The Use of Ketamine as Rescue Analgesia in the Recovery Room Following Opioid Administration. A Double-blind Randomised Trial in Postoperative Patients

The Use of Ketamine as Rescue Analgesia in the Recovery Room Following Opioid Administration. A Double-blind Randomised Trial in Postoperative Patients

The Use of Ketamine as Rescue Analgesia in the Recovery Room Following Opioid Administration. A Double-blind Randomised Trial in Postoperative Patients.

This clinical trial will determine if postoperative patients who have postoperative pain, which has been refractory to morphine administration, will have improved pain relief following a bolus administration of ketamine as compared with an ongoing morphine dosing regimen

Some patients require large doses of opioids to control postoperative pain, which can result in a prolonged period of poor pain control, and potentially increased side effects associated with large morphine doses. This may be due to insufficient morphine dose to that individual or acute tolerance ( 1 ). Ketamine is not just an anaesthetic agent but at lower doses is known to provide efficacious analgesia ( 2, 3 ). Ketamine has been shown to have a marked analgesic effect on high intensity nociceptive stimuli ( 4 ) as exhibited in postoperative pain. When given for opioid analgesia resistant cancer pain in bolus doses at two different concentrations it has been shown to be effective and have a morphine-sparing effect, without undue complications ( 5 ). Ketamine has been suggested to work pre-emptively and also by many other routes other than intravenously ( 6 - 9 ) . Previous studies have compared morphine with morphine and ketamine administered as PCA or intramuscularly ( 10 - 12 ) in postoperative patients with varying effects. Javery et al. ( 11 ) showed that pain scores were lower in patients who received ketamine but Reeves et al. in a later but similar study showed no significant difference ( 13 ). The authors have noted that in the postoperative situation with morphine resistant pain, a bolus dose of ketamine not only leads to a marked decline in pain but it also remains efficacious for several hours. This prolonged effect was also noted in opioid resistant cancer pain ( 5 ). This indeed may have relevance to the prevention of onset of chronic post surgical pain ( 14 ) and earlier discharge from the Post Anaesthetic Care Unit. Morphine and ketamine are not without side effects. Respiratory depression, nausea, vomiting and vivid dreams, being well documented will hence be a secondary endpoint. A quality of recovery score will also be measured ( 15 ) and four hours postoperatively. This study is designed to compare a morphine regimen in the form of a standard Post Anaesthetic Care Unit pain protocol with a bolus dose of ketamine to be implemented if the pain protocol has been inadequate. Any patient in pain, despite two doses of morphine will be included. Thereafter the patients will be randomised to receive either a further solution of ketamine or continuation of the morphine protocol. This randomised, double-blinded, trial will be based in the Post Anaesthetic Care Unit under close anaesthetic and nursing staff supervision.

Adverse events (vivid dreams, nausea, hallucinations, respiratory depression, pruritus) - Recovery Room and at four hours.

Inclusion Criteria: 1. Those patients requiring the routine pain protocol to be implemented as used in the Post Anaesthetic Care Unit who need more than two doses of morphine (and having received intraoperative morphine). Exclusion Criteria: Exclusion Criteria Known allergy to morphine or ketamine. Past history of major psychiatric disturbance or currently taking psychiatric medication/s. Chronic morphine usage. Chronic pain syndrome or chronic painful medical condition. Unable to obtain a reliable pain score in recovery due to language barriers or residual anaesthesia. Known pregnancy. Cases where primary anaesthetist prefers alternate therapy. Aged less than 18 years. Weight less than 50 kilograms or greater than 100 kilograms. Use of ketamine intraoperatively. Use of major regional block.

Mercadante S, Portenoy RK. Opioid poorly-responsive cancer pain. Part 2: basic mechanisms that could shift dose response for analgesia. J Pain Symptom Manage. 2001 Mar;21(3):255-64. doi: 10.1016/s0885-3924(00)00236-0.

