///2014 Abstract Details
2014 Abstract Details2019-07-18T14:34:47-06:00

General Anesthesia and Endotracheal Intubation Experience from an Academic Labor & Delivery Service

Abstract Number: S-26
Abstract Type: Original Research

Adam J Sachs MD1 ; Rich Smiley MD, PHD2

Introduction: General anesthesia (GA) is discouraged during cesarean delivery (CD) because the physiological changes of pregnancy are thought to result in a higher incidence of difficult intubation (DI) and aspiration, although this has been questioned in recent years.

Methods: The records for all GA used for cesarean section at an academic institution from September 2008-March 2012 were extracted. Information collected included age, BMI, ASA class (ASA), anesthetic start time, intubation attempts, Cormack-Lehane grade (CLG), esophageal intubation, airway equipment used, difficulty of mask ventilation, and indication for GA. Characteristics of the general anesthetic group were described, and factors potentially associated with difficult intubation were examined. DI was defined as any case requiring more than one attempt at placement of the endotracheal tube. T-tests and Fishers exact test were used to compare the groups (difficult versus not difficult intubation).

Results: 220 (3.5% of 6323 anesthetics) GA cases were performed predominantly for obstetrical emergencies (53%) and failed regional (RA) anesthesia (32%). Overall, 18 (8%) parturients were CLG 3 or 4, 14 (6%) required multiple attempts, 7 (3%) required special airway devices (Glidescope, bougie, etc.), and (3) 1% had esophageal intubations. Of the 14 cases of multiple intubation attempts, 3 required more than two attempts, but all patients were successfully intubated with a combination of Glidescope or bougie. Eleven of the 14 patients (78%) requiring multiple intubation attempts needed ventilation prior to another attempt. One patient required an oral airway (grade 2) to facilitate ventilation, while the remainder needed no airway device (grade 1). No reported cases of aspiration occurred although cricoid pressure was maintained in all cases. Age, BMI, ASA, day versus night cases, or classification as an emergency were not associated with an increased risk of DI.

Discussion: The incidence of DI (6-8%) in parturients may be higher then the quoted 5% in the general surgical population. However, there were no reported cases of aspiration despite 78% of DI patients requiring positive pressure ventilation. This may be secondary to the use of adequate cricoid pressure, low peak pressures, a low incidence of aspiration, or NPO guidelines in laboring parturients. Almost 90% of GA occurred in patients with preexisting RA (failed RA and emergency procedures) reinforcing that practitioners should not have a false sense of security with functioning RA. Our data are consistent with other reports that failed intubation is low in this population because of the accessibility of difficult airway equipment on L and D. Although predictive models of DI in parturients have been largely unsuccessful there is some evidence that increased BMI is associated with DI. Our data contradicts this finding and found that none of the factors analyzed were predictive.

SOAP 2014