Progesterone Effects on Airway Outcomes in Outpatient Deep Sedation at the Massachusetts General Hospital Oral and Maxillofacial Surgery Clinic

Parenteral anesthesia is an integral part of oral and maxillofacial surgery. In 95.5% of outpatient parenteral anesthesia cases the operating surgeon is the primary anesthetist¹. Therefore, loss of ventilatory drive and airway patency during anesthesia can require the surgeon to employ maneuvers to support patient respiratory function, interrupting the procedure.

Pregnant females demonstrate increased ventilatory drive attributable to increased progesterone levels.  Additionally, the phase of a woman’s menstrual cycle may affect ventilatory drive due to varying progesterone levels.² Finally, oral contraceptive pills (OCPs) induce a state of anovulation that mimics pregnancy through negative feedback effects of synthetic progesterone on the hypothalamus-pituitary-ovary axis.

This study compared maneuvers employed on OCP females and non-OCP females during outpatient anesthesia to determine if a high-progesterone state decreases procedural interruptions. This study also examined airway maneuver differences between females in the follicular phase (FP) and the high progesterone luteal phase (LP).

Females aged 18-45 undergoing outpatient oral and maxillofacial surgery procedures under anesthesia at Massachusetts General Hospital between August 2013 and January 2015 were approached to participate in the study. Non-OCP females were eligible if they self-reported eumenorrhea. Subjects replied to an oral survey about their menstrual status, gave a blood sample to test their pre-operative serum progesterone level and were observed during their procedure for airway maneuvers performed by the surgeon in response to oxygen desaturations. Five surgeons were involved in the study and were not blinded to the presence of the single trained observer. This study was approved by the MGH Institutional Review Board #2013P-001143.

Descriptive statistics were completed. A univariate analysis model was done and independent variables with p ≤ 0.15 were utilized in a multivariate analysis model to determine significance which was set at p ≤ 0.05.

A total of thirty-two females participated in the study; sixteen females on OCPs, and sixteen females not on OCPs (ten FP, six LP). Mean progesterone level for OCP females was 0.29 (range 0.1-1). For non-OCP FP females the mean was 0.30 (range 0.2-0.6). In non-OCP LP females the mean was 4.33 (range 1.5-8.4). Five airway maneuvers were executed throughout all thirty-two procedures. Four in three females on OCPs, one in a non-OCP female in the FP of her menstrual cycle and none in females in the LP of their menstrual cycle.  All non-OCP females accurately predicted the phase of their menstrual cycle.

There was no significant difference in necessary airway maneuvers between OCP and non-OCP females (p > 0.05). There was also no statistical significance in the effect of progesterone level on necessary airway maneuvers (p > 0.05).

This preliminary study was likely under-powered due to an incorrect assumption about the number of airways maneuvers that occur and the potential for difference in the two groups. Though no statistical significance was found between the OCP and non-OCP groups, all airway maneuvers occurred in females with FP levels of progesterone regardless of OCP use. This preliminary study indicates that low endogenous progesterone levels either through OCP use or a natural menstrual cycle follicular phase may increase occurrence of oxygen desaturations necessitating airway maneuvers that interrupt procedural flow. Further studies with adequate power are necessary to determine if there is a true correlation.

1. Perrot DH, Yuen JP, Andresen RV, Dodson TB. Office-based ambulatory anesthesia: outcomes of clinical practice of oral and maxillofacial surgeons. J Oral Maxillofac Surg. 61:983-95; 2003

2. Bayliss DA, Millhorn DE. Central neural mechanisms of progesterone action: application to the respiratory system. J Appl Physiol 73:393–404; 1992