Airway Assessment Tests Research Articles

Comparison of Upper Lip Bite Test and Thyromental Distance with Other Airway (Malampatti and Inter Incisor Distance) Assessment Tests for Predicting Difficult Endotracheal Intubation

Objective: To study the ability of upper lip bite test and thyromental distance to predict difficult endotracheal intubation when compared to standard assessment tests such as Mallampati and inter incisor distance. Study Design: Cross-sectional validation study. Place and Duration of Study: Department of Anesthesiology, Pak-Emirates Military Hospital, Rawalpindi, Pakistan, Sep 2020 to Mar 2021. Methodology: We studied a total of 50 patients who reported for the administration of general anesthesia. All patients underwent evaluation with modified Mallampati test, upper lip bite test and thyromental distance test. All participants underwent subsequent intubation according to a standard protocol. The researcher documented difficult intubations. Results: We found the upper lip bite test to have a sensitivity of 75.7%, a specificity of 84.2%, and a diagnostic accuracy of 78.6%. Thyromental distance had a sensitivity, specificity, and diagnostic accuracy of 51.4%, 78.9% and 60.7%, respectively while the modified Mallampati had a sensitivity of 64.9%, 89.5%, specificity and a diagnostic accuracy of 73.2%. Conclusion: Upper lip bite test is a useful bedside assessment tool with which to predict the probability of a difficult endotracheal intubation. Height to thyromental distance ratio test is also acceptable for rapid assessment.

Magnitude, associated factors of difficult airway, and predictive value of airway examinations among maxillofacial surgery patients at public hospitals in Southern Ethiopia: a multicentre cross-sectional study

Background: “Difficult airway” is the clinical situation in which a conventionally trained anesthesiologist experiences difficulty with mask ventilation, laryngoscopy, and difficulty with tracheal intubation, or both. Associated factors and predictive value difficult airways, maxillofacial surgery study setup is under studied. Objective: To determine the magnitude and associated factors of difficult airways and predictive value of airway examinations among adult patients who underwent maxillofacial surgery at public hospitals in Southern Ethiopia 2022. Methods and materials: An institutional-based multicenter cross-sectional study was conducted among 250 maxillofacial patients from March to 30 June 2022 at selected hospitals. The data were entered into Epi_Data software version 4.3 and analyzed by STATA software version 14. All variables that were statistically significant in bivariate analysis, at the P less than 0.25, were included in the multivariate logistic regression analysis. The predictive value or the effectiveness of airway examinations in predicting difficult airways was analyzed by receiver operating curve. Results: In the current study, the magnitude of difficult airways was 21.2% (95% CI = 16.3–26.1%) and the magnitude of difficult intubation, difficult laryngoscopy, and difficult mask ventilation was 6.4% (95% CI 3.3–9.4%), 9.6% (95% CI 6.1–13%), and 13.6% (95% CI (9.1–16.8%), respectively. History of head and neck surgery adjusted odds ratio (AOR)=6.3, 95% CI (2.85–14.34), cervical collar AOR=4.9, 95% CI (1.96–12.49), and cervical spine injury AOR=2.4, 95% CI (1.07–5.38) were independently and significantly associated with difficulty of airway. Modified Mallampati class and sternomental distance were identified as good preoperative tests to predict difficult laryngoscopy, intubation, and mask ventilation. Conclusion and recommendation: The magnitude of difficult airways was maxillofacial surgery. Among various airway assessment tests, no single test was perfectly accurate. Anaesthesia professionals are recommended to use a combination of preoperative airway assessments.

STUDY OF THE FACTORS AFFECTING DIFFICULT ENDOTRACHEAL INTUBATION WHO PRESENTED TO EMERGENCY DEPARTMENT IN RAMKRISHNA CARE HOSPITAL, RAIPUR, CHHATTISGARH

