Post Operative Pain Management: Epidurals Beyond the Operating Room

1. IANA 2009 Spring meeting- St. Louis, MO Post Operative Pain Management: Epidurals Beyond the Operating Room Misty Kirby-Nolan MSN, APN-CNP Northwestern University Anesthesia Pain Service mnolan@nmh.org

3. Northwestern Memorial Hospital • 873 bed academic medical center • 46,182 in patient admissions • 31,825 Operating room cases • Feinberg-18, 281 • Olson-8,215 • Prentice-5,329

4. Objectives • Discuss the role of the Nurse Practitioner in the Anesthesia pain service • Discuss the advantages & disadvantages of epidural analgesia • Review the pathophysiology of Opioid-induced hyperalgesia • Summarize epidural analgesia protocols • Review Anesthesia pain service case study

5. CNPs role in Anesthesia Pain service • Evaluate & treat pain in the PACU • Follow up on all surgical patients with Epidurals and continuous nerve block catheters • Pre & post op pain consults • Maintain quality data

6. CNPs role cont…….. • Educate nursing staff • Coordinate pain service activities • Policy development & maintenance • Call responsibility • Procedures

7. Regional Acute Pain Service • Attendings, residents, fellows, Nurse Practitioners • 9 Pain physicians • 5 Regional

8. Anesthesia Pain Service Volume

9. Post Surgical Pain • 70-80% of 23 million Americans that have a surgical procedure experience moderate to severe pain despite treatment • Balance of pain relief & opioid side effects

10. Key Points from the JCAHO Pain Management Standards • Patients have a right to pain management. • Pain must be assessed at regular intervals. Pain should be reassessed soon following an intervention to treat pain to ensure a response. • Institutions are required to have policies and procedures for pain assessment and treatment. • Patient education for pain management is mandated. • Staff education concerning pain management is required. • Pain assessments are required as a discharge criterion

11. Predictors of acute pain leading to chronic pain • Poorly controlled acute pain • Intensity of acute post op pain • Pre operative pain • Amount of opioids consumed in period after surgery

12. Chronic Post OP Pain Syndromes • Post thoracotomy • Post mastectomy • Post inguinal hernia repair • Phantom • Stump • Post Cholecystectomy • Post op CRPS

13. Epidural Advantages • Improved pain control • Decreased length of hospital stay • Increased gut motility • Less overall opioid d use

14. Mean visual analog scale (VAS) for each treatment group with 95% confidence intervals is shown from postoperative day 0 to 4. P<.001 for all days after surgery PCEA VS IV PCA Block et al Efficacy of postoperative epidural analgesia: a meta-analysis.JAMA. 2003 Nov 12;290(18):2455-63. Review

15. Contraindications to Epidural Removal/Insertion • INR > 1.5 • COAGULOPATHY • LOW MOLECULAR WEIGHT HEPARIN THERAPY • COMBINED HERBAL THERAPY • INCREASED ICP • PRE-EXISTING NERVE DAMAGE • SPINAL FUSION AT NEEDED INSERTION SITE • INFECTIONS

16. Epidural Complications • Postdural puncture headache (PDPH) • Back pain at insertion site • Catheter migration/ displacement • Epidural abscess • Epidural hematoma • Aseptic mennigitis • Unexplained neurological damage (transient neurologic syndrome) • Non working

17. Surgical Indications • Abdominal Whipple, colon resection, nephrectomy, AAA repair Pancreatectomy, TAH BSO w/staging, Uterine artery embolization • Orthopedic Hip, knee and Ankle replacements • Thoracic Surgery • Lung resection, Esophagectomy, pleuradesis • Chronic Pain Syndromes Trial prior to intrathecal analgesia or tunneled epidural cath

18. ANATOMY • Outside dural sac but inside vertebral canal • Contains spinal nerve roots, areolar tissue, fat, arteries and a plexus of veins • It is a discontinious space • Epidural space ends at the sacral hiatus

19. Epidural Anatomy

20. Acute Pain Transmission Gottschalk A.,& Smith DS (2001) AM Fam Physician

22. Epidural Pharmacodynamics Spinal Arteries Dorsal Horn Brain dural Epidural Opioid Epidural veins CSF transfer Epidural Veins (Arachnoid Granulations) Non specific binding Brain Epidural Fat Systemic circulation

