Upper Lip Bite Test Research Articles

Comparing ease of intubation in obese and lean patients using intubation difficulty scale.

Background:Difficult tracheal intubation contributes to significant morbidity and mortality during induction of anesthesia. There are divided opinions regarding ease of intubation in obese patients. Moreover, the definition of difficult intubation is not uniform; hence we have use the Intubation Difficulty Scale (IDS) to find the incidence of difficult intubation in obese patients.Aims:The primary aim of the following study is to find out the incidence of difficult intubation in obese and lean patients using IDS and secondary aim is to assess the performance of bedside screening tests to predict difficult intubation, mask ventilation and laryngoscopy in obese and lean patients.Materials and Methods:A prospective, observational cohort study of 200 patients requiring general anesthesia were categorized into 100 each based on body mass index (BMI) into lean (BMI <25 kg/m2) and obese (BMI ≥25 kg/m2) groups. IDS score ≥5 was termed as difficult intubation. Pre-operative airway assessment included Mallampati score, mouth opening, neck circumference (NC), upper lip bite test, thyromental distance, sternomental distance (SMD) and head neck mobility. Patients having difficulty in mask ventilation and laryngoscopy was recorded.Results:Over all in 200 patients the incidence of difficult intubation was 9%. Obese patients were slightly more difficult to intubate than lean (11% vs. 7%, P = 0.049). Age >40 years, NC >35 cm, SMD <12.5 cm and restricted head neck mobility were factors which were associated with IDS ≥5. Multivariate analysis revealed SMD <12.5 cm to predict difficult intubation in obese patients. Obese patients were difficult to mask ventilate (6% vs. 1%, P = 0.043). There was no difference regarding grading of laryngoscopy between the two groups.Conclusion:Obese patients are difficult to mask ventilate and intubate. During intubation of obese patients who is more than 40 years age and SMD <12.5 cm, it is preferable to have a second skilled anesthesiologist.

Does upper lip bite test predict difficult intubation?

Does upper lip bite test predict difficult intubation?

Comparison of upper lip bite test with thyromental distance for predicting difficulty in endotracheal intubation: A prospective study

The present study has aimed to compare the upper lip bite test (ULBT) and thyromental distance (TMD) in predicting difficulty in intubation. 140 consecutive patients aged 18 – 60 years were included in the study. Each patient was evaluated regarding ULBT, TMD. Laryngoscopy was assessed by an attending anesthesiologist blinded to the study. In our study we found both the tests have a negative predictive value more than 90%, thus stressing the fact that, these tests can be good predictors of easy intubation, rather as positive predictors of difficult intubation which has a very low incidence. But out of the two tests, positive predictive value of ULBT is more and statistically significant, so better than TMD.

English

BACKGROUND: Unanticipated difficult tracheal intubation is a significant source of morbidity and mortality in anaesthetic practice which can be reduced by identification of potential difficult intubation. OBJECTIVE: We aimed the present study to know the incidence of difficult intubation, factors associated with it and the predictive value of various airway predictors in anticipating difficult visualization of larynx and difficult intubation. METHODS: 435 adult patients (>18 year) undergoing general anaesthesia with intubation were examined preoperatively for demographic details (age, sex, weight), dentition, airway pathology and six airway predictors i.e. Inter Incisor Gap (IIG), Modified Mallampatti Grading (MMPG), Upper lip bite test (ULBT), Thyromental distance (TMD), Sternomental distance (SMD) and subluxation of mandible (SLM). All patients were anaesthetized using standard protocol with thiopentone (5mg/kg) and succinylcholine (1.5 mg/kg). On direct laryngoscopy, Cormack Lehane (CL) grading was noted. CL grade I, II was defined as easy visualization of larynx (EVL) and CL grade III, IV as difficult visualization of larynx (DVL). Difficult intubation score (DIS) was calculated as sum of CL grade and number of intubation attempts. DIS of less than or equal to 4 was defined as easy intubation (EI) and DIS > 4 was defined as difficult intubation (DI).Sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratios(LR) and odd's ratio value for six airway predictor tests was calculated by standard formulae. RESULTS: Incidence of DVL was 12.65% (n=55) and DI was 9.65% (n=42), with no failed intubation. All airway tests had very high negative predictive value (>90%) which implicates they identify easy intubations more precisely. MMPG and ULBT were found as airway predictors for difficult intubation having odds ratio of 85.23 (95% CI 25.42- 285.89%) and 65.45 (95% CI 25.69-166.7%) respectively, along with very high sensitivity of 92.80% and 85.7% respectively. Presence of ULBT III is the best predictor of difficult intubation (+LR 21.97) and absence of MMPG III, IV is the best predictor of difficult intubation (-LR 0.091). Abnormal dentition and airway pathology also increase the risk of difficult intubation, P<0.001. CONCLUSION: We conclude that ULBT and MMPG are nearly perfect airway predictors and should be used routinely during pre-anesthetic visit for screening of difficult intubation.

