Efecto de la maniobra de fijación en línea en la clasificación de Cormack-Lehane / Effect of the in-line fixation maneuver on Cormack-Lehane classification

Resumen: Introducción: El manejo correcto de la vía aérea en los pacientes politraumatizados es crucial, ya que es necesario tener una vía aérea segura y proveer adecuada ventilación sin emperorar una probable lesión medular. Objetivo: Determinar el efecto de la maniobra de fijación en línea (MILS del inglés Manual In-Line Stabilisation) en la clasificación de Cormack-Lehane (CL), así como la correlación con el índice de masa corporal (IMC). Material y métodos: En un estudio descriptivo en el Centro Hospitalario del Estado Mayor Presidencial en la Ciudad de México se incluyeron 56 pacientes con estado físico ASA I a IV. El anestesiólogo realizó la laringoscopía directa bajo MILS y valoró el grado de CL. Inmediatamente después se reposicionó al paciente en posición de olfateo, se efectuó nueva laringoscopía directa y se revaloró de nuevo el grado de CL. Resultados: Los grados del CL fueron significativamente diferentes entre la posición MILS versus olfateo. Los grados de CL fueron en su mayoría altos cuando se posicionó al paciente en MILS (75% de los pacientes clasificados entre III y IV) y disminuyeron significativamente al ser cambiados a posición de olfateo. Conclusión: Se observa mejoría del CL cuando se cambia de posición MILS a olfateo.

Abstract: Introduction: Correct airway management of polytraumatized patients is crucial because of the necessity of securing the airway and providing adequate ventilation without worsening a probable spinal cord injury. Objective: Determine the effect of manual inline stabilization (MILS) on Cormack-Lehane classification and if there is any correlation with body mass index (BMI). Material and methods: In a descriptive study at the Centro Hospitalario del Estado Mayor Presidencial in Mexico City, we included 56 patients with ASA physical status I to IV. The anesthesiologist performed direct laryngoscopy while MILS was performed and observed the CL grade. Immediately after, the patient was repositioned into the sniffing position, direct laryngoscopy was performed, and the CL grade was observed again. Results: The CL grades observed were significantly different between MILS vs. Sniffing position. CL grades were mainly high when positioned in MILS (75% classified as grades III and IV) and diminished significantly when changed to the sniffing position. Conclusion: Improvement of CL grade was observed when changing from MILS to sniffing position.

Evaluation of bedside tests and proposal of a model for predicting difficult laryngoscopy: an observational prospective study / Avaliação de testes à beira leito e proposta de modelo para prever laringoscopia difícil: estudo prospectivo observacional

Abstract Background and objectives: The prediction of difficult laryngoscopy is based on tests that assess anatomic characteristics of face and neck. We aimed to identify the most accurate tests and propose a multivariate predictive model. Methods: This prospective observational study included 1134 patients. Thyromental Distance (TMD), Sternomental Distance (STMD), Ratio of Height-to-Thyromental Distance (R-H/TMD), Neck Circumference (NC), Ratio of Neck Circumference-to-Thyromental Distance (R-NC/TMD), Hyomental Distance with head in Neutral Position (HMD-NP) and at Maximal Extension (HMD-HE), Ratio of Hyomental Distance at Maximal head extension-to-hyomental distance in neutral position (R-HMD), Mallampati Class (MLC), Upper Lip Bite Test (ULBT), Mouth Opening (MO) and Head Extension (HE) were assessed preoperatively. A Cormack-Lehane Grade ≥ 3 was defined as Difficult Laryngoscopy. Sensitivity, specificity, positive and negative predictive values were assessed for all tests. Multivariate analysis with logistic regression was used to create the predictive models. Results: A model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed high prognostic accuracy; x2(5) = 109.12, p < 0.001, AUC = 0.86, p < 0.001). Its sensitivity, specificity and negative predictive value were 82.3%, 74.8% and 97.4%, respectively. A second model including two measurements not requiring patient's cooperation (R-NC/TMD and HMD-HE) exhibited good prognostic performance; x2(2) = 63.5, p < 0.001, AUC = 0.77, p < 0.001. Among single tests, HE had the highest sensitivity (78.5%) and negative predictive value (96%). Conclusions: A five-variable model incorporating MLC, ULBT, HE, HMD-HE and R-NC/TMD showed satisfyingly high predictive value for difficult laryngoscopy. A model including R-NC/TMD and HMD-HE could be useful in incapable patients. The most accurate single predictor was HE.

