Positive End-Expiratory Pressure (PEEP) Titration With Fraction of Inspired Oxygen (FiO₂)/PEEP Table and Esophageal Balloon Guidance in Obese Patients With Acute Respiratory Distress Syndrome: Description of Four Cases at 2600 m Above Sea Level

The COVID-19 pandemic led to a global surge in acute respiratory distress syndrome (ARDS), frequently presenting with a phenotype characterized by preserved respiratory system compliance and low lung recruitability. While mechanical ventilation is essential for oxygenation, it can induce ventilator-induced lung injury (VILI) indistinguishable from ARDS. High-altitude environments (2,600 meters above sea level) and morbid obesity further complicate positive end-expiratory pressure (PEEP) titration. This study describes a personalized PEEP titration protocol guided by transpulmonary pressure (PTP) in obese patients with COVID-19-associated ARDS. We retrospectively analyzed a case series of four obese patients with severe ARDS managed in an intensive care unit. A PEEP titration protocol was implemented using esophageal pressure (Pes) monitoring to estimate PTP in both supine and prone positions. Oxygenation indices and lung mechanics were recorded. While transpulmonary driving pressure showed variable values, titrating PEEP to achieve an expiratory transpulmonary pressure (Ptpexp) close to 0 cmH2O revealed that lower PEEP levels were required during pronation to maintain alveolar stability, which coincided with significant improvements in oxygenation indices. Our findings suggest that PEEP should be personalized in obese patients with COVID-19-associated ARDS, particularly when managed at high altitudes. Esophageal manometry serves as a valuable tool to distinguish between lung and chest wall elastance, preventing overdistension and alveolar collapse. Although personalized titration optimized physiological variables, further research is needed to determine its impact on long-term clinical outcomes and mortality in this specific population.