Increased carbon dioxide absorption during retroperitoneal laparoscopy.
BACKGROUND: Retroperitoneoscopy for renal surgery is now a common procedure. We compared carbon dioxide absorption in patients undergoing retroperitoneoscopy for adrenal or renal surgery with that of patients undergoing laparoscopic cholecystectomy. METHODS: We measured carbon dioxide elimination with a metabolic monitor in 30 anaesthetized patients with controlled ventilation, undergoing retroperitoneoscopy (n=10), laparoscopy (n=10) or orthopaedic surgery (n=10). RESULTS: Carbon dioxide production increased by 38, 46 and 63% at 30, 60 and 90 min after insufflation (P<0.01) in patients having retroperitoneoscopy. Carbon dioxide production (mean (SD)) increased from 92 (21) to 150 (43) ml x min(-1) m(-2) 60-90 min after insufflation and remained increased after the end of insufflation. During laparoscopy, V(.)(CO(2)) increased less (by 15%) (P<0.05 compared with retroperitoneoscopy) and remained steady throughout the procedure. CONCLUSION: Retroperitoneal carbon dioxide insufflation causes more carbon dioxide absorption than intraperitoneal insufflation, and controlled ventilation should be increased if hypercapnia should be avoided.