Effects of Intraoperative Low Dose Ketamine on Hemodynamic Changes and Postoperative Opioid Consumption in Patients Undergoing Laparoscopic Cholecystectomy

Laparoscopic Cholecystectomy (LC) as a minimally invasive surgery has become extremely common in recent decades. Despite being less invasive, these surgeries require postoperative analgesia. In this regard Ketamine, can reduce postoperative pain and opioid consumption.Owing to the wide heterogeneity of studies on efficacy of ketamine in pain management in different operations, anesthetics methods, and the way and dose of consumption, the present study sought to evaluate the effects of intraoperative low-dose ketamine on postoperative pain, opioid consumption, and hemodynamic changes of patients undergoing LC in the 5th Azar hospital of Gorgan in 2019.

66 patients with the need for LC were randomly selected. After induction of anesthesia and intubation, and before surgical incision, 0.5 mg/kg of Ketamine was injected as a bolus for target group (n=33), and the equivalent volume of normal saline for control group (n=33). Systolic, diastolic and mean arterial pressure were recorded before, during, after anesthesia and during surgery at 5-minute intervals. Postoperative pain was evaluated through Visual Analog Scale(VAS). We recorded the time of the first dose of opioid, total amounts of opioid consumption during the first 24 hours after surgery and doses of antihypertensive drug.

VAS score (opioid requirement) were lower in the intervention group only in the recovery period (p=0.049). There was no difference between two groups in total amounts of opioid consumption during 24 hours even in cases with increase of the length of surgery (p= 0.742). Blood pressure trend increased from the beginning of induction to the end of anesthesia (p-value<0.001); however, there was no statistically significant difference between two groups (p=0.786). The need for labetalol was higher in control group (p<0.0001).

Although 0.5 mg/kg ketamine could not reduce overall opioid consumption within 24 hours after surgery, it had significant pain relief during awakening and recovery. Additionally, it reduced the need for further interventions, such as labetalol and other drugs and therefore was associated with lower costs.