Modified Mallampati Test Research Articles

The Importance of Neck Circumference to Thyromental Distance Ratio (Nc/Tm Distance Ratio) as a Predictor of Difficult Intubation in Obese Patients Coming for Elective Surgery under General Anaesthesia in a Teritatry Care Hospital - A Prospective Observational Study

BACKGROUND AND OBJECTIVES : This study was done to assess the ability of neck circumference to thyromental distance ratio (NC/TM distance ratio) for predicting difficult intubation among obese patients coming for surgery under general anaesthesia. It enabled us to compare NC/TM distance ratio to routinely used Mallampati score and neck circumference as reliable tests for predicting difficult intubation. This study also identified incidence of difficult intubation among obese individuals. PATIENTS AND METHODS : After approval of institutional review board and ethical committee of Christian Medical College Vellore, 250 obese patients (body mass index greater than or equal to 30) within time frame of September 2014 and March 2015 was assessed preoperatively with the help of performa after obtaining informed consent. Neck circumference / thyromental distance ratio (NC/TM distance ratio) was calculated from the performa. Validated Intubation difficulty score (IDS score) for each obese patient was assessed intra operatively by the anaesthetist who performed intubation . The entire study population were divided into easy and difficult intubation groups based on the IDS score. IDS score greater than or equal to five was considered as difficult intubation. NC/TM distance ratio greater than or equal to five was correlated with IDS score greater than or equal to five. The study assessed the statistical significance of NC/TM distance ratio and difficult intubation by univariate and multivariate logistic regression analysis and its comparison with Mallampati score and neck circumference with respect to sensitivity / specificity/ positive predictive value and negative predictive value. The study also calculated the incidence of difficult intubation among obese patients. RESULTS : Binary univariate logistic regression analysis of predictors of difficult intubation showed age greater than sixty, increased neck circumference, decreased thyromental distance, modified Mallampati test, NC/TMD ratio ≥ 5 as statistically significant variables that were associated with a difficult intubation (p ≤ 0.05). Binary multivariate logistic regression analysis showed only neck circumference (p=0.030 [odd ratio 2.519 (1.094-5.802)] and NC/TMD ratio (p <0.001 [odd ratio 23.680 (10.638-52.713)] independently predicted difficult intubation. However NC/TMD ratio had higher specificity / PPV and larger AUC on an ROC curve compared to neck circumference. The incidence of difficult intubation among obese patients was 20.8 %. INTERPRETATION AND CONCLUSIONS : Among obese patients, NC/TMD ratio can be considered as a better preoperative predictor of difficult intubation and incidence of difficult intubation among them was as high as 20.8 percent.

Prediction of Difficult Airway Among Patients Requiring Endotracheal Intubation in a Tertiary Care Hospital in Eastern Nepal

Various screening tests are done for predicting difficult laryngoscopy with variable diagnostic accuracy. Difficult laryngoscopy is being considered a surrogate indicator of difficult intubation, though it is not the exact measure of intubation difficulty. Our objectives were to find out the better predictor of difficult laryngoscopy amongst the routinely used tests and also to find the ability of difficult laryngoscopy to predict difficult intubation. This prospective, observational study involved 314, ASA I/II adult patients requiring endotracheal intubation. Measurement of sternomental, thyromental and inter-incisor distances and gradings of mandibular protrusion and modified Mallampati were done. Statistical values including sensitivity and specificity of these tests were calculated to find the better predictor of difficult laryngoscopy. Cormack and Lehane laryngoscopy grade III/IV was defined as difficult laryngoscopy. Requirement of >3 attempts for endotracheal intubation was defined as difficult intubation. The sensitivity of the Modified Mallampatti Test for predicting difficult laryngoscopy was highest, 83% compared to other tests. Total 12 (3.8%) patients had difficult laryngoscopy. Intubation was difficult in 7 (2.2%) patients, of which four had difficult laryngoscopy (P<0.001). Modified Mallampati test was better for predicting difficult laryngoscopy compared to other bedside screening tests. Difficult laryngoscop could significantly predict difficult intubation in our patients.

