Use of simple clinical predictors on preoperative diagnosis of difficult endotracheal intubation in obese patients.

BACKGROUND AND OBJECTIVES: Although the incidence of difficult laryngoscopy is similar in obese and non-obese patients, there are more reports of difficult intubation in obese individuals. Alternatives for the diagnosis and prediction of difficult intubation in the preoperative period may help reduce anesthetic complications in obese patients. The aim of this study was to identify predictors for the diagnosis of difficult airway in obese patients, correlating with the clinical methods of pre-anesthetic evaluation and polysomnography. We also compared the incidence of difficult facemask ventilation and difficult laryngoscopy between obese and non-obese patients, identifying the most prevalent predictors.
METHODS: Observational, prospective and comparative study, with 88 adult patients undergoing general anesthesia. In the preoperative period, we evaluated a questionnaire on the clinical predictors of the obstructive sleep apnea syndrome (OSAS) and anatomical parameters. During anesthesia, we evaluated difficult facemask ventilation and laryngoscopy. Descriptive statistics and correlation test were used for analysis.
RESULTS: Patients were allocated into two groups: obese group (n=43) and non-obese group (n=45). Physical status, prevalence of snoring, hypertension, diabetes mellitus, neck circumference, and Mallampati index were higher in the obese group. Obese patients had a higher incidence of difficult facemask ventilation and laryngoscopy. There was no correlation between anatomical or clinical variable and difficult facemask ventilation in both groups. In obese patients, the diagnosis of OSAS showed strong correlation with difficult laryngoscopy.
CONCLUSIONS: The clinical and polysomnographic diagnosis of OSA proved useful in the preoperative diagnosis of difficult laryngoscopy. Obese patients are more prone to difficult facemask ventilation and laryngoscopy.