu® Mark IV; without oxygen reservoir bag) were analyzed. Spontaneous breathing was simulated on a bench study. A two-compartment model of adult test lung (Dual Test Lung® DTL, Michigan Instrument) was connected to a Servo i® ventilator. One compartment of