Prone Positioning Improves Pulmonary Function in Obese Patients During General Anesthesia

We investigated the effects of prone position on func-tional residual capacity (FRC), the mechanical proper-ties (compliance and resistance) of the total respiratory system, lung and chest wall, and the gas exchange in 10 anesthetized and paralyzed obese (body mass index more than 30 kg/m*) patients, undergoing elective sur-gery. We used the esophageal balloon technique to-gether with rapid airway occlusions during constant in-spiratory flow to partition the mechanics of the respiratory system into its pulmonary and chest wall components. FRC was measured by the helium dilution technique. Measurements were taken in the supine po-sition and after 15-30 min of prone position maintain-ing the same respiratory pattern (tidal volume 12 mL/kg ideal body weight, respiratory rate 14 breaths