Background: A thorough but brief airway assessment is important and challenging for patients requiring advanced airway assessment. The study aimed to provide knowledge about the factors leading to difficult endotracheal intubation, reduce the number of attempts which will lead to more successful intubation and improve the overall quality of the procedure. Material Methods: A total of 293 patients were selected based on consecutive sampling methods. After ethical committee clearance data was collected using a data collection form. Age, gender, obesity,pre-existing medical conditions, and facial malformations were recorded for each participant. Airway assessment tests such as mouth opening, thyromental distance, hyomental distance, short neck, and Mallampati classes were conducted by investigators. Inclusion criteria were based on 1. The patient who is alive 2. The patient who needs advanced airway management The exclusion criteria were 1. The patient presented in the emergency department with ventilator support 2. Patient who didnt give consent 3. Patients below 14 years of age(pediatric age group) Data was initially entered into an Excel data sheet and then exported to SPSS Statistics version 22 for analysis. Results:From July 2022 to Aug 2023, a total of 293 patients were included in the study. Of these, 170 were male and 123 were female. Under 65 years of age 40 (43.5%) had difficult intubation whereas above 65 years 52(56.5%) had difficult intubation. 134 patients were obese resulting in difficult intubation. Female patients, those suffering from systemic diseases and facial malformation or fracture were found to be more difficult to intubate. We recognized that Mallampati classes ≥3, mouth opening < 4cm, short thyromental distance, and hyomental distance, were also associated with difficult intubation. Multiple logistic regression analysis of the related factors determined that the odds ratio was highest for mouth opening <4 cm (OR = 3.613) and Thyromental distance <6cm (OR = 3.157) Conclusion: Factors affecting difficult intubation were constructed from the patients demographic characteristics and clinical examination. This may help in discriminating against difficult intubation.This will also help in the overall success rate of first attempts of endotracheal intubation in the emergency department.

Effectiveness and Validity of Preoperative Ultrasonographic Airway Assessment and Clinical Screening Tests to Predict Difficult Laryngoscopy: A Prospective, Observational Study.

The anticipation of a challenging airway can be demanding in emergency care settings. Due to the patient's clinical condition, executing the pre-intubation clinical screening tests during the management of the airway in an emergency situation can besometimes troublesome. Ultrasonographic airway assessment may become a helpful tool, but no specific sonographic measurements can precisely visualize the prospect of meeting a difficult airway. Therefore, the present study aimed to verdict some correlation between preoperative sonographic airway assessment parameters and the Cormack-Lehane (CL) grading at laryngoscopic view in patients undergoing general anesthesia with endotracheal intubation. Thisobservational study was conducted on 150 elective surgery subjects undergoing general anesthesia. The clinician in the pre-anesthetic clinic performed clinical airway and ultrasonographic airway assessments to predict difficult intubation and correlated with the CL grade viewed at laryngoscopy in the operative room during intubation. The parameters assessed were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). In this study, the incidence of difficult intubation was 13.3%. The Mallampatti Grading (MPG) showed the maximum receiver operating characteristic (ROC) and area under the curve (AUC) among the clinical predictors, with 86.7% sensitivity. At the same time, the skin-to-hyoid distance has the maximum ROC among the sonographic parameters, and the skin-to-thyroid isthmus has the utmost sensitivity to predict difficult laryngoscopy. Among the clinical predictors, MPG and the sonographic parameters, like the skin-to-hyoid distance and skin-to-thyroid isthmus, are favorable predictors of difficult laryngoscopy.

Global research trends in prediction of difficult airways: A bibliometric and visualization study.

Many tools are used to predict difficult airway, including bedside screening tests, radiological variables, and ultrasonography. However, the "gold standard" to identify difficult airway before intubation has not been established. The assessment and prediction of difficult airway is receiving increasing attention in clinical practice due to the devastating results of failed oxygenation or intubation. A literature visualization study is necessary to understand the research trend and help tailor future research directions. Science citation index-expanded web of Science database were used to search for literature related to assessment and prediction of difficult airways published before May 9th, 2022. VOS viewer software was used for visual analysis, including literature statistics, and co-occurrence analysis. A total of 2609 articles were included. The amount of relevant research interest and literature is increasing every year. According to co-occurrence network analysis, the research results can be grouped into the following 5 clusters, intubation approaches, intubation in special populations, difficult airway assessment tests, intubation in critical care/emergency settings and education, and laryngoscopes. Co-occurrence overlay analysis showed that video laryngoscopes and index prediction (including computed tomography and ultrasonography), emerged recently and comprised an important percentage of current studies. It can be predicted that future studies should focus on understanding the upper airway anatomy and constructing risk index predictions. Based on current global research trends, risk index predictions are the next hot topics in the evaluation and prediction of difficult airways, and video laryngoscopes will continue to be a hot topic in this field.

