Liver blood flow changes during laparoscopic surgery in pigs

BACKGROUND: Physiological effects caused by abdominal insufflation in the course of laparoscopic surgery are partially unknown. The purpose of the present study was to determine if indocyanine green (ICG) pharmacokinetic parameters, as an index of hepatic blood flow, change during laparoscopic surgery in the presence of a CO2 pneumoperitoneum. This effect could cause important alterations in the kinetics of anesthetic drugs. METHODS: Eighteen female pigs were anaesthetized under constant ventilation and randomly assigned to three groups undergoing insufflation with CO2 (I), laparoscopic oophorectomy with CO2 pneumoperitoneum (LS), or oophorectomy by open surgery (OS). CO2 pneumoperitoneum was performed at 14 mmHg. ICG (1 mg/kg) was injected into a marginal vein on two separate occasions: 30 min before and 30 min after the start of insufflation or surgery. Blood was sampled from the carotid artery at time intervals after the injection of ICG and after pharmacokinetic parameters were obtained by a computer program. RESULTS: The area under the curve (AUC0-infinity) indicated important dysfunctions in ICG availability in all three groups of animals, with significant increases of 104%, 82%, and 48% for groups I, LS, and OS, respectively. The ICG apparent half-life did not significantly change in group OS, but it rose in groups I (+17%) and LS (+28%). ICG clearance was significantly reduced by 32% in group OS and to a larger extent in groups I and LS (-45% and -46%, respectively). CONCLUSION: These findings confirm the contribution of CO2 pneumoperitoneum to decreased liver blood flow during laparoscopic surgery.