B103-15 Lifting the Weight of Hypoxemia: A Case Series

Introduction Acute respiratory distress syndrome (ARDS) is a critical illness marked by severe hypoxemia and impaired gas exchange, often requiring mechanical ventilation. Management is particularly challenging in morbid (BMI >40) and super-morbid (BMI >60) obesity due to altered respiratory mechanics and increased intra-abdominal pressure. Prone positioning is a proven intervention for severe ARDS (PaO2/FiO2 <150), improving oxygenation and reducing mortality, but data in extreme obesity are limited. Case Reports Case 1: A 55-year-old woman (BMI 64) with hypertension, obstructive sleep apnea, and psoriasis presented with acute hypoxemic and hypercapnic respiratory failure from decompensated heart failure and new-onset atrial flutter. Despite maximal ventilatory support (PEEP 16-20 cm H2O, FiO2 100%), her PaO2/FiO2 remained <100, and she developed severe right ventricular dysfunction with shock. Prone positioning for 12-16 hours daily improved oxygenation (ABG pO2 from 55 to 57.7 mmHg, SpO2 from low 70s to low-mid 80s). She tolerated proning without complications, but progressive multi-organ failure precluded ECMO due to body habitus. Case 2 (Chergui et al., 2007): A 56-year-old man (BMI 42) with hypertension and diabetes developed severe ARDS from Legionella pneumonia, requiring intubation, deep sedation, and paralysis. Persistent hypoxemia and acute cor pulmonale prompted prone positioning for 12 hours daily over 3 days, resulting in marked improvement in oxygenation and respiratory mechanics (PEEPi reduced from 12 to 2 cm H2O). He was weaned from the ventilator by day 19, discharged from the ICU on day 24, and recovered to home. Conclusion These cases demonstrate that prone positioning is feasible and beneficial in morbidly and super-morbidly obese patients with severe ARDS, improving oxygenation and respiratory mechanics even with significant RV dysfunction. Technical challenges, such as increased staffing needs and risk of pressure injuries, were manageable with multidisciplinary coordination. Notably, the first case underscores the limitations of rescue therapies such as ECMO in super-obese patients, underscoring the importance of optimizing conventional ARDS management strategies. While the physiologic response to proning was favorable in both cases, overall outcomes were influenced by comorbidities and the severity of multi-organ dysfunction. These observations support early consideration of prone positioning in this population and highlight the need for further research to define best practices and outcomes in the super-obese ARDS cohort. References Chergui, K., Choukroun, G., Meyer, P., & Caen, D. (2007). Prone positioning for a morbidly obese patient with acute respiratory distress syndrome: an opportunity to explore intrinsic positive end-expiratory pressure-lower inflexion point interdependence. Anesthesiology, 106(6), 1237-1239. https://doi.org/10.1097/01.anes.0000265419.50900.f4 This abstract is funded by: None