Evaluation of Efficacy of Extended Prone Ventilation in Patients with Acute Respiratory Distress Syndrome in a Tertiary Care Centre

INTRODUCTION: Prone ventilation has traversed a journey from salvage therapy to a first line management strategy in severe ARDS patients which has high mortality(1,2). Meta-analysis of eight RCTs was conducted by Munshi L et al; reported lower mortality in patients with severe ARDS, particularly in those with 12 hours or more of proning (risk ratio [RR] 0.74)(3) Prone ventilation helps to improve the oxygenation by improving ventilation perfusion mismatch and by alteration of lung mechanics which is a time dependent process(4,5). PROSEVA trial documented mortality benefit with 16 hours proning cycles(14). Later multiple studies have extended the duration of proning from standard duration of 16 hours to extended duration of 36–48 hours and have found it to be as effective and safe as standard therapy(16 hours) with respect to the improvement in the respiratory parameters and the incidence of adverse events(7,8,14,15,21,22,23,24). Prone positioning is not a bengin procedure caries potential risk to both patient and the healthcare workers(6) During the COVID pandemic extended proning has decreased the frequency of turning procedures minimising the associated complications, viral exposure and the workload on healthcare personnel(4,8,24) OBJECTIVES: To evaluate the efficacy and the safety of extended duration of prone ventilation in severe acute respiratory distress syndrome patients.(1–10) MATERIALS AND METHODS: We have conducted a prospective monocentric observation study on 72 severe ARDS patient(Berlin's criteria) and excluded those with contraindications to proning(3,9,10,15). We evaluated the efficacy of extended proning of 36(32–40) hours by recording and comparing the respiratory parameters including the blood gases and lung mechanics at T0(prior to proning), T1(24 hours after proning) and T2(one hour after patient is made supine after 36 hours of proning). We also recorded the morbidity data including the NIV duration received prior to proning, the number of proning cycles, the adverse events attributable to prolonged proning therapy(11,12,13,14–20,27) duration of invasive mechanical ventilation, length of ICU stay and the outcome of every patient in the study. We have compared these parameters between the survivors and non survivors in the study population as well as with the results of prior studies(14–30). RESULTS: It was noted that P/F ratio increased from 79.74+/-25.22 to 137.1+/-45.72 (p value of <0.0001****), Oxygenation Index(OI) improved from 24.91+/- 8.77 to 13.97+/-5.42 (p value of <0.0001****) and PaCO2 decreased from 54.81+/-11.50 mm Hg to 48.54+/-10.15 mm Hg (p value of <0.0001 ****) after the first extended prone ventilation session. A statistically significant improvement in lung mechanics was also noted at same time. The peak airway pressures decreased from 32.78+/-3.74 cm of H2O to 30.24+/-3.75 cm H2O(p value of <0.0001****), Plateau pressures from 26.94 +/- 3.53 cm H2O to 24.61+/-3.66 cm of H2O(p value of <0.0001****) Driving pressures from 15.94+/-3.61 cm H2O to 13.46+/-3.72 cm H2O (p value of <0.0001****) and Static lung compliance increased from 24.97+/-5.46 mL/cm H2O to 30.37+/-8.18 mL/cm H2O (p value<0.0001****). We noted minimal adverse events during extended prone ventilation therapy including 30%(n=21) of our patients had either facial edema(predominantly), dependent edema of thorax or limb and nearly 25%(n=18) developed pressure sore. The study population received a mean of 3.097 +/- 1.57 prolonged proning cycles and average length of ICU stay was 16.61 +/- 9.14 days. There was 50%(n=36) mortality noted in our study population(28,29,30). DISCUSSIONS/CONCLUSIONS: We could conclude extended proning is equally effective, safe and feasible. Our results were comparable to results of Peter Fridrich et al (1996)(15), D F McAuley (2002) et al(17), Jordi Mancebo et al (2006)(19), Carlos M Romero et al (2009)(20), Luciano Gattinoni et al (2013)(26), Antoine Kimmoun et al (2015)(21), Sebastein Jochmans et al (2020)(22), Andrea Carsetti et al (2020)(23), Elizabeth M. Parker et al (2021)(24), Cuirong Ba et al (2021)(25), Thaïs Walter et al (2022)(8). extended duration of proning has high potential for both clinical and organisational benefits.