Phase 4: Study of Ketamine Inhibition of Interleukin 6 in Hepatic Resections Requiring Temporary Porto-arterial Occlusion

Introduction: Many complications in liver resection surgery, such as post-operative hepatic insufficiency, sepsis, and multi-organ liver failure, have been attributed to ischemia-reperfusion injury and the release of pro-inflammatory agents. Previous studies had shown that ketamine inhibited the synthesis of interleukin 6 (IL-6) in some cardiac surgeries, and that IL-6 levels had a direct correlation with mortality in critically ill patients.

Goal: The purpose of our study was to determine the effect of ketamine on IL-6 levels in patients undergoing liver resections with temporary porto-arterial occlusion (Pringle maneuver).

Material and Methods: Our prospective, controlled, randomized, and blinded study was approved by the Research Ethics Committee of the Hospital Italiano of Buenos Aires (CEPI). All procedures were carried out according to the Declaration of Helsinski. All patients voluntarily consented to the study and signed the appropriate informed consent approved by the CEPI.

Inclusion criteria were age of 21 years or older and planned liver resection with Pringle maneuver lasting 30-60 minutes. Those with chronic illness requiring corticosteroids, cirrhosis, hemodynamic instability prior to the surgery, diabetes, sepsis, surgical interventions or chemotherapy treatments within the past 30 days, pregnancy, illnesses that could potentially affect the hepatic circulation, arterial or ocular hypertension (contraindications for the use of ketamine), ketamine allergy, preoperative portal embolization / radiofrequency ablation, or requiring emergency surgeries were not considered. From March 2002 to June 2008, 44 consecutive patients agreed to participate and were enrolled in the study. Those who did not require the Pringle maneuver during the resection, who did not undergo the planned procedure, or whose hematocrit was less than 20% for over 30 minutes were excluded.

Patients were assigned to one of two groups according to a computer generated randomization.