Brazilian Journal of Anesthesiology
Brazilian Journal of Anesthesiology
Scientific Article

Correlation between oro and hypopharynx shape and position with endotracheal intubation difficulty

Correlação entre os formatos da orofaringe e hipofaringe e posicionamento em intubação endotraqueal difícil

Daher Rabadi; Ahmad Abu Baker; Mohannad Al-Qudah

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Background and objective: Prediction of intubation difficulty can save patients from major preoperative morbidity or mortality. The purpose of this paper is to assess the correlation between oro-hypo pharynx position, neck size, and length with endotracheal intubation difficulty. The study also explored the diagnostic value of Friedman Staging System in prediction cases with difficult intubation. Method: The consecutive 500 ASA (I, II) adult patients undergoing elective surgery were evaluated for oro and hypopharynx shape and position by modified Mallampati, Cormack and Lehane score as well as Friedman obstructive sleep apnea classification systems. Neck circumference and length were also measured. All cases were intubated by a single anesthesiologist who was uninformed of the above evaluation and graded intubation difficulty in visual analog score. Correlation between these findings and difficulty of intubation was assessed. Sensitivity, Specificity, Positive and Negative Predictive Values were also reported. Results: Cormack-Lehane grade had the strongest correlation with difficulty of intubation followed by Friedman palate position. Friedman palate position was the most sensitive and had higher positive and negative predictive values than modified Mallampati classification. Cormack-Lehane grade was found to be the most specific with the highest negative predictive value among the four studied classifications. Conclusion: Friedman palate position is a more useful, valuable and sensitive test compared to the modified Mallampati screening test for pre-anesthetic prediction of difficult intubation where its involvement in Multivariate model may raise the accuracy and diagnostic value of preoperative assessment of difficult airway.


Intubation, Airway, Pharynx, Classification, Correlation, Value


Justificativa e objetivo: A previsão de intubação difícil no período pré-operatório pode salvar pacientes de morbidade e mortalidade graves. O objetivo deste estudo foi avaliar a correlação entre intubação endotraqueal difícil e a posição oro-hipofaríngea, circunferência e comprimento do pescoço. O estudo também avaliou o valor diagnóstico do Sistema de Classificação de Friedman para prever casos de intubação difícil. Método: Avaliamos consecutivamente o formato oro-hipofaríngeo e a posição de 500 pacientes adultos (ASA I-II) submetidos à cirurgia eletiva, usando o escore de Mallampati modificado, escore de Cormack e Lehane, bem como o sistema de classificação de Friedman para apneia obstrutiva do sono. A circunferência e comprimento do pescoço também foram mensurados. Todos os casos foram intubados por um único anestesiologista que desconhecia o estudo e classificou a intubação difícil em escala visual analógica. A correlação entre os achados e intubação difícil foi avaliada. Sensibilidade, especificidade e valores preditivos positivos e negativos também foram registrados. Resultados: A classificação em graus de Cormack e Lehane apresentou uma correlação mais forte com intubação difícil, seguida pela posição palatal de Friedman. A posição palatal de Friedman foi a mais sensível e apresentou valores preditivos positivos e negativos mais altos que a escala de Mallampati modificada. Descobrimos que o grau de Cormack e Lehane foi o mais específico e apresentou o maior valor preditivo negativo entre as quatro classificacões estudadas. Conclusão: A posição palatal de Friedman é um teste mais útil, valioso e sensível comparado ao teste modificado de triagem de Mallampati para prever intubação difícil pré-anestesia e o seu envolvimento no modelo multivariado pode aumentar a precisão e o valor diagnóstico da avaliação pré-operatória de via aérea difícil.


Intubação, Vias aéreas, Faringe, Classificação, Correlação, Valor


Lundstrøm LH, Vester-Andersen M, Møller AM. Danish Anaesthesia Database Poor prognostic value of the modified Mallampati score: a meta-analysis involving 177 088 patients. Br J Anaesth. ;107:667-659.

Shiga T, Wajima Z, Inoue T. Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance. Anesthesiology. ;103:429-437.

Friedman M, Ibrahim H, Joseph NJ. Staging of obstructive sleep apnea/hypopnea syndrome: a guide to appropriate treatment. Laryngoscope. ;114:459-454.

Friedman M, Ibrahim H, Bass L. Clinical staging for sleep-disordered breathing. Otolaryngol Head Neck Surg. ;127:13-21.

Liistro G, Rombaux P, Belge C. High Mallampati score and nasal obstruction are associated risk factors for obstructive sleep apnoea. Eur Respir J. ;21:252-248.

Cook TM, Woodall N, Frerk C. Fourth National Audit Project Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth. ;106:631-617.

Rose DK, Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anaesth. ;41:372-383.

Mallampati SR, Gatt SP, Gugino LD. A clinical sign to predict difficult tracheal intubation: a prospective study. Can Anaesth Soc J. ;32:429-434.

Lee A, Fan LT, Gin T. A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway. Anesth Analg. ;102:1878-1867.

Pilkington S, Carli F, Dakin MJ. Increase in Mallampati score during pregnancy. Br J Anaesth. ;74:638-642.

Wong SH, Hung CT. Prevalence and prediction of difficult intubation in Chinese women. Anaesth Intensive Care. ;27:52-49.

Butler PJ, Dhara SS. Prediction of difficult laryngoscopy: an assessment of the thyromental distance and Mallampati predictive tests. Anaesth Intensive Care. ;20:139-142.

Reed MJ, Dunn MJ, McKeown DW. Can an airway assessment score predict difficulty at intubation in the emergency department?. Emerg Med J. ;22:99-102.

Naguib M, Scamman FL, O'Sullivan C. Predictive performance of three multivariate difficult tracheal intubation models: a double-blind, case-controlled study. Anesth Analg. ;102:818-824.

Wilson ME, Spiegelhalter D, Robertson JA. Predicting difficult intubation. Br J Anaesth. ;61:216-211.

Arné J, Descoins P, Fusciardi J. Preoperative assessment for difficult intubation in general and ENT surgery: predictive value of a clinical multivariate risk index. Br J Anaesth. ;80:146-140.

Practice guidelines for management of the difficult airway: a report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. ;78:597-602.

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