Evaluation of difficult airway in paediatric population ranging from 5-12 years age group

Background: The aim of this study is to predict difficult airway on the basis of various airway assessment parameter in the paediatric population between 5-12 years age group. To assess the value of modified Mallampati test (MMT), upper-lip-bite test (ULBT), thyromental distance (TMD), ratio of height to thyromental distance (RHTMD) from which Cormack Lehane grade was derived to predict difficult airway i.e. difficult intubation in paediatric patients ranging from 5-12 years age. Material and Methods: 100 ASA grade I & II paediatric patients of either sex between the age group of 5-12 years posted for elective surgery under general anaesthesia requiring endotracheal intubation were included in the study. Modified Mallampati test, upper lip bite test, thyromental distance and ratio of height to thyromental distance of the patients were measured and recorded. All the distances were measured with the help of a flexible measuring tape so as to measure the distances accurately. Results: Modified Mallampati test has the highest sensitivity (75%) and specificity (92.05%) among all the other screening tests. It also has high positive predictive value (56.25%), negative predictive value (96.43%) and diagnostic accuracy (90%). Upper Lip Bite test has high specificity (79.55%) and negative predictive value (93.33%) with high diagnostic accuracy (77%). It has a sensitivity of 58.33% which is similar to the sensitivity of thyromental distance and ratio of height to thyromental distance. Thyromental distance has high specificity (65.90%) with high negative predictive value (92.06%). Conclusion: Modified Mallampati test is a useful bedside screening test for predicting difficult intubation in patients between 5-12 years age group. The Upper Lip bite test and thyromental distance has high specificity with high negative predictive value and diagnostic accuracy. The ratio of height to thyromental distance is least useful predictor of airway assessment.

Comparison Of Upper Lip Bite Test And Modified Mallampati Classification In Predicting Difficult Intubation

Introduction : Airway management is of prime importance to the Anaesthesiologist for securing the airway, tracheal intubation using direct laryngoscopy remains the method of choice in many cases. Difficult laryngoscopic endotracheal intubation still remains an important concern of anaesthesiologists. The incidence of difficult endotracheal intubation were reported to be between 1.5% to 13% among patients undergoing surgery. The present study was conducted with the primary aim to evaluate sensitivity, specificity, accuracy, negative predictive value and positive predictive value of Upper Lip Bite Test and Modified Mallampati Classification to predict difficult intubation in patients undergoing any elective surgery under general anesthesia. Material & Methods : A single-blind, Prospective Observational (Analytical) study was conducted in Krishna Institute of Medical Sciences, Hospital and Research Centre, Karad, Maharashtra after the approval from the institutional ethical committee. Asample size of 181 patients of both gender, between 20 and 50 years of age, belonging to ASAphysical Status I-II scheduled to undergo elective surgery under general anaesthesia with endotracheal intubation were evaluated for both test before surgery after fulfilling the inclusion criteria. A senior Anaesthesiologists having minimum five years of experience in clinical anaesthesia who unaware of preoperative airway assessment, performed laryngoscopy and grading as per Cormack and Lehane's classification. Senstivity, specificity,accuracy, positive and negative predictive values of Upper lip bite test and Modified Mallampati Classification were calculated. Results:We compared various accuracy parameters of both the methods (MMTand ULBT), we observed that MMT(88.23% Vs. 76.47%) has got higher sensitivity, higher specificity of (89.02% Vs. 87.19%), higher positive predictive value (45.45% Vs. 38.23%) and higher negative predictive value (98.64% Vs. 97.27%) as compared to ULBT. Conclusion : In comparison with ULBT, MMT has got better predictive ability for difficult endotracheal intubation. MMT and ULBT appear to be better predictors for easy intubations rather than difficult intubations (high negative predictive value). Combination of MMT and ULBT has got better diagnostic accuracy as compared to MMTor ULBTalone.