Resumo Justificativa e objetivos: A previsão de laringoscopia difícil se baseia em testes que avaliam as características anatômicas da face e pescoço. Nosso objetivo foi identificar os testes mais precisos e propor modelo preditivo multivariado. Método: Estudo observacional prospectivo incluiu 1134 pacientes e avaliou no pré-operatório: Distância Tireomentoniana (DTM), Distância Esternomentoniana (DEM), razão Altura-Distância Tireomentoniana (A/DTM), Circunferência Cervical (CC), razão Circunferência Cervical-Distância Tireomentoniana (CC/DTM), Distância Hiomentoniana com a cabeça na Posição Neutra (DHM-PN) e em Extensão Máxima (DHM-EM), razão Distância Hiomentoniana com Cabeça em Extensão Máxima/Distância Hiomentoniana na posição Neutra (DHME/DHMN), Classe Mallampati (CML), Teste da Mordida do Lábio Superior (TMLS), Abertura da Boca (AB) e Extensão da Cabeça (EC). Grau Cormack-Lehane ≥ 3 foi definido como Laringoscopia Difícil. A sensibilidade, especificidade, valores preditivos positivo e negativo foram avaliados para todos os testes. A análise multivariada com regressão logística foi usada para criar modelos preditivos. Resultados: Um modelo incorporando CML, TMLS, EC, DHM-EM e CC/DTM demonstrou alta precisão prognóstica (x2(5) = 109,12, p < 0,001, AUC = 0,86, p < 0,001). A sensibilidade, especificidade e valor preditivo negativo foram 82,3%, 74,8% e 97,4%, respectivamente. Um segundo modelo incluindo duas medidas que não necessitavam da cooperação do paciente (CC/DTM e DHM-EM) demonstrou bom desempenho prognóstico (x2 (2) = 63,5; p < 0,001; AUC = 0,77, p < 0,001). Entre os testes individuais, EC teve a maior sensibilidade (78,5%) e valor preditivo negativo (96%). Conclusões: O modelo de cinco variáveis incorporando CML, TMLS, EC, DHM-EM e CC/DTM mostrou valor preditivo satisfatoriamente alto para laringoscopia difícil. Um modelo que incluísse CC/DTM e DHM-EM poderia ser útil em pacientes com incapacidade. O preditor individual mais preciso foi EC.

Una vía para la predicción de una laringoscopia anatómicamente difícil / A way to predict an anatomically difficult laryngoscopy / Uma maneira de prever uma laringoscopia anatomicamente difícil

RESUMEN Introducción: En la valoración de dificultad para realizar la laringoscopia convencional no se realza la integración necesaria de aspectos clínicos esenciales relacionados con el control respiratorio. Objetivo: Validar un modelo de predicción de una laringoscopia anatómicamente difícil en el paciente que requiere de intubación orotraqueal. Método: Se realizó un estudio analítico en una población de 17 966 pacientes con necesidad de laringoscopia directa para una intubación orotraqueal con fines quirúrgicos en el Hospital General Docente "Dr. Agostinho Neto" de Guantánamo entre el 2015 y el 2018. Se determinó por muestreo aleatorizado una muestra de 17 068 pacientes. Se estudiaron las siguientes variables: estigma periférico para laringoscopia difícil, laringoscopia difícil pos-inducción anestésico, evaluación laringoscópica según Cormack-Lehane, valor diagnóstico del modelo de evaluación predictiva para laringoscopia. Resultados: Los altos grados en la clasificación de aspectos clínicos predictivos y la coexistencia con la alteración morfológica de la epiglotis fueron los marcadores más asociados con la probabilidad de laringoscopia anatómicamente difícil. Con la integración de cuatros aspectos clínicos esenciales se identificó el grado de dificultad probable para visualizar las cuerdas vocales. Conclusiones: Se diseñó un modelo que posibilitó la predicción de una laringoscopia anatómicamente difícil, cuya validación certificó su viabilidad para aplicarlo en la práctica médica.

ABSTRACT Introduction: In assessing the difficulty of performing conventional laryngoscopy, the necessary integration of essential clinical aspects related to respiratory control is not enhanced. Objective: To validate a prediction model of an anatomically difficult laryngoscopy in the patient that requires orotracheal intubation. Method: An analytical study was carried out in a population of 17,966 patients in need of direct laryngoscopy for an orotracheal intubation for surgical purposes at the General Teaching Hospital "Dr. Agostinho Neto" from Guantanamo between 2015 and 2018. A sample of 17,068 patients was determined by randomized sampling. The following variables were studied: peripheral stigma for difficult laryngoscopy, difficult laryngoscopy after anesthetic induction, laryngoscopic evaluation according to Cormack-Lehane, diagnostic value of the predictive evaluation model for laryngoscopy. Results: The high degrees in the classification of predictive clinical aspects and the coexistence with the morphological alteration of the epiglottis were the markers most associated with the probability of anatomically difficult laryngoscopy. With the integration of four essential clinical aspects, the degree of probable difficulty in visualizing the vocal cords was identified. Conclusions: A model was designed that allowed the prediction of an anatomically difficult laryngoscopy, whose validation certified its feasibility to apply it in medical practice.

