ABSTRACT
INTRODUCTION: Severe ARDS has mortality rates exceeding 45% particularly when meeting criteria for ECMO. APRV has been used for over 4 decades to improve oxygenation when failing conventional MV strategies and may reduce the need for ECMO rescue if implemented early. METHOD(S): Retrospective study of all adult patients referred for V-V ECMO evaluation at UF-Jacksonville for ARDS from 7/17 - 8/2021 including COVID-19 illness that were managed on APRV without ECMO. The EMR was used to search for the datapoints: survival to discharge, P/F ratio at time of referral and then at 1, 6, and 24 hours after initiating APRV when ECMO was not implemented, paralytic and vasopressor usage prior to and 6 hours after initiating APRV, and lactate levels at time 0, 6 hours and 24 hours after initiating APRV. RESULT(S): There were 65 consults for V-V ECMO due to ARDS that were managed on APRV without ECMO. The mean age was 40.1 years;59% men and 41% women;category of ARDS was medical in 72%, trauma in 26%, and surgical in 2%. All patients were on ARDsnet ventilation strategy when referred. The survival to discharge was 79.3% with 50% going home, 39% to rehab, and 11% to an LTAC. The mean P/F ratio at time of evaluation was 77.1;1 hour after initiating APRV it was 122.7;6 hours after initiating it was 163.8;24 hours after initiating it was 211.8 and the mean FiO2 at 24 hours was 59.2%. At time of evaluation 50.8% of patients were on paralytic infusions and 33.3% were on vasopressors while 6 hours after initiating APRV it was 0% for the former and 14.5% for the latter. Mean serum lactate was 3.1 mmol/L at time 0, then 2.6 mmol/L 6 hours after APRV was initiated, and 2.3 mmol/L 24 hours after initiating APRV. CONCLUSION(S): We had excellent success using APRV to improve severe hypoxia in patients failing on standard ventilation using ARDSnet strategy, with a survival rate without ECMO of nearly 80%. The reduction in paralytic use and vasopressor requirements likely contributed to improved pulmonary and cardiovascular function allowing the vast majority of survivors to go home directly or home after shortterm rehab stay. APRV should be considered in severe ARDS and may avoid the need for ECMO in some patients if applied before the patient is in extremis.
ABSTRACT
INTRODUCTION: Severe ARDS has mortality rates exceeding 45% particularly when meeting criteria for ECMO;COVID-19 patients requiring MV for ARDS have even higher mortality rates. APRV has been used for over 4 decades to improve oxygenation when failing conventional MV strategies, but it was implemented in many ICUs for the 1st time during the COVID-19 pandemic. METHOD(S): Retrospective study of all adult patients referred for V-V ECMO evaluation at UF-Jacksonville due to COVID-19 induced ARDS from 6/2020 - 9/2021. The EMR was used to search for the datapoints: survival to discharge, P/F ratio at time of referral and then at 1, 6, and 24 hours after initiating APRV when ECMO was not implemented, and paralytic and vasopressor usage prior to and 6 hours after initiating APRV. RESULT(S): A total of 30 patients were referred for V-V ECMO. 20 patients (12 men, 8 women, mean age 41.4 years) were managed without ECMO utilizing APRV. The survival rate was 55% (11/20) with 91% discharged to home and 9% to rehab;five deaths were attributed to other specific causes such as: loss of airway, STEMI, myocarditis (VF) in 2 patients, and MSSA bacteremia. All patients were on ARDsnet ventilation strategy when referred. The mean P/F ratio at time of evaluation was 71.0;1 hour after initiating APRV it was 129.2;6 hours after initiating it was 135.5;24 hours after initiating it was 172.9 and the mean FiO2 at 24 hours was 67.9%. At time of evaluation 52.6% of patients were on paralytic infusions and 15.8% were on vasopressors while 6 hours after initiating APRV it was 0% for both. 10 patients required ECMO with survival rate of 30%. Six of the 10 patients went on ECMO immediately at the time of ECLS consult due to being in extremis from severe hypoxia as well as some patients also with critical respiratory acidosis. CONCLUSION(S): We had good success using APRV to improve severe hypoxia in patients failing on standard ventilation using ARDSnet strategy with a survival rate without ECMO of 55%. The reduction in paralytic use and vasopressor requirements likely contributed to >90% of survivors being able to go directly home. APRV should be considered in COVID-19 induced ARDS and may avoid the need for ECMO in some patients.