Comparison of predictors of difficult intubation

Context: Unanticipated difficult laryngoscopy and tracheal intubation always remain a primary concern for an anaesthesiologist as the failure to maintain a patent airway during induction of anaesthesia may lead to anaesthesia related morbidity and mortality. Aims: The aim of our study was to predict difficult intubation and to identify best predictor(s) among them and also to compare the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of various airway parameters.Airway parameters taken in our study were Modified Mallampati Classification (MMT), Thyromental Distance (TMD), Sternomental Distance (SMD), Interincisor Gap (IIG), Upper Lip Bite Test (ULBT), Degree of Neck Extension (DNE), Anterior Subluxation of Mandible (ASM) and Protruding Teeth (PT). Methods and Material: 350 patients of ASA Grade 1 and 2 scheduled for various elective surgeries under general anaesthesia were included in our study and were assessed preoperatively for different airway parameters. Intraoperatively all patients were classified as difficult and easy intubation group according to Cormack and Lehane laryngoscopic view. Clinical data of each test was collected, tabulated and analyzed to obtain the sensitivity, specificity, positive predictive value and negative predictive value. Results: The upper lip bite test had the highest sensitivity (80%); Anterior subluxation of mandible had highest specificity (99.06%) and both of above were most accurate tests. The overall incidence of difficult intubation was 8.57%. Conclusion: Upper lip bite test was the best predictor of difficult intubation and it should be included as a routine test along with Modified mallampati test in preanaesthetic evaluation.

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.

Prediction of Difficulty in Endotracheal Intubation in Patients with Obstructive Sleep Apnea: Comparison of Modified Mallampati Test and Upper Lip Bite Test / 대한마취과학회지

BACKGROUND: Patients with obstructive sleep apnea (OSA) may exhibit difficult endotracheal intubation and mask ventilation because of anatomical abnormalities of their upper airway. Many anesthesiologists try to predict difficult endotracheal intubation using simple bedside screening tests. Among these tests, modified Mallampati test (MMT) is the most popular one, but a newer method, called upper lip bite test (ULBT) has been investigated. We compared the clinical accuracy of modified Mallampati test and upper lip bite test for patients with OSA. METHODS: 65 patients with OSA were included in the study. Preoperatively, anestheiologist not involved in endotracheal intubation evaluated patient's airway with MMT and ULBT. Another anesthesiologist assessed the direct laryngoscopic grade. Using Fisher's exact test, we analyzed the correlation of MMT and ULBT with direct laryngoscopic grade and calculated the sensitivity, specificity, positive predictive value and negative predictive value. Furthermore, AUC of ROC (area under a receiver operating characteristic) curve were used to estimate the predictive accuracy of each tests. RESULTS: MMT grade III, IV and ULBT class III was significantly correlated with Cormack-Lehane grade III, IV (P < 0.05). The ULBT showed higher specificity and positive predictive value, but sensitivity and negative predictive value were higher in MMT. AUC of ROC curve was poor for MMT (0.656) and ULBT (0.617). CONCLUSIONS: These results suggest that MMT and ULBT has a poor diagnostic accuracy for predicting difficult intubation in OSA patients as a single bedside screening test.

The Evaluation of Predictability of Difficult Intubation Using Upper Lip Bite Test / 대한마취과학회지

BACKGROUND: The unexpected difficult endotracheal intubation is a significant contributor to mortality and morbidity in clinical practice. Although there are many methods to predict difficult intubation, modified Mallampati test (mMT) and airway score were popular tests. The authors wanted to compare upper lip bite test (ULBT) with those two tests and also explored the possibility that ULBT could be a good sole predictor for difficult intubation. METHODS: 322 patients who were ASA I or II, aged > 16yr were enrolled in this study. Three residents visited patients to obtain airway measurements such as 1) ULBT, 2) mMT, 3) airway score (inter-incisor gap, mMT, thyromental distance, head & neck movement, history of difficult intubation, buck teeth). They were not involved in the intubation of patients they evaluated. The accuracy, specificity, positive and negative predictive values were calculated from the data of three tests, and three tests were compared with patient's laryngoscopic view grade according to Cormack & Lehane criteria by using Chi-square test. RESULTS: The incidence of Cormack & Lehane grade III, IV was 14.6% (not applied external laryngeal pressure). ULBT showed significantly higher specificity, positive predictive value than mMT, but sensitivity was lower than other tests. There were significant correlations between ULBT class III and Cormack & Lehane laryngoscopic grade III, IV (P< 0.001). CONCLUSIONS: ULBT is good for predicting difficult intubation as a simple, single test. But because of it's low sensitivity, it seems better to incorporate ULBT as a factor of airway score tests for more reliable prediction.