Myles PS, Hunt JO, Nightingale CE, Fletcher H, Beh T, Tanil D, Nagy A, Rubinstein A, Ponsford JL. Development and psychometric testing of a quality of recovery score after general anesthesia and surgery in adults. Anesth Analg. 1999 Jan;88(1):83-90. doi: 10.1097/00000539-199901000-00016.

Macrae W A, Davies H T O Chronic post surgical pain Epidemiology of Pain edited by Crombie I K. IASP Press. Seattle 1999. 125 - 142

Reeves M, Lindholm DE, Myles PS, Fletcher H, Hunt JO. Adding ketamine to morphine for patient-controlled analgesia after major abdominal surgery: a double-blinded, randomized controlled trial. Anesth Analg. 2001 Jul;93(1):116-20. doi: 10.1097/00000539-200107000-00025.

Marcus RJ, Victoria BA, Rushman SC, Thompson JP. Comparison of ketamine and morphine for analgesia after tonsillectomy in children. Br J Anaesth. 2000 Jun;84(6):739-42. doi: 10.1093/oxfordjournals.bja.a013585.

Javery KB, Ussery TW, Steger HG, Colclough GW. Comparison of morphine and morphine with ketamine for postoperative analgesia. Can J Anaesth. 1996 Mar;43(3):212-5. doi: 10.1007/BF03011736.

Adriaenssens G, Vermeyen KM, Hoffmann VL, Mertens E, Adriaensen HF. Postoperative analgesia with i.v. patient-controlled morphine: effect of adding ketamine. Br J Anaesth. 1999 Sep;83(3):393-6. doi: 10.1093/bja/83.3.393.

Schmid RL, Sandler AN, Katz J. Use and efficacy of low-dose ketamine in the management of acute postoperative pain: a review of current techniques and outcomes. Pain. 1999 Aug;82(2):111-125. doi: 10.1016/S0304-3959(99)00044-5.

Azevedo VM, Lauretti GR, Pereira NL, Reis MP. Transdermal ketamine as an adjuvant for postoperative analgesia after abdominal gynecological surgery using lidocaine epidural blockade. Anesth Analg. 2000 Dec;91(6):1479-82. doi: 10.1097/00000539-200012000-00034.

Aida S, Yamakura T, Baba H, Taga K, Fukuda S, Shimoji K. Preemptive analgesia by intravenous low-dose ketamine and epidural morphine in gastrectomy: a randomized double-blind study. Anesthesiology. 2000 Jun;92(6):1624-30. doi: 10.1097/00000542-200006000-00020.

Stubhaug A, Breivik H, Eide PK, Kreunen M, Foss A. Mapping of punctuate hyperalgesia around a surgical incision demonstrates that ketamine is a powerful suppressor of central sensitization to pain following surgery. Acta Anaesthesiol Scand. 1997 Oct;41(9):1124-32. doi: 10.1111/j.1399-6576.1997.tb04854.x.

Mercadante S, Arcuri E, Tirelli W, Casuccio A. Analgesic effect of intravenous ketamine in cancer patients on morphine therapy: a randomized, controlled, double-blind, crossover, double-dose study. J Pain Symptom Manage. 2000 Oct;20(4):246-52. doi: 10.1016/s0885-3924(00)00194-9.

Arendt-Nielsen L, Petersen-Felix S, Fischer M, Bak P, Bjerring P, Zbinden AM. The effect of N-methyl-D-aspartate antagonist (ketamine) on single and repeated nociceptive stimuli: a placebo-controlled experimental human study. Anesth Analg. 1995 Jul;81(1):63-8. doi: 10.1097/00000539-199507000-00013.

Owen H, Reekie RM, Clements JA, Watson R, Nimmo WS. Analgesia from morphine and ketamine. A comparison of infusions of morphine and ketamine for postoperative analgesia. Anaesthesia. 1987 Oct;42(10):1051-6. doi: 10.1111/j.1365-2044.1987.tb05167.x.

Clements JA, Nimmo WS. Pharmacokinetics and analgesic effect of ketamine in man. Br J Anaesth. 1981 Jan;53(1):27-30. doi: 10.1093/bja/53.1.27.