Effect of pneumoperitoneum on interatrial pressure gradient during laparoscopic cholecystectomy

Alterations of the left atrial/right atrial pressure gradient were determined using a Swan-Ganz thermodilution catheter in 20 patients who underwent laparoscopic cholecystectomy with 12 mmHg pneumoperitoneum (LAP) and 13 patients who underwent minilaparotomy cholecystectomy (MINI). Right and left atrial pressures were both elevated by pneumoperitoneum. A diminished or reversed left/right interatrial pressure gradient was recognized during pneumoperitoneum in 4 of the 20 patients (20%) in the LAP group, whereas it was not recognized during operation in any of the 13 patients in the MINI group. Evaluation of the elevation of intrathoracic pressure during pneumoperitoneum using peak inspiratory airway pressure or pulmonary arterial pressure could not predict the occurrence of this paradoxical interatrial pressure gradient.