Reader response

Myron Yaster MD

From Randall Flick, MD, MPH, Mayo Clinic

I read with interest the recent PAAD addressing the benefit or lack thereof of adenotonsillectomy in children.  For those of us who have been around for awhile this question is hardly new.  In 2017 I was fortunate to participate in a comparative effectiveness review of 

Tonsillectomy for Obstructive Sleep-Disordered Breathing or Recurrent Throat Infection in Children for the Agency for Health Quality and Research (AHRQ).  The AHRQ process was rigorous and exhaustive culminating in a 964 page report that I am sure all of you will immediately download and read completely and carefully.  Fortunately, the structured abstract is one-page, and the main body of the report is about 100 pages. Given the size of the file the pdf is not included but is available via the following link (https://www.ncbi.nlm.nih.gov/books/NBK424048/pdf/Bookshelf_NBK424048.pdf).  Also linked is a JAMA Otolaryngoscopy head and Neck Surgery summary of the report which is much more digestible (https://jamanetwork.com/journals/jamaotolaryngology/article-abstract/2656715).

Copied below are the conclusions from the structured abstract.

Conclusions. Tonsillectomy can produce short-term improvement in sleep outcomes compared with no surgery in children with OSDB (moderate SOE). In children with recurrent throat infections undergoing tonsillectomy, number of throat infections (moderate SOE) and associated health care utilization and work/school absences (low SOE) improved in the first postsurgical year. These benefits did not persist, and data on longer term results are lacking. Short-term improvements must be weighed against the risk of PTH (high SOE for low frequency of PTH). Surgical technique had little bearing on return to normal diet or activity (low SOE). Perioperative vii dexamethasone and pre-emptive 5-HT receptor antagonist antiemetics reduced the need for additional analgesics or antiemetics (low SOE). Dexamethasone did not increase risk of PTH compared with placebo, but estimates had wide confidence bounds (low SOE). Little evidence addressed the use of postoperative medications for pain-related outcomes (insufficient SOE).

As is apparent to the reader of the AHRQ review the benefit of adenotonsillectomy are relatively modest and did not persist with regard to OSDB, infections, and utilization of healthcare.  The paper reviewed in the PAAD by Friedman et. al. suggests that in children with mild OSDB there is no benefit in assessments of executive function, but some benefit was achieved in other measures of quality of life. Ultimately, tonsillectomy as among the most common surgical procedures in children (15% of surgical procedures for children under age 15 years) is of limited benefit, not without risk and therefore almost certainly overutilized.

From Audra Webber MD, FASA, Associate Professor, Program Director, Pediatric Anesthesiology Fellowship, University of Rochester School of Medicine and Dentistry

Thank you so much for highlighting this recent paper by Okada et al.  The topic of appropriate opioid dosing in children with obesity is of great importance to our specialty, particularly in the case of tonsillectomy - one of the most common pediatric surgeries.  The results of the Okada study are not surprising and the science behind it well explained in the paper and subsequent editorial.  

I did want to point out an additional issue that impacts the effect and effectiveness of fentanyl in this particular population - that of opioid sensitivity in patients with OSA. Patients with OSA (adults and children) are more sensitive to both the analgesic and respiratory depressant effects of opioids.   All the patients in the Okada paper were undergoing tonsillectomy +/- adenoidectomy and those patients with sleep disordered breathing were NOT excluded (which makes sense because most of the children were probably undergoing tonsillectomy for that very reason).  It is well established that children with obesity are more likely to have sleep apnea, and that the more severe the degree of obesity, the more (likely) severe the degree of sleep apnea.  It is also well established that the majority of children undergoing tonsillectomy for suspected sleep apnea will not have undergone polysomnography, and that they are generally assigned the diagnosis of "sleep disordered breathing".  Therefore the degree (mild, moderate or severe) of their OSA is unknown.  

The fact that the cohort of children with obesity were less likely to require additional analgesia in PACU is probably due to both the higher plasma fentanyl concentrations AND a greater sensitivity due to OSA.   The SPA recommendations for use of opioids in the perioperative period (PMID 30929307) highlight this with the recommendation 

" Patients with obstructive sleep apnea, obesity (>95 percentile BMI), and recurrent nighttime oxygen desaturations are at higher risk for opioid induced respiratory depression. Opioid dosing should be based on ideal or lean body weight and the dose of opioid should be reduced by 50% to 67% for OSA patients. Additionally, extended respiratory monitoring is required when opioids are being administered to this population in the perioperative period. Strength of evidence: B."

Fentanyl, as a short acting opioid whose cessation of action is via redistibution with small doses (1-2 mcg/kg) is probably the "safest" opioid in the event of excess dosage to utilize in obese patients.  I imagine had this played out with an intermediate or long acting opioid dosed to actual instead of lean bodyweight, there may have been more respiratory issues in the cohort with obesity.

In my practice I utilize short acting opioids in decreased doses (plus non opioid adjuncts) for patients with obesity, suspected or diagnosed OSA, or both for tonsillectomy/airway surgery because I want the largest margin of safety possibly in the event of airway issues.     

From Francis Veyckemans

I agree with you, calculating the lean body weight is not easy. Personally, I use the nomogram published in Anaesthesia 2015; 70: 176-82 (below). It is easy to use but you need to know the patient's height.

From Benjamin Pritts

I am a dentist anesthesiologist who graduated from the University of Pittsburgh Dental Anesthesiology residency. The endocannibinoid system is quite a fascinating story. I studied neuroscience as an undergrad at the University of Pittsburgh and during my studies there, the endocannabinoid system was never mentioned. Over time it’s becoming more and more clear that the endocannabinoid system is one of the most robust neurotransmitter networks in the body. Obviously in our practice the effects on pain and and as anti-emetic will be profound. And who would have guessed that acetaminophen may produce its analgesic effects through these pathways! Finally, I think that many clinical aspects are more pronounced with the plant as a whole vs isolated components. The entourage effect. Thanks for bringing this to our attention.