Comparison of airway assessment tests for prediction of difficult intubation in obese patients: importance of thyromental height and upper lip bite test

Introduction: The prediction of difficult intubation using simple bedside test is of great importance to prevent mismanagement of airway. This study was conducted to compare Upper Lip Bite Test (ULBT) with Modified Mallampati Test (MMT) and Thyromental Distance (TMD) for the prediction of difficult intubation. Method: This was descriptive cross-sectional study conducted in 121 patients of American Society of Anaesthesiologists Physical Status (ASA PS) I and II patients scheduled for elective surgery requiring general anaesthesia with endotracheal tube. The airway assessment of the patients was done one day prior to the surgery using Upper Lip Bite Test (ULBT), Modified Mallampati Test (MMT) and measurement of Thyromental Distance (TMD) . On the day of surgery during laryngoscopy, Cormack-Lehane (CL) grading was recorded. The CL grading of III and IV was labeled as difficult intubation. The Sensitivity, Specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), Likelihood Ratio (LR) of ULBT, MMT and TMD were calculated and compared. Results: The total percentage of difficult intubation, defined by Cormack-Lehane (CL) III and IV was 16.52 %. The sensitivity, specificity, PPV, NPV and accuracy of Upper Lip Bite Test (ULBT) was 50%, 100%, 100%, 91% and 91.74% respectively. ULBT had a significantly higher sensitivity, specificity and PPV when compared to MMT or TMD or MMT and TMD when combined together. Conclusions: Upper Lip Bite Test (ULBT) is better predictor of difficult intubation and it should be used along with other test during airway assessment.

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Comparison of validity of airway assessment tests for predicting difficult intubation

The Indian Anaesthetists Forum ◽

10.4103/theiaforum.theiaforum_31_17 ◽

2017 ◽

Vol 18 (2) ◽

pp. 63 ◽

Cited By ~ 2

Author(s):

Balaji Kuppuswamy ◽

Chitra Srinivasan

Keyword(s):

Difficult Intubation ◽

Airway Assessment ◽

Assessment Tests

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Comparison of Upper Lip Bite Test and Ratio of Height to Thyromental Distance in Predicting Difficult Tracheal Intubation in South Indian Population – A Descriptive Study

Journal of Evidence Based Medicine and Healthcare ◽

10.18410/jebmh/2021/447 ◽

2021 ◽

Vol 8 (27) ◽

pp. 2412-2416

Author(s):

Baseema Thayyil ◽

Neetha Thattaparambil Chandran ◽

Asish Karthik ◽

Maya Gomathy Amma

Keyword(s):

Tracheal Intubation ◽

General Anaesthesia ◽

Difficult Intubation ◽

Descriptive Study ◽

Kappa Statistics ◽

Fisher Exact Test ◽

South Indian Population ◽

Upper Lip ◽

Airway Assessment ◽

South Indian

BACKGROUND Failure in managing the airway is the most important cause of death in patients undergoing general anaesthesia (GA). For effectively preventing airway catastrophe it is essential to have a meticulous airway assessment pre-operatively. Many methods are in use to predict difficult airway like Mallampati, Wilson’s scoring, percentage of glottic opening (POGO) scoring, Cormack - Lehane classification, thyromental distance, mandibular hyoid distance, atlantooccipital joint extension etc. In this study, we compared between two popular methods of airway assessment, upper lip bite test (ULBT) and height to thyromental distance ratio (RHTMD) to predict the difficulty in tracheal intubation. METHODS This descriptive study was conducted at Government Medical college, Thrissur, over a period of one year , on 76 patients of American society of Anaesthesiologist (ASA) - PS l - lll, requiring general anaesthesia. ULBT and RHTMD were used to assess the patient’s airway. It was correlated with Cormack - Lehane classification during direct laryngoscopy. The data was analysed using Fisher exact test (P < 0.05) and Kappa statistics. RESULTS Out of the 76 patients, 41 (53.9%) were women 35 were men (46.1 %). ULBT predicted 89.6 % [25 + 43] belonging to class 1 and 2 as easy, while 10.5 % [8] of class 3 as difficult. RHTMD predicted 35 patients (46 %) as easy (grade 1) and 41 patients (54 %) as grade 2. Using ULBT, of the 8 patients predicted to have difficult intubation (Class 3), 2 were found practically difficult and 6 were easy. In remaining 68 patients, 23 patients had difficult view and 45 had easy view. According to Cormac and Lehane, among 41 patients who predicted difficult by RHTMD, 19 patients were practically difficult and 22 were easy. Of 35 patients, 6 patients were difficult and 29 were easy. CONCLUSIONS The RHTMD is more sensitive compared to ULBT in predicting difficult intubation. As assessed by Cormack - Lehane classification. KEYWORDS Difficult Intubation, Ratio of Height to Thyromental Distance, Upper Lip Bite Test

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There is a new scale for difficult intubation in obese patients undergoing elective surgery-The neck circumference and other airway assessment test

Trends in Anaesthesia and Critical Care ◽

10.1016/j.tacc.2018.09.058 ◽

2018 ◽

Vol 23 ◽

pp. 31

Author(s):

Nicoleta Alice Dragoescu ◽

Andreea Doriana Stanculescu ◽

Alin Ionut Patru ◽

Anca Lidia Vilcea ◽

Andreea Badea ◽

...