Analysis of various airway evaluation tests to prognosticate difficult endotracheal intubation

Background: Unanticipated difficult intubation or failure of intubation is a major source for anesthesia associated deaths. Hence pre-anesthetic checkup should include a detailed airway evaluation to foresee difficult endotracheal intubation. Some easy bedside tests to predict difficult airway include modified Mallampati test (MMT), ratio of height to thyromental distance (RHTMD), and upper lip bite test (ULBT). Actual difficulty of airway can be estimated using Cormack Lehane (CL) grading while performing laryngoscopy. Combination of two or more bedside clinical tests is used to identify difficult airway and act accordingly. Aims and Objectives: We aimed at identifying those airway assessment tests which best predicted difficult airway. The objectives were to determine the agreement between MMT, RHTMD, ULBT with CL grading, and also the agreement between MMT and ULBT, MMT and RHTMD. Materials and Methods: This observational research was done in 88 individuals between 18 and 75 years planned for elective procedures requiring endotracheal intubation as a part of general anesthesia. The clinical assessment tests such as ULBT, RHTMD, and MMT were done on eligible participants during pre-anesthetic check-up. In the operation theater, patient was prepared, premedicated, and induced. CL grading was used to assess the laryngoscopic view. We tried to determine the agreement between MMT, ULBT and RHTMD with CL grading. We also tried to determine the agreement between MMT and ULBT., MMT and RHTMD. Results: MMT showed moderate, RHTMD showed slight, and ULBT showed no agreement with CL grading. MMT showed highest sensitivity and RHTMD showed highest specificity. No agreement was found for ULBT and RHTMD with MMT. Conclusion: MMT and RHTMD can be used in predicting difficult airway access; out of which MMT is better than RHTMD. ULBT is not an ideal test to identify difficult endotracheal intubation. Laryngoscopic view becomes difficult with increase in weight and age.

Measurement of Neck Circumference, Tongue thickness and Skin to Epiglottis Distance as Predictors of Difficult Intubation: A Prospective Study

Airway Assessment is essential in pre anesthetic assessment. Anticipating and preparing for difficulty in airway management is crucial to avoid airway catastrophes. Routine pre operative airway examination usually includes mouth opening and dentition, Mallampati classification, thyromental distance and neck movements. Neck circumference is a quick bedside test to determine difficult laryngoscopy. Increased tongue thickness and skin to epiglottis distance affects performance of laryngoscopy and tracheal intubation increasing the risk of difficult airway. Presently there is a search for non-invasive and accurate tools to overcome limitations of clinical airway assessment tests. Ultrasonography has been evolving as a useful device for airway assessment especially soft tissue structures in anterior surface of neck. Here we studied the measurement of neck circumference and ultrasound measurement of tonguethickness and skin to epiglottis distance as predictors for difficult intubation. The Aim of the study is to predict difficulty in intubation by measuring neck circumference, thickness of tongue and thickness of skin to epiglottis. Prospective observational study, 120 patients posted for surgery under general anesthesia, Department of anesthesia, Meenakshi medical college, Kanchipuram. After institutional Human ethical committee clearance, 120 Patients were screened during preoperative assessment for undergoing procedures under general anaesthesia. Neck circumference and other airway parameters were measured with measuring tape and distance between Skin to epiglottis and tongue thickness were measured with ultrasound linear probe. Patients were grouped into Group E( Easy Intubation) whose Cormack-lehane grade was 1 and 2 and Group D ( Difficult intubation) whose Cormack-lehane grade was 3 and 4. SPSS version 16 was used for statistical analysis. There was no statistical significance seen between age, sex, height among easy and difficult intubation but significance was seen with weight (p <0.05), Thyromental distance(p<0.05) and Sterno-mental distance(p<0.05). High significance was seen in Distance between skin to epiglottis distance(p<0.001), Tongue thickness(p<0.001) and Neck Circumference(p<0.001) in difficult intubation cases. Neck circumference and ultrasonographic measurement of tongue thickness and skin to epiglottis can avoid unanticipated difficult intubation.

A prediction model for difficult intubation using skeletal features in patients affected by apnea-hypopnea syndrome.

