Effects of Subanesthetic Ketamine on Pain and Cognitive Functions in TIVA

Aim: It was aimed to compare the effects of subanesthetic dose ketamine on analgesic consumption, cognitive functions, perioperative hemodynamics and postoperative recovery in patients scheduled for laparoscopic cholecystectomy under total intravenous anesthesia (TIVA). Material and Method: The study was approved by Institutional Ethics Committee and all patients gave written informed consent. Sixty ASA I-III patients aged 20-70 years scheduled for elective laparoscopic cholecystectomy were randomly assigned into 2 groups [group 1 (TIVA-ketamine) and group 2 (TIVA)]. Both groups underwent Mini Mental Test (MMT) before the operation. In the group 1, 0.25 mg.kg-1 ketamine was given 2 minutes before induction via intravenous route. Anesthesia was induced by using 2mg.kg-1 propofol, 1µg.kg-1fentanyl (iv) and 0.6 mg.kg-1 rocuronium (iv) in both groups. Anesthesia was maintained by 5-8mg.kg-1.h-1 propofol, 0,15µg kg-1 remifentanil (iv) and 50:50 mixtures of O2 and air. Postoperative pain management was achieved by tramadol HCl via patient-controlled analgesia (PCA) device. Total dose within 24 hours was recorded. Hemodynamic parameters during surgery and times to extubation, eye opening, receiving verbal commands and orientation time were recorded. Ramsey sedation score (RSS) and Aldrete recovery score (ARS) were recorded after extubation. MMT was repeated on the postoperative hour 24. Results: Hemodynamic parameters were found to be similar in both groups. Total analgesic consumption was found to be significantly lower in patients received ketamine (p0.05). Discussion: Addition of subanesthetic dose ketamine to total intravenous anesthesia had no adverse effect on intraoperative hemodynamic parameters; it provided more effective postoperative analgesia; however, we think that a meticulous monitoring is required during early postoperative period as it prolonged awakening and recovery times