Keyword(s):

Difficult Intubation ◽

Elective Surgery ◽

Neck Circumference ◽

Obese Patients ◽

Airway Assessment

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Comparative Study between two Ultrasound Aided Methods in PreoperativeAssessment of Difficult Airway in Obese Patients

QJM ◽

10.1093/qjmed/hcab086.036 ◽

2021 ◽

Vol 114 (Supplement_1) ◽

Author(s):

Galal Aboul-so’od Saleh ◽

Sherif Anis George ◽

Gamal Eldin Adel Abdelhamid ◽

Hazem Sameer Swedan

Keyword(s):

Difficult Intubation ◽

Direct Laryngoscopy ◽

Neutral Position ◽

Obese Patients ◽

Tissue Thickness ◽

Exclusion Criteria ◽

Airway Assessment ◽

Thyrohyoid Membrane ◽

Lehane Grade ◽

Significant Difference

Abstract Background Unpredictable difficult laryngoscopy remains a challenge for anaesthesiologists, especially if difficult ventilation occurs. So, accurate airway assessment should always be performed so as to provide appropriate planning and management of expected difficult intubation and to limit any unexpected difficulties. Airway assessment using ultrasound has been proposed recently as a useful, simple and non-invasive bed side tool as an adjunct to clinical methods. Objective To establish whether correlations existed between two ultrasound measurements and the Cormack–Lehane grade during direct laryngoscopy, and whether these measurements are useful in predicting are stricted or difficult view especially in morbid obese individuals. The first is the measurement of the hyomental distance of the patient in neutral position of the neck and in fully extended neck calculating the ratio between both of them. While the second is the measurement of anterior cervical soft tissue thickness at three anatomical levels (hyoid bone, thyrohyoid membrane or ‘pre epiglottic space’ and anterior commissure). We chose these two new measurements from among the various ultrasound assessments made in previous studies because of their simplicity of execution in normal clinical and in emergency settings. Patients and Methods The current study is a prospective comparative clinical trial of assessment of difficult air way using two different ultrasound aided techniques in comparison to Cormack and lehane scoring system. Those patients were chosen upon some inclusion and exclusion criteria; inclusion criteria were (Age of the patient (25-60y), ASA I-II patients, Obese patients with body mass index > 30 kg /m2 and Pts undergoing bariatric surgery) and exclusion criteria were (Pathology of the airway (tumors), Deformity of the airway anatomy (burns, scars), History of facial, cervical, pharyngeal and epiglottis surgery or trauma, Patients with most teeth lost and Patient refusal). Results Regarding U/S measurements in method A patients; the average HMD-neutral of A patients was (53.58±5.33) mm, the average HMD-extension was (58±7.82) mm, and the average HMDR was (1.07±0.06). It showed highly significant decrease in HMD extension and HMDR in difficult group, compared to easy group, in A group of patients (p < 0.01respectively). Non-significant difference as regards HMD-neutral U/S measurements in method A (p > 0.05). Conclusion Ultrasonography can be a valuable adjunct in this aspect of airway assessment. Ultrasound assessment of pre-epiglottic tissue thickness at the level of the thyrohyoid membrane may be useful to predict restricted/difficult direct laryngoscopy and difficult intubation. The ratio of hyomental distance between neutral and extended positions may also be a good predictor of difficult direct laryngoscopy.

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Description and comparison of the performance of the upper lip bite test, the ratio of height to thyromental distance and other methods of preoperative airway assessment in a Nigerian population – a pilot study

Southern African Journal of Anaesthesia and Analgesia ◽

10.36303/sajaa.2019.25.5.a1 ◽

2019 ◽

pp. 6-12

Author(s):

OF Dada ◽

AF Faponle ◽

AT Adenekan

Keyword(s):

Test Performance ◽

Cross Sectional Study ◽

Adverse Outcomes ◽

Upper Lip ◽

Likelihood Ratios ◽

Cross Sectional ◽

Predictive Values ◽

Airway Assessment ◽

Assessment Tests ◽

Predictive Tests

Background: The ability to reliably predict difficult intubation can prevent airway related adverse outcomes. The upper lip bite test (ULBT) and ratio of height to thyromental distance (RHTMD) are airway predictive tests that have been evaluated in Caucasian populations with promising results. This study determined the test performance of the ULBT and RHTMD and compared with commonly employed predictive tests (modified Mallampati [MMT], thyromental distance [TMD] and inter-incisor gap [IIG]) in adult Nigerians. Methods: This was a cross-sectional study. Two hundred and sixteen consecutive, consenting ASA I-III patients presenting for surgery and planned for general anaesthesia with endotracheal intubation over a six month period in our teaching hospital, had all five airway assessment tests (ULBT, RHTMD, MMT, TMD and IIG) assessed preoperatively. The Cormack and Lehane grading was used to determine easy or difficult visualisation of the larynx (EVL or DVL). Sensitivity, specificity, predictive values and likelihood ratios of the tests were determined. Results: The sensitivities, specificities, positive and negative predictive values and positive and negative likelihood ratios respectively for the tests were: ULBT (11.8%, 99.0%, 50.0%, 92.9%, 11.71 and 0.89), RHTMD (35.3%, 92.5%, 28.6%, 94.4%, 4.68 and 0.70), TMD (29.4%, 97.5%, 50.0%, 94.2%, 11.71 and 0.72), MMT (52.9%, 86.4%, 25.0%, 95.6%, 3.90 and 0.54), and IIG (11.8%, 97.0%, 25.0%, 92.8%, 3.90 and 0.91). Conclusion: The modified Mallampati test had the highest sensitivity in this study, however all the tests evaluated showed only low to moderate sensitivity. The ULBT and RHTMD had low sensitivities in this population. However, based on the high positive likelihood ratios of the ULBT and the TMD, whenever positive, these tests do show a high probability of DVL and these two tests would probably perform similarly in this population. Anthropometric differences may account for differences in performance of preoperative airway assessment tests in various populations.

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