Preoperative Predictors of Poor Laryngoscope Views in Pediatric Population Undergoing Cardiac Catheterization

BACKGROUND: The primary objective of this study was to identify pre-anesthetic airway assessment parameters that would predict Cormack and Lehane grade III and IV laryngoscopy views in pediatric patients undergoing cardiac catheterization procedures. The secondary end points were to identify factors that would contribute to difficult laryngoscope views in this subset of patients. SETTINGS AND DESIGN: Prospective observational study performed at a single tertiary cardiac care center. MATERIALS AND METHODS: 199 children below 5 years of age undergoing elective cardiac catheterization were included. Pre-anesthetic airway assessment was done by modified Mallampati grading, lower lip to chin distance [LCD], tragus to mouth angle [TMA], thyromental distance [TMD], neck circumference [NC], and the ratio of height to thyromental distance [RHTMD]. Demographic data including American Society of Anesthesiologists physical status [ASA PS] were recorded for each child. Receiver Operating Characteristic curves were plotted and Areas Under the Curve were measured to identify the best cut off values for each of the airway evaluation method that would predict poor laryngoscopy views as well as assess their accuracy in doing so. RESULTS: LCD, TMD and low body mass index were found to have good sensitivity, specificity and accuracy in predicting Grade III and IV laryngoscope views. ASA PS grade III and above patients had a significantly higher incidence of poor laryngoscope visualization. CONCLUSIONS: LCD, TMA, TMD, NC, RHTMD and BMI could all be used combinedly as screening tools during pre-anesthetic airway evaluation for predicting difficult laryngoscope views in children. Among these, LCD, TMD along with low body mass index might have better accuracy.