Determining the Efficiency of Different Preoperative Difficult Intubation Tests on Patients Undergoing Caesarean Section

Background:Pregnancy-induced anatomical and physiological changes in the airway make airway management difficult in obstetric patients; thus, preoperative evaluation of the airway is important for obstetric patients.Aims:To determine the effectiveness of the modified Mallampati test; the interincisor, sternomental and thyromental distances and the upper limb bite test. The second aim was to assess the effectiveness of the combination of the upper limb bite test with the other tests in obstetric patients.Study Design:Cross-sectional study.Methods:Pregnant women (n=250) scheduled for caesarean section were analysed. The patients’ ages, heights and weights were collected. Preoperative airway evaluation was done by using a modified version of the Mallampati test. The interincisor, sternomental and thyromental distances were measured, and the upper limb bite test was performed. The laryngoscopy difficulty was evaluated by using Cormack-Lehane classification.Results:No statistically significant differences were found between groups in age, height or weight (p>0.05). The modified Mallampati test and interincisor, sternomental and thyromental distances revealed a lower number of easy intubations than that determined by the Cormack-Lehane classification and a higher number of difficult intubations than the actual number of cases (p<0.05). The sensitivity and specificity of the modified Mallampati test, the upper limb bite test, the interincisor distance test and the sternomental and thyromental distance tests were found to be 73.08, 57.69, 84.62, 80.77 and 88.46 and 90.62, 99.11, 83.04, 84.37 and 87.05, respectively. When the combinations were examined, the sensitivity and specificity of the combination of the upper limb bite test with the modified Mallampati test were found to be 57.69 and 100, respectively. When the upper limb bite test was combined with the interincisor distance, the sensitivity and specificity were 46.15 and 100, respectively. We found a sensitivity and specificity of 93.75 and 95.30, respectively, for the combination of the upper limb bite test with the thyromental distance test. The sensitivity and specificity of the combination of the upper limb bite test with the modified Mallampati test and interincisor distance test were found to be 46.15 and 100, respectively. For combination of all the tests, the sensitivity and specificity was 42.31 and 100, respectively.Conclusion:When all combinations are evaluated in the decision of difficult intubation, the combination of the upper limb bite test and thyromental distance test is superior to the use of other methods alone to predict difficult intubation in pregnant women.

Neck circumference to inter-incisor gap ratio: a new predictor of difficult laryngoscopy in cervical spondylosis patients

BackgroundPreoperative airway assessment help anticipate a difficult airway. We hypothesized that a close association existed between difficult laryngoscopy and the neck circumference/inter-incisor gap ratio (RNIIG). Our aim was to determine its utility in predicting difficult laryngoscopy in cervical spondylosis patients.MethodsTwo hundred thirteen consecutive patients, aged 20–70 years, scheduled to undergo cervical spine surgery under general anesthesia, were recruited. Preoperative assessments included inter-incisor gap (IIG), thyromental distance (TMD), neck circumference (NC), NC/IIG ratio (RNIIG), NC/TMD ratio (RNTMD) and modified Mallampati test (MMT). Cormack–Lehane scales were assessed during intubation. The anesthesiologist was blinded to the airway assessments. RNIIG’s ability to predict difficult laryngoscopy was compared with that of established predictors.ResultsDifficult laryngoscopy incidence was 16.4%. Univariate analysis showed that male gender, increased age, weight, NC, RNIIG and RNTMD, decreased IIG and TMD, and MMT 3 and 4 were associated with difficult laryngoscopy. Binary multivariate logistic regression analyses identified only one factor that was independently associated with difficult laryngoscopy: RNIIG. The odds ratio and 95% confidence interval (95% CI) were 1.932 (1.504–2.482). RNIIG (≥9.5) exhibited the largest area under the curve (0.80; 95% CI 0.73–0.86) and the highest sensitivity (88.6%; 95% CI 78.1–99.1) and negative predictive value (96.6%; 95% CI 94.0–99.2), confirming its better predictive ability.ConclusionsRNIIG is a new and simple predictor with a higher level of efficacy, and could help anesthetists plan for difficult laryngoscopy management in cervical spondylosis patients.Trial registrationChiCTR-OON-16008320 (April 19th, 2016).

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.

