The influence of timing of systemic ketamine administration on postoperative morphine consumption

• Published in: Journal of clinical anesthesia 2005-12, Vol.17 (8), p.592-597
• Main Authors: Bilgin, Hülya, Özcan, Berin, Bilgin, Tufan, Kerimoğlu, Beklen, Uçkunkaya, Nesimi, Toker, Abit, Alev, Tijen, Osma, Selcan
• Format: Article
• Language: English
• Subjects: Adult; Analgesia; Analgesia, Patient-Controlled - methods; Analgesics; Analgesics - administration & dosage; Analgesics - pharmacology; Analgesics, Opioid - administration & dosage; Anesthesia; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood pressure; Consumption; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug dosages; Female; Gynecologic Surgical Procedures - methods; Humans; Ketamine; Ketamine - administration & dosage; Ketamine - pharmacology; Medical sciences; Middle Aged; Morphine - administration & dosage; Nitric oxide; Pain; Pain management; Pain Measurement; Pain, Postoperative - prevention & control; Postoperative; Postoperative period; Preemptive; Prospective Studies; Sodium Chloride - administration & dosage; Spinal cord; Studies; Surgery; Time Factors
• ISSN: 0952-8180; 1873-4529
• DOI: 10.1016/j.jclinane.2005.04.005

To determine the influence of timing of systemic ketamine administration on postoperative morphine consumption. Prospective randomized study. Operating rooms, postanesthesia care unit, and gynecology service of a university hospital. Forty-five patients undergoing laparotomy for benign gynecologic pathologies were randomized into 3 groups. In Group 1, before surgical incision, patients received 0.5 mg/kg ketamine IV, followed by normal saline infusion and normal saline IV at wound closure in group 1 (n = 15). In group 2 (n = 15), patients received 0.5 mg/kg ketamine IV before surgery, followed by ketamine infusion 600 μg · kg −1 · h −1, until wound closure and normal saline IV at that time. In the other group (group 3, n = 15), patients received normal saline IV before surgery, followed by saline infusion and then 0.5 mg/kg ketamine IV at wound closure. In the postoperative period, patient-controlled analgesia IV morphine was used for postoperative pain relief. First requested analgesic medication time was recorded. Postoperative pain was assessed by measuring morphine consumption at 0 to 2, 0 to 4, and 0 to 24 hours and visual analog scale (VAS) pain scores in response to cough at 2nd, 4th, and 24th hours and during rest at 0 to 2, 0 to 4, and 0 to 24 hours after surgery. First requested analgesia was shorter in group 1 than the others ( P < .01). Mean VAS pain scores in response to cough at 24th hour in groups 2 and 3 were significantly lower than in group 1 ( P < .001 and P < .01, respectively). Mean VAS pain scores during rest at 0 to 24 hours in groups 2 and 3 were significantly lower than in group 1 ( P < .01 and P < .05, respectively). Morphine consumption was lower in groups 2 and 3 at 0 to 2 hours ( P < .001 and P < .01). Moreover, morphine consumption at 0 to 4 hours in group 2 was significantly lower ( P < .01). Lower pain scores and morphine consumption in groups 2 and 3 may be related to higher plasma ketamine concentrations caused by the higher doses and later administration. Our findings suggest that a single preoperative dose of ketamine provided less analgesia compared with other dosing regimens that included intraoperative infusions or postoperative administration.