Comprehensive Acute Pain Management Guide

1. Acute Pain Management

2. Objectives/Discussion Topics • Appropriate assessment of acute pain • Concept of multi-modal analgesia • Indications and side effects of analgesics • How to rationally prescribe opioids • side effects and complications of opioids • Special populations ie elderly, opioid tolerant • Neuraxial/regional analgesia • side effects and complications of neuraxial analgesia • interaction of various anticoagulant medications and neuraxial analgesia

3. Goal • To provide patients with a level of pain control that allows them to actively participate in recovery • This level will be individual to each patient • To minimize nausea and vomiting • To minimize other side effects of analgesics • Sedation • Ileus • Weakness • Hypotension

4. Why all the fuss? • Pain is a miserable experience • Pain increases sympathetic output • Increases myocardial oxygen demand • Increases BP, HR • Pain limits mobility • Increases risk for DVT/PE • Increases risk for pneumonia, atelectasis secondary to splinting

5. Assessment • Intensity • Location • Onset • Duration • Radiation • Exacerbation • Alleviation

6. How do we do it? • Multimodal analgesia: Several analgesics with different mechanisms of action, each working at different sites in the nervous system • Acetaminophen • Non-steroidal anti-inflammatory drugs (NSAIDs) • Opioids • Anticonvulsants • Antidepressants • Local anaesthetics • NMDA Antagonists • Non-pharmacologic methods

7. OPIOIDSEfficacy is limited by Side-Effects The harder we “push” with single mode analgesia, the greater the degree of side-effects Side-effects Analgesia

8. Multimodal Analgesia Lower doses of each drug can be used therefore minimizing side effects With the multimodal analgesic approach there is additive or even synergistic analgesia, while the side-effects profiles are different and of small degree (Pasero & Stannard, 2012). Side-effects Analgesia

9. Systemic Analgesia • Opioids • Potent analgesics • Drug of choice for moderate to severe pain • Unfortunately, they are often the only drug ordered • Side effects:

10. Opioids 10 fold variability between patients All opioids have same side effects but efficacy:side effect ratio is different for everyone Stick with what works and keep it simple Always by mouth if possible Avoid pro-drugs ie. codeine Avoid combo preparations

11. Equianalgesia

12. NALOXONE (Narcan) • Mu opioid antagonist • Dilute 1 mL of naloxone 0.4 mg/mL (ie. one vial) with 9 mL of NS for a total of 10 mL of solution and a final concentration of 0.04 mg/mL • Administer 0.04 mg at a time until reversal of respiratory depression has been achieved, ie. when they’re sitting up awake and talking to you!

13. NALOXONE (Narcan) • REMEMBER: the half-life of naloxone is only 30 minutes, while the half-life of opioid is 2-3 hr so you may have to repeat dosing OR place pt on naloxone infusion until all opioid has been metabolized to prevent further respiratory depression

14. Elderly Patient • Pronounced effect therefore, lower doses • Cognitive dysfunction is a major issue • Organ dysfunction/insufficiency affects metabolism • Interaction with other medications, increased incidence of polypharmacy

15. Addiction • Primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. • Characterized by behaviors that include one or more of the following: • impaired control over drug use • compulsive use • continued use despite harm • craving Definitions Related to the Use of Opioids for the Treatment of Pain. American Academy of Pain Medicine; American Pain Society; American Society of Addiction Medicine. 2001.

16. Physical Dependence • State of adaptation that is manifested by a drug class-specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction, decreasing blood level of the drug, and/or administration of an antagonist

17. Tolerance • The body's physical adaptation to a drug: • Greater amounts of the drug are required over time to achieve the initial effect as the body adapts to the intake

18. Pseudo Addiction • Term used to describe patient behaviors that may occur when pain is undertreated • May become focused on obtaining medications, "clock watch," seem inappropriately "drug seeking." • Illicit drug use and deception can occur in the patient's efforts to obtain relief • Distinguished from true addiction in that the behaviors resolve when pain is effectively treated.

