Preadministration of low-dose ketamine reduces tourniquet pain in healthy volunteers

Abstract

We evaluated whether preadministration of low-dose ketamine could attenuate tourniquet pain and arterial pressure increase using high tourniquet pressure in ten healthy awake volunteers. Ketamine, 0.1 mg x kg(-1), or normal saline was given intravenously in a double-blind fashion before tourniquet inflation with a pressure of 400 mmHg at the thigh. Visual analog scale (VAS) scores and systolic blood pressure (SBP) were measured at 5-min intervals. Ketamine significantly reduced VAS scores compared to saline just after tourniquet inflation [90 (64-100) mm, median (range), with saline versus 66 (50-81) mm with ketamine, P < 0.01] and at 30 min [92 (61-100) mm with saline versus 70 (50-100) mm with ketamine, P < 0.03), and significantly prolonged tourniquet time (28 +/- 6 min with saline, mean +/- SD, versus 37 +/- 7 min with ketamine, P < 0.01). SBP (120 +/- 9 mmHg) significantly increased before tourniquet deflation (133 +/- 16 mmHg) in the saline trial, but not in the ketamine trial. The results show that preadministration of low-dose ketamine attenuates tourniquet pain and arterial pressure increase during high-pressure tourniquet application and prolongs tourniquet time in healthy volunteers.

Comparison of ketorolac and low-dose ketamine in preventing tourniquet-induced increase in arterial pressure

“…[ 8 ] Takada et al . [ 9 ] found that low-dose ketamine attenuates tourniquet pain and arterial pressure increase during high-pressure tourniquet inflation in healthy volunteers. Lee et al .…”

“…[ 10 17 ] This increase in C fibre activity leads to induction of central sensitisation and activation of NMDA receptors,that is part of the mechanism of central sensitisation. [ 5 6 18 ] Although ketamine is an NMDA receptor antagonist and has been shown to be effective in preventing tourniquet-induced hypertension,[ 3 8 9 ] there is a possibility that this effect could be due to relief in tourniquet-induced pain rather than antagonism of NMDA receptors, as ketamine has potent analgesic properties. Furthermore, ketamine is associated with side effects, such as, delirium, hallucinations, tachycardia, hypertension, etc.…”

“…[ 6 7 ] Studies have been performed using different analgesics and NMDA receptor antagonists to find an agent that would effectively attenuate tourniquet-induced increases in systemic arterial pressure. [ 1 2 3 4 7 8 9 10 ] Ketamine, an NMDA receptor antagonist, and a potent analgesic, has been found to be effective in this respect by many researchers. [ 3 8 9 ] Comparative analyses among the various agents studied have not been performed, except for comparison between magnesium sulphate and ketamine, both of which are NMDA receptor antagonists.…”

“…[ 1 2 3 4 7 8 9 10 ] Ketamine, an NMDA receptor antagonist, and a potent analgesic, has been found to be effective in this respect by many researchers. [ 3 8 9 ] Comparative analyses among the various agents studied have not been performed, except for comparison between magnesium sulphate and ketamine, both of which are NMDA receptor antagonists. [ 10 ] Ketamine can cause cardiovascular side effects, which could be deleterious in patients with ischaemic heart disease, although these effects are reduced when ketamine is used in low-doses.…”

A randomized controlled trial to assess the effect of a ketamine infusion on tourniquet hypertension during general anaesthesia in patients undergoing upper and lower limb surgery

“…Prolonged tourniquet inflation is associated with a gradual increase in arterial blood pressure. The increase in blood pressure is resistant to analgesics and/ or an increase in the depth of anaesthesia 5,6 . The mechanisms involved in tourniquet pain are not well understood but have been postulated to be conducted by A-delta and C-fibres which are thought to mediate somatic pain 3,[8][9][10] .…”