Mechanical ventilation practice and outcomes of patients with obesity and acute respiratory distress syndrome from covid-19

SESSION TITLE: Outcomes of Mechanical Ventilation in the ICU SESSION TYPE: Rapid Fire Original Inv PRESENTED ON: 10/10/2023 12:55 pm - 01:40 pm PURPOSE: Over 40% of US adults are obese (BMI ≥30 kg/m2), causing 500,000 deaths per year. During COVID-19, obese patients were at increased risk of ARDS and mortality. Morbid obesity (BMI ≥35 kg/m2) was an exclusion criterion for landmark ARDS trials on low tidal volume ventilation (LTVV) and optimal PEEP. Obese patients are more likely to receive LTVV based on actual body weight, but high volumes (10-12 cc/kg) based on predicted body weight (PBW). We assessed ventilation strategies and outcomes of patients with obesity and ARDS compared to non-obese patients in a large registry. METHODS: This is an ancillary study for the Society of Critical Care Medicine Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS): COVID-19 (VIRUS: COVID-19) registry collected from 183 hospitals across 24 countries from March 2020 to December 2022. Participation required IRB approval and waiver of consent. De-identified data were analyzed. Patients were included if they received IMV with volume control (VC) modalities. Patients were excluded if pregnant, < 18 years old, or had a BMI < 18.5 kg/m2. We defined compliance with LTVV as tidal volumes (TV) ≤ 8 cc/kg of PBW ≥ 80%. Primary outcomes were ICU mortality, duration of IMV, and ICU length of stay (LOS). Analysis was performed using SAS software. RESULTS: A total of 4573 patients were included; 3204 patients received VC IMV with 2515 (83%) receiving LTVV > 80% of their intubation. The mean age was 58.7 and 64.64 for obese and non-obese patients, respectively (p<0.0001). Mean BMI was 37.7 kg/m2 and 25.9 kg/m2 respectively. Non-obese patients received LTVV slightly more (85%) than obese patients (81%). The average TV were 6.37 cc/kg and 6.39 cc/kg of PBW for non-obese and obese patients (p=0.54). Obese patients received higher PEEP (11.52 vs 9.89 cm H20, p<0.0001), consistent with a “low PEEP: high FiO2” strategy based on mean FiO2 of 67%. Obese patients had a lower PaO2 (94.08 vs 99.12, p=0.026) and PaO2:FiO2 ratio (159.23 vs 171.69, p=0.008). Rates of proning were lower in obese than non-obese patients (27% vs 35%, p<0.008). Obese patients suffered worse unadjusted ICU mortality (59% vs 53%, p=0.0018). Duration of IMV and ICU LOS did not differ. There was no significant mortality difference among patients who received LTVV and those who did not. CONCLUSIONS: Tidal volumes were similar regardless of BMI. Patients with obesity received slightly more PEEP (1.63 cm H2O) than non-obese patients. Adherence to proning is suboptimal in this population. Our findings suggesting variance in practice patterns in the care of obese patients. Patients with obesity and ARDS were at risk of increased mortality, although it is unclear if elevated mortality was due to insufficient ventilator mechanics or due to confounding factors (e.g. comorbidities) associated with obesity. CLINICAL IMPLICATIONS: To improve V/Q mismatch and offload increased thoracoabdominal pressures, personalized ventilation strategies may be required for patients with obesity. Prior studies have demonstrated a low PEEP strategy for patients with obesity to be suboptimal. With growing global rates of obesity, additional research is required to optimize respiratory mechanics of this population. DISCLOSURES: No relevant relationships by Vikas Bansal No relevant relationships by Erica Bjornstad No relevant relationships by Joshua Denson No relevant relationships by Sheetal Gandotra No relevant relationships by Anneka Hutton No relevant relationships by Rahul Kashyap No relevant relationships by Syed Khan No relevant relationships by Young-il Kim No relevant relationships by Vishakha Kumar No relevant relationships by Rekha Ramachandran No relevant relationships by Sahar Takkouche No relevant relationships by Allan Walkey