POSITIVE END-EXPIRATORY PRESSURE (PEEP) INDEX: A NOVEL, BETTER DISCRIMINATION MARKER THAN PAO2/FIO2 FOR RESCUE MEASURES IN COVID-RELATED ARDS

ABSTRACT

SESSION TITLE ECMO and ARDS in COVID-19 Infections SESSION TYPE Rapid Fire Original Inv PRESENTED ON 10/17/2022 1215 pm - 115 pm PURPOSE: COVID-related acute respiratory distress syndrome (ARDS) is associated with significant morbidity and mortality. PaO2/Fio2 (PFR) is a prognostic and severity marker for ARDS. Other markers have been posited for ARDS. PEEP Index (PIx) [PEEP/PFR] or [(PEEP*Fio2)/PaO2] could serve as a new discriminatory marker to assess rescue therapies such as proning or ECMO referral. METHODS: Retrospective cohort study of all intubated COVID-19 patients with ARDS hospitalized at our institution between February 5th – May 11th, 2020. ARDS were calculated within first 24 hours of worst PaO2/FIO2 and their associated PEEP with bilateral infiltrates on Chest X-ray manually confirmed within 24hours of intubation fulfilling 2012 Berlin criteria. Outcomes of interest were all-cause in-hospital mortality, need for pronation and paralysis use. Binomial logistic regression with ROC curve were performed for univariate association for outcomes of interest. Cox proportional hazard regression modeling was performed and adjusted for potential confounders. PFR was transformed into a denominator of itself to reflect a direct proportional relationship. RESULTS: Data was analyzed from 113 hospitalized COVID-19 patients with identified ARDS. Mean age was 56.4 (STD 14.4);24% (27/113) were female. Median BMI was 30.3 [IQR 48.5,65.5]. Mean Tidal Volume (Vt) was 430 (STD 54). 64% (72/113) were compliant with low Vt (=<6mL/kg based on IBW). Median PFR 125 [IQR 99,192]. Mortality was 66% (74/113). 44% (50/113) were proned. 62% (70/113) required paralysis. PEEP Index outperformed PFR for discrimination for proning use AUC 0.73 [95%CI 0.63,0.82], p< 0.005;vs AUC 0.674 [95%CI 0.58,0.77], p= 0.02. PEEP Index performed mildy better than PFR for discrimination of requiring paralytic use in ARDS with AUC 0.68 [95% 0.57,0.78], p< 0.05;vs AUC 0.62 [95%CI 0.51,0.73], p<0.05. APACHE2 score showed poor discrimination for both proning and paralytic use (AUC= 0.46 [95%CI 0.35,0.56];p=0.43 and respectively, AUC=0.45 [95%CI 0.34,0.56];p=0.36). After adjusting for confounders, PEEP Index nor PFR didn’t for predict for mortality (p>0.05);however, our sample was not powered. CONCLUSIONS: PEEP Index (PIx) is a novel tool that can serve as a better discriminatory function to evaluate patients with ARDS in the ICU who will require proning in comparison to traditional used PFR. CLINICAL IMPLICATIONS PEEP Index (PIx) can serve as an easy alternative calculation to Oxygenation Index (OI) [(FiO2 x PAW) / PaO2] to identify patients that would benefit from early proning and other rescue therapies. Further studies are required to compare and validate PIx and OI prospectively as well as benefit cut-off points between proning and ECMO. DISCLOSURES No relevant relationships by Perminder Gulani No relevant relationships by Manuel Hache Marliere no disclosure on file for Adarsh Katamreddy;No relevant relationships by Hyomin Lim No relevant relationships by Marzio Napolitano No relevant relationships by Leonidas Palaiodimos No relevant relationships by Anika Sasidharan Nair No relevant relationships by Jee Young You