Diagnostic value of the upper lip bite test in predicting difficulty in intubation with head and neck landmarks obtained from lateral neck X-ray

Background:Unanticipated difficult tracheal intubation remains a primary concern of anaesthesiologists and upper lip bite test (ULBT) is one of the assessments used in predicting difficult intubation. In this study, we aimed to check the utility of lateral neck X-ray measurements in improving the diagnostic value of the ULBT.Methods:In a prospective study conducted from January 2007 until December 2010, we recorded personal and demographic data of 4500 patients who entered the study and subjected them to standard lateral neck radiography. Before the induction of anaesthesia, clinical examination and ULBT results were recorded and during induction of anaesthesia laryngoscopic grading was evaluated and recorded in questionnaires. All the compiled data were analysed by SPSS 14.0 (SPSS Inc., Chicago, IL, USA) software. Diagnostic value for each test was calculated and compared.Results:Negative predictive values (NPVs) were high in all tests. ULBT had the highest specificity and NPV compared with the other tests. The positive predictive value for all the tests had been low, but marginally high in the ULBT.Conclusion:Although all the tests used had relatively acceptable predictive values, combination of tests appeared to be more predictive. Highest sensitivities were observed with ULBT, mandibulohyoid distance and thyromental distance respectively. Use of radiological parameters may not be suitable as screening tools, but may help in anticipating and preparing for a difficult scenario.

Predictive value of upper lip bite test and ratio of height to thyromental distance compared to other multivariate airway assessment tests for difficult laryngoscopy in apparently normal patients

Background:Various anatomical measurements and non-invasive clinical tests, singly or in various combinations can be performed to predict difficult intubation. Recently introduced “Upper lip bite test” (ULBT) and “Ratio of height to Thyromental distance” (RHTMD) are claimed to have high predictability. We conducted a study to compare the Predictive Value of ULBT and RHTMD with Mouth opening (Inter-Incisor gap) (IIG), Modified Mallampatti Test (MMT), Head and neck movement (HNM) and Thyromental Distance (TMD) for Difficult Laryngoscopy.Materials and Methods:In this prospective, single blinded observational study, 480 adult patients of either sex, ASA grade I and II were assessed and graded for ULBT, RHTMD, TMD, MMT, IIG, and HNM according to standard methods and correlated with the Cormack and Lehane grade.Results:ULBT and RHTMD had highest sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio, i.e., 74.63%, 91.53%, 58.82%, 95.7%, 31.765 and 71.64%, 92.01%, 59.26%, 95.24%, 8.96 respectively, compared to TMD, MMT, IIG and HNM.Conclusions:ULBT is the best predictive test for difficult laryngoscopy in apparently normal patients but RHTMD can also be used as an acceptable alternative.

Predictors of difficult intubation defined by the intubation difficulty scale (IDS): predictive value of 7 airway assessment factors

