Perioperative Pain Management in Children with Sleep-Disordered Breathing: A Difficult Balancing Act
Sleep disordered breathing and its most severe form, obstructive sleep apnea, present unique challenges to the anesthesiologist; this is particularly true in pediatric patients undergoing tonsillectomy and adenoidectomy, where obstruction may be related both to enlarged nasopharyngeal structures, as well as obesity, in some cases. While an abundance of caution must be exercised in treatment of these patients with opioids, the severe nature of their pain demands that opioid therapy form at least part of the pain management plan. Dr. Olubukola Naifu, MD, anesthesiologist and assistant professor at University of Michigan School of Medicine, shared his work and experiences in dealing with this universal problem.
Sleep Disordered Breathing and Pain Perception
Though tonsillectomy and adenoidectomy has long been recognized as a fairly painful procedure in its own right, the population in which this procedure is often performed may further compound this fact. Sleep disordered breathing in pediatric patients predicts emergence agitation and increased pain requirements in the PACU. Interestingly, hypoxic rats (a model of sleep disordered breathing’s consequences for the brain) exhibit increased mu-receptors in their brain stems, suggesting they may face enhanced nociception in the setting of painful stimuli. While addressing emergence agitation with dexmedetomidine seems like an obvious choice, our presenter stresses that its administration extended PACU stays, and while it reduced PACU opioid demand, it is unclear the mechanism for this. On the one hand, dexmedetomidine has recognized analgesic value; on the other hand, children may have simply been “sleeping through” some of the more acute pain.
However, there are medications that clearly do reduce opioid demand via their own analgesic effect–and a few that don’t.
Multi-modal Analgesia and Treatment of Pain in Sleep Disordered Breathing
While a variety of agents can improve our treatment of post-tonsillectomy and adenoidectomy pain in sleep disordered breathers, opioids remain the cornerstone of therapy. Providers should resist the temptation to sharply reduce opioid dosing based on the existence of SDB; our speaker also urges anesthesiologists to reconsider dosing obese patients based on ideal body weight as this may grossly undertreat pain symptoms. Making patient’s “earn” their opioid dose based on respiratory function may also leave pain inadequately addressed. Recall: these patients exhibit enhanced nociception, so withholding medication may simply cause these patients to fall further behind on their needs, creating a vicious cycle of elevated pain requirements and potential for hypoventilation when these requirements are addressed with larger opioid doses.
Acetaminophen: IV? PO? PR? Does It Matter?
While it is clear that acetaminophen seems to reduce opioid requirements in this cohort, the optimal dosing schedule and route remains unclear. Literature review reveals that PR acetaminophen may provide the longest window of decreased opioid requirement based on a single dose; IV acetaminophen may provide little benefit over its PO and PR counterparts. Thanks to its side effect profile, ease of administration for the anesthesiologist and effectiveness (whether real or perceived), IV acetaminophen has exploded in popularity, despite its relatively high cost per unit. Regardless of the route chosen, acetaminophen is a sensible addition to most anesthetic and pain management plans in this setting.
NSAIDS: Ibuprofen Need Not Be Avoided
Postoperative tonsilar bleeding is one of the most feared complications of T&A; NSAIDs, therefore, have often been avoided given their propensity to increase bleeding. While IV preparations (ketorolac, for example) may be wisely avoided, PO medications such as ibuprofen are likely benign and seem to be helpful in reducing opioid demand.
Steroids and Postoperative Pain Reduction: Can We Optimize Timing?
Dexamethasone has been recognized for its action in preventing post-operative nausea and vomiting–to be sure, this make it a worthy addition to anesthetic management for patients undergoing airway surgery. It may also contribute to pain management in this population. However, its mechanism for preventing PONV is likely quite different than that which could potentially address post-operative pain. While dexamethasone exerts its anti-nausea effects in the area prostrema, its effect on local tissue edema may be responsible for its impact on pain. And for that to occur, its administration needs to be optimized. Studies are now underway to examine PO dexamethasone given the night before T&A in SDB patients, in addition to the usual IV dose on induction–could this extra time allow the medication to truly reduce tissue edema and therefore, improve pain?
Local Anesthetics Aren’t Helpful
With the attention surrounding regional anesthesia’s potential to reduce opioid requirements in a vast array of patients, it’s tempting to think of the role of local anesthetics in the SDB T&A patient. Unfortunately, their utility is limited. While local infiltration and peri-tonsilar blockade was hoped to reduce opioid requirements, this combination didn’t seem to provide much benefit. It is suspected that tissue edema, pH, and anatomy of the area make it fairly challenging to block; besides dealing with distorted anatomy, local anesthetics don’t work as well in acidic surroundings. Ultimately, this modality doesn’t reduce opioid requirements in children.
Though one of the most common surgeries in the pediatric population, we are just beginning to understand the best combination of therapy to treat post-operative pain following T&A, particularly in cases complicated by SDB. Multi-modal pain management has emerged as incredibly useful, with improved safety over opioid therapy alone. Continued study will not only benefit our pediatric patients but will likely be generalizable to the adult SDB patient as well.
*Coverage from the Review Course Lecture, Perioperative Pain Management in Children with Sleep-Disordered Breathing: A Difficult Balancing Act