Reader response
Myron Yaster MD
From Mark Schreiner MD
Comparing minority representation in pediatric anesthesia to the distribution in the US population is the wrong metric. Instead one has to compare it to the distribution of US medical school graduates. See for example the AAMC statistics for 2018-2019.
To more closely mirror the US population we need to increase minority admissions to medical school. Pediatric Anesthesia can’t compensate for biased admissions.
From Annika Webb, MD
We are so excited with the response to our post on Tuesday and appreciate all of the enthusiasm people have expressed regarding this important initiative. It is clear that we are filling a necessary gap given the overwhelming response from prospective mentees. At this time, we have reached our cap on mentees and have closed the mentee application. If you are interested in participating as a mentee, please be reassured that we will reopen applications in the fall. Thanks again for all of the interest in this new exciting program and we are excited to see how it impacts the future of the specialty.
Pauline Wong, DVM, DACVAA (emeritus), a long time reader of the PAAD found this letter to the journal Anesth Analgesia about LMA, sevoflurane and TIVA
Francisco Reinoso-Barbero 1, Pascual Sanabria-Carretero, Mercedes
Alonso-Prieto. Sevoflurane Versus Propofol for LMA® Removal in Awake
Children: More Respiratory Adverse Effects or Faster Recovery of Airway
Reflexes in More Awake Children? Anesth Analg. 2023 Jul 1;137(1):e4-e5.
doi: 10.1213/ANE.0000000000006541. Epub 2023 Jun 16. PMID: 37326873
To the Editor
We read with great interest the suggested article by Karam et al1 in which they found a higher incidence of “respiratory adverse effects” (cough, laryngospasm, and lower levels of oxygen saturation) in children anesthetized for minor procedures with sevoflurane (36.2%) versus total intravenous anesthesia with propofol (10.8%) immediately after laryngeal mask airway (LMA®) removal. This finding unequivocally
contradicts our own clinical experience in the pediatric anesthesiology department of a tertiary university hospital, where approximately 8000 children are yearly anesthetized, and almost half of them in areas outside of the operating room where volatile anesthesia is predominantly used.2 More importantly, it also contradicts the results of a large retrospective cohort study that shows only 0.43% upper respiratory events in a sample of 2777 pediatric patients.3
We would like to comment on some aspects of the article’s methodology that we hope can help to cautiously interpret its conclusions.
First, the main differences in “adverse” respiratory events and in airway hyperreactivity scores were basically due to cough, present in 21.7% of the sevoflurane patients versus 1.5% of the propofol group. Cough is considered an adverse effect when it
is prolonged or if it impairs respiratory functionality or disturbs the patient’s comfort. However, a short but effective cough can help to expel respiratory secretions and may indicate an appropriate level of respiratory recovery. It is actually included as the
most valuable respiratory item in common postanesthesia recovery scores such as Aldrete or Steward scores.4
Second, the sevoflurane group presented a high incidence of laryngospasm (10.1%) as compared with the propofol group (1.5%), although laryngospasms described were of moderate intensity and resolved after continuous positive airway pressure. Authors removed LMA when patients “were awake as judged by physiologic and neurologic recovery to a degree to permit a safe, natural airway demonstrated by facial grimace, adequate respiratory rate and volume, eye opening, and purposeful movements.” According to this, in the end, clinical criteria were used. However, there is a general recommendation to remove LMA in patients who are breathing spontaneously after
sevoflurane anesthesia “in an anesthetic state” or “fully awake.” “Fully awake” means patients who keep their eyes continuously open, who are able to follow commands, or who are fully reactive and connected to the environment. Removing LMA in an “intermediate state” after volatile anesthesia is obviously associated with a higher incidence of airway events in young children5 and should be avoided in all cases. The clinical judgment to determine when a pediatric patient is in an “intermediate state” is not always easy, and it requires a certain level of expertise or experience.6 Information derived from electroencephalogram analysis and from end-tidal sevoflurane concentrations can be important tools, but the article’s researchers did not use them (even in a blinded way). Therefore, it was impossible to determine the level of
residual sedation-hypnosis at the moment of LMA removal in each group.
Third, the authors found a statistically significant difference in oxygen saturation during emergence from anesthesia after LMA removal (98.12% in the sevoflurane group vs 99.45% in the propofol group). Although the clinical significance of
this small difference seems to be very difficult to interpret, there is no mention regarding other, more significant respiratory parameters such as the respiratory rate or carbon dioxide levels by capnography, specifically before and after LMA removal, which inform us not only about the level of respiratory recovery but also indirectly about neurologic recovery levels.
Finally, there is also an absence of qualitative information about the recovery in the postanesthetic care unit because nonspecific postanesthetic recovery scores were used,4 and the authors only mention conventional discharge criteria at 62 minutes (a relatively long time of recovery for these very short minor procedures, compared with our experience) that do not seem to indicate clinical criteria.
Under these circumstances, the article fails to clarify if the lesser respiratory reactivity observed in the propofol group was due to a higher level of residual sedation; meanwhile, the “hyperreactivity” in the sevoflurane group can be due to a lower level of residual sedation evidencing a faster recovery of the laryngeal reflexes.
It is important to perform randomized clinical trials that can serve as a base for later meta-analyses and also to try avoiding bias that can impair the interpretation
of the data. We agree that propofol is a potent suppressor of laryngeal reflexes with a beneficial effect on the treatment and prevention of laryngospasm, and also with
well-proven positive effects on postanesthetic agitation and postoperative emesis when added as a bolus to volatile anesthesia. We are not sure that to obtain these advantages, we must always use total intravenous propofol anesthesia in children, even for minor procedures.
REFERENCES
1. Karam C, Zeeni C, Yazbeck-Karam V, et al. Respiratory
adverse events after LMA mask removal in children: a randomized
trial comparing propofol to sevoflurane. Anesth
Analg. 2023;136:25–33.
2. Alonso M, Builes L, Morán P, Ortega A, Fernández E,
Reinoso-Barbero F. Clinical experience with desflurane for
paediatric anaesthesia outside the operating room. Rev Esp
Anestesiol Reanim. 2017;64:6–12.
3. No HJ, Koo BW, Oh AY, et al. Retrospective cohort investigation
of perioperative upper respiratory events in children
undergoing general anesthesia via a supraglottic airway:
a comparison of sevoflurane and desflurane. Medicine
(Baltimore). 2016;95:e4273.
4. Kotwani MB, Malde AD. Comparison of maintenance,
emergence and recovery characteristics of sevoflurane and
desflurane in pediatric ambulatory surgery. J Anaesthesiol
Clin Pharmacol. 2017;33:503–508.
5. Park JS, Kim KJ, Oh JT, Choi EK, Lee JR. A randomized controlled
trial comparing Laryngeal Mask Airway removal
during adequate anesthesia and after awakening in children
aged 2 to 6 years. J Clin Anesth. 2012;24:537–541.
6. Schleelein LE, Vincent AM, Jawad AF, et al. Pediatric perioperative
adverse events requiring rapid response: a retrospective
case-control study. Paediatr Anaesth. 2016;26:734–741.