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Anesthesiologist Specialization and Use of General Anesthesia for Cesarean Delivery

Cobb, B.T.*; Lane-Fall, M.B.*; Month, R.C.*,†; Onuoha, O.C.*,†; Srinivas, S.K.*,†; Neuman, M.D.*

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doi: 10.1097/01.aoa.0000603596.24954.fb
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Abstract

This was a retrospective cohort study of patients at the Hospital of the University of Pennsylvania with singleton gestation undergoing cesarean delivery between July 1, 2013 and March 30, 2017. The data were collected from anesthesia billing claims. Patients with intrauterine fetal demise were excluded from the study. Patient and team member characteristics were manually extracted via medical record review. The primary outcome was use of general anesthesia for cesarean delivery. Urgency of cesarean delivery was classified as emergent (indicating a threat to the life of the mother or fetus), urgent (maternal or fetal compromise but no immediate threat to life), and elective (cesarean delivery is needed but no maternal or fetal compromise was present).

Of the 4052 cesarean deliveries analyzed, 2649 (65.4%) were performed by obstetric-specialized anesthesiologists, and 1403 (34.6%) were performed by generalists. The rate of general anesthesia in the sample was 9.0% (n=363). Obstetric anesthesiologists performed 193 (53.2%) and generalists performed 170 (46.8%) of the general anesthetics. In the univariate analysis, patients treated by obstetric anesthesiologists were less likely to receive general anesthesia for cesarean delivery (7.3% vs. 12.1%; P<0.001). After adjusting for covariates, the odds of receiving general anesthesia were lower for patients receiving care from an obstetric-specialized anesthesiologist among all patients [adjusted odds ratio (aOR), 0.71; 95% confidence interval (CI), 0.55-0.92; P=0.011]. A subgroup analysis restricted to urgent or emergent cesarean deliveries found treatment by a subspecialist compared with a generalist was associated with reduced odds of general anesthesia (aOR, 0.75; 95% CI, 0.56-0.99; P=0.049). Another subgroup analysis restricted to cesarean deliveries during evening or weekend shifts (on-call) found no association between care by an obstetric-specialized anesthesiologist and the odds of receiving general anesthesia (aOR, 0.76; 95% CI, 0.56-1.03; P=0.085).

In conclusion, the use of general anesthesia for cesarean delivery varied between generalist anesthesiologists and obstetric-subspecialized anesthesiologists. Patients who were treated by a generalist had a 29% increase in the odds of receiving general anesthesia for cesarean delivery. Future studies should focus on confirming these observations in different settings. In addition, differences in the decision-making processes between obstetric-specialized and generalist anesthesiologists should be examined.

COMMENT

In the United States, cesarean delivery accounts for 32% of all births, with ∼1.3 million procedures performed annually.1 General anesthesia, once the primary anesthesia technique for cesarean delivery, is now uncommonly used and represents <5% of anesthetics for elective cesarean delivery in the United States.2 Factors that have contributed to the increased adoption of neuraxial anesthesia for cesarean delivery include increased use of neuraxial labor analgesia techniques (now >70%3) and the potential to convert to epidural surgical anesthesia for an urgent cesarean delivery, better quality of neuraxial anesthesia with addition of neuraxial opioids, increased popularity of spinal anesthesia due to improved spinal needle design (which has reduced the incidence of postdural puncture headache), and the ability for the mother to be awake (and her partner to be present) to experience the childbirth. Parturients have an increased risk of airway complications such as failed intubation and pulmonary aspiration during general anesthesia, and overall anesthesia-related maternal mortality has declined appreciably with transition to neuraxial techniques.4

However, there may be situations when general anesthesia is unavoidable, due to the urgency of delivery, failed attempt to initiate neuraxial anesthesia, or because it is contraindicated.

The retrospective cohort study by Cobb et al5 studied the association between anesthesia provided by an obstetric-subspecialized anesthesiologist and the mode of anesthesia for cesarean delivery. This single-center study was conducted at a large academic medical center with a mixed staffing model of obstetric-specialized and nonobstetric-specialized (ie, generalist) anesthesiologists in the labor and delivery unit.