RESUMO Introdução: Na avaliação da dificuldade na realização da laringoscopia convencional, a integração necessária dos aspectos clínicos essenciais relacionados ao controle respiratório não é aprimorada. Objetivo: Validar um modelo de previsão de uma laringoscopia anatomicamente difícil no paciente que necessita de intubação orotraqueal. Método: Foi realizado um estudo analítico em uma população de 17.966 pacientes com necessidade de laringoscopia direta para intubação orotraqueal para fins cirúrgicos no Hospital Geral de Ensino "Dr. Agostinho Neto" de Guantánamo entre 2015 e 2018. Uma amostra de 17.068 pacientes foi determinada por amostragem aleatória. Foram estudadas as seguintes variáveis: estigma periférico para laringoscopia difícil, laringoscopia difícil após indução anestésica, avaliação laringoscópica segundo Cormack-Lehane, valor diagnóstico do modelo de avaliação preditiva para laringoscopia. Resultados: Os altos graus na classificação dos aspectos clínicos preditivos e a coexistência com a alteração morfológica da epiglote foram os marcadores mais associados à probabilidade de laringoscopia anatomicamente difícil. Com a integração de quatro aspectos clínicos essenciais, foi identificado o grau de provável dificuldade na visualização das cordas vocais. Conclusões: Foi elaborado um modelo que permitia prever uma laringoscopia anatomicamente difícil, cuja validação atestava sua viabilidade de aplicá-la na prática médica.

Comparative Evaluation of Macintosh, McCoy and Truview Laryngoscope in Simulated Difficult Laryngoscopy Using Rigid Neck Collar in Overweight Patients : A Randomized, Controlled Clinical Trial

Background: To compare the safety and efficacy of Macintosh, McCoy and Truview laryngoscope in simulated difficult laryngoscopy using rigid neck collar in overweight patients. Methods: It was a Prospective, randomized, controlled clinical trial conducted in a tertiary care teaching hospital. Overweight patients (BMI= 25-29.9) with American Society of Anesthesiologists physical status I and II, age 18 to 60 years and scheduled recruited for elective surgery requiring general anesthesia with oral endotracheal intubation were included. The patients were divided into three groups comprising of 40 patients each in which Macintosh, McCoy and Truview laryngoscopes were used respectively. Difficult laryngoscopy was simulated using rigid neck collar. The primary outcome measure was modified Intubation Difficulty Score (IDS ). The secondary outcome measures were number of attempts, ease of intubation, overall success rate, time of intubation, Percentage of Glottic Opening score, hemodynamic parameters and complications. Results: The mean Intubation Difficulty Score was significantly lower with Truview Laryngoscope (1.68) as compared to Macintosh (4.21)and MacCoy (3.03) laryngoscopes. The median Percentage of Glottic Opening score was also significantly improved in the Truview group(78.21) compared to the other groups. Number of successful first intubation attempt was significantly higher in the Truview group(63.16%) compared to the other groups. The overall success rate was similar among groups. However, the time of intubation was significantly higher for Truview (41.21±2 sec) compared to Macintosh and McCoy laryngoscopes. Conclusion: The Truview laryngoscope allowed better glottic visualization, greater ease of intubation, fewer intubation attempts, but a longer intubation time compared to Macintosh and MacCoy laryngoscopes.

Anatomic Features of the Neck as Predictive Markers of Difficult Direct Laryngoscopy in Men and Women : A Prospective Study

Recognising a potential difficult airway at the time of preanaesthesia check-up,is very crucial. Several bedside screening tests have been used in clinical practice for predicting the difficult laryngoscopy/intubation. Aim: The study was undertaken to compare diagnostic value of Thyromental distance(TMD) and ratio of height to thyromental distance (RHTMD) in predicting a Cormack Lehane grade> or =3. Design: Prospective, comparative, observationl study Methods: 320 ASA 1 & 2 patients were subjected to pre-operative measurements of the thyromental distance (TMD)and ratio of height to thyromental distance (RHTMD) during the routine pre anaesthesia checkup. In the operating room, direct laryngoscopy performed with a Macintosh blade by an experienced anesthetist not aware of the pre-op measurements. Difficult laryngoscopy was defined as inadequate exposure of the glottis (Cormack-Lehane grade 3 or 4) under direct laryngoscopy with a blade of appropriate length, without any external pressure or other manoeuvre applied. The preoperative data of TMD & RHTMD and the laryngoscopic findings are correlated to evaluate the sensitivity, specificity,Positive predictive value, & Negative predictive value of each test according to standard formulae. Results: RHTMD had a better sensitivity(65.3% vs 59.2% for TMD) as well as a better specificity (50.6% vs 45.8 for TMD) and positive and negative predictive values. Conclusion: Among the tests studied, ratio of height to thyromental distance proved to be more accurate test for predicting difficulty larngoscopy.