Obstructive sleep apnea-hypopnea syndrome (OSAHS) has been linked to increased risk of perioperative morbidity and mortality because of difficult intubation (DI). However, there is a lack of clinically validated tools to identify OSAHS patients who are likely to have an increased the risk of DI. For model development, a prospective cohort study included patients with OSAHS who underwent elective surgery between September 2018 to December 2020. The outcome was DI and classified according to the Cormack-Lehane grading. Conventional airway assessment tests, skeletal features, and the severity of OSAHS were recorded, and LASSO regression was used. Validation was performed on an external sample of patients from the same hospital between January 2021 and December 2021. The development (prevalence of DI: 44%) and validation cohorts (prevalence of DI: 32%) included 247 and 82 patients, respectively. Based on the result of LASSO, age and four skeletal features (thyromental height, maximum mandibular protrusion, mandibulohyoid distance, and neck hypokinesis grade) were included in the final model. Discrimination and calibration of the model were satisfactory with high AUC (0.97), sensitivity (88.5%), specificity (94.6%), accuracy (92.7%), PPV (88.5%) and NPV (94.6%) from external validation. Our study developed and externally validated a DI prediction model using skeletal features in OSAHS patients. The final model had an NPV of nearly 95%, suggesting that a simple nomogram including only five predictors was quite helpful for ruling out the presence of difficult intubation in OSAHS patients who underwent elective surgery.

Predisposing Factors of Difficult Tracheal Intubation Among Adult Patients in Aliabad Teaching Hospital in Kabul, Afghanistan - A Prospective Observational Study.

BackgroundAirway management may be a considerable challenge for anesthesiologists. Currently used preoperative screening tests are known to lack sufficient specificity and sensitivity. Nevertheless, preoperative screenings and the combination of various tests are highly recommended to reduce the risk of unexpected difficult or failed airway management.PurposeThis study aims to determine if socio-demographic characteristics can predict difficult intubation among adult patients scheduled for elective surgeries under general anesthesia in Aliabad Teaching Hospital, Kabul, Afghanistan.MethodsA total of 341 patients were selected based on consecutive sampling method. Informed consent forms were obtained before inclusion in the study. Data were collected using a data collection form. Age, gender, ASA physical status and ethnicity were recorded for each participant. Airway assessment tests such as mouth opening (MO), thyromental distance (TMD), and Mallampati classes, inability to prognath (AP) and neck mobility and size (NM) category were conducted by research team. Data were initially entered into an Excel data sheet and then exported to SPSS Statistics version 22 for analysis.ResultsFrom 28 October 2018 to 30 January 2019, a total of 341 patients included in the study. Of these, 193 (56.6%) were male and 148 (43.4%) were female. The mean age of the subjects was 36.98 ± 15.048 years. More than half (54.5%) of the study population were Tajiks. Patients from the Hazara ethnicity, female patients, older patients and those suffering from systemic diseases found to be more difficult to intubate. We recognized that, Mallampati classes ≥3, small MO, short TMD, AP, reduced NM were also associated with difficult intubation. Multiple logistic regression analysis of the associated factors determined that increased age more than 40 years, AP and small MO were independent predictors of difficult intubation.ConclusionThe study findings show that Hazara ethnicity, female patients, increasing age and systemic disease have significant associations with difficult intubation. Mallampati classes III and IV, MO ≤4 cm, TMD ≤6 cm, and reduced NM had higher risks of difficult intubation. Multiple logistic regression analysis determined that increased age, AP and MO were independent predictors for difficult intubation.

The assessment of risk factors associated with difficult intubation as endocrine, musculoskeletal diseases and intraoral cavity mass: A nested case control study.

