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.

[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.

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.

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.

Recognition of the difficult airway in normal Nigerian adults (a prospective study)

Difficulty with laryngoscopy and intubation is known to be the most frequent cause of anaesthetic related deaths. Awareness of the possibility of difficulty would enable the anaesthetist to be adequately prepared. 57 "normal" adult patients were examined pre-operatively and at laryngoscopy using the Mallampatti (1985) and the Cormack (1984) classification respectively. The result showed that none of the patients was in the IV Mallampatti nor IV Cormack groups. Four patients with class III Mallampatti features were seen, two of which were classified Cormack III at laryngoscopy. Intubation failed in these two patients. The majority of patients were classified as Mallampatti class I (68.42%) and Cormack grade I (63.16%). This in effect demonstrates that in most "normal" patients laryngoscopy and intubation should be fairly easy.

Prediction of difficult laryngoscopy: an assessment of the thyromental distance and Mallampati predictive tests

Two hundred and fifty patients were assessed preoperatively using the Mallampati classification and by measuring their thyromental distances. The ease or difficulty of direct laryngoscopy was assessed at the time of induction of anaesthesia. Retrognathia was seen in 15.6% of patients and the incidence of difficult laryngoscopy without external laryngeal pressure was 8.2%. It was found that both assessments predicted less than two in three difficult laryngoscopies and had high false positive rates. It was found that external laryngeal pressure often improved the view of the glottis in difficult laryngoscopies.