Efficacy of ketamine for postoperative pain following robotic thyroidectomy: A prospective randomised study

Abstract

Objective Although robotic thyroidectomy (RoT) is a minimally invasive surgery, percutaneous tunneling causes moderate to severe pain immediately postoperatively. We evaluated the efficacy of ketamine for postoperative pain management in patients following RoT. Methods Sixty-four patients scheduled for RoT were randomly divided into two groups. In the ketamine group (n = 32), ketamine was infused from induction of anaesthesia until the end of the procedure (0.15-mg/kg bolus with continuous infusion at 2 µg/kg/min). In the control group (n = 32), the same volume of saline was infused. Visual analogue scale (VAS) scores for acute and chronic pain, the incidence of hypoesthesia, postoperative analgesic requirements, and complications related to opioids or ketamine were compared between the two groups. Results The VAS pain scores were significantly lower in the ketamine group up to 24 h postoperatively. The VAS pain score when coughing was significantly higher in the control group than in the ketamine group at 24 h postoperatively. A significantly greater proportion of patients in the control group required rescue analgesics. Complications were comparable in both groups. Conclusions Ketamine infusion decreased pain scores for 24 h postoperatively and reduced analgesic requirements without serious complications in patients following RoT.

Trial registration: Clinicaltrials.gov Identifier: NCT01997801.

Keywords: Ketamine; minimally invasive surgical procedures; pain; percutaneous tunneling; postoperative; thyroidectomy.

Figure 1.

CONSORT diagram.

Figure 2.

Visual analogue scale pain scores (0 = no pain, 10 = worst imaginable) at rest and on coughing. Visual analogue scale pain scores were significantly higher in the control group up to 24 h postoperatively than in the ketamine group. The box represents the interquartile range, and the line across the box indicates the median. *P < 0.01 vs. control group (Student’s t-test or Mann–Whitney U-test). VAS, visual analogue scale.