BackgroundThe intubation difficulty scale (IDS) has been used as a validated difficulty score to define difficult intubation (DI). The purpose of this study is to identify airway assessment factors and total airway score (TAS) for predicting DI defined by the IDS.MethodsThere were 305 ASA physical status 1-2 patients, aged 19-70 years, who underwent elective surgery with endotracheal intubation. During the pre-anesthetic visit, we evaluated patients by 7 preoperative airway assessment factors, including the following: Mallampati classification, thyromental distance, head & neck movement, body mass index (BMI), buck teeth, inter-incisor gap, and upper lip bite test (ULBT). After endotracheal intubation, patients were divided into 2 groups based on their IDS score estimated with 7 variables: normal (IDS < 5) and DI (IDS ≥ 5) groups. The incidence of TAS (> 6) and high score of each airway assessment factor was compared in two groups: odds ratio, confidence interval (CI) of 95%, with a significant P value ≤ 0.05.ResultsThe odds ratio of TAS (> 6), ULBT (class III), head & neck movement (< 90°), inter-incisor gap (< 4 cm), BMI (≥ 25 kg/m2) and Mallampati classification (≥ class III) were respectively 13.57 (95% CI = 2.99-61.54, P < 0.05), 12.48 (95% CI = 2.50-62.21, P < 0.05), 3.11 (95% CI = 0.87-11.13), 2.32 (95% CI = 0.75-7.19), 2.22 (95% CI = 0.81-6.06), and 1.22 (95% CI = 0.38-3.89).ConclusionsWe suggest that TAS (> 6) and ULBT (class III) are the most useful factors predicting DI.

INTER-OBSERVER REPRODUCIBILITY OF 15 TESTS USED FOR PREDICTING DIFFICULT INTUBATION

To determine the inter-observer reproducibility of 15 tests used for predicting difficult tracheal intubation (DI). Following local ethics committee approval and informed consent, 101 volunteers were examined by two assessors using 15 tests for predicting DI. The two assessors who were blinded to the results of the other, examined each volunteer independently. Cohen's kappa (κ) or first-order agreement coefficient (AC1) were used to measure agreement between assessor ratings on a qualitative scale. Agreement between two quantitative outcomes was described using the intraclass correlation coefficient (ICC) and Pearson's (PCC) or Spearman's (SCC) correlation coefficients. The following interpretation of the coefficients was used: poor (< 0.20), fair (0.21-0.40), satisfactory (0.41-0.60), good (0.61-0.80), and excellent (0.81-1.00). Respective coefficients of inter-rater agreement and correlation coefficients were determined for the following parameters: pathologies associated with DI (κ=0.662, AC1=0.990), clinical impression (κ=-0.013, AC1=0.969), modified Mallampati test (κ=0.503, AC1=0.861), upper lip bite test (κ=0.370, AC1=0.897), temporo-mandibular joint movement (κ=0.088, AC1=0.797), max. anteroflexion of C-spine (ICC=0.136, SCC=0.391), max. retroflexion of C-spine (ICC=0.020, SCC=0.284), mandibular length (ICC=0.301, SCC=0.553), neck circumference (ICC=0.832, SCC=0.928), hyo-mental distance (ICC=0.378, SCC=0.472), thyro-mental distance (ICC=-0.002, PCC=0.265), sternomental distance (ICC=0.674, PCC=0.815), and finally, inter-incisor gap (ICC=0.695, PCC=0.785). Two tests (positive history of DI and retrogenia), were excluded from calculation because no positive cases were found. Best inter-rater agreement was found for the assessment of neck circumference while the highest discrepancies between raters were in goniometrically-measured mobility of the C-spine. Many of the pre-operative airway tests had only fair inter-observer reproducibility. This may be one reason why models for predicting difficult intubation are not universally reliable.

Comparison of modified Mallampati classification, upper lip bite test and neck circumference in prediction of difficult intubation

s and Programme: EUROANAESTHESIA 2011: The European Anaesthesiology Congress: Airway Management

CAN DIFFICULT INTUBATION BE EASILY AND RAPIDLY PREDICTED?

Failed endotracheal intubation and inadequate ventilation with subsequent insufficient oxygenation can result in serious complications potentially leading to permanent health damage. Difficult intubation may occur not only in patients with apparent pathologies in the orofacial region but also, unexpectedly, in those without abnormalities. This study aimed at finding anthropometric parameters that are easy to examine and that would aid in predicting difficult intubation. A case-control study was undertaken. Based on defined criteria, 15 parameters were examined in patients with unanticipated difficult intubation. The parameters included a previous history of difficult intubation, pathologies associated with difficult intubation, clinical symptoms of airway pathology, the Mallampati score, upper lip bite test, receding mandible, and cervical spine and temporomandibular joint movement. Thyromental, hyomental and sternomental distances and inter-incisor gap were measured. The methods were precisely defined and the measurements were carried out by a trained anesthesiologist. Statistical analysis was performed on data from 74 patients with difficult intubation and 74 control patients with easy intubation. Significant predictors of difficult intubation were inter-incisor gap (IIG), thyromental distance (TMD) and class 3 limited movement of the temporomandibular joint. The IIG and TMD cut-offs were set at 42 mm and 93 mm, respectively. The results will be used to confirm these predictors in an anesthesiology clinic along with the aid of the laryngoscopic findings to improve the prediction of unanticipated difficult intubation.

A comparison of the upper lip bite test with hyomental/thyrosternal distances and mandible length in predicting difficulty in intubation: A prospective study

The incidence of difficulty in tracheal intubation has been reported to range from 0.5 to 18% in patients undergoing surgery. We aimed to elucidate the role of upper lip bite test (ULBT) with other prevailing tests, hyomental/thyrosternal distances (HMD/TSD), and the mandible length (ML) and their possible correlation in predicting difficulty in intubation. After institutional approval and informed consent were obtained, 300 consecutive patients aged 20–60 years of ASA physical status I and II, scheduled for elective surgical procedures requiring tracheal intubation and meeting the inclusion criteria, were enrolled in this study. Each patient was evaluated regarding ULBT, HMD, TSD and ML. Laryngoscopy was assessed by an attending anaesthesiologist blinded to the measurements. The laryngoscopic result was graded according to Cormack and Lehane’s Grading system. The negative predictive value (NPV) and positive predictive value (PPV) of ULBT were found to be 94 and 100%, respectively. These corresponding figures for TSD were 88.5 and 0%, respectively. Specificities for ULBT, HMD, ML and TSD were 100, 98.9, 98.9 and 98.1%, respectively. ULBT class and laryngoscopic grading showed the greatest agreement (kappa = 0.61, P < 0.001). An agreement between laryngoscopic grading and HMD and ML also existed (0.003 and <0.001, respectively), but was comparatively weaker. The high specificity, NPV, PPV and accuracy of ULBT as revealed in this study could be a good rationale for its application in the prediction of difficulty or easiness in intubation. ML > 9 cm and HMD > 3.5 cm were good predictors of negative difficult intubation.

A comparison of the ratio of patient's height to thyromental distance with the modified Mallampati and the upper lip bite test in predicting difficult laryngoscopy.

Background:The aim of the present study was to compare the ability to predict difficult visualization of the larynx from the following preoperative airway predictive indices, in isolation and combination: modified Mallampati test (MMT), the ratio of height to thyromental distance (RHTMD) and the Upper-Lip-Bite test (ULBT).Methods:We collected data on 603 consecutive patients scheduled for elective surgery under general anesthesia requiring endotracheal intubation and then evaluated all three factors before surgery. An experienced anesthesiologist, not informed of the recorded preoperative airway evaluation, performed the laryngoscopy and grading (as per Cormack and Lehane's classification). Sensitivity, specificity, and positive and negative predictive value, Receiver operating characteristic (ROC) Curve and the area under ROC curve (AUC) for each airway predictor in isolation and in combination were determined.Results:Difficult laryngoscopy (Grade 3 or 4) occurred in 41 (6.8%) patients. The main endpoint of the present study, the AUC of the ROC, was significantly lower for the MMT (AUC, 0.511; 95% CI, 0.470–0.552) than the ULBT (AUC, 0.709; 95% CI, 0.671–0.745, P=0.002) and the RHTMD score (AUC, 0.711; 95% CI, 0.673–0.747, P=0.001). There was no significant difference between the AUC of the ROC for the ULBT and the RHTMD score. By using discrimination analysis, the optimal cutoff point for the RHTMD for predicting difficult laryngoscopy was 21.06 (sensitivity, 75.6%; specificity, 58.5%).Conclusion:The RHTMD is comparable with ULBT for prediction of difficult laryngoscopy in general population.

A comparison of upper lip bite test and the modified mallampati classification in airway assessment

Objective To compare preoperative anesthetic airway evaluation methods of the modified Mallamapti test and Upper lip bite test (ULBT),and to discuss the feasibility of Upper lip bite test on airway assessment. Methods 820 patients admitted for elective surgical procedure requiring endotracheal intubation were prospectively studied to predict difficultly level of intubation. All the patients were assessed preoperatively using the Modified Mallampati Classification and Upper Lip Bite Test. The sensitivity, specificity,positive predictive value, negative predictive value and accuracy were calculated. Results The accuracy, sensitivity, specificity,positive predictive value and negative predictive value of ULBT and the modified Mallamapti test are 86.1%, 63.46%, 89.39%, 46.48%,94.4% and 73.66%, 51.92%, 76.82%, 24.55%, 91.67% repectively. Conclusion Compared to the Modified Mallampati Classification,ULBT has higher accuracy, sensitivity, specificity, positive predictive value and negative predictive value, and should be served as a complementary to other methods. It is also worthy of promotion and application. Key words: Upper lip bite test; Modified Mallampati test; Airway assessment

First International Congress of Airway Management and Anesthesia in Head and Neck Surgery, Tehran, Iran, May 20–22, 2009

First International Congress of Airway Management and Anesthesia in Head and Neck Surgery, Tehran, Iran, May 20–22, 2009

The Diagnostic Value of the Upper Lip Bite Test Combined With Sternomental Distance, Thyromental Distance, and Interincisor Distance for Prediction of Easy Laryngoscopy and Intubation

The Diagnostic Value of the Upper Lip Bite Test Combined With Sternomental Distance, Thyromental Distance, and Interincisor Distance for Prediction of Easy Laryngoscopy and Intubation

Evaluation of the upper lip bite test in predicting difficult laryngoscopy

Study Objective To evaluate the accuracy of the upper lip bite test (ULBT) in predicting difficult laryngoscopy. Design Prospective, observational outcome study. Setting Operating room of a large tertiary-care academic medical center. Patients 6,882 consecutive adult, ASA physical status I, II, III, IV, and V patients, scheduled for procedures in all surgical specialties. Interventions Upper lip bite test class was determined for all patients preoperatively. Measurements The Cormack & Lehane grade of laryngeal view was determined at endotracheal intubation. Main Results Only 171 patients had ULBT class III, predicting a difficult laryngoscopy, while 173 patients presented with a Cormack & Lehane grade of 3 or 4. Of the 173, 14 patients had a previous ULBT class of III. Sensitivity and positive predictive value of the ULBT were 8.1% and 8.2%, respectively. Conclusions The ULBT is a poor predictor of difficult laryngoscopy when used as the single bedside screening test in a North American patient population. Its use cannot be recommended.

Predicting Difficult Laryngoscopy in Acromegaly: A Comparison of Upper Lip Bite Test With Modified Mallampati Classification

Upper lip bite test (ULBT) is a simple test for predicting difficult intubation. However, it has not been evaluated in acromegalic patients. The primary aim of this study was to compare ULBT with modified Mallampati classification (MMPC) to predict difficult laryngoscopy in acromegalic patients. Over a 5-year period, 64 acromegalic and 63 nonacromegalic patients presenting for excision of pituitary tumor were enrolled. Preoperative airway assessment was done using MMPC and the ULBT. Under anesthesia, laryngoscopic view was assessed using Cormack-Lehane (CL) grading. MMPC III/IV and ULBT grade III were considered predictive of difficult laryngoscopy that was defined as Cormack-Lehane grades III or IV. Difficult intubation was defined as more than 2 direct laryngoscopy attempts involving change of blade or use of bougie/fiberoptic bronchoscope/intubating laryngeal mask airway. Sensitivity, specificity, positive and negative predictive values, and accuracy of both tests in predicting difficult laryngoscopy were calculated. Incidence of difficult laryngoscopy and intubation in acromegalics were 24% and 11%, respectively. MMPC and ULBT predicted difficulty in 61% and 14% acromegalics, respectively. However, only 26% and 44% of the laryngoscopies predicted to be difficult by MMMC and ULBT, respectively, were actually difficult. MMPC failed to predict 33% of difficult laryngoscopies whereas ULBT failed to predict 73%. Neither test predicted difficulty in 33% laryngoscopies that turned out to be difficult. Twenty-seven percent of the difficult laryngoscopies were correctly predicted by both tests. In acromegalic group, MMPC was more sensitive, whereas ULBT was more specific. Sensitivity and accuracy of both tests were less in acromegalic patients compared with nonacromegalic controls.

Upper lip bite test in a patient with McCune Albright syndrome with acromegaly

We report a patient with McCune Albright syndrome with acromegaly and features predictive of difficult airway except a class I upper lip bite (ULB) test. Our patient, a 33-year-old woman, had a history of polyostotic fibrous dysplasia. Tracheal intubation was performed under general anaesthesia. Although we did not find any difficulty in visualizing the glottis by direct laryngoscopy; our patient had multiple poor predictive signs of airway assessment including a Mallampati grade III, restricted neck movement and macroglossia. Our report suggests that the ULB test in people with acromegaly may act as an indicator of easy intubation in spite of other poor predictive signs. However, this finding needs further corroboration by a large study to evaluate the role of the ULB test in people with acromegaly.

The Diagnostic Value of the Upper Lip Bite Test Combined with Sternomental Distance, Thyromental Distance, and Interincisor Distance for Prediction of Easy Laryngoscopy and Intubation: A Prospective Study

Accuracy of upper lip bite test (ULBT) has been compared with the Mallampati classification. In this study, we investigated whether the combination of the ULBT classification with sternomental distance (SMD), thyromental distance (TMD), and interincisor distance (IID) or a composite score can improve the ability to predict easy laryngoscopy and intubation compared with each test alone. In a prospective study, 380 patients who were scheduled for elective surgery were selected randomly and enrolled in the study. Before inducing anesthesia, the airways were assessed, and ULBT class, SMD, TMD, and IID determined. Laryngoscopic view according to the Cormack and Lehane grading system was determined after induction of anesthesia and Grades 3 and 4 defined as "difficult intubation." By using receiver operating characteristic analysis, the best cutoff points of the tests were calculated. Finally, sensitivity, specificity, positive and negative predictive values and accuracy of these tests and their combinations with the ULBT were calculated. The prevalence of difficult intubation was 5% (n = 19). Class III ULBT, IID <4.5 cm, TMD <6.5 cm, and SMD <13 cm were defined as predictors of difficult intubation. There was no significant difference regarding difficult intubation based on gender (P < 0.05), whereas there were significant differences between the older tests and laryngeal view (P < 0.05, Mc-Nemar test). Specificity and accuracy of the ULBT were significantly higher than TMD, SMD, and IID individually (specificity was 91.69%, 82.27%, 70.64%, and 82.27%, respectively, and accuracy was 91.05%, 71.32%, 81.84%, and 76.58%, respectively). The combination of the ULBT with SMD provided the highest sensitivity. We conclude that the specificity and accuracy of the ULBT is significantly higher than the other tests and is more accurate in airway assessment. However, the ULBT in conjunction with the other tests could more reliably predict easy laryngoscopy or intubation.

Comparison of upper lip bite test with modified mallampati classification for prediction of difficult obstetric intubation

Failed obstetric intubation is a major contributory factor in anaesthesia related morbidity and mortality. Upper lip bite test (ULBT) is a relatively new test for prediction of difficult intubation, introduced in the year 2003. Here we have compared ULBT with Modified Mallampati classification (MMC) for prediction of difficult intubation in obstetric patients scheduled for caesarean section. Preoperative airway assessment for prediction of difficult laryngoscopy and intubation was done using the MMC and ULBT in hundred consecutive parturients undergoing elective as well as emergency Cesarean section under general anesthesia. Class III ULBT and a MMC of III or IV were considered to be predictive of difficult intubation (Cormack & Lehane class III or IV). Fourteen patients in the study had difficult intubation (14%). The sensitivity (92 Vs 85.7%), specificity (86 Vs 69.7%), positive predictive value (52.3 Vs 31.5%), negative predictive value (98.6 Vs 96.7%), and accuracy (87 Vs 72%) were as observed for ULBT and MMC respectively. Thus ULBT was found to be superior in every aspect studied.