The predictive factors of difficult airway have been studied to reduce especially the incidence of unanticipating difficult intubation, provide patient safety, and avoid wasting resources. In this study, it was aimed to investigate whether endocrine, musculoskeletal diseases, presence of intraoral mass, and demographic factors have predictive values in the evaluation of difficult air-way as well as frequently used airway assessment tests. This study was designed a nested-case control study. After eligibility criterions, totally 1012 patient data were collected, 92 of them were difficult intubation, 920 of them were non-difficult intubation patients (1: 10 ratio). Demographic characteristics of the patients (age, gender), body mass index (BMI), Mallampati, Cormack-Lehane Score (CLS), sternomental distance (SMD), inter incisor gap (IIG), type of surgery, endocrine, musculoskeletal and cardio-pulmonary diseases, and the presence of intraoral mass were compared between groups. Age >52 years, male gender, ASA 3-4, higher BMI, CLS 3-4, Mallampati 3-4, IIG <4 cm, and SMD <10 cm were found statistically significant in terms of difficult intubation. Besides, a statistically significant relationship was found when the groups were compared in the presence of intraoral mass (17.57 times higher, p<0.05), endocrine diseases (3.51 times more common, p<0.05) and musculoskeletal system diseases (4.5 times higher, p<0.05). In this study, it was demonstrated that endocrine disorders such as diabetes mellitus and thyroid disorders, musculoskeletal system diseases, and the presence of intraoral cavity mass should be used as predictors for difficult intubation with commonly used airway assessment tests.

How to predict a difficult airway

According to The American Society of Anaesthesiologists Task Force, a difficult airway is defined as a clinical situation in which a conventionally– trained anaesthesiologist experiences difficulty with face mask ventilation and/or difficulty with tracheal intubation. Failing at efficient airway management is a source of major apprehension for physicians. Predicting difficult airway management is a mandatory part of clinical practice for paediatric and adult patients so as to avoid unexpected difficult airway management and adverse outcomes. Predicting a difficult airway is based on a focused medical history, review of prior medical records, physical examination, and specific tests for airway assessment. Each feature or airway test has its own sensitivity and specificity for the prediction of a difficult airway. All airway assessment tests are characterised by low sensitivity, reasonable specificity, and a low positive predictive value. Several scoring system models have been developed by multivariate analysis with multiple different integrated tests or risk factors to improve the prediction of a difficult airway, but with considerably different effectiveness to predict a difficult airway. According to the European Society of Anaesthesiology, systematic multimodal screening before airway management should include the Mallampati classification and thyromental distance, mouth opening or interincisor distance, range of motion of head and neck, compliance of the mandibular space, and the upper lip bite test.

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

Prediction of difficult intubation (DI) has remained challenging for anesthesiologists and validity of airway assessment tests has not been fully investigated. This study aims to compare predictive values of these tests for prediction of DI in obese patients. One hundred ninety-six patients with Body Mass Index (BMI) ≥30 kg/m2 were included in this prospective study. Variables including intubation Difficulty Scale (IDS), thyromental height (TMH), hyomental distance (HMD) in extent and neutral neck position, HMD ratio (HMDR), sternomental distance (SMD), thyromental distance (TMD), ratio of height to TMD (RHTMD), width of mouth opening (MO), mandibular length (ML), Cormack-lehane (C-L) grade, upper lip bite test (ULBT), history of snoring, and obstructive sleep apnea were collected. Multiple logistic regression and receiver operating characteristic (ROC) curve analysis were used to determine independent predictors of DI (defined as IDS≥5) and their cut off points. DI and difficult laryngoscopy (defined as C-L grade ≥3) were observed in 23% and 24.5% of the study population, respectively. Multiple logistic regression identified TMH (Odds ratio (OR):0.28, 95% confidence interval (CI):0.14-0.58, P=0.001), BMI (OR:1.18, 95% CI: 1.11-1.26, P<0.001), HMDR (OR:0.45, 95% CI:0.36-0.56, P<0.001) and ULBT (OR: 3.91, 95% CI: 2.14-7.14, P<0.001) as independent predictors of DI. Sensitivity of TMH<4.8 cm, BMI>34.9 kg/m2, HMDR<1.4 and ULBT class ≥2 were determined as 75.1%, 73.3%,62.3% and 93.3% respectively. TMH and ULBT had the highest sensitivity for prediction of DI in obese patients in this study and it is recommended to be considered as part of airway assessment in this patient population.

Study comparing different airway assessment tests in predicting difficult laryngoscopy: A prospective study in geriatric patients.