Comparison of validity of airway assessment tests for predicting difficult intubation

Aim and Objective of the Study: This prospective study was undertaken at Christian Medical College and Hospital Vellore, India. In this study we evaluated the sensitivity and specificity of airway examination tests including: modified Mallampati test (MMT) Thyromental Distance (TMD), ULBT (Upper Lip Bite Test). BMI (Body Mass Index) was also included as one of the predictors. The tests were evaluated individually and in combination. Methods: Total of 354 patients was recruited. Preoperative airway assessments of patients by Mallampati test, Thyromental Distance measurement, ULBT were done. The BMI was also calculated. The tests were done by the investigator and Laryngoscopic grading done by another experienced Anaesthetist according to modified Cormack and Lehane classification. The sensitivity, specificity, positive predictive and negative predictive values were analyzed for the individual tests and in combination. Statistical analysis was performed using SPSS version 11.0. Results: The modified Mallampati had the highest sensitivity of 70% which was statistically significant with a P = 0.001. Conclusion: From this study we conclude that the modified Mallampati test was a better predictor of difficult intubation than the upper lip bite test and Thyromental Distance.

Difficult airway Assessment: Comparison of Upper Lip Bite Test (ULBT) and Modified Mallampati Test (MMT)

Difficult airway Assessment: Comparison of Upper Lip Bite Test (ULBT) and Modified Mallampati Test (MMT)

Thyromental height test for prediction of difficult laryngoscopy in patients undergoing coronary artery bypass graft surgical procedure.

Background:Patients undergoing coronary artery bypass graft (CABG) procedures have higher incidence of difficult laryngoscopy and intubation than general surgery population. Accurate prediction of difficult laryngoscopy in CABG patients is desirable to reduce the hemodynamic response and myocardial oxygen requirements. Recently, thyromental height test (TMHT) has been proposed as one of the highly sensitive and specific bedside tests to predict difficult airway. We, in our prospective observational study, evaluated the accuracy of the TMHT in predicting difficult laryngoscopy.Methodology:A total of 345 patients undergoing CABG of either sex, in the age group of 35–80 years, American Society of Anesthesiologists 111, undergoing CABG, were studied. Airway assessment was performed with modified Mallampati test with the addition of thyromental distance, sternomental distance, and TMHT. Intraoperatively, direct laryngoscopy was done in accordance with Cormack and Lehane grade of laryngoscopy. The preoperative data and laryngoscopic findings were used together to evaluate the accuracy of TMHT. The sensitivity, specificity, positive and negative predictive values of other three tests were calculated according to standard formula.Results:A total of 345 patients were in the group with mean age of study population at 56.7 (standard deviation 9.1) years (35–80 years). This study showed that almost all tests had good specificity, but sensitivity was poor. However, sensitivity of TMHT was 75% with accuracy of 95%. Receiver operating characteristic curve analysis of TMHT-derived cutoff was 52.17 which increased sensitivity to 81.25% and specificity to 92.3%.Conclusion:TMHT had a higher sensitivity compared to other tests along with good positive and negative predictive value and a very high specificity.

Evaluation of the reliability of preoperative descriptive airway assessment tests in prediction of the Cormack-Lehane score: A prospective randomized clinical study

Study objectiveIn this study we investigated and compared the predictive values of different airway assessments tests including thyromental height measurement test, which has been recently suggested, in difficult laryngoscopy (Cormack and Lehane [C-L] scores 3 and 4). In addition, we compared the effectiveness of methods and C-L scores, by IDS, in terms of predicting difficult intubation. DesignProspective, blinded study. SettingMaltepe University. PatientsFour hundred fifty-one patients selected randomly who underwent general anesthesia. InterventionsIn this study we compared predictive value of thyromental height measurement test (TMH), which has been recently suggested, modified Mallampati test (MMT), upper lip bite test (ULBT), and thyromental distance measurement test (TMD) in difficult laryngoscopy. Final C-L scores were compared with intubation difficulty scale (IDS) in terms of predicting difficult intubation. MeasurementsPatient's American Society of Anesthesiology score, age and weight were recorded. TMH, TMD, MMT, ULBT, IDS and C-L scores were measured and determined. Main resultsThe optimal cut-off point for TMH for predicting difficult laryngoscopy was 43.5 mm and for TMD was 82.06 mm. Use of TMH <43.5 with MMT has the highest sensitivity for predicting difficult intubation (78.38) with 75.36% specificity and 97.50% negative predictive value. TMH showed sensitivity of 91.89% and specificity 52.17% at 50 mm cut-off value. In the comparison of the area under the receiver operating characteristic curve values, none of the tests came forth individually or in combination with MMT test. ConclusionsThe present study demonstrates the practicality of TMH as a digitalized test however the clinical benefits of TMH in daily medical practice are drawn into question. The additional variable of race may have had some bearing on this and further studies, larger in patient sample size, may need to use different methodology concerning age-, sex-, and race-dependent variables in evaluating these tests.

