The Effectiveness Of Airway Assessment Tools In Predicting A Difficult Airway By Anesthesiologists At Kenyatta National Hospital

Abstract

Introduction: Airway management is the core responsibility of the anesthesiologist in the operating room. Difficult airway has varied definitions and encompasses difficult bag mask ventilation, difficult supraglottic device placement, difficult laryngoscopy, difficult endotracheal intubation and difficult surgical airway. Different predictor methods have been assessed with varying results. Objective: the objective of this study is to determine the effectiveness of the commonly used airway assessment tools by anesthesiologists at Kenyatta National Hospital in predicting difficult airway and to establish the incidence of difficult airway among patients undergoing emergency and elective surgery at Kenyatta National Hospital. Methods: A prospective cross-sectional study at the KNH on 375 patients above 18yrs old undergoing surgery under general anesthesia was done for difficult airway after approval by the research and ethics committee KNH/UON. Upon consenting, the patients’ history, assessment for difficult bag mask ventilation, inter-incisor gap, mallampati score, thyromental distance and sternomental distance were filled in a questionnaire by anesthesia care providers during the pre-anesthesia assessment. During conduct of anesthesia, difficult bag mask ventilation, laryngoscopic view and difficulty or ease of endotracheal intubation and supraglottic device placement was filled in the questionnaire by anesthesia care providers. Results: the incidence of difficult bag mask ventilation, difficult laryngoscopy and difficult intubation were 6.9%, 6.9% and 4.3% respectively. The presence of upper airway mask deformity was a predictor of difficult bag mask ventilation. Interincisor distance less than 3.5cm, mallampati score more than 3, thyromental distance less than 6.5cm were predictors of difficult intubation. The odds of difficult intubation were 2.4 times for every unit increase in Mallampati score. Conclusion: the difficult airway is a significant problem in KNH. Commonly used tools for prediction are effective. A high index of suspicion is required in patients with obesity.