A randomized controlled trial to compare aprv and simv mode in patients with ards

Background: Acute respiratory distress syndrome (ARDS) is the most com¬mon organ failure leading to intensive care. Airway pressure release ventilation (APRV) mode produces tidal ventilation using an inverse ratio method,it releases airway pressure from an elevated baseline to simulate expiration which facilitates oxygenation and the timed releases aid in carbon dioxide removal. We compared this relatively newer mode withSynchronized intermittent mandatory Ventilation (SIMV) mode in managing ARDS patients
Aims: Patients oxygenation, sedation requirement, hemodynamics, vasopressor use were compared and also the impactof twoventilatory modes on patient outcome and duration of hospital stay were studied
Methods: We randomized 40 patients to receive either APRV or SIMV using random number table during August 2013 to August 2014.With 95% confidence and 80% power, the calculated sample size was 3.The data was analyzed using Statistical Package for Social Sciences version 15.0. Comparison was done using independent samples "t"-test or Mann-Whitney U test, depending on the normality of distribution.Mechanically ventilated patients between age group of 16 -60 years with a preformed diagnosis of ARDS were included. Patients who required deeper levels of sedation or Obstructive lung diseases were excluded.
Results: APRV group had higher P/F ratio (238.00. +/- 59.40) as compared to SIMV group (200.30+/- 35.99), NMBD and sedation use was lower in APRV group (p= 0.008), Mean reduction in lung injury score was greater in APRV (p= 0.004)
Conclusion: Primary use of APRV as compared to SIMV showed better clinical improvement in terms of P/F ratio, chest X-ray and lung compliance, lower sedation and NMBD requirement in ARDS patients, but no improvement in hemodynamic variables or the outcome of the patients.