Calculated decisions: Modified Mallampati classification.

The Modified Mallampati Classification stratifies predicted difficulty of endotracheal intubation based on anatomic features.

Intraoperative Endotracheal Cuff Pressure Study: How Education and Availability of Manometers Help Guide Safer Pressures.

INTRODUCTION: Endotracheal intubation is a medical procedure that is often indicated in both the perioperative and critical care environments. Cuffed endotracheal tubes (ETT) allow for safer and more efficient delivery of positive pressure ventilation, as well as create a barrier to reduce the risk of micro-aspiration and anesthetic pollution in the operating room environment. Over-inflation of the endotracheal cuff can lead to serious and harmful sequelae. This study aimed to assess if departmental education paired with ready access to a manometer to assess cuff pressure would result in an improvement in the proportion of ETT cuff pressures in the goal range. MATERIALS AND METHODS: A quality improvement study was conducted at the San Antonio Military Medical Center (SAMMC; Department of Defense hospital in San Antonio, TX). The initiative was divided into three key periods: pre-implementation, implementation, and post-implementation. During the pre-implementation period, ETT cuff pressures were obtained to assess the baseline state of ETT cuff pressures for patients in the operating room; the proportion of in-range (20-30 cmH2O) pressures was calculated. During the implementation phase, operating rooms were equipped with manometers and anesthesia departmental education was performed regarding the use of the manometers. Three months later, post-implementation cuff pressures were measured in the OR, and the proportion of in-range pressures was again calculated. RESULTS: The pre-implementation data showed an average cuff pressure of 48.92 cmH2O and a median of 38.5 cmH2O. Of the 100 pre-implementation pressures, 20 were in the goal range. Post-implementation data had an average cuff pressure of 41.96 cmH2O and a median of 30 cmH2O. A chi-squared test of pressures in the safe range from the pre-implementation versus post-implementation values yielded a highly significant p-value of 0.0003. CONCLUSION: The data from this study clearly demonstrated a statistically significant improvement in the proportion of in-range cuff pressures following the quality improvement initiative. This study supports the use of department-wide education and the availability of manometers in each OR to yield safer cuff pressures for intubated patients. This study did not aim to determine an optimal ETT cuff pressure, but utilized data already available to determine a safe cuff pressure. Further research needs to be performed to assess whether routine monitoring of cuff pressure results in improved patient outcomes.

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.

Estudio prospectivo, aleatorizado y cruzado que compara 2 tubos endotraqueales de polivinilo. ¿Son todos los tubos iguales? / A prospective, randomised, cross-over trial comparing two standard polyvinyl chloride tracheal tubes. Are all the tubes the same?

Introducción. Los autores comparan de forma aleatorizada el número de intentos durante la intubación endotraqueal convencional de un maniquí utilizando 2 tubos de polivinilo (PVC) aparentemente similares pero de distinto fabricante: Intersurgical (IS; Intersurgical S.L., Madrid, España) y Mallinckrodt (ML; Mallinkrodt Medical S.A., Madrid, España). Método. Veintiséis anestesiólogos experimentados intubaron 2 veces un maniquí utilizando un tubo diferente en cada ocasión y cuyo orden fue establecido de forma aleatoria (secuencia aleatoria generada por Epidat 3.1.). El tubo fue pintado para enmascararlo y no ser reconocido por el participante. El objetivo principal del estudio era comparar el número de intentos necesarios para completar la maniobra con cada tubo. El tiempo de intubación y las intubaciones fallidas también fueron recogidos. Resultados. El número de intentos con el tubo de ML fue significativamente menor que con el tubo de IS. Con el de ML se completó la intubación al primer intento en el 93,3% de los casos, mientras que con el de IS el porcentaje se redujo al 30,8% (test exacto de Fisher, p < 0,001). El tiempo necesario para completar la maniobra fue mayor con el tubo de IS (mediana 10,8 s, rango intercuartílico 6-22) que con el tubo de ML (mediana 4,4 s, rango intercuartílico 3,5-6,3). Conclusiones. El tubo de PVC de la casa ML se mostró superior al compararlo con el de IS, asociándose este último a la necesidad de un mayor número de intentos para completar la intubación de un maniquí. Los autores han atribuido estos resultados a un defecto en la curvatura de la punta del tubo de IS (AU)

