Airway Complications in Morbidly Obese Patients Undergoing General Anaesthesia: a Systematic Review

Introduction

The worldwide prevalence of morbid obesity (BMI ≥40 kg/m²) is rising rapidly.¹ While airway complications in obese patients (BMI ≥30 kg/m²) undergoing general anesthesia are well-documented, evidence specifically focusing on morbidly obese patients remains limited.² This systematic review aims to identify airway complications in morbidly obese compared to non-morbidly obese patients undergoing general anesthesia.

Methods

Following the PRISMA 2020 guidelines, five databases were reviewed (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) for studies published from January 2015 to February 2025. The inclusion criteria were as follows: patients ≥18 years with BMI ≥40 kg/m² undergoing general anaesthesia compared to non-morbidly obese patients. Cohort studies, RCTs, case–control studies, and large case series were included. The extracted data was not suitable for meta-analysis due to the heterogeneous nature of the research. Thus, a SWiM approach was undertaken using Stive synthesis and vote counting for direction of effect.

Results

Out of the 2,062 studies screened, 19 publications met the inclusion criteria. Perioperative desaturation was most frequently reported (nine studies), with seven studies showing significant associations (incidence 2.2-35%). Difficult intubation (seven studies) and difficult mask ventilation (five studies) showed inconsistent associations. Airway device failure, reduced apnea time (halved in morbidly obese patients), and increased hospital/ICU length of stay demonstrated positive associations.

Discussion

Perioperative desaturation was consistently associated with morbid obesity. The inconsistent links with difficult intubation or ventilation likely stem from varied outcome definitions and the multifactorial nature of airway difficulty. Future research with standardized outcome measures is needed for this growing patient population.

References

1. World Obesity Federation. Prevalence of Obesity [Internet]. [cited 2025 Feb 23]. Available from: https://www.worldobesity.org/about/about-obesity/prevalence-of-obesity
2. Seyni-Boureima R, Zhang Z, Antoine MMLK, Antoine-Frank CD. A review on the anesthetic management of obese patients undergoing surgery. BMC Anesthesiol. 2022 Apr 5;22(1):98.