Background and Aims:Limited studies are available comparing diagnostic accuracy of various airway predictors in geriatric patients. We conducted this study with primary aim to evaluate and validate the predictive value of 'standard airway predictors' like modified Mallampati test, thyromental distance (TMD), sternomental distance, neck movement (NM), mouth opening (MO), dentition and 'new airway predictors' like upper lip bite test (ULBT), ratio of height to thyromental distance and thyromental height test (TMHT) for predicting difficult laryngoscopy in geriatric patients.Methods:This prospective, observational study was conducted on 140 patients above 65 years of age of either sex, scheduled for elective surgery under general anaesthesia requiring endotracheal intubation. The age, weight, height, body mass index (BMI) and airway parameters were recorded. The laryngoscopic view was assessed by modified Cormack-Lehane scale. Standard formulae were used to calculate validity indexes.Results:The incidence of difficult larygoscopy found in our study was 25%. The mean age of our study population was 69.37 ± 4.23 years. TMD exhibited the highest sensitivity (80%) and negative predictive value (NPV) (91.86%) as compared to other studied airway predictors. The positive predictive value (PPV) of ULBT was 100%. Moreover, ULBT exhibited highest accuracy (82.14%) and odds ratio (86.88) and high specificity (91.30%) for predicting difficult laryngoscopy in geriatric patients. NM and TMHT also exhibited high accuracy (77.85%, 77.14%) and PPV (59.09%, 52.94%).Conclusions:TMD and ULBT both showed good predictive value in diagnosing difficult laryngoscopy in geriatric patients. Furthermore, NM and TMHT also exhibited higher diagnostic accuracy in predicting difficult airway in these patients.

Prediction of difficult intubation in apparently normal patients by combining modified mallampati test and thyromental distance: A prospective observational study

Introduction: Difficult intubation, often unexpected, remains a primary concern for the anesthesiologist. None of the bedside airway assessment tests have proven to be efficacious and highly predictive. This study was done to determine the sensitivity and specificity of Modified Mallampati test alone, Thyromental distance alone and in combination of both for predicting difficult intubation. Material and Methods: A prospective observational study was conducted in Universal College of Medical Sciences Teaching Hospital (UCMSTH), which involved 80 American Society of Anesthesiologist Physical Status (ASA PS) I patients undergoing elective surgeries under general anesthesia with endotracheal intubation. All patients were included for preoperative assessment by Modified Mallampati test alone and Thyromental distance measurement. The correlation between these tests and Cormack and Lehane laryngoscopic grading was done to find out the result. Results: Prediction of difficult intubation among 80 patients by Modified Mallampati test alone showed sensitivity of 72.7% and specificity of 98.6% whereas with Thyromental distance alone, showed sensitivity of 36.4% and specificity of 100%. When both predictors were combined, result showed sensitivity of 72.7% and specificity of 98.6% which was similar to that of Modified Mallampati test alone. Conclusion: This study concluded that sensitivity to predict difficult intubation was higher with Modified Mallampati test alone or in combination with Thyromental distance test whereas specificity was highest with Thyromental distance test alone.

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

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.

The value of preoperative endoscopic airway examination in complex airway management of a patient with supraglottic cancer

The standard bedside airway assessment tests are poorly predictive for difficult tracheal intubation, and do not assess the presence of the inside pathology of the upper airway, such as base of the tongue lesions, glottic and vallecular lesions, pyriform sinus pathology, supraglottic tumors, etc. The preoperative endoscopic airway examination, also commonly called nasal endoscopy, or nasendoscopy, is the only technique that assesses the upper airway in its entirety, under dynamic conditions prior to induction of anesthesia, and is recommended for routine use by NAP4 even for high acuity cases. We present a case of a patient with a malignant partial upper airway obstruction and largely normal external airway exam where preoperative endoscopic airway examination findings were used in real-time to devise successful ventilation and intubation strategies.

Assessment of Airway in Patients with Acromegaly Undergoing Surgery: Predicting Successful Tracheal Intubation

