Safe and Evidence Based Perioperative Pain Management in an Opioid-Dependent Child Undergoing Lower Extremity Amputation for Necrotizing Fasciitis

Transcription

1 Safe and Evidence Based Perioperative Pain Management in an Opioid-Dependent Child Undergoing Lower Extremity Amputation for Necrotizing Fasciitis International Assembly for Pediatric Anesthesia 2012 Moderator: Andrew Franklin, MD Assistant Professor of Anesthesiology Pediatric Pain Management Monroe Carell Jr. Children s Hospital at Vanderbilt Vanderbilt University Medical Center Nashville, Tennessee Goals: 1) Discuss and compare modalities used to provide postoperative analgesia in children such as parenteral opioids, epidural analgesia, and continuous peripheral nerve catheters. Focus on the implications of each modality on various comorbid conditions including opioid tolerance, systemic infection, and coagulopathy. 2) Discuss the current medical evidence regarding the safety of the above mentioned perioperative analgesic strategies, including management of common and uncommon complications. 3) Discuss the current medical evidence regarding the use of adjuncts such as clonidine, naloxone, ketamine, gabapentin, acetaminophen, and ketorolac to reduce risk of opioid toxicity and mitigate side effects. 4) Discuss the implications of acute pain management on the development of chronic pain syndromes such as post-surgical neuropathy, complex regional pain syndrome, and phantom limb pain as well as basic treatment options for these pain states. 5) Discuss the role of a dedicated pediatric pain management team to improve safety, quality, and patient satisfaction in the perioperative period. Case History: An eight year-old girl presents for surgical debridement of devitalized tissue in both lower extremities. The patient initially presented six weeks ago with lethargy, fever, and rash with subsequent development of lower extremity streptococcal necrotizing fasciitis progressing to septic shock. She has spent her entire hospital admission in the pediatric intensive care unit for management of respiratory failure, hemodynamic instability, disseminated intravascular coagulopathy, and renal insufficiency. She underwent three surgical debridements during the first week of admission. To facilitate critical care management, she received high dose infusions of fentanyl and midazolam for over four weeks. She was extubated one week ago, remains on one liter nasal cannula oxygen, and

2 has been transitioned to oral methadone and diazepam, supplemented with intravenous morphine and lorazepam. Hemodynamic instability and coagulopathy have resolved, though she continues to have poorly perfused and necrotic tissue on both lower extremities. The surgeons plan staged operative procedures for additional debridement and possible bilateral below knee amputations after intraoperative assessment of tissue. Wound care, skin grafting, and daily dressing changes are planned in the weeks to follow. The surgeon wishes to consult the pediatric pain service regarding safe and effective perioperative pain management for this patient. The case is scheduled for five hours and blood loss is expected to be moderate. Preoperative discussion: 1) Discuss the optional strategies for comprehensive perioperative pain management for this patient 1 2. If the disease process was unilateral, discuss how this affects your plan. 2) Discuss the benefits and risks associated with each option given the child s coexisting medical problems. 3) Discuss how the patient s chronic opioid and benzodiazepine regimen affects your preoperative planning and intraoperative management 3. 4) Discuss the effect of the patient s recent history of sepsis and coagulopathy on your perioperative analgesic strategy. 5) Discuss the implications of the patient s current oxygen requirement on your analgesic strategy. 6) If a regional technique is chosen, will you perform this awake, under light sedation, or after induction of general anesthesia? Discuss the risks, benefits, and medical evidence of each choice 4. 7) Discuss the risks, benefits, and medical evidence for catheter tunneling 5. Intraoperative Course: You choose to place a subcutaneously tunneled lumbar epidural catheter as part of your comprehensive analgesic strategy. Consent is obtained. General endotracheal anesthesia is administered and a tunneled epidural catheter is placed at the L3/L4 interspace using the loss-of-saline resistance technique without complication. Intraoperative Discussion: 1) Discuss the role of ultrasound, conventional x-ray, fluoroscopy, and electrical guidance in the placement of epidural catheters and continuous peripheral nerve catheters 6. 2) Discuss the local anesthetic options for bolus and continuous infusion. Discuss risks and benefits of each. Discuss infusion options if a continuous peripheral nerve catheter technique is chosen.

