Airway events in pregnant patients with morbid obesity undergoing caesarean delivery under general anaesthesia: a retrospective cohort study (2015-2024).

BACKGROUND

Airway management in morbidly obese obstetric patients is challenging, with increased risk of difficult ventilation, failed intubation, and maternal morbidity. By focusing exclusively on pregnant patients with a BMI 40 kg/m2, this study aimed to quantify the frequency and types of airway complications occurring during cesarean section under general anesthesia, stratified by obesity class. The secondary objective was to identify risk factors for difficult mask ventilation, difficult laryngoscopy, and difficult airway.

METHODS

This retrospective cohort study included all 315 pregnant patients aged ≥ 18 years with a BMI ≥ 40 kg/m2 who underwent caesarean delivery under general anaesthesia between January 2015 and December 2024. Data on demographics, comorbidities, airway assessments, intubation metrics, and perioperative complications were extracted from electronic medical records. Statistical analyses included correlation testing, group comparisons, and multivariable logistic regression (adjusted for age, BMI, and comorbidties).

RESULTS

A total of 315 patients with morbid obesity were analyzed (Class III: 94.3%; Class IV/V: 5.7%). Overall, the most common airway-related complication was cardiovascular instability (7.9%), followed by laryngospasm (1.6%). When stratified by obesity class, cardiovascular instability was similar in Class III and IV, while other airway complications were generally rare and varied. A positive correlation was observed between BMI and peak airway pressure post-intubation. Thyromental distance inversely correlated with intubation attempts (r = -0.150, P = 0.008) and showed the strongest predictive value (OR 0.22, 95% CI 0.11-0.44; P < 0.001) for difficult mask ventilation. Perioperative complications were infrequent: cardiovascular instability (7.9%) and desaturation < 94% during intubation (1.0%).

CONCLUSION

In conclusion, cardiovascular instability was the most common airway-related complication, difficult airway incidence increased with obesity class, and thyromental distance was the most consistent predictor, highlighting the need for tailored airway management in obstetric patients with morbid obesity.