The outcome of early pressure-controlled inverse ratio ventilation on patients with severe acute respiratory distress syndrome in surgical intensive care unit

Background: Pressure-controlled inverse ratio ventilation (PC-IRV) was used in patients with acute respiratory distress syndrome (ARDS) after failed volume-cycled conventional ratio ventilation (VC-CRV). The aim of this study was to evaluate the outcome of early PC-IRV in severe ARDS. Methods: Twenty patients with severe ARDS were switched from VC-CRV to PC-IRV if they failed to maintain SaO2 >90% by the following criteria: peak inspiratory pressure (PIP) >35 cm H2O, FIO2 = 60%, and positive end-expiratory pressure (PEEP) 10 cm H2O. Results: The values of PIP, mean airway pressure, minute volumes, and lung injury score in VC-CRV were 43.9 ± 8.0 cm H2O, 19.5 ± 6.4 cm H2O, 11.0 ± 2.1 L/min, and 2.8 ± 0.2 respectively. In PC-IRV, the corresponding data were 31.8 ± 5.1 cm H2O, 25.4 ± 4.6 cm H2O, 8.3 ± 0.9 L/min, and 2.5 ± 0.4. All of these parameters were significantly different. Fifteen patients (75%) survived their intensive care unit stay. Conclusions: Early PC-IRV in severe ARDS improves oxygenation, facilitates tapering of high fraction of inspiratory oxygen, and decreases high PEEP or PIP, and then results in the improvement of the patient’s outcome.