3 3) Discuss your strategy for the administration of intravenous and neuraxial opioids intraoperatively. 4) Discuss the risks and benefits of starting the epidural infusion intraoperatively as opposed to postoperatively. 5) Suppose the child develops cardiovascular collapse after an epidural bolus is given and local anesthetic toxicity is suspected. Discuss resuscitation options 7. Discuss readiness planning at your institution in the event of local anesthetic toxicity. Immediate postoperative course: The epidural catheter is bolused and an infusion is started intraoperatively. Significant devitalized tissue in the left lower extremity prompts left below knee amputation with extensive debridement in the right lower extremity. The operation concludes uneventfully with minimal intraoperative opioid required to supplement the epidural block. Surgical blood loss requires transfusion of packed red blood cells. The patient is extubated and taken to the recovery room. In the recovery room, the patient is crying and complains of pain. The operative limb demonstrates dense residual surgical block and is completely insensate to direct palpation of the stump. Postoperative course and questions: 1) The recovery room nurse and parents adamantly request that an opioid be administered. Discuss your evaluation and management. 2) Discuss the benefits and risks associated with use of a demand feature in addition to the basal rate of epidural infusate. Discuss the dosing regimen for basal and demand patient controlled epidural analgesia (PCEA) and how this changes if PCEA-by proxy is administered 8. 3) Discuss the risks and benefits of continuing the preoperative scheduled long acting opioid and benzodiazepine. How will you use opioids and benzodiazepines for breakthrough symptoms? Discuss the risks and benefits of providing a demand only opioid intravenous PCA in addition to the PCEA 9. 4) Discuss the risks and benefits of adding clonidine, naloxone, ketamine, gabapentin, acetaminophen, and ketorolac to your multimodal analgesic strategy 10. 5) Daily dressing changes are planned for this patient with significant anxiety surrounding medical care personnel. Discuss your plan for analgesia and anxiolysis? 6) On postoperative day three, the patient develops a fever to 38.5 with initial blood culture reports positive for gram-positive cocci in clusters. The PICC line is removed, empiric antibiotics are started, and the patient is afebrile within 36 hours of initial fever. The infectious disease physician asks you if the epidural catheter should be removed. Discuss your evaluation and response. 7) On postoperative day seven, the patient reports burning, shooting, throbbing pain

4 distal to her left lower extremity stump and states that her toes in the amputated limb keep twitching and interrupt her sleep. Discuss your evaluation of this situation. 8) Discuss the pathophysiology of phantom limb pain, focusing on incidence, therapies, and outcomes 11. 9) Discuss the benefits, if any, of managing a complex patient such as the one described with a dedicated pediatric pain service. 10) Discuss the challenges in starting and maintaining a full time pediatric pain service. Discussion: Intravenous opioids and benzodiazepines are commonly used to provide sedation and analgesia for critically ill children undergoing mechanical ventilation. However, prolonged administration of these medications results in tolerance and dependence, necessitating weaning of medications over days to weeks to avoid symptoms of withdrawal. In addition, opioid tolerance may result in markedly increased opioid requirements during the perioperative period as well as for subsequent management of pain problems. Pain control may require rapid titration of opioids, based upon preoperative opioid requirements, intraoperative requirements, and the anticipated severity of postoperative pain. Intravenous patient-controlled analgesia (PCA) provides effective pain management in children with acute as well as chronic pain problems. School age children can be instructed to safely and effectively control IV PCA. Surrogate control of PCA by parents or nurses is effective for children unable to control PCA. However, surrogate control compromises the fundamental safety provided by patient regulation of PCA and may increase the risk for respiratory depression. Consequently, close patient monitoring is mandatory 9,12. Opioid administration by IV PCA was a reasonable option for this patient and could have been controlled by the patient or parent. However, opioid tolerance had already developed secondary to prolonged administration of fentanyl while in the PICU and would likely lead to rapid escalation of opioid requirements following her staged operative procedures and dressing changes. Epidural analgesia is a highly effective alternative to IV PCA in opioid naïve as well as opioid tolerant patients. The combination of local anesthetic and opioid provides synergistic neuraxial analgesia with limited side effects. For this patient, epidural analgesia was selected to provide targeted neuraxial analgesia while avoiding the systemic side effects of IV opioid administration. Adjuncts such as clonidine may be added to the epidural regimen to enhance analgesia or reduce dosage requirements for other medications. Epidural analgesics may be administered by continuous infusion or combined with patient-controlled demand dosing (PCEA) to enable titration of drug delivery in response to variation in pain perception 8.