Background. A randomised study was conducted on the number of attempts made during the conventional endotracheal intubation of a mannequin using two polyvinyl (PVC) tracheal tubes, apparently similar but from different manufactures: INTERSURGICAL (IS; Intersurgical S.L., Madrid, Spain) and Mallinckrodt (ML; Mallinkrodt Medical S.A., Madrid, Spain). Methods. A total of 26 anaesthesiologists, in randomly established order (generated by Epidat 3.1) intubated a mannequin twice using a different tube each time. The tubes were masked by painting them to prevent recognition. The main outcome of the study was to compare the number of attempts needed to complete the manoeuvre for each tube. Data on intubation time and failed intubations were also collected. Results. The number of attempts with the ML tube was significantly lower than with the IS tube. Intubation was completed on the first attempt with the ML tube in 93.3% of cases, while using the IS tube the percentage fell to 30.8% (Fisher exact test, P < .001). The time required to complete the manoeuvre was greater with the IS tube (median 10.8 seconds, interquartile range 6-22) than with the ML tube (median 4.4 seconds, interquartile range 3.5 to 6.3). Conclusions. The PVC tube from the ML manufacturer was superior when compared with the IS, the latter was also associated with a larger number of attempts to complete intubation using a conventional Macintosh blade (AU)

Does a patient's Mallampati score predict outcome after maxillomandibular advancement for obstructive sleep apnoea?

The Mallampati airway classification has been used to estimate the success of uvulopalatopharyngoplasty in patients with obstructive sleep apnoea (OSA) but its predictive value in maxillomandibular advancement has not been proved. We aimed to explore the association between preoperative Mallampati scores and surgical outcome after bimaxillary advancement for OSA. We retrospectively analysed data on 50 patients who had maxillofacial operations for OSA at our hospital and stratified them into two groups based on Mallampati scores: high (class III/IV) and low (class I/II). We compared pre- and postoperative apnoea/hypopnoea indices (AHIs), Epworth sleepiness scores, and lowest recorded oxygen saturation in both groups. The postoperative values for all three outcome measures were not significantly different when patients were stratified according to the Mallampati classification (mean (SD) AHI was 41(19) before and 7 (6) after operation in the low group, and 42 (15) before and 9 (7) after in the high group). Success rates (AHI less than 15 postoperatively) were similar in both low and high score groups (p>0.05). Maxillomandibular advancement alleviates obstruction at multiple levels and our study has shown comparable surgical outcomes in both groups. The Mallampati score can be used to optimise patient selection for surgeons considering single-level procedures for OSA. Our study suggests that the Mallampati classification is less useful for the prediction of surgical outcome after maxillomandibular advancement surgery.

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.

Development of the Connecticut Airway Risk Evaluation (CARE) system to improve handoff communication in pediatric patients with tracheotomy.

IMPORTANCE: National attention has focused on the importance of handoffs in medicine. Our practice during airway patient handoffs is to communicate a patient-specific emergency plan for airway reestablishment; patients who are not intubatable by standard means are at higher risk for failure. There is currently no standard classification system describing airway risk in tracheotomized patients. OBJECTIVE: To introduce and assess the interrater reliability of a simple airway risk classification system, the Connecticut Airway Risk Evaluation (CARE) system. DESIGN, SETTING, PARTICIPANTS: We created a novel classification system, the CARE system, based on ease of intubation and the need for ventilation: group 1, easily intubatable; group 2, intubatable with special equipment and/or maneuvers; group 3, not intubatable. A "v" was appended to any group number to indicate the need for mechanical ventilation. We performed a retrospective medical chart review of patients aged 0 to 18 years who were undergoing tracheotomy at our tertiary care pediatric hospital between January 2000 and April 2011. INTERVENTIONS Each patient's medical history, including airway disease and means of intubation, was reviewed by 4 raters. Patient airways were separately rated as CARE groups 1, 2, or 3, each group with or without a v appended, as appropriate, based on the available information. MAIN OUTCOMES AND MEASURES: After the patients were assigned to an airway group by each of the 4 raters, the interrater reliability was calculated to determine the ease of use of the rating system. RESULTS: We identified complete data for 155 of 169 patients (92%), resulting in a total of 620 ratings. Based on the patient's ease of intubation, raters categorized tracheotomized patients into group 1 (70%, 432 of 620); group 2 (25%, 157 of 620); or group 3 (5%, 29 of 620), each with a v appended if appropriate. The interrater reliability was κ = 0.95. CONCLUSIONS AND RELEVANCE: We propose an airway risk classification system for tracheotomized patients, CARE, that has high interrater reliability and is easy to use and interpret. As medical providers and national organizations place more focus on improvements in interprovider communication, the creation of an airway handoff tool is integral to improving patient safety and airway management strategies following tracheotomy complications.

