Use of a fully closed-loop ventilation mode in long-term ventilated ICU patients: a prospective study
© Arnal et al.; licensee BioMed Central Ltd. 2012
Published: 20 March 2012
IntelliVent-ASV® is a closed-loop ventilation mode that automatically adjusts ventilation and oxygenation settings in passive and active breathing patients. The minute volume is adjusted according to end-tidal CO2 (ETCO2) information in passive breathing patients (and respiratory rate in active breathing patients), and oxygenation is adjusted according to SpO2 information. This study reports the ventilation and oxygenation delivered by IntelliVent-ASV® in long-term ventilated ICU patients.
This prospective, observational study included 100 patients invasively ventilated using IntelliVent-ASV® from admission to weaning or death. The rate and reason for stopping automation were recorded. Settings automatically selected, delivered ventilation, respiratory mechanics and arterial blood gas results were collected once a day. Patients were categorized in different lung conditions: normal lung, ALI/ARDS, COPD. Analysis of variance compared the ventilation-days for each type of lung condition for active and passive breathing patients.
Patients (age 73 (64 to 79) years; SAPS II 56 (48 to 69)) were ventilated using IntelliVent-ASV® to weaning or death (31%) for a median duration of 3.0 (2.0 to 7.0) days without any safety issue. The ventilation controller was deactivated in two patients because of high PaCO2-ETCO2 gradient. Oxygenation controller was deactivated in seven patients for 1 day because of a poor SpO2 signal. In passive and active ventilation-days, minute volume, VT/PBW, respiratory rate, FiO2, and PEEP were statistically different based on lung condition. In passive ALI/ARDS ventilation-days, VT/PBW was significantly lower (7.5 (6.9 to 7.9) ml/kg) than passive normal lung (8.1 (7.3 to 8.9) ml/kg; P < 0.05) and passive COPD patients (9.9 (8.3 to 11.1) ml/kg; P < 0.05). In passive ALI/ARDS ventilation-days, FiO2 and PEEP were statistically higher than passive normal lung (35 (33 to 47)% vs. 30 (30 to 31)% and 11 (8 to 13) cmH2O vs. 5 (5 to 6) cmH2O, respectively; P < 0.05). In active normal lung ventilation-days, VT/PBW was not different (8.4 (7.8 to 9.1) ml/kg) than in active ALI/ARDS (8.1 (7.5 to 9.3) ml/kg), and in active COPD (9.3 (8.6 to 11.6) ml/kg). In active ALI/ARDS and COPD ventilation-days, PEEP was significantly higher than active normal lung (8 (5 to 10) cmH2O, 7 (5 to 10) cmH2O, and 5 (5 to 5) cm H2O, respectively; P < 0.05).
IntelliVent-ASV® can be used safely in long-term ventilated ICU patients and selects automatically different ventilation and oxygenation settings according to the lung condition, especially for passive breathing patients.
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