A not-uncommon dilemma

You’re on call, it’s 1900 and the bleep goes off It’s the recovery nurse –“Please doctor, this 65 year old man has had an emergency laparotomy, the epidural didn’t work and he’s in 9/10 pain after 2g of paracetamol, 40mg paracoxib and 25mg of morphine. What else can I give?”

What are your options? Ignore – he’ll just have to live with it and it’s probably all psychological anyway Ignore – he’ll just have to live with it and it’s probably all psychological anyway More morphine? He’s already had quite a bit… More morphine? He’s already had quite a bit… Resite the epidural – going to be tricky! Resite the epidural – going to be tricky! Or… Or…

Can you be a bit more clever? A “Difficult Post-Op Pain Guideline” might help! A “Difficult Post-Op Pain Guideline” might help! One that’s: One that’s: –Non-binding! –More or less an “aide-memoire” –Designed to draw attention to the options rather than be prescriptive –Evidence-based Clinical judgement still required when referring to it! Clinical judgement still required when referring to it!

Why ketamine / clonidine / gabapentin? Levels of evidence I Evidence obtained from a systematic review of all relevant randomised controlled trials IIEvidence obtained from at least one properly designed randomised controlled trial III-1Evidence obtained from well-designed pseudo-randomised controlled trials (alternate allocation or some other method) III-2 Evidence obtained from comparative studies with concurrent controls and allocation not randomised (cohort studies), case-controlled studies or interrupted time series with a control group III-3 Evidence obtained from comparative studies with historical control, two or more single-arm studies, or interrupted time series without a parallel control group IV Evidence obtained from case series, either post-test or pre-test and post-test

The case for gabapentin Improves pain scores and patient satisfaction, reduces opioid side-effects but increases sedation and dizziness (level I) – –Straube S, Derry S, Moore RA, Wiffen PJ, McQuay HJ. Single dose oral gabapentin for acute postoperative pain in adults Cochrane Library – –Dahl JB, Mathiesen O, Moniche S. Protective premedication: an option with gabapentin and related drugs? A review of gabapentin and pregabalin in the treatment of post-operative pain. Acta Anaesthesiol Scand 2004; 48: 1130–36

The case for ketamine Opioid-sparing but inconsistent results about whether pain scores are improved (opioid naïve) (level I) Opioid-sparing but inconsistent results about whether pain scores are improved (opioid naïve) (level I) –Subramaniam K, Subramaniam B, Steinbrook RA. Ketamine as adjuvant analgesic to opioids: a quantitative and qualitative systematic review Anesth Analg. 99(2):482 –Bell RF, Dahl JB, Moore RA, Kalso E. Perioperative ketamine for acute postoperative pain Cochrane Library Improves pain score in opioid-tolerant patients (level II) Improves pain score in opioid-tolerant patients (level II) – –Urban MK, Ya Deau JT, Wukovits B et al (2008) Ketamine as an adjunct to postoperative pain management in opioid tolerant patients after spinal fusions: a prospective randomized trial. HSS J 4(1): 62–5 – –Eilers H, Philip LA, Bickler PE et al (2001) The reversal of fentanyl-induced tolerance by administration of “small-dose” ketamine. Anesth Analg 93(1): 213–4 No increased incidence of adverse effects with infusion cf morphine PCA alone (level I) No increased incidence of adverse effects with infusion cf morphine PCA alone (level I) – –Elia N, Tramer MR Ketamine and postoperative pain—a quantitative systematic review of randomised trials Pain 113(1-2):61–70.

The case for clonidine Opioid-sparing and effective but use may be limited by side-effects (level II) Opioid-sparing and effective but use may be limited by side-effects (level II) – –Bernard JM, Hommeril JL, Passuti N et al Postoperative analgesia by intravenous clonidine.1991 Anesthesiology 75(4): 577–82 – –De Kock MF, Pichon G & Scholtes JL Intraoperative clonidine enhances postoperative morphinepatient- controlled analgesia Can J Anaesth 39(6): 537– 44 – –Park J, Forrest J, Kolesar R et al Oral clonidine reduces postoperative PCA morphine requirements Can J Anaesth 43(9): 900–6.