Comparison of the effects of Truview PCD™ video laryngoscopy and Macintosh blade direct laryngoscopy in geriatric patients

Study ObjectiveTo compare the effects of Truview PCD™ video laryngoscopy (TVL) and Macintosh blade direct laryngoscopy (MDL) on hemodynamic responses observed during laryngoscopy and orotracheal intubation conditions in geriatric patients. DesignRandomized prospective study. SettingOperating room. PatientsOne hundred patients in the risk group American Society of Anesthesiologists I to III aged 65 years and older underwent elective surgery under general anesthesia. InterventionsThis prospective study was performed between January 2014 and February 2015 after institutional ethics committee approval. Patients were randomly allocated to 2 groups, namely, TVL and MDL. MeasurementsHemodynamic parameters, modified Cormack-Lehane grade, intubation period, and preoperative examination (age, sex, American Society of Anesthesiologists, modified Mallampati test score, and thyromental and sternomental distances) of patients were evaluated. Main ResultsThere were no statistically significant differences in hemodynamic responses (heart rates and mean arterial pressure) between the 2 groups (P>.05). The median intubation period in the TVL group was significantly higher than observed in the MDL group (t=4.594; P<.05). The laryngoscopy views in TVL group were better than the views in MDL group. The Cormack-Lehane grade in the TVL group was lower when compared to the MDL group. ConclusionThe TVL system does not provide significant hemodynamic response sparing or shorten orotracheal intubation times when compared to MDL in geriatric patients.

Abstract PR529

Background & Objectives: Airway management remains one of the most important responsibilities of an anaesthesiologist. The purpose of this study was to compare preoperative anaesthetic airway evaluation methods of Modified Mallampati Test (MMT) and Upper Lip Bite Test (ULBT) to predict difficult intubation with the direct laryngoscopy views obtained during tracheal intubations. Materials & Methods: 200 patients (of either sex aged between 18 years and 55 years) undergoing elective surgical procedures under general anaesthesia with endotracheal intubation were evaluated for both tests before surgery. An experienced anesthesiologist, unaware of preoperative airway evaluation, performed the laryngoscopy and grading (as per Cormack and Lehane’s classification). Sensitivity, specificity, accuracy, positive and negative predictive values of upper lip bite test and Modified Mallampati test were calculated. Results: On comparing both the tests, we found that, MMT is more sensitive (75.00%) than ULBT (25.00%), both tests had high specificity (MMT 91.30%; ULBT 95.11%). Positive predictive value was 42.86% for MMT while it was 30.77% for ULBT. Similarly negative predictive value was 97.67% and 93.58% for MMT and ULBT respectively. Accuracy of MMT was 90.00% for MMT while it was 89.5% for ULBT. Conclusion: Both the tests are poor predictors of difficult intubation (low positive predictive values) when used as single preoperative bedside screening tests. MMT is a better test at predicting difficult endotracheal intubation when compared to ULBT. Both the tests are better predictors of easy intubations rather than difficult intubations (high negative predictive value).

Abstract PR204

Background & Objectives: Pregnancy induced anatomical and physiological changes in the airway makes airway management difficult in obstetric patients, thus the preoperative evaluation of the airway is important for obstetric patients. The first aim of this study was determine the effectiveness of the modified mallampati test, the interincisor, sternomental, thyromental distances, the upper limb bite tests and the second aim was to access the effectiveness of the combination of the upper limb bite test with the other tests in obstetric patients. Materials & Methods: 250 pregnant women scheluded for caesarean section were analyzed. Age, height and weight of the patients were all collected. Preoperative airway evaluation was done by using modified mallampati test. The interincisor, sternomental and thyromental distances and the upper limb bite test was performed. The laryngoscopy difficulty was evaluated by using Cormack-Lehane classification. Results: No statistically significant difference was found between age, height and weight (p>0.05). The modified mallampati test, interincisor, sternomental, and thyromental distances revealed a lower number than the number of easy intubations determined by the Cormack-Lehane classification and a higher number than the case number of difficult intubations (p<0.05). Combination of the upper limb bite with the other tests revealed high sensitivity and specificity than single tests. The incidence of difficult intubation was found as 10,4 %. Conclusion: In conclusion, we suggest combination of the upper limb bite with the other tests to predict difficult airway instead of using a single tests.

