Use of noninvasive mechanical ventilation with pressure support guaranteed with average volume in de novo hypoxaemic respiratory failure. A pilot study.

BACKGROUND: This study was designed to determine the results associated with the use of noninvasive mechanical ventilation (NIV) using the BiPAP S/T-AVAPS ventilation strategy in subjects with mild to moderate de novohypoxaemicrespiratory failure.

METHODS: This is a prospective study that includes subjects with de novohypoxaemic respiratory failure (not produced by acute exacerbations of COPD, chronic lung disease, or congestive heart failure) with mild to moderate PaO₂/FiO₂, who were admitted to the Intensive Care Unit (ICU) of Santa Maria Clinic in Guayaquil, Ecuador. Subjects were divided into two groups and compared according to their PaO₂/FiO₂: higher than 100 and up to 200 mm Hg (moderate ARDS) or between 200 and 300 mm Hg (mild ARDS) (both groups were ventilated with the BiPAP S/T-AVAPS strategy). A value of P < 0.05 was considered significant.

RESULTS: A total of 38 subjects were analysed in this study. The total rate of intubation was 34.2% while the mortality rate was 28.9%. Significant differences were observed when comparing success versus failure in exhaled tidal volumes (P = 0.04), peak inspired pressure (P < 0.001), PaO₂ (P < 0.001), SaO₂ (P < 0.002), PaO₂/FiO₂ (P < 0.002), RR (P < 0.001), HR (P < 0.001), and inspiratory time (P = 0.029) measured at baseline and at 12-hour, 24-hour and 48-hour intervals.

CONCLUSION: The BiPAP S/T-AVAPS ventilatory mode can be used in subjects with de novo hypoxaemic respiratory failure with special vigilance concerning exhaled tidal volumes and inspired pressure.