AbstractBackground In the field of anesthesia, acromegaly is considered a cause of difficult tracheal intubation and airway management. There is a high probability of unanticipated difficult intubation in acromegalic patients despite a lower percentage of patients being identified preoperatively as having a difficult airway. In this study, we carried out various airway assessment tests preoperatively and during induction of anesthesia to find out the predictors of easy tracheal intubation in patients with acromegaly.Methods All patients of either sex, diagnosed as a case of acromegaly and scheduled to undergo pituitary surgery were enrolled over a period of 3 years. Various airway assessment tests were performed prior to surgery, which included modified Mallampati (MP) classification (sitting and supine), mouth opening (MO), upper lip bite test (ULBT), neck movement (NM), thyromental (TM) distance, thyrohyoid (TH) distance, sternomental (SM) distance, hyomental (HM) distance, length of upper incisors (IL), receding mandible (RM), any history of obstructive sleep apnea (OSA), mask ventilation (MV), Cormack-Lehane (CL) III and IV, and external laryngeal manipulation (ELM). Results were reported as odds ratios (95% confidence interval [CI]). The p-value &lt; 0.05 was considered statistically significant.Results A total of 42 patients were enrolled over a period of 3 years. The male-to-female ratio was 19:23 with a mean age of 37.95 years and mean weight of 72.7 kg. Out of 15 airway assessment parameters, only ULBT and CL grade showed significant results.Conclusion We conclude that ULBT and CL grading are reliable predictors of easy intubation in patients with acromegaly undergoing surgery.

Comparative study of airway assessment tests to predict difficult laryngoscopy &amp; intubation

Comparative study of airway assessment tests to predict difficult laryngoscopy & intubation - IJCA- Print ISSN No: - 2394-4781 Online ISSN No:- 2394-4994 Article DOI No:- 10.18231/j.ijca.2019.032, Indian Journal of Clinical Anaesthesia-Indian J Clin Anaesth

Comparison of Upper Lip Bite Test and Ratio of Height to Thyromental Distance with Other Airway Assessment Tests for Predicting Difficult Endotracheal Intubation.

Background and Aims:Unanticipated difficult intubation or the failed intubation in operating room and in emergency department is an imperative source of anesthesia-related patient's mortality. The aim of this study is to compare the predictive value of upper lip bite test (ULBT) and ratio of height to thyromental distance (RHTMD) with other commonly used preoperative airway assessment tests for predicting difficult intubation in Indian population.Materials and Methods:In this prospective, single-blinded observational study, 260 adult patients of either sex, belonging to American Society of Anesthesiologists physical Status I and II undergoing elective surgical procedure under general anesthesia were included in the study. ULBT, RHTMD, inter-incisor gap, modified Mallampati grade, horizontal length of the mandible, head and neck movements, sternomental distance, and TMD were assessed preoperatively and correlated with Cormack and Lehane's grading during laryngoscopy under anesthesia. Statistical analysis was done by Chi-square and Fisher's exact test.Results:ULBT and RHTMD had highest sensitivity (66.7% and 63.3%), specificity (99.1% and 89.6%), positive predictive value (90.9% and 44.2%), and negative predictive value (96.9% and 95.0%), respectively, when compared to other parameters in predicting difficult airway.Conclusion:ULBT and RHTMD may be used as a simple bedside airway assessment tools for prediction of difficult intubation.

The performance of neck circumference and other airway assessment tests for the prediction of difficult intubation in obese parturients undergoing cesarean delivery

BackgroundPregnancy and obesity each increase the chance of difficult tracheal intubation. This study assessed the performance of the neck circumference and other bedside tests in predicting difficult intubation, and aimed to identify the optimal cutoff point of the test(s) with the highest performance. MethodsParturients with a body mass index ≥30kg/m2, undergoing a cesarean delivery employing conventional tracheal intubation, were enrolled. Preoperative neck circumference, sternomental distance and modified Mallampati test were examined. Difficult intubation was defined as intubation difficulty scale score ≥5. ResultsFive hundred and seventy parturients of mean body mass index 34.1 (±SD 3.8) kg/m2 were recruited. The incidence of difficult intubation was 3.5%. The performance of the neck circumference test, conducted with the patient sitting or supine, and using the area under the receiver operating characteristic (ROC) curves, was 0.6 (95% CI 0.5 to 0.7) and 0.6 (95% CI 0.4 to 0.7) respectively. The area under the ROC for the modified Mallampati test was 0.6 (95% CI 0.5 to 0.7) and for the sternomental distance test was 0.7 (95% CI 0.6 to 0.8). A sternomental distance less than 14.5cm, and a ratio of neck circumference in the sitting position to sternomental distance of greater than or equal to 2.7, were optimal cutoff points to identify difficult intubation. ConclusionThe neck circumference, the sternomental distance, the modified Mallampati test and the ratio of neck circumference to the sternomental distance show limited performance as screening tests to predict difficult intubation among obese parturients.