Evaluation of thyromental height as a predictor of difficult laryngoscopy and difficult intubation: a cross-sectional observational study
Avaliação da altura tireomentoniana como preditor de laringoscopia difícil e