Correlation between neck circumference measurement and obesity type with difficult intubation in obese patients undergoing elective surgery

Abstract

Background/Aim: The number of obese patients undergoing elective surgery is increasing day by day. However, there are conflicting data in the literature about factors predicting difficult tracheal intubation in obese patients. The aim of this study was to evaluate the commonly used predictors of difficult intubation in obese patients (body mass index (BMI) >35 kg/m2) who wish to undergo elective surgery and to examine the association of neck circumference and obesity type with difficult intubation. Methods: This observational, cross-sectional, prospective study was performed after obtaining approval from the ethics committee. Obese patients over the age of 18 years, requiring tracheal intubation, undergoing elective surgery, and with a BMI greater than 35 were included in this study. Patients with a history of cervical spine anomaly or trauma, congenital facial anomaly or trauma affecting this region, those who would undergo emergency surgery, patients with a known history of difficult airway or upper respiratory tract disease, and those with planned awake intubation were excluded from the study. Preoperative anesthetic evaluation was performed for all patients, their relevant measurements were obtained, and medical histories were taken as required for the study. The association of the patients’ BMI, Mallampati classification, thyromental distance, Cormack–Lehane grade, obstructive sleep apnea, neck circumference, and obesity type with difficult intubation was evaluated. Preoperative and peroperative measurements were recorded in the follow-up forms. Results: A total of 85 patients, 62 females and 23 males, between the ages of 19 and 77 years were included in this study. A significant difference was found in the patients’ BMI, neck circumference, thyromental distance, Mallampati classifications, and Cormack–Lehane grades in terms of intubation difficulty (P<0.001, P<0.001, P<0.001, P<0.01, P<0.01, respectively). Patients who underwent difficult intubation had lower thyromental distance but greater BMI, neck circumference, Mallampati classification, and Cormack–Lehane grade. It was determined that a neck circumference of >50 cm increased the risk of difficult intubation 8.323 times. Conclusion: Neck circumference and thyromental distance are significant predictors for difficult intubation and laryngoscopy in morbidly obese patients.