19. NSAIDS • Work at site of tissue injury to prevent the formation of the nociceptive mediators Prostaglandins • Can decrease opioid use ~30% therefore decreasing opioid-related side effects • Minor surgeries can use NSAIDs instead of opioids to completely eliminate opioid-associated side effects • Side effects:

20. NSAIDS • Newer NSAIDS selectively (primarily) inhibit cyclooxygenase-2 (COX-2) which is induced by surgical trauma with minimal effect on COX-1 which is responsible for GI and platelet side effects • Celecoxib (Celebrex)

21. Neuraxial TechniquesWho Gets Them? Patient factors: • Low pain tolerance, opioid tolerance • Sleep apnea • Narcolepsy • Obesity • COPD • Cardiac disease • Elderly – those at risk for post-operative cognitive dysfunction

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25. Epidural Infusions • Used for major surgery ie. oncologic TAH BSO, thoracotomy • Ideally placed pre-operatively and used in combination with a GA for surgery and continued ~ 2 days • Usually patient is tolerating diet and ambulation to chair when epidural is D/C

26. Ideal Epidural Infusions • When placed at the level of the incision and with a constant infusion of LA and opioid: • Minimal or no pain at all, particularly with movement • No motor block • Can ambulate • Speedier return of bowel function • With more LA and less opioid –Cochrane review 2003 • Less nausea • Less sedation • Less delerium • Do not require supplemental IV opioids and associated side effects • Less pulmonary complications • Quicker extubation, better oxygen saturation, less pneumonia

27. Side Effects of Epidural Infusions • Hypotension • LA causes a sympathectomy which leads to vasodilatation • Mild volume depletion, which can normally be compensated for with vasoconstriction, will be unmasked with an epidural • Pts require adequate volume status with an epidural

28. Side Effects • Hypotension • Pts will initially c/o dizzyness, lightheadedness and nausea when sitting up or standing • Can document orthostatic hypotension • Will then progress to supine hypotension if not corrected • Major problem POD #1 when 3rd spacing still occurring, minimal IV fluids infusing and pt NPO

29. Side Effects • Leg weakness or numbness • Can occur if catheter is too low (low thoracic or lumbar) or if it is one-sided • Inhibits ambulation and distressing to pt therefore must be fixed • Infusion can be adjusted or catheter pulled back • Must be addressed as this is the first sign of epidural hematoma leading to permanent paralysis

30. Complications • Post dural puncture headache 1:100 • Only if dura is unintentionally punctured • More likely in younger people • Infection • Some reports of epidural abscess as high as 1:1900 • Usually just superficial skin infections • Increased risk in immunosuppressed

31. Complications • Epidural hematoma • Most feared complication • Incidence of 1:180 000 – 1:220 000 • Increased with heparin, age, gender, ASA, NSAIDs, traumatic placement, spinal stenosis • Leg weakness, numbness and bladder/bowel disturbance are first signs • If not evacuated within 8-12 hours, usually leads to permanent paralysis

32. Complications • Epidural Hematoma • Risks • Abnormal coagulation • Elderly • Female • Debilitated patients • Traumatic insertion • Unknown spinal pathology

33. Complications Anticoagulation and Epidurals: • ASA – OK • NSAIDS – OK • UFH 5000 sc bid – OK if no other antiplatelets • UFH 5000 sc tid – sort of OK, but not really (according to ASRA) • LMWH (Dalteparin)– increased risk – not really OK • IV heparin – not OK • Clopidigrel, ticlodipine – not OK • Coumadin – not OK

34. Ideal Patient Care • Surgeons, APMS, nursing all working for same goal • Pre-operative optimization • Intra-operative care • Post-operative • Ambulation, pain, bowels, voiding Improved patient recovery

35. Acute Pain Management Service (APMS) • Consulting service, mostly post-op patients • PCAs, non-labour epidurals, regional techiques • Don’t need to co-sign our orders • Can’t order any analgesics, anti-emetics, antihistamines, neuropathic pain agents, or sedatives while patient being followed by APMS • “Suggest Orders” once APMS signs off DO need to be co-signed