The effects of pneumoperitoneum on respiratory mechanics during general anesthesia for bariatric surgery

Background: The effects of pneumoperitoneum (PPM) on respiratory mechanics during bariatric surgery were investigated. Patients and Methods: 10 patients with BMI 50.5 +/- 8 kg/m(2) (range 40.9-66.8) who underwent laparoscopic adjustable gastric banding with the Swedish band under general anesthesia were studied. Besides routine monitoring of vital signs and lung volumes, respiratory mechanics (compliance and resistance) were measured during positive pressure ventilation using an anesthesia delivery unit. (Datex Ohmeda type A_Elec). Data were recorded at the following stages: 1) before PPM, 2) during PPM, and 3) after gas deflation. One-way analysis of variance was used for analysis of data. P<0.05 was considered significant. Results: The airway, peak inspiratory and plateau pressures increased significantly during PPM. Dynamic lung compliances were 44.6 +/- 7.8 SD, 31.8 +/- 5.5 and 44.5 +/- 8.3 cm/H2O before, during and after PPM respectively with significant differences (P<0.05). Conclusions: Although significant decrease in lung mechanics was found in the present study, these variations were well tolerated in morbidly obese patients with PPM pressure of 15 mmHg.