Comparison and evaluation of various bedside tests to predict difficult endotracheal intubation.

Introduction: As difficult laryngoscopy is a multifactorial problem, therefore any preoperative assessment of difficult tracheal intubation should have high sensitivity and specificity and result in minimal false positive and false negative values. This study was conducted in an attempt to devise a method of predicting difficult intubation and to assess the reliability of six simple bedside tests to predict difficult intubation. Material and Methods: This double blind prospective study involved 100 adult patients posted for elective surgery under general anesthesia. The airways were assessed for modified Mallampati test, Thyromental Distance, Sternomental Distance, Inter incisor gap; Atlanto-Occipital joint extension and Upper Lip bite Test. The laryngoscopic view and difficulty of intubation were noted. The sensitivity, specificity, positive and negative predictive values were calculated. Results: No method either individual or in combination with others had 100% sensitivity. The Modified Mallampati test had 76% sensitivity. Upper Lip bite Test had 98.66% specificity. The combination of Modified Mallampati test and Inter incisor gap had 52% sensitivity and 86.66% specificity. Conclusion: The “composite intubation difficulty score” is an easy and reliable method of predicting difficult intubation.

The predictive value of five factors to the maternal difficulty airway / 实用医学杂志

Objective To research the most commonly used five method to evaluated the difficulty airway , and compare which methods were more suited for the pregnant woman in general anesthesia. Methods 214 patients with full-term pregnancy who requested emergency or elective caesarean-section were assigned. During the pre-anesthetic visit,we evaluated patients from Mallampati score, thyromental distance, body mass index (BMI), inter-incisor gap, and upper lip bite test. After endotracheal intubation ,patients were divided into 2 groups based on Cormack classification. Results Five ways sensitivity descending order were upper lip bite test (79.5%)、Mallampati score (76.9%)、BMI (56.4%)、inter-incisor gap (51.3%)、thyromental distance (35.9%); specificity descending order were upper lip bite test (93.1%)、Mallampati scores (86.3%)、inter-incisor gap (85.1%)、thyromental distance (76.6%)、BMI (62.3%). Conclusions In pregnant women ,Mallampati score and the upper lip bite test are the better indicators to predict difficult airway.