A randomized control trial to assess the effect of aketamineinfusion on tourniquet hypertension during General anaesthesia in patients undergoing upper and lower limb surgery

Date of Award


Document Type


Degree Name

Master of Medicine (MMed)

First Supervisor/Advisor

Thikra Sharif

Second Supervisor/Advisor

Vitalis Munga’yi

Third Supervisor/Advisor

Jimmy Kabugi


Anaesthesia (East Africa)


Background: Tourniquet hypertension arising from tourniquet inflation remains of primary concern to the anaesthetist. One drug commonly used to manage tourniquet hypertension is ketamine. Several studies show that ketamine attenuated the blood pressure rise associated with tourniquet inflation. None of the studies carried out examined the effect of ketamine on tourniquet hypertension for a period of more than one hour or an infusion of the same.

Objective: To compare the effect of an intravenous infusion of ketamine, versus placebo on tourniquet induced hypertension in patients undergoing upper and lower limb surgery under general anaesthesia

Study design: Single blinded Randomized Controlled Trial

Study setting: The Aga Khan University Hospital, Nairobi, Kenya

Methods: Forty six adult patients scheduled for upper and lower limb surgery under general anaesthesia were randomized into two equal groups. The first group (referred to as the ketamine group), received an intravenous bolus of 0.1mg/kg of ketamine in a 10ml syringe followed by an infusion of 2ug/kg/min of ketamine in a 20ml syringe. The second group (referred to as the saline group) received an intravenous bolus of physiological saline in a 10ml syringe followed by an infusion of saline in a 20ml syringe. All the patients were reviewed post operatively. Data of the baseline characteristics, haemodynamic changes, post tourniquet pain and side effects were collected. If post tourniquet pain was present post-operatively, a visual analogue scale (VAS) was used to assess its severity.

Results: 46 patients were entered into the study and all successfully completed the trial. There were no significant differences between the groups for baseline patient demographics.

The incidence of tourniquet hypertension was higher in the saline group (26.1%) as compared with ketamine group (4.6%) with a 95% confidence interval. The difference was shown to be statistically significant (‘P’<0.05)

There was an increase in systolic blood pressure after 60 minutes of tourniquet inflation in the saline group but the difference was not statistically significant(‘P’>0.866).

There were no significant differences between the groups as regards, diastolic blood pressure and heart rate. VAS scores did not differ between the two groups. Statistically there was no difference found between the two groups.

Side effects were minimal in the ketamine group whilst in the saline group nausea and vomiting was predominant but was also not statistically significant.

Conclusion: Based on the results of this study, it was found that there was a difference in the proportion of hypertension after tourniquet inflation between those who received ketamine and those who received saline, and the difference was statistically significant, for patients undergoing upper and lower limb orthopaedic surgery under general anaesthesia.

This document is available in the relevant AKU library