Comparison of Supreme laryngeal mask airway versus endotracheal intubation for airway management during general anesthesia for cesarean section: a randomized controlled trial

Abstract

Background: The obstetric airway is a significant cause of maternal morbidity and mortality. Endotracheal intubation is considered the standard of care but the laryngeal mask airway (LMA) has gained acceptance as a rescue airway and has been incorporated into the obstetric airway management guidelines. In this randomized controlled equivalence trial, we compared the Supreme LMA (SLMA) with endotracheal intubation (ETT) in managing the obstetric airway during cesarean section.

Methods: Parturients who underwent elective cesarean section under general anesthesia were randomized to receive either an SLMA or ETT as their airway device. Our primary outcome was first-attempt insertion success. Successful insertion was defined as adequate bilateral air entry with auscultation and the presence of end-tidal carbon dioxide on the capnogram. The first-attempt insertion success rate was compared using the Chi-Square test. Secondary outcomes included time-to-ventilation, seal pressure, ventilation/hemodynamic parameters, occurrence of clinical aspiration, fetal outcomes, and maternal side effects associated with the airway device.

Results: We recruited 920 parturients (460 SLMA, 460 ETT) who underwent elective cesarean section under general anesthesia. Patient characteristics were similar between the groups. First attempt success was similar (Odds Ratio--OR_SLMA/ETT: 1.00 (95%CI: 0.25, 4.02), p = 1.0000). SLMA was associated with reduced time to effective ventilation (Mean Difference--MD -22.96; 95%CI: - 23.71, - 22.21 s) compared to ETT group (p < 0.0001). Ventilation parameters, maternal and fetal outcomes were similar between the groups, and there was no aspiration.

Conclusions: SLMA could be an alternative airway management technique for a carefully selected low-risk obstetric population, with similar insertion success rates, reduced time to ventilation and less hemodynamic changes compared with ETT. Our findings are consistent with the airway guidelines in recommending the second-line use of LMA in the management of the obstetric airway.

Trial registration: The study was registered at http://www.clinicaltrials.gov , identifier: NCT01858467 , retrospectively registered. Date of registration: May 21, 2013.

Keywords: Cesarean section; General anesthesia; Laryngeal mask airway; Obstetric.

Fig. 1

Consort diagram. 998 parturients who were planned for elective cesarean section in Quanzhou Women’s and Children’s Hospital were screened between May 2013 and July 2014. Inclusion criteria: singleton pregnancy, aged 18 to 50 years old, ASA 2, and fasted for at least 6 h. Parturients with potentially difficult airway, known reflux disease, or with BMI ≥ 35 kg/m² were excluded. 49 parturients refused consent, and 29 did not meet the recruitment criteria. The remaining 920 parturients were randomized by opaque envelope to obtain 460 in each group. There were no dropouts or withdrawal