A child with a difficult airway: what do I do next?

PURPOSE OF REVIEW: Difficulties in pediatric airway management are common and continue to result in significant morbidity and mortality. This review reports on current concepts in approaching a child with a difficult airway. RECENT FINDINGS: Routine airway management in healthy children with normal airways is simple in experienced hands. Mask ventilation (oxygenation) is always possible and tracheal intubation normally simple. However, transient hypoxia is common in these children usually due to unexpected anatomical and functional airway problems or failure to ventilate during rapid sequence induction. Anatomical airway problems (upper airway collapse and adenoid hypertrophy) and functional airway problems (laryngospasm, bronchospasm, insufficient depth of anesthesia and muscle rigidity, gastric hyperinflation, and alveolar collapse) require urgent recognition and treatment algorithms due to insufficient oxygen reserves. Early muscle paralysis and epinephrine administration aids resolution of these functional airway obstructions. Children with an 'impaired' normal (foreign body, allergy, and inflammation) or an expected difficult (scars, tumors, and congenital) airway require careful planning and expertise. Training in the recognition and management of these different situations as well as a suitably equipped anesthesia workstation and trained personnel are essential. SUMMARY: The healthy child with an unexpected airway problem requires clear strategies. The 'impaired' normal pediatric airway may be handled by anesthetists experienced with children, whereas the expected difficult pediatric airway requires dedicated pediatric anesthesia specialist care and should only be managed in specialized centers.

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.

Is the modified Mallampati test performed in supine position a reliable predictor of difficult tracheal intubation?

Management of the airway is central to the practice of anesthesia. Several bedside airway assessment methods have been proposed for preoperative identification of patients who are difficult to intubate. The modified Mallampati test (MMT) remains a time-tested technique to date for recognizing an anticipated difficult tracheal intubation as assessed by Cormack-Lehane grade. Both Mallampati and its further modification by Samsoon and Young evaluate patients in the seated position. Recently a study mentioned a change in MMT score from sitting to supine position toward the higher side. However, there is a lack of data regarding the relationship of positional change in MMT with Cormack-Lehane grade. The aim of this prospective study was to assess if MMT score observed in sitting or supine position is a better predictor of difficult tracheal intubation. One hundred and twenty-three patients of ASA physical status I and II, aged 18-60 years, who were scheduled to undergo various neurosurgical procedures were enrolled for the study. We found that the MMT in supine position has a higher positive predictive value and is associated with more true positives as compared to MMT in the sitting position.

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.

Effect of posture on mouth opening and modified Mallampati classification for airway assessment.

Several bedside airway assessment methods have been proposed for preoperatively identifying patients who are difficult to intubate. To date, the Mallampati grading remains a time-tested technique for difficult airway assessment. Both Mallampati and the further modification by Samsoon and Young assessed patients in the seated position. During clinical practice, situations may arise where it may not be feasible for the patient to sit up for airway assessment. The aim of our prospective study was to determine whether there was any difference between the sitting and supine positions for the assessment of Mallampati grade. Eighty adult patients of American Society of Anesthesiologists (ASA) physical status I and II, aged 18-65 years, admitted to our neurosurgical ward were enrolled and assessed for airway. Our study revealed that change in posture produced a significant change in the mouth openings and Mallampati grades of the patients. This change was always toward a higher grade when the patient was turned supine from the sitting position.

Performance of the Airtraq laryngoscope after failed conventional tracheal intubation: a case series.

BACKGROUND: The Airtraq, a new disposable indirect laryngoscope, was evaluated in patients with difficult intubation. METHODS: The Airtraq was used in 47 patients with predicted or unpredicted difficult intubation after failed orotracheal intubation performed by two senior anaesthesiologists with the Macintosh laryngoscope. RESULTS: Tracheal intubation with Airtraq was successful in 36 patients (80%). The Cormack and Lehane score was IIb-III in 35 patients, and IV in 12 patients, with the Macintosh laryngoscope, while Cormack and Lehane score was I-IIa in 40 patients, IIb-III in three and IV in four with Airtraq. A gum elastic bougie was used to facilitate tracheal access in one-third (11/36) of the cases. Orotracheal intubation was not possible with Airtraq in nine cases, five of whom had a pharyngeal, laryngeal or basal lingual tumour. CONCLUSION: In patients with difficult airway, following failed conventional orotracheal intubation, Airtraq allows securing the airway in 80% of cases mainly by improving glottis view. However, the Airtraq does not guarantee successful intubation in all instances, especially in case of laryngeal and/or pharyngeal obstruction.

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.