Comparison of the Mallampati Classification in Sitting and Supine Position to Predict Difficult Tracheal Intubation: A Prospective Observational Cohort Study.

BACKGROUND: The Mallampati classification (MLPT) is normally evaluated in the sitting position. However, many patients cannot be evaluated in the sitting position for medical reasons. Thus, we compared the MLPT in sitting and supine positions in predicting difficult tracheal intubation (DTI). We hypothesized that the diagnostic accuracy of the MLPT performed in sitting and supine positions would differ. METHODS: We performed a single-center prospective observational study in adult patients who received general anesthesia and orotracheal intubation for noncardiac surgery. During the preanesthesia consultation, the MLPT in the sitting position was recorded. The day of surgery, the MLPT in the supine position and the difficulty of intubation (DTI) were recorded by an independent observer. The diagnostic performance of the MLPT for the prediction of DTI was evaluated in the sitting and supine positions through the area under the receiver operating characteristic (ROC) curve. The performance of the Naguib score in predicting DTI was calculated with the MLPT in sitting and supine positions. RESULTS: Among the 3036 patients, 157 (5.1%) had DTI. The area under the ROC curve for the MLPT in supine position (0.82 [0.78-0.84]) was greater than that for the MLPT in the sitting position (0.70 [0.66-0.75]; P < .001). The relationship between the sitting and supine MLPTs was moderate (Spearman rank correlation coefficient: 0.50; P < .001). The area under ROC curve for predicting DTI by the Naguib score calculated with the supine MLPT (0.78 [95% confidence interval, 0.74-0.82]) was greater than that for the Naguib score calculated with MLPT in the sitting position (0.69 [95% confidence interval, 0.63-0.74)]; P < .001). CONCLUSIONS: The MLPT performed in the supine position is possibly superior to that performed in the sitting position for predicting difficult intubation in adults.

Mallampati class, obesity, and a novel airway trajectory measurement to predict difficult laryngoscopy.

OBJECTIVES/HYPOTHESIS: To determine whether Mallampati class correlates with Cormack-Lehane grade in obese adults, and investigate a novel airway trajectory measurement (ATM) to anticipate difficult laryngoscopy. STUDY DESIGN: Retrospective cohort plus a pilot study. METHODS: One hundred eighty-four nonobese and 160 obese adults underwent laryngoscopy. Spearman correlations, gamma coefficients (G), and Kendall's τ investigated body mass index (BMI):Mallampati, BMI: Cormack-Lehane, and Mallampati:Cormack-Lehane. A z test compared the two groups. Twenty-six volunteers had neck x-rays taken in the sniffing position to examine trajectories to the larynges (ATM). RESULTS: Positive predictive value of high Mallampati for difficult laryngoscopy was 8.57%. BMI did not correlate with Mallampati (r = 0.055 [nonobese], r = -0.056 [obese]) or Cormack-Lehane [r = -0.014 [nonobese], r = -0.022 [obese]). Among nonobese adults, gamma coefficients for BMI:Mallampati was 0.039 (P = .63), for BMI:Cormack-Lehane was 0.02 (P = .85), and for Mallampati:Cormack-Lehane was 0.43 (P = .004). Among obese adults, gamma coefficients for BMI:Mallampati was -0.127 (P = .16), for BMI:Cormack-Lehane was 0.014 (P = .88), and for Mallampati:Cormack-Lehane was 0.365 (P = .01). Kendall's τ were comparable to gamma coefficients in all analyses. When comparing gamma coefficients for Mallampati:Cormack-Lehane among the nonobese and obese, z = 0.04 (P = .98). In the ATM study, only Mallampati and upper lip bite test had a significant relationship (G = 1.00, P < .001). CONCLUSIONS: Mallampati correlates poorly with Cormack-Lehane, regardless of BMI. Pilot data suggest that ATM is feasible.

Accurate classification of difficult intubation by computerized facial analysis.