5 Continuous peripheral nerve catheter techniques, especially when paired with ultrasound guidance, may be an attractive option for perioperative analgesia. These techniques are useful for upper extremity injuries or when cardiovascular or infectious comorbidities preclude epidural analgesia. Because of the potential difficulty and risk of insertion of epidural or peripheral nerve catheters in awake children, experienced pediatric anesthesiologists routinely insert epidural catheters following induction of general anesthesia 13. Following standard insertion technique, epidural catheters may be routinely left in place for three days without significant risk of infection. Tunneling of the epidural catheter substantially reduces the risk of catheter contamination or infection, substantially prolonging catheter life 5,14,15. Preemptive regional anesthesia and analgesia have been advocated to reduce the risk of phantom limb pain following amputation. Initiation of epidural analgesia 24 hours prior to surgery resulted in reduced severity of postoperative pain, although long-term benefits were not observed 16. Thus, the efficacy of preoperative epidural analgesia in reducing phantom limb pain may not extend beyond the immediate postoperative period. This patient had excellent pain relief initially with an epidural regimen of fentanyl and bupivicaine. Maintenance oral methadone and diazepam were resumed in the postoperative period to avoid withdrawal symptoms. Escalation of pain over the course of this patient s treatment may have been due to increasing opioid tolerance. However, pain complaints also correlated with the development of burning pain, symptomatic of phantom limb pain. In the weeks immediately following amputation of an extremity, nearly all patients experience phantom sensations, i.e., non-painful sensations perceived to originate in the amputated extremity. Stump pain may occur in up to 50% of amputees and may be associated with localized abnormalities such as tissue infection, bone spurs, and neuromas. The majority of amputees experience phantom sensations, which may be variable in intensity, duration, and frequency but usually diminish over time 17. References: 1. Tsui BC, Suresh S. Ultrasound imaging for regional anesthesia in infants, children, and adolescents: a review of current literature and its application in the practice of neuraxial blocks. Anesthesiology 2010;112: Suresh S, Birmingham PK, Kozlowski RJ. Pediatric pain management. Anesthesiol Clin 2012;30: Anand KJ, Willson DF, Berger J, et al. Tolerance and withdrawal from prolonged opioid use in critically ill children. Pediatrics 2010;125:e Polaner DM, Taenzer AH, Walker BJ, et al. Pediatric Regional Anesthesia Network (PRAN): A Multi- Institutional Study of the Use and Incidence of Complications of Pediatric Regional Anesthesia. Anesth Analg Strafford MA, Wilder RT, Berde CB. The risk of infection from epidural analgesia in children: a review of 1620 cases. Anesth Analg 1995;80:234-8.

6 6. Tsui BC. Innovative approaches to neuraxial blockade in children: the introduction of epidural nerve root stimulation and ultrasound guidance for epidural catheter placement. Pain Res Manag 2006;11: Corman SL, Skledar SJ. Use of lipid emulsion to reverse local anesthetic- induced toxicity. Ann Pharmacother 2007;41: Birmingham PK, Wheeler M, Suresh S, et al. Patient- controlled epidural analgesia in children: can they do it? Anesth Analg 2003;96:686-91, table of contents. 9. Voepel- Lewis T, Marinkovic A, Kostrzewa A, Tait AR, Malviya S. The prevalence of and risk factors for adverse events in children receiving patient- controlled analgesia by proxy or patient- controlled analgesia after surgery. Anesth Analg 2008;107: Monitto CL, Kost- Byerly S, White E, et al. The optimal dose of prophylactic intravenous naloxone in ameliorating opioid- induced side effects in children receiving intravenous patient- controlled analgesia morphine for moderate to severe pain: a dose finding study. Anesth Analg 2011;113: Rusy LM, Troshynski TJ, Weisman SJ. Gabapentin in phantom limb pain management in children and young adults: report of seven cases. J Pain Symptom Manage 2001;21: Monitto CL, Greenberg RS, Kost- Byerly S, et al. The safety and efficacy of parent- /nurse- controlled analgesia in patients less than six years of age. Anesth Analg 2000;91: Giaufre E, Dalens B, Gombert A. Epidemiology and morbidity of regional anesthesia in children: a one- year prospective survey of the French- Language Society of Pediatric Anesthesiologists. Anesth Analg 1996;83: Kost- Byerly S, Tobin JR, Greenberg RS, Billett C, Zahurak M, Yaster M. Bacterial colonization and infection rate of continuous epidural catheters in children. Anesth Analg 1998;86: Bubeck J, Boos K, Krause H, Thies KC. Subcutaneous tunneling of caudal catheters reduces the rate of bacterial colonization to that of lumbar epidural catheters. Anesth Analg 2004;99:689-93, table of contents. 16. Lambert A, Dashfield A, Cosgrove C, Wilkins D, Walker A, Ashley S. Randomized prospective study comparing preoperative epidural and intraoperative perineural analgesia for the prevention of postoperative stump and phantom limb pain following major amputation. Reg Anesth Pain Med 2001;26: Manchikanti L, Singh V. Managing phantom pain. Pain Physician 2004;7: