Perioperative Pain Management in the Obese Patient

Educational Objectives

The goal of this program is to improve perioperative pain management in obese patients. After hearing and assimilating this program, the clinician will be better able to:

1. Recognize various challenges in developing multimodal analgesic pathways in obese patients.
2. Select appropriate strategies for managing perioperative pain in overweight and obese patients.

Summary

Epidemiology: in the United States, 20% to 30% of pediatric patients suffer from obesity; 25% of this population have unresolved obstructive sleep apnea (OSA); ≈33% of adults worldwide are overweight or obese

Effect of obesity on perioperative pain management (PPM): a significant proportion of obese patients have OSA and may be impacted by sedating analgesic agents; protocols, guidelines, and pathways are available for enhanced recovery after surgery (ERAS) for management of obesity with anesthesia; however, guidelines for PPM in obese patients are limited

Factors to consider: include biological sex, age, and weight; presence of OSA in patients undergoing surgery influences preoperative technique for airway management; the type (eg, open, laparoscopic) and duration of procedure affect analgesic need

Developing multimodal analgesia (MA) pathways in obesity: the core foundation of MA is to incorporate regional and neuraxial anesthesia when appropriate; clinicians should evaluate anesthesia intolerance in obesity and opioid epidemics as they are significantly intertwined; obese individuals tend to have more pain associated with other comorbidities and historically are prescribed more opioids than nonobese individuals, potentially leading to development of some tolerance; obesity is not a contradiction to excellent analgesia; some clinicians refrain from giving analgesia to overweight patients until recovery because of concerns about breathing issues; individuals with obesity deserve a level of analgesia similar to those without obesity; challenges — balancing clinical judgement and preferences by creating standardized protocol guidelines is the best way to ensure delivery of a multimodal approach to optimizing PPM in obese patients; stakeholder buy-in is the biggest challenge for creating MA pathways; reasons for an MA approach include patient advocacy, decreased opioid exposure and morbidity, and more rapid emergence; stakeholder buy-in is influenced by demonstration of evidence-based practices that translate to better outcomes; doses of opioids, especially longer-acting, should be reduced in patients with airway challenges or children undergoing adenotonsillectomy

Adjusting doses of analgesics: total body weight should not be used to calculate medication dosages; some medications (eg, acetaminophen [Actamin, Aurophen, Tylenol], midazolam) should be dosed based on ideal body weight; some medications are dosed based on lean body mass; patients of normal weight have a total body weight consisting of lean and adipose body weight in a 4:1 ratio; in obese patients, excess adipose weight plus 20% to 40% increase in lean body weight results in a ratio of 3:2; a quick method for estimating lean body weight is to evaluate height and weight on a body mass index scale

MA in obesity: foundation should include acetaminophen or ibuprofen or an equivalent nonsteroidal anti-inflammatory drug (NSAID); scheduled NSAID and acetaminophen uncoupled with opioids is preferred; for more major surgeries, ketamine, dexmedetomidine, and lidocaine infusions reduce overall opioid consumption; there may be sufficient evidence supporting one or two doses of gabapentin and pregabalin, but it may not be worth the effort for outpatients; at the speaker’s institution, omission of gabapentin has had a profound effect on analgesia in some patients; the speaker suggests 3 to 5 mg/kg of gabapentin, or 100 to 300 mg twice daily in larger patients

Use of opioids in obesity: longer-acting opioids may be considered early in long cases; a typically successful approach is titrating shorter-acting opioids to supplement a good pre-, intra-, and postoperative regimen and providing oral analgesics postoperatively

Perioperative strategies: provide prophylaxis and treatment for postoperative nausea and vomiting; use an opioid-sparing regimen; administer acetaminophen pre- or intraoperatively; administer ketorolac (Toradol) if approved by the surgeon and there is no concern for bleeding, and titrate short-acting opioids; if patients have a regional or epidural catheter, analgesia can be optimized in the recovery room; nonpharmacologic approaches include heat, ice, elevation, positioning, and anxiety treatment; consider muscle relaxation; consider caffeine for headaches in patients who consume large amounts of caffeine; prophylactically treat anxiety

Adenotonsillectomy: thinner children tend to benefit the most as they can sleep better and have less trouble learning; 25% of patients who undergo adenotonsillectomy as a way of managing OSA do not have significant improvement from obstruction removal; American Academy of Otolaryngology-Head and Neck Surgery — reported that perioperative ibuprofen and other NSAIDs do not increase the risk for hemorrhage after tonsillectomy; shifted from a postoperative regimen of hydrocodone-acetaminophen to scheduled acetaminophen and ibuprofen; pain management is better with NSAIDs than opioids as patients develop an inflammatory response from surgery; as regulations regarding opioid prescriptions increase in response to the opioid epidemic, clinicians find that opioids are not needed; other procedures are also found to have lower requirements for postoperative opioids than previously believed

Cystoscopy and ureteroscopy: the speaker notes that there is no response to opioids in teenagers undergoing cystoscopy and ureteroscopy without stent placement; patients respond to oxybutynin or tamsulosin (Flomax) because the etiology of pain in such cases is spasm of the bladder or ureter; opioids are ineffective for pain related to spasm

Summary of MA in obesity: ERAS pathways have significantly improved outcomes; fear of respiratory depression, oversedation, nausea, and vomiting related to opioid administration may lead to undertreatment of pain; inadequate analgesia indirectly contributes to postoperative complications; opioid-free pathways might not be effective in all cases requiring pain management; multimodal opioid-sparing analgesia is required; pathways and guidelines improve consistency

Readings

Bedwell JR, Pierce M, Levy M, et al. Ibuprofen with acetaminophen for postoperative pain control following tonsillectomy does not increase emergency department utilization. Otolaryngol Head Neck Surg. 2014;151(6):963-966. doi:10.1177/0194599814549732; Benyamin R, Trescot AM, Datta S, et al. Opioid complications and side effects. Pain Physician. 2008;11(2 Suppl):S105-S120; Chanowski EJP, Horn JL, Boyd JH, et al. Opioid-free ultra-fast-track on-pump coronary artery bypass grafting using erector spinae plane catheters. J Cardiothorac Vasc Anesth. 2019; 33(7):1988-1990; Stokes A, Berry KM, Collins JM, et al. The contribution of obesity to prescription opioid use in the United States. Pain. 2019;160(10):2255-2262. doi:10.1097/j.pain.0000000000001612.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Goeller was recorded at the 69th Annual Convention and Conclave of the American Osteopathic College of Anesthesiologists, held September 25-28, 2021, and presented by the American Osteopathic College of Anesthesiologists. For information on future CME activities from this presenter, please visit https:// www.aocaonline.org. Audio Digest thanks the speakers and the American Osteopathic College of Anesthesiologists for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

Lecture ID:

AN641302

Qualifies for:

ABA MOCA, Pain Management, Clinical Pharmacology

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.