BACKGROUND: Bedside airway evaluation is conduced before anesthesia, but all current methods perform modestly, with low sensitivity and positive predictive value. We hypothesized that subjective features of patients' anatomies improve anesthesiologists' ability to predict difficult intubation, and derived a computer model to do so, based on analysis of photographs of patients' faces. METHODS: Eighty male patients were divided into 2 equal cohorts for model derivation and validation. Each cohort consisted of 20 easy and 20 challenging intubations, defined as >1 attempt by an operator with at least 12 months of anesthesia experience, grade 3 or 4 laryngoscopic view, need for a second operator, or nonelective use of an alternative airway device. Photographs of each subject's face were analyzed by software that resolves each face into 61 facial proportions derived from an algorithm that models the face as a single point in a 50-dimensional eigenspace. Each parameter was tested for discriminatory ability by logistic regression, and combinations of 11 variables with P ≤ 0.1, plus Mallampati class and thyromental distance, were tested exhaustively by all possible binomial quadratic logistic regression models. Candidate models were cross-validated by maximizing the product of the area under the receiver operating characteristic curves obtained in the derivation and validation cohorts. RESULTS: The best model included 3 facial parameters and thyromental distance. It correctly classified 70 of 80 subjects (P < 10(-8)). In contrast, the best combination of Mallampati class and thyromental distance correctly classified 47 of 80 (P = 0.073). Sensitivity, specificity, and area under the curve for the computer model were 90%, 85%, and 0.899, respectively. CONCLUSIONS: Computerized analysis of facial structure and thyromental distance can classify easy versus difficult intubation with accuracy significantly outperforming popular clinical predictive tests.

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.

[Comparison of Cormack/Lehane classification grades decided by novice residents and those by board certified anesthesiologists].

BACKGROUND: Tracheal intubation training is one of the most important ones in anesthesia training. But it is difficult to evaluate from the outside whether the laryngeal view obtained with the laryngoscope is appropriate or not. METHODS: We chose a total of 389 cases of tracheal intubation performed by 12 novice residents in 2 months, and compared the grades of Cormack/Lehane classification of the same patients decided by novice residents and board certified anesthesiologists. RESULTS: During the 2-month period, the average number of tracheal intubation performed by a novice resident was 32 +/- 12 cases (mean +/- SD). A significant difference was found between Cormack/Lehane classification (P<0.05) decided by novice residents and those by board certified anesthesiologists. When the number of intubation performed by a novice resident was fewer than 30, the grade was grade II > III > I > IV. On the contrary, when it was more than 30, the ratio of grades I and II (appropriate laryngeal view) increased and the distribution changed to grade II > I >III > IV. CONCLUSIONS: We considered it useful in the tracheal intubation training that certified anesthesiologists evaluate patients' Cormack/Lehane classification grades before novice residents do, because we can obtain necessary information on laryngeal view and intubation difficulty in advance.

Review of video laryngoscopy and rigid fiberoptic laryngoscopy.

PURPOSE OF REVIEW: Recent advances in fiberoptic systems and video technology have resulted in the development of new intubation devices and techniques. A defining characteristic of rigid fiberoptic and videolaryngoscopic techniques is that glottic opening is viewed indirectly in place of direct line-of-sight. Various issues common to all instruments in this group are highlighted, and a few recently released tools are described. The aim of this article is to review material published since January 2007. RECENT FINDINGS: Indirect laryngoscopic techniques seemed to be easy to learn by both novice and experienced intubators, and can be used to teach both direct laryngoscopy and fiberoptic intubation. An adequate glottic view is generally easily obtained, which is frequently superior to that obtained by direct laryngoscopy. However, endotracheal tube insertion may be problematic, and various techniques have been developed to facilitate this procedure. Indirect laryngoscopic techniques are proving useful in situations of both anticipated and unanticipated difficult intubations, and therefore challenge the preeminence of flexible fiberoptic intubation. SUMMARY: As indirect laryngoscopic tools become more available, and clinicians become more facile in their use, the management of (potentially) difficult intubations is likely to change. Further technological advances are likely to lead to the development of even more new instruments.

CPT coding for upper airway endoscopies.

The Spring issue (Rudy, 2005) of ORL-Head and Neck Nursing presented a broad review of endoscopic procedures for evaluation and management of upper airway problems. Zarnitz (2005) briefly addressed billing for the most commonly performed upper airway endoscopies in that issue. This paper presents, in detail, the coding for a wider range of upper airway endoscopies performed in the office setting, along with how to report them to third-party payors.

Lateral neck radiography for prediction of difficult orotracheal intubation.

BACKGROUND AND OBJECTIVES: Failed endotracheal intubation is a principal cause of morbidity and mortality in anesthetized patients. The aim of this study was to investigate the efficiency of lateral neck radiography in predicting difficult intubation. METHODS: In a prospective triple-blind study, 100 patients (aged 18-89 yr), scheduled for elective surgery were randomly selected. Lateral neck X-ray was obtained from each of the patients before operation. Several angles and parameters on the X-ray were proposed to illustrate a relationship with easy or difficult intubation. A radiologist recorded these angles before the operation. An anaesthesiologist also determined the Mallampati score preoperation. At the time of intubation, two other anesthesiologists performed a laryngoscopy and, according to established criteria, identified the patients as easy or difficult intubation. The results were then compared with each other. RESULTS: Fifteen patients were identified as having difficult intubation (laryngoscopy Grades III and IV). Sensitivity and specificity of the Mallampati Class test were 26% and 100%, respectively. The sensitivity and specificity of the lateral neck X-ray for three measured angles were 100%. The positive and negative predictive values (NPVs) for those angles were 100% and for Mallampati classification were 100% and 80%, respectively. CONCLUSIONS: Compared to the Mallampati Class test, our method of analyzing the lateral X-ray, although not as easy and universally applicable as Mallampati Class test, proved to be a suitable method for predicting difficult intubation.

Reliability of paramedic ratings of laryngoscopic views during endotracheal intubation.

BACKGROUND: Prior studies have related prehospital endotracheal intubation (ETI) difficulty to paramedic visualization of the vocal cords using the Cormack-Lehane (C-L) scale. However, the reliability of paramedic C-L ratings has not been formally studied. OBJECTIVE: To evaluate the reliability of C-L and a more recently described scale, percentage of glottic opening (POGO), when used by paramedics to rate laryngoscopic views during ETI. METHODS: Twenty-five standard slide images of laryngoscopic views were obtained during ETI. The 25 images were duplicated to facilitate evaluation of intrarater agreement (total 50 slides). Seven paramedics rated the degree of vocal cord visualization in each image using C-L (I-IV, ordinal scale; I = full visualization of vocal cords, IV = only epiglottis seen) and POGO (0-100 continuous scale; 0 = no vocal cords seen, 100 = full visualization of vocal cords). We assessed intra- and interrater reliabilities using Cohen's multirater kappa for C-L and intraclass correlation coefficients (ICCs) for POGO. RESULTS: C-L showed variable intrarater reliability (kappa range = 0.37-0.90) and poor interrater reliability (Cohen's multirater kappa = 0.22). POGO demonstrated good to excellent intrarater reliability (one-way random-effects ICC range = 0.57-0.87) and fair to good interrater reliability (two-way random-effects ICC = 0.59, 95% Confidence interval: 0.48-0.71). CONCLUSIONS: Paramedic C-L ratings exhibit poor intra- and interrater reliabilities. Paramedic POGO ratings exhibit fair to good intra- and interrater reliabilities. POGO may be more appropriate than C-L for prehospital clinical and scientific application. Reliability must be formally evaluated for any proposed laryngoscopic exposure classification system.

The reliability and validity of the upper lip bite test compared with the Mallampati classification to predict difficult laryngoscopy: an external prospective evaluation.

Recently, a new bedside screening test to predict the occurrence of a difficult laryngoscopy has been developed as a substitute for the Mallampati classification. The Upper-Lip-Bite test (ULBT) evaluated the patient's ability to reach or completely cover the upper lip with the lower incisors. It is often accepted that new predictive tools should undergo an external evaluation before the tool is used in clinical practice. Thus, we evaluated this test with respect to applicability, interobserver reliability, and discriminating power and compared it with the Mallampati-score (using Samsoon and Young's modification). The ULBT could not be applied in 12% of all patients (Mallampati score, <1%). However, the interobserver reliability was better for the ULBT (kappa = 0.79 versus kappa = 0.59). The discriminating power to predict a patient with difficult laryngoscopy was evaluated in 1425 consecutive patients. Both tests were assessed simultaneously in these patients by two specially trained independent observers. After the induction of anesthesia, the laryngoscopic view was assessed by the attending anesthesiologist using the classification of Cormack and Lehane. A grade I or II was called easy laryngoscopy and grade III and IV difficult laryngoscopy. The discriminating power for both tests was low (0.60 for the ULBT [95% confidence interval, 0.57-0.63] and 0.66 [0.63-0.69]) for the Mallampati score), indicating that both tests are poor predictors as single screening tests.