23. Intraop Epidural dosing • Consider a low infusion of LA through epidural or intermittent boluses • Turn off infusion 30-45 min prior to end of case • Opioid dose 60-45 min prior to end of case • Hydromorphone 0.5-1mg • Duramorph

24. Post operative PCEA infusion • Fentanyl • 5mcg/ml • 10mcg/ml • Hydromorphone • 10mcg/ml • Bupivacaine • 0.1% • 0.2%

25. Pain in the PACU • Assess sensory level • Bilateral levels • Evaluate introp dosing • Local anesthetic • Opioid • Titrate local anesthetic • Epidural cath assessment • Anatomic location • Appropriate depth

26. OIH vs. Opioid Tolerance • Tolerance • Desensitization of antinociceptive opioid pathways • Right shift in the dose response curve • Reduction of analgesic effect • OIH • Upregulation of pronociceptive pathways • Downward shift in the dose response curve • Loss of analgesic effect

27. Pathophysiology of OIH • NMDA receptors play a role • Alteration in the G protein coupling of opioid receptors • Increase in neurotransmitters • Cellular changes in afferent neurons, spinal cord,, brain, and descending modulatory pathway

28. Pathophysiology cont • Involvement of spinal prostaglandins & nitric oxide pathways • Alterations within the brain • Rostroventral medulla • Increase in the descending facilitation • Upregulation of the cAMP pathway

29. Opioid Induced Hyperalgesia (OIH) • Clinically seen as hyperasthesia • Associated with opioid dependence • Worsening pain despite accelerating opioids

30. Predisposing Factors • Genetic links • Type of opioid • High dose • Rapidly escalating doses • Acute, chronic non malignant & malignant pain • History of opioid dependence

31. OIH Characteristics • High dose opioids intraoperative • Observed after acute administration of an opioid • Duration of OIH is related to opioid dose • Hyperalgesia state may be secondary to nicotinic inhibition

32. Treatment OIH • Reduction in opioid • Discontinue completely if on low dose opioids (<10mg/24 hrs) • Concomitant administration • NMDA antagonist • Alpha2-agonist • NSAIDS

33. Treatment of OIH • Opioid switch • Initiate epidural, regional or local anesthesia • Evaluate for hypomagnesemia • Ultra low doses of opioid antagonist

34. Ketamine • Antagonist of the N-methyl-D-asparate (NMDA) receptor • Most effective as a continuous low dose infusion • Effective as a rescue analgesic in patients with acute post op pain • Major is as an antihyperalgesic, anti-allodynic

35. Adverse effects • Psycho-cognitive (is dose related) • ~200-300mg/24 hrs • Sedation • Respiratory depression • Decrease in attention

36. Dose Conversions Dose of new medication Conversion Factor of current med = Conversion factor of new med Dose of current medications

37. Conversion Table

38. Dose Conversions Dose of current medications = Dose of new medication Conversion factor of new med Conversion Factor of current med 75mg po MSO4 is converted to IV fentanyl 75mg/30mg= Fentanyl dose (0.2mg) (Fentanyl dose)= (75/30) 0.2= 0.5mg

39. Acute Pain management Case Studies

40. History of Present Illness 31 yo M hx of crohns, adrenal insuffenciency, pitutary Adenoma S/P C5-6 Anterior Cervical Decompression Fusion Hx of PONV

41. Past Surgical History • T&A • Repair of Nasal fx • L THA • No hx of anesthetic problems

42. Medications • Home- Clonazepam, 1mg bid, gabapentin, lexapro, klonipin, oxycontin 80mg Q 6 Oxycodone 15mg q 6 hours, phenergan, soma • Intra op- (4 hour case) • 250mcg fentanyl • 6mg dilaudid • 100mg ketamine • PACU • 8mg dilaudid • PCA titrating up

43. Treatment • Ketamine gtt 5mg/hr • IV PCA hydromorphone 0.5mg Q 15min • Pain score 3/10 next am & pt requesting ketamine be stopped.

44. Review of Objectives • Discuss the role of the Nurse Practitioner in the Anesthesia pain service • Discuss the advantages & disadvantages of epidural analgesia • Review the pathophysiology of Opioid-induced hyperalgesia • Summarize epidural analgesia protocols • Review Anesthesia pain service case study

45. Questions