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  • Open Access

Which positive end expiratory pressure (PEEP) should be used during noninvasive positive pressure ventilation (NPPV) in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) patients?

  • 1,
  • 1,
  • 1,
  • 1 and
  • 1
Critical Care20048 (Suppl 1) :P10

https://doi.org/10.1186/cc2477

  • Published:

Keywords

  • Arterial Blood Pressure
  • Respiratory Distress Syndrome
  • Distress Syndrome
  • Respiratory System
  • Applied Pressure

Objective

To establish the effects of different levels of PEEP on blood oxygenation and intra-abdominal pressurization (IAP), in order to select a sufficient level of PEEP during NPPV of ALI/ARDS patients.

Methods

Six early ALI/ARDS patients, four male/two female, aged 49.67 ± 16.28 years, paO2/FIO2 = 202.50 ± 79.69, with bilateral infiltrates on thoracic roentgenogram, APACHE II = 15.67 ± 5.43, were prospectively studied.

Patients were ventilated on a BIPAP Vision. Pressure support was fixed at 10 cmH2O. EPAP (PEEP) was applied at 5, 8, 11, 14, 17 and 20 cmH2O. paO2/FiO2 and gradients between paCO2 and EtCO2 were calculated after 20 min at each level of EPAP. IAP was measured through intravesical catheters. Arterial blood pressure (ABP) and heart rate (HR) were continuously monitored.

Results

Increased levels of EPAP had positive effects on oxygenation and little effect on IAP and on hemodynamic features, showing that most of the applied pressure was dissipated at the respiratory system, probably recruiting collapsed alveolar units (Table 1). Mean EPAP was 12 ± 4.90 cmH2O (range = 8–20 cmH2O). Only one of these six patients was invasively ventilated. All patients survived.

Table 1

 

EPAP level (cmH2O)

 

0

5

8

11

14

17

20

paO2/FIO2

202.50 ± 79.69*

234.68 ± 79.69*

217.85 ± 79.13

242.03 ± 69.54

240.12 ± 77.83

279.52 ± 94.31*

279.07 ± 83.26*

paCO2–EtCO2

4.30 ± 3.44

6.82 ± 4.10

7.18 ± 3.97

4.43 ± 3.83

6.70 ± 3.44

6.92 ± 4.94

6.40 ± 3.53

IAP

16.50 ± 6.25

16.17 ± 6.27

16.75 ± 7.0

18.50 ± 4.88

18.67 ± 4.84

19.75 ± 5.67

19.25 ± 4.58

ABP

96.50 ± 17.66

96.00 ± 14.90

93.83 ± 20.25

91.67 ± 22.0

90.33 ± 20.64

91.17 ± 21.18

94.50 ± 20.81

HR

85.67 ± 19.10

80.83 ± 20.15

78.50 ± 14.35

76.33 ± 13.63

76.67 ± 13.72

79.00 ± 13.78

79.17 ± 14.97

*P < 0.05 (ANOVA/Bonferroni correction).

Conclusions

These EPAP levels have improved gas exchange without aditional abdominal distension. These preliminary results of high survival should mean that an adequate level of EPAP has been chosen.

Authors’ Affiliations

(1)
University of São Paulo Medical School, São Paulo, Brazil

Copyright

© BioMed Central Ltd. 2004

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