Phonosurgery of the vocal folds: a classification proposal.

The Phonosurgery Committee of the European Laryngological Society (ELS) has examined the definition and technical description of phonosurgical procedures. Based on this review, the committee has proposed a working classification. The current presentation is restricted to vocal fold surgery (VFS) with phonosurgical intent. Both the pathology and the therapeutic aim define VFS: (1). vocal fold lesions that impair vibratory movements require excision (e.g., vocal fold nodule), incision and suction (e.g., Reinke's edema), dissection and/or augmentation (e.g., sulcus-vergeture), coagulation or vaporization (e.g., varicosity) and incision and stenting (e.g., glottal web); (2.vocal fold movement disorders require position and/or tension correction by augmentation (e.g., vocal fold paresis), injection (e.g., botulinum toxin for spasmodic dysphonia) and excision (e.g., dysphonia plicae ventricularis). This presentation excludes surgical instrumentation, implants or injectable materials. Being essentially surgeon-dependent, usage may vary over time and with experience.

The modified Cormack-Lehane score for the grading of direct laryngoscopy: evaluation in the Asian population.

The use of a modified Cormack-Lehane scoring system (MCLS) of laryngoscopic views, as previously introduced in the Western population, was investigated during direct laryngoscopy in the Asian population. We studied the distribution of the different grades of MCLS, the predictive factors and rate of difficult laryngoscopy, and the association with difficult intubation. Six hundred and five patients requiring tracheal intubation during general anaesthesia were prospectively studied. The optimal views during direct laryngoscopy were scored using the 5-grade MCLS system. The distribution of the laryngoscopy scores was 73.9% Grade 1 (full view of the vocal cords), 21.0% Grade 2A (partial view of the vocal cords), 3.3% Grade 2B (only the arytenoids and epiglottis seen), 1.6% Grade 3 (only epiglottis visible) and 0.2% Grade 4 (neither the epiglottis nor glottis seen). External laryngeal pressure was necessary in 45.3% of cases to optimize laryngoscopic views. Grade 2B was associated with significantly higher incidence of difficult intubation compared with Grade 2A (65% vs 13.4%). The rates of difficult laryngoscopy and intubation were 5.1% and 6.9% respectively. The Mallampati classification and thyromental distance were associated with low predictive value for difficult laryngoscopy. The MCLS better delineates the difficulty experienced during laryngoscopy than the original Cormack-Lehane grading

Endoscopic cordectomy. A proposal for a classification by the Working Committee, European Laryngological Society.

The European Laryngological Society is proposing a classification of different laryngeal endoscopic cordectomies in order to ensure better definitions of post-operative results. We chose to keep the word "cordectomy" even for partial resections because it is the term most often used in the surgical literature. The classification comprises eight types of cordectomies: a subepithelial cordectomy (type I), which is resection of the epithelium; a subligamental cordectomy (type II), which is a resection of the epithelium, Reinke's space and vocal ligament; transmuscular cordectomy (type III), which proceeds through the vocalis muscle; total cordectomy (type IV); extended cordectomy, which encompasses the contralateral vocal fold and the anterior commissure (type Va); extended cordectomy, which includes the arytenoid (type Vb); extended cordectomy, which encompasses the subglottis (type Vc); and extended cordectomy, which includes the ventricle (type Vd). Indications for performing those cordectomies may vary from surgeon to surgeon. The operations are classified according to the surgical approach used and the degree of resection in order to facilitate use of the classification in daily practice. Each surgical procedure ensures that a specimen is available for histopathological examination.