Application of ultrasound in predicting difficult laryngoscopy in children / 临床麻醉学杂志

Objective To compare the effect of ultrasound measurements of the distance from skin to vocal folds (DSV), neck diameter (d) and the ratio among the two measurements (R) used to predict difficult laryngoscopy. Methods Seventy-two toddelers scheduled to undergo general anesthesia, aged ≤ 3 years, falling into ASA physical status Ⅰ or Ⅱ, were included and categorized as having easy (n = 48, grades Ⅰ and Ⅱ) or difficult (n = 24, grades Ⅲ and Ⅳ) laryngoscopy based on the criteria of Cormack and Lehane. When children were ventilated by mask, we measured DSV by ultrasound; obtained d and R. Receiver operating characteristic (ROC) curve analysis was used to determine the DSV, d and R in predicting difficult laryngoscopy. The value of cutoff was obtained by maximizing the Youden's index. Results DSV was significantly shorter in difficult laryngoscopy group (P ＜ 0.05). The areas under the ROC curve of R was 0.807, and the cutoff value was 0.090. the sensitivity was 70.83％, the specificity was 83.33％ Conclusion The ratio of distance from skin to vocal folds to neck diameter is a good predictor of difficult laryngoscopy in children under 3 years old.

Effect of the LEMON method in predicting patients with difficult airway / 临床麻醉学杂志

Objective To evaluate the effect of the LEMON method in predicting difficult air-way.Methods A total of 1 528 patients scheduled for elective surgery requiring tracheal intubation under general anaesthesia,680 males and 848 females,aged 18-83 years,ASA physical status Ⅰ orⅡ,were enrolled in the study.We used the LEMON method to assess airway conditions before an-aesthesia and recorded the scores.The primary end point was difficult tracheal intubation.The sec-ondary end point was difficult laryngoscopy.Receiver operating characteristic (ROC)curve analysis and the area under the curve (AUC)were used to evaluate the clinical effect of the LEMON mothod. Results There were 37 cases with difficult tracheal intubation and 106 cases with difficult laryngosco-py.The incidence of difficult tracheal intubation and difficult laryngoscopy were 2.4% and 6.9%,re-spectively.The area under the curve of the LEMON method for predicting difficult laryngoscopy and difficult tracheal intubation were 0.884 (95% CI 0.867-0.899)and 0.934 (95% CI 0.921-0.946), respectively.Conclusion The LEMON method has good clinical effect in predicting difficult airway.

A Comparison Between Measured Maxillopharyngeal Angle On Lateral Cervical Radiograph with Modified Mallampati Classification In Predicting Difficult Larnygoscopy: A Blinded Interventional Study

@#Background: Existing techniques of predicting difficult laryngoscopy are inadequate requiring evaluation of Maxillopharyngeal Angle (MP-A) on lateral cervical radiograph described. Objectives: This study aimed to compare MP-A test with Modified Mallapati Test (MMT) in predicting their diagnostic values and Area Under Curve of Receiver Operating Characteristic Curve (AUCROCC) of both test. Methods: This is a double blinded interventional study of 93 patients. Each patient’s MMT score was assessed during preoperative assessment and subsequent MP-A test done by obtaining lateral cervical radiograph with the head in neutral position. Laryngeal view was assessed using Cormack-Lehane grade after induction of anesthesia, was used as reference standard to determine the diagnostic values of MMT and MP-A respectively. Results: The MP-Acompared to MMT in predicting difficult larngoscopy had higher sensitivity (77.78 vs 44.44) specificity (88.10 vs 67.86) and accuracy (87.10 vs 65.59) with higher Odd Ratio(26.12 vs 1.68). The AUCROCC was significantly higher in MP-A test 0.83(95%CI: 0.67, 0.99) (P = 0.001) vs MMT 0.56(95%CI: 0.36, 0.76) (P = 0.546) with LR+ of 6.53 vs 1.38. Conclusion: The Maxillopharyngeal Angle test was superior in predicting difficult laryngoscopy as compared to Modified Mallampati Test.difficult intubation