Abstract PR542

Background & Objectives: Difficult intubation is an undesirable situation for an anaesthesiologist particularly if it is not anticipated. Although considered a surrogate indicator, difficult laryngoscopy is not the true measure of difficult intubation. The objectives of this study were (i) to determine the association between difficult laryngoscopy and difficult intubation and to determine their prevalence. (ii) to determine the usefulness of routinely used airway measurements for prediction of difficult laryngoscopy. Materials & Methods: This prospective study involved 314, ASA I/II adult patients requiring endotracheal intubation for various routine surgical procedure. A value of sternomental distance < 12 cm, thyromental distance < 6.5cm, inter-incisor distance < 3.5 cm, mandibular protrusion grade >2 and Modified Mallampati class III or IV were defined as the predictors of difficult laryngoscopy.1 Cormack and Lehane grade III or IV of laryngoscopic view was defined as difficult laryngoscopy.2 Requirement of more than three attempts for insertion of the tracheal tube with conventional laryngoscopy was defined as difficult intubation.3 Alternate techniques were applied only after three attempts of intubation. Results: Twelve (3.8%) patients had grade III laryngoscopic view and none had a grade of IV. Increased age (p=0.014) and higher Mallampati score (p<0.001) were associated with difficult laryngoscopy as compared to easy laryngoscopy. Of all the airway measurements, Modified Mallampati class had the highest sensitivity (83.3%) and negative predictive values (99%). Significant association was found between Modified Mallampati Class and Cormack and Lehane laryngoscopic view (p<0.001). No intubations failed. More than three attempts of intubation were required in 7(2.2%) patients. Of these, stylet was used in four patients and Mc-coy laryngoscope was used in two patients as an alternate technique. Strong association was observed between difficult laryngoscopy and an increased attempts (>3) of intubation (p<0.001). Conclusion: The prevalence of difficult laryngoscopy and difficult intubation was 3.8% and 2.2%. Strong association was observed between difficult laryngoscopy and difficult intubation. Of the airway measurements, Modified Mallampati Test had the highest sensitivity and negative predictive values and showed strong association with difficult laryngoscopy.

Predictors of Difficult Intubation Among Malay Patients in Indonesia.

BackgroundFailure to maintain an adequate airway can lead to brain damage and death. To reduce the risk of difficulty in maintaining an airway during general anesthesia, there are several known predictors of difficult intubation. People with a Malay background have different craniofacial structures in comparison with other individuals. Therefore, different predictors should be used for patients of Malay race.ObjectivesThe aim of this study was to determine the ability to predict difficult visualization of the larynx (DVL) in Malay patients based on several predictors, such as the modified Mallampati test (MMT), thyromental distance (TMD), and hyomental distance ratio (HMDR).Patients and MethodsThis cross-sectional study included 277 consecutive patients requiring general anesthesia. All subjects were evaluated using the MMT, TMD, and HMDR, and the cut-off points for the airway predictors were Mallampati III and IV, < 6.5 cm, and < 1.2, respectively. During direct laryngoscopy, the laryngeal view was graded using the Cormack-Lehane (CL) classification. CL grades III and IV were considered difficult visualization. The area under the curve (AUC), sensitivity, and specificity for each predictor were calculated both as sole and combined predictors. Logistic regression analysis was used to determine independent predictors of DVL.ResultsDifficulty in visualizing the larynx was found in 28 (10.1%) patients. The AUC, sensitivity, and specificity for the three airway predictors were as follows: MMT: 0.614, 10.7%, and 99.2%; HMDR: 0.743, 64.2%, and 74%; and TMD: 0.827, 82.1%, and 64.7%. The combination providing the best prediction in our study involved the MMT, HMDR, and TMD with an AUC, sensitivity, and specificity of 0.835, 60.7%, and 88.8%, respectively. Logistic regression analysis showed that the MMT, HMDR, and TMD were independent predictors of DVL.ConclusionsThe TMD, with a cut-off point of 65 mm, had superior diagnostic value compared with the HMDR and Mallampati score. Therefore, the TMD could be used in Malay patients to predict the difficulty of larynx visualization during laryngoscopy.

