Remembering the classics: Does the newborn require anesthesia for surgery?
Robert H. Friesen MD
If you live long enough what is new becomes old and what is old becomes new. Up until the early 1980s, newborn anesthesia was considered a “resuscitation” rather than an “anesthetic”. Think of the gunshot wound to the chest in which patients are provided minimal to no anesthesia other than perhaps an amnestic…and the newborn has “built in amnesia” (after all do any of you remember anything from the 1st year of life?) so anesthesia/resuscitation consisted of paralysis and airway control and little else…In today’s PAAD, one of our resident historians, Rob Friesen, provides the background story of how and why newborn anesthesia developed. To be honest, I thought this would be a historical tale of yesteryear but in reality because of what I think is an unwarranted perceived fear of anesthetic induced neuroapoptosis, this, the return of no anesthesia for the newborn, has reared its ugly head once again. Myron Yaster MD
Original article: Berry FA, Gregory GA. Do premature infants require anesthesia for surgery? Anesthesiology 1987;67:291-293 PMID: 3631601
There was an era in the history of anesthesia in which anesthesia was withheld from neonates, especially fragile preterm neonates, during surgery. Due to significant advances in neonatal medicine, anesthesia and surgery for the preterm neonate was a new and rapidly growing field in the 1970s and 1980s. In 1985, pain pioneer Sunny Anand reviewed over 40 published reports describing anesthetic techniques for the preterm neonate and revealed that 76% of patients were “anesthetized” with only a muscle relaxant with or without nitrous oxide.1 There were several contributing factors to this practice. First, it was believed by some that neonates did not feel pain because their nervous system was immature at birth (although this belief was not universally held). Second, neonatal anesthesia was high risk: the intraoperative cardiac arrest rate in infants less than 1 year of age was three times greater than that of older children,2 and 63% of perioperative deaths in the first year of life were suffered by neonates.3 Since relative anesthetic overdose was recognized as a major contributor to cardiac arrest in infants, withholding anesthetics was thought by many to be justified. Third, there existed a paucity of studies of neonatal pain, and specific anesthetic requirements for neonates were undefined.
This situation changed during the remarkable decade of the 1980s. First, studies by Paul Williamson and Lynne Maxwell independently demonstrated that the neonate exhibited vigorous behavioral and hemodynamic responses to a painful procedure (circumcision) that were attenuated by dorsal penile nerve block with a local anesthetic.4,5 Then, a landmark investigation by Anand proved that the neonate mounted a vigorous catecholamine, hormonal, and metabolic stress response to major surgery that could be blocked by the addition of 10 µg/kg fentanyl to a nitrous oxide anesthetic.6 These studies concluded that the neonate feels and responds to pain appropriately and that anesthesia can prevent the response.
Specific anesthetic dose requirements for the neonate were defined in further studies. Observing motor responses to incision, George Gregory and Jerry Lerman identified the neonate’s MAC for halothane7 and isoflurane8 (preterm neonates included in the latter study). Observing hemodynamic responses to incision following various doses of fentanyl, Myron Yaster demonstrated that 10 µg/kg fentanyl provided adequate anesthesia for major surgery in neonates.9
Thus, a handful of historically important studies published between 1983 and 1987 dispelled older beliefs and fears of anesthetizing neonates by demonstrating that the neonate reacts to surgical stimuli with appropriate behavioral, hemodynamic, and hormonal stress responses, that these responses are attenuated by adequate anesthesia, and that the neonate’s anesthetic requirement can be quantified. This story was told in greater depth in an editorial by Fritz Berry and George Gregory in today’s PAAD, cited above.
References:
1. Anand KJS, Aynsley-Green A. Metabolic and endocrine effects of surgical ligation of patent ductus arteriosus in the human preterm neonate: are there implications for further improvement of postoperative outcome? Mod Prob Paediatr 1985;23:143-157. [This article is difficult to find, as it was published in a quarterly journal that went out of business before online collections were available. I will be happy to send readers a copy on request.]
2. Rackow H, Salanitre E, Green LT. Frequency of cardiac arrest associated with anesthesia in infants and children. Pediatrics 1961;28:697-704. PMID: 14489693
3. Smith RM. The pediatric anesthetist, 1950-1975. Anesthesiology 1975;43:144-155. PMID: 1098517
4. Williamson PS, Williamson ML. Physiologic stress reduction by a local anesthetic during newborn circumcision. Pediatrics 1983;71:36-40. PMID: 6848976
5. Maxwell LG, Yaster M, Wetzel RC, Niebyl JR. Penile nerve block for newborn circumcision. Obstet Gynecol 1987;70:415-419. PMID: 3627593
6. Anand KJ, Sippell WG, Aynsley-Green A. Randomised trial of fentanyl anaesthesia in preterm babies undergoing surgery: effects on the stress response. Lancet 1987;1:243-248. PMID: 20928962
7. Lerman J, Robinson S, Willis MM, Gregory GA. Anesthetic requirements for halothane in young children 0-1 month and 1-6 months of age. Anesthesiology 1983;59:421-424. PMID: 6638549
8. LeDez KM, Lerman J. The minimum alveolar concentration (MAC) of isoflurane in preterm neonates. Anesthesiology 1987;67:301-307. PMID: 3631603
9. Yaster M. The dose response of fentanyl in neonatal anesthesia. Anesthesiology 1987;66:433-435. PMID: 3826708
So glad to see one of the greats of Pediatric Anesthesia recognized in this PAAD: My friend Lynne Maxwell. A true leader and mentor to female anesthesiologists.