After adjusting for covariates, the investigators found that patients managed by an obstetric-specialized anesthesiologist were less likely to receive general anesthesia for cesarean delivery than patients managed by a generalist anesthesiologist. This finding was confirmed in a subgroup analysis restricted to urgent or emergent cesarean deliveries. Although a subgroup analysis of on-call cesarean deliveries did not show a difference between specialist and generalist anesthesiologists, the 95% CI of the odds ratio was wide and a clinically significant difference cannot be ruled out.

Other investigators have found a similar relationship between obstetric specialization and lower odds of receiving general anesthesia for cesarean delivery in populations restricted to women who had an epidural catheter sited for labor analgesia and subsequently had an intrapartum cesarean delivery.6,7 Although there are obvious differences in the training and skills of the obstetric-specialized anesthesiologist compared with the generalist, the reason(s) for the differences in practice patterns between the 2 groups remains unknown. Possible reasons include differences in knowledge of guidelines regarding mode of anesthesia and different skill sets and comfort levels with different modes of anesthesia, including the ability to successfully convert epidural labor analgesia to surgical anesthesia. The difference between the 2 groups may be due to the smaller number of obstetric-specialized anesthesiologists, and therefore, less variability in clinical practice compared with generalists.5 It is likely that the urgency to deliver the fetus is the main factor that influences the decision to administer general anesthesia. As noted by the authors, differences in communication and the level of trust between the obstetric-specialized anesthesiologist and obstetricians may allow for more nuanced shared decision-making when a specialist is caring for the patient, especially for urgent and emergent deliveries.

The primary goal of any chosen anesthesia technique is to provide the best maternal and neonatal outcomes, and a one size fits all approach is not appropriate. Although it is generally thought that neuraxial anesthesia is preferred to general anesthesia, this is not the case for every patient, and some patients will require general anesthesia to facilitate the best outcome for mother and neonate. Thus, a high general anesthesia rate is probably not appropriate, but a rate of 0 is also not appropriate. Where is the “sweet spot (rate)”? We do not know. Does the “sweet spot” differ for anesthesiologists with different training? We do not know this either. This study sheds light on the differences in practice patterns between the obstetric-specialized anesthesiologist and the generalist, but it does not shed light on the reasons for this difference, nor whether this difference should be cause for concern. Future research should investigate the differences in decision-making between obstetric-specialized and the generalist anesthesiologist and its influence on mode of anesthesia and outcomes.

Comment by Unyime Ituk, MBBS and Cynthia A. Wong, MD

REFERENCES

1. Martin JA, Hamilton BE, Osterman MJK. Births in the United States, 2018. NCHS Data Brief. 2019:1–8.
2. Traynor AJ, Aragon M, Ghosh D, et al. Obstetric Anesthesia Workforce Survey: a 30-year update. Anesth Analg. 2016;122:1939–1946.
3. Butwick AJ, Wong CA, Guo N. Maternal body mass index and use of labor neuraxial analgesia: a population-based retrospective cohort study. Anesthesiology. 2018;129:448–458.
4. Hawkins JL, Chang J, Palmer SK, et al. Anesthesia-related maternal mortality in the United States: 1979–2002. Obstet Gynecol. 2011;117:69–74.
5. Cobb BT, Lane-Fall MB, Month RC, et al. Anesthesiologist specialization and use of general anesthesia for cesarean delivery. Anesthesiology. 2019;130:237–246.
6. Bauer ME, Kountanis JA, Tsen LC, et al. Risk factors for failed conversion of labor epidural analgesia to cesarean delivery anesthesia: a systematic review and meta-analysis of observational trials. Int J Obstet Anesth. 2012;21:294–309.
7. Campbell DC, Tran T. Conversion of epidural labour analgesia to epidural anesthesia for intrapartum cesarean delivery. Can J Anaesth. 2009;56:19–26.
Keywords:

General Anesthesia for Cesarean Section; Regional Anesthesia for Cesarean Section; Systems Based Practice

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