Prediction of difficult laryngoscopy in patients undergoing endotracheal intubation: A comparative study of various airway assessment tests

Introduction: Predicting a difficult airway is one of the necessities in anesthetic practice. Multiple tests used singly and in combination have been used to predict it, with varied results. We conducted a study to compare the exactitude of various airway assessment tests individually and in combination with parameters suited to the Indian population for the prediction of difficult laryngoscopy. Aims: The aim of this study was to compare various airway assessment tests individually and to statistically analyze the three best tests from our analysis in combination with the Modified Mallampati Test (MMT) for their efficiency in predicting a difficult laryngoscopy in apparently normal individuals undergoing endotracheal intubation. Materials and Methods: This was a prospective, single-blinded, observational study, where 250 patients of American Society of Anesthesiologists Physical Status Grade I and II, without predictors for difficult airway undergoing elective surgeries, were assessed and graded for thyromental distance (TMD), ratio of height-to-TMD (RHTMD), inter-incisor gap, head and neck movement (HNM), MMT and upper lip bite test (ULBT), and correlated intraoperatively with Cormack and Lehane score, and combinations of the best three tests with MMT were then statistically analyzed using standard formulae and the IBM SPSS version 20 statistics software. Results: Analysis of tests for difficult laryngoscopy showed that RHTMD and TMD had the highest sensitivity (90.0% and 70%). ULBT and HNM had the highest specificity of 99.0% and 91.4%. ULBT and TMD were highest in positive predictive value (PPV) (90% and 58.3%) and RHTMD and TMD in negative predictive value (NPV) (97.8% and 94.1%). Of the combinations, MMT + RHTMD had the highest sensitivity (95.0%), NPV (98.4%), odds ratio (23.5), and relative risk, but MMT + ULBT had higher specificity (65.7%), PPV (32.1%), and likelihood ratio (2.5). The combination of MMT + ULBT + RHTMD had 100% sensitivity and 100% NPV and 57% specificity and 30.8% PPV. Conclusion: Ratio of height to TMD is the single best test for difficult laryngoscopy. A combination of MMT + RHTMD + ULBT would be the best option for the prediction of difficult laryngoscopy in apparently normal patients.

Prediction of ease of laryngoscopy and intubation-role of upper lip bite test, modified mallampati classification, and thyromental distance in various combination.

Background:The incidence of difficult intubation in patients undergoing general anaesthesia is estimated to be approximately 1-18% whereas that of failure to intubate is 0.05-0.35%.1,2,3 Various methods have been used for prediction of difficult laryngoscopy. Although, upper lip bite has been shown to be a promising test in its introductory article, repeated validation in various populations is required for any test to be accepted as a routine test. We have compared upper lip bite test (ULBT), modified Mallampati test (MMC) and thyromental distance (TMD) individually and in various combinations to verify which of these predictor tests are significantly associated with difficult glottic exposure.Methods:After obtaining institutional ethics committee approval, 402 ASA I and II adult patients undergoing elective surgical procedures requiring endotracheal intubation were included. All the three test were performed in all the patients preoperatively and their glottic exposure was recorded by Cormack-Lehane classification during intubation. Sensitivity, specificity, positive predictive value and negative predictive value were used for comparison.Results:In our study, the incidence of difficult laryngoscopy was 11.4% and failure to intubate 0.49%. None of the three are a suitable predictive test when used alone. Combination of tests added incremental diagnostic value.Conclusion:We conclude that all three screening tests for difficult intubation have only poor to moderate discriminative power when used alone. Combinations of individual tests add some incremental diagnostic value.

Predictors of Difficult Intubation in Patients With Ankylosing Spondylitis: Do Disease Activity and Spinal Mobility Indices Matter?

Objectives: This study aims to determine the predictors of difficult intubation and their possible correlations with disease activity and spinal mobility indices in patients with ankylosing spondylitis. Patients and methods: Forty-five ankylosing spondylitis patients were included in the study. Disease activity was evaluated with the Bath Ankylosing Spondylitis Disease Activity Index and spinal mobility with Bath Ankylosing Spondylitis Metrology Index (BASMI). The predictors of difficult intubation were evaluated by using the modified Mallampati test, upper lip bite test, thyromental distance, sternomental distance, interincisor distance and neck extension. Results: There was no correlation between Bath Ankylosing Spondylitis Disease Activity Index and predictive test values (all p>0.05). There were significant correlations between BASMI with modified Mallampati test, sternomental distance, neck extension, and inter-incisor distance values (all p<0.05). The BASMI scores in patients with two or more predictors were significantly higher than BASMI scores in patients with none or one predictor (5.28±2.12 vs. 1.58±1.50; p<0.001). Among the patients with moderate to severe BASMI, the number of patients with two or more predictors was higher than in those patients with none or one predictor (p=0.001). Conclusion: Neck extension, inter-incisor distance, sternomental distance and modified Mallampati test are significant predictors for difficult intubation in patients with ankylosing spondylitis. These predictors were found to be correlated with spinal mobility index, but not with disease activity index. Clinicians should be aware of difficult intubation in ankylosing spondylitis patients with moderate to severe spinal mobility limitation.

