Conflict of Interest. Learning Objectives. The Link Between Acute and Chronic Pain. None

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1 The Link Between Acute and Chronic Pain James P. Rathmell, M.D. Chief, Division of Pain Medicine Department of Anesthesia, Critical Care and Pain Medicine Massachusetts General Hospital Associate Professor of Anaesthesia Harvard Medical School Boston, MA USA Conflict of Interest None Massachusetts Society of Anesthesiologists Meeting Bermuda November 5, 2009 Learning Objectives Define the term preemptive analgesia Discuss the clinical effectiveness of employing preemptive analgesia Explain why preemptive analgesia is marginally effective in reducing postoperative pain Describe risk factors for persistent postsurgical pain and the concept of preventative analgesia Massachusetts Society of Anesthesiologists Meeting Bermuda November 5,

2 What is preemptive analgesia? Woolf CJ. Evidence for a central component of post-injury pain hypersensitivity. Nature 1983; 208: Sensitization 10 Hyperalgesia Pain Intensity Allodynia Injury Normal pain response Hyperalgesia heightened sense of pain to noxious stimuli Allodynia pain resulting from normally painless stimuli Stimulus Intensity 2

3 Clinical studies of preemptive analgesia Møiniche S, Kehlet H, Dahl JB. A qualitative and quantitative sytematic review of preemptive analgesia for postoperative pain relief. Anesthesiology 2002; 96: Møiniche S, Kehlet H, Dahl JB. A qualitative and quantitative sytematic review of preemptive analgesia for postoperative pain relief. Anesthesiology 2002; 96:

4 Møiniche S, Kehlet H, Dahl JB. A qualitative and quantitative sytematic review of preemptive analgesia for postoperative pain relief. Anesthesiology 2002; 96: Conclusions Statistical improvements in postoperative pain relief by preemptive treatment were seen at some time points in 24/80 trials; quantitative analysis of VAS scores within 24 hours were in no case significant Lack of evidence for preemptive treatment Future studies should redirect focus from timing to protective analgesia, aimed at preventing pain hypersensitivity Møiniche S, Kehlet H, Dahl JB. A qualitative and quantitative sytematic review of preemptive analgesia for postoperative pain relief. Anesthesiology 2002; 96: Ong CK-S, Lirk PL, Seymour RA, Jenkins BJ. The efficacy of preemptive analgesia for acute postoperative pain management: a meta-analysis. Anesth Analg 2005; 100:

5 Ong CK-S, Lirk PL, Seymour RA, Jenkins BJ. The efficacy of preemptive analgesia for acute postoperative pain management: a meta-analysis. Anesth Analg 2005; 100: Pain scores Supplemental analgesic Time to first analgesic Ong CK-S, Lirk PL, Seymour RA, Jenkins BJ. The efficacy of preemptive analgesia for acute postoperative pain management: a meta-analysis. Anesth Analg 2005; 100: Ong CK-S, Lirk PL, Seymour RA, Jenkins BJ. The efficacy of preemptive analgesia for acute postoperative pain management: a meta-analysis. Anesth Analg 2005; 100:

6 Conclusions Significant preemptive effect for epidural analgesia, local anesthetic wound infiltration, and NSAID administration No preemptive effect for systemic NMDA antagonist Is this at odds with the earlier conclusions of Møiniche et al.? Ong CK-S, Lirk PL, Seymour RA, Jenkins BJ. The efficacy of preemptive analgesia for acute postoperative pain management: a meta-analysis. Anesth Analg 2005; 100: Why doesn t preemptive analgesia work? Nociception 6

7 Persistent post-surgical pain: risk factors and prevention Persistent postsurgical pain Kehlet H, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet 2006; 367: Kehlet H, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet 2006; 367:

8 Risk factors for persistent postsurgical pain Genetic susceptibility Preceding pain Psychosocial factors Age and sex Kehlet H, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet 2006; 367: From preemptive to preventative analgesia Potential for prevention of post-surgical pain Surgical technique Pre-emptive and aggressive multimodal analgesia New targets for prevention and treatment Symptom control Disease modification Kehlet H, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet 2006; 367:

9 Preventive Analgesia 85 patients undergoing colon resection Randomized to receive IV or epidural local anesthetic / clonidine / sufentanil All patients received antihyperalgesic dose of ketamine intraoperatively VAS, analgesic consumption, hyperalgesia, and residual pain measured from 2 wks - 12 mos Lvand homme P, De Lock M, Waterloos H. Intraoperative epidural Lavand homme P, De Lock M, Waterloos H. Intraoperative epidural Lavand homme P, De Lock M, Waterloos H. Intraoperative epidural 9

10 Lavand homme P, De Lock M, Waterloos H. Intraoperative epidural Lavand homme P, De Lock M, Waterloos H. Intraoperative epidural Lavand homme P, De Lock M, Waterloos H. Intraoperative epidural 10

11 Preventive Analgesia Analgesic requirements, VAS, and hyperalgesia were higher in the intravenous group, and more patients (28%) reported residual pain from 2 wks 1 yr The incidence of residual pain at 1 yr was 11% in those receiving postoperative epidural analgesia compared to 0% in the group receiving intraoperative epidural analgesia Lavand homme P, De Lock M, Waterloos H. Intraoperative epidural Conclusions Preemptive analgesia is no more effective than traditional approaches to perioperative pain management Persistent post-surgical pain in common Aggressive suppression of the symptom of pain at the time of surgery is probably inadequate Treatment should be targeted at the progression of mechanisms that lead to the neurodegenerative disease known as neuropathic pain Under the Falls Niagara Falls, Ontario, Canada