Incidence and Predictors of Difficult Intubation in Patients Undergoing Thyroid Surgery

Abstract

Introduction: Thyroid enlargement is considered a risk factor for challenging direct laryngoscopy and intubation. Airway management in patients with thyroid swelling presents unique challenges, requiring thorough preparation for potential difficult airways. Although airway management in the overall population has been thoroughly researched, there is a scarcity of literature specifically addressing airway management in individuals who have thyroid enlargement. Aim: To evaluate the incidence of difficult intubation in patients undergoing thyroid surgery, utilising the Intubation Difficulty Score (IDS). Materials and Methods: This cross-sectional observational study was conducted among 258 patients in the Department of Anaesthesiology, Government TD Medical College, Alappuzha, Kerala, India. Various parameters including Modified Mallampati score, neck circumference, Body Mass Index (BMI), inter-incisor distance, retrognathia, neck extension, thyromental distance, tracheal deviation, and tracheal compression were assessed for all patients with thyroid swelling. The incidence of difficult endotracheal intubation was analysed using the IDS and the time taken for successful intubation was recorded. Data were presented as mean±standard deviation (SD), frequencies, and percentages. The association between variables was analysed using the Chi-square test. Results: Thyroid disorders were more common in females 220 (85.3%) than in males 38 (14.7%). The variables such as BMI, Mallampati score, thyromental distance, inter-incisor distance, and neck mobility were not found to be associated with difficult intubation. However, increased neck circumference (>43 cm) was statistically significant (p-value=0.007) in relation to difficult intubation. According to IDS, 94.2% of patients had easy intubation, while 5.8% experienced difficult intubation. In terms of intubation times, 72.5% of patients were intubated within 10-15 seconds, 24.4% within 16-20 seconds, and 3.1% took longer than 20 seconds. Conclusion: Thyroid surgery itself is not an independent predictive factor for difficult intubation. Among the predictive factors in the study population, a neck circumference greater than 43 cm was found to be associated with difficult endotracheal intubation during thyroid surgery