Comparación de diferentes test para determinar la intubación difícil en pacientes pediátricos

BackgroundThe difficulties with airway management is the main reason for pediatric anesthesia-related morbidity and mortality. ObjectiveTo assess the value of modified Mallampati test, Upper-Lip-Bite test, thyromental distance and the ratio of height to thyromental distance to predict difficult intubation in pediatric patients. DesignProspective analysis. Measurements and resultsData were collected from 5 to 11 years old 250 pediatric patients requiring tracheal intubation. The Cormack and Lehane classification was used to evaluate difficult laryngoscopy. Sensitivity, specificity, positive predictive value and AUC values for each test were measured. ResultsThe sensitivity and specificity of modified Mallampati test were 76.92% and 95.54%, while those for ULBT were 69.23% and 97.32%. The optimal cutoff point for the ratio of height to thyromental distance and thyromental distance for predicting difficult laryngoscopy was 23.5 (sensitivity, 57.69%; specificity, 86.61%) and 5.5cm (sensitivity, 61.54%; specificity, 99.11%). The modified Mallampati was the most sensitive of the tests. The ratio of height to thyromental distance was the least sensitive test. ConclusionThese results suggested that the modified Mallampati and Upper-Lip-Bite tests may be useful in pediatric patients for predicting difficult intubation.

Comparação de diferentes testes para determinar intubação difícil em pacientes pediátricos

BackgroundThe difficulties with airway management is the main reason for pediatric anesthesia‐related morbidity and mortality. ObjectiveTo assess the value of modified Mallampati test, Upper‐Lip‐Bite test, thyromental distance and the ratio of height to thyromental distance to predict difficult intubation in pediatric patients. DesignProspective analysis. Measurements and resultsData were collected from 5 to 11 years old 250 pediatric patients requiring tracheal intubation. The Cormack and Lehane classification was used to evaluate difficult laryngoscopy. Sensitivity, specificity, positive predictive value and AUC values for each test were measured. ResultsThe sensitivity and specificity of modified Mallampati test were 76.92% and 95.54%, while those for ULBT were 69.23% and 97.32%. The optimal cutoff point for the ratio of height to thyromental distance and thyromental distance for predicting difficult laryngoscopy was 23.5 (sensitivity, 57.69%; specificity, 86.61%) and 5.5cm (sensitivity, 61.54%; specificity, 99.11%). The modified Mallampati was the most sensitive of the tests. The ratio of height to thyromental distance was the least sensitive test. ConclusionThese results suggested that the modified Mallampati and Upper‐Lip‐Bite tests may be useful in pediatric patients for predicting difficult intubation.

Comparison of different tests to determine difficult intubation in pediatric patients

BackgroundThe difficulties with airway management is the main reason for pediatric anesthesia-related morbidity and mortality. ObjectiveTo assess the value of modified Mallampati test, Upper-Lip-Bite test, thyromental distance and the ratio of height to thyromental distance to predict difficult intubation in pediatric patients. DesignProspective analysis. Measurements and resultsData were collected from 5 to 11 years old 250 pediatric patients requiring tracheal intubation. The Cormack and Lehane classification was used to evaluate difficult laryngoscopy. Sensitivity, specificity, positive predictive value and AUC values for each test were measured. ResultsThe sensitivity and specificity of modified Mallampati test were 76.92% and 95.54%, while those for ULBT were 69.23% and 97.32%. The optimal cutoff point for the ratio of height to thyromental distance and thyromental distance for predicting difficult laryngoscopy was 23.5 (sensitivity, 57.69%; specificity, 86.61%) and 5.5cm (sensitivity, 61.54%; specificity, 99.11%). The modified Mallampati was the most sensitive of the tests. The ratio of height to thyromental distance was the least sensitive test. ConclusionThese results suggested that the modified Mallampati and Upper-Lip-Bite tests may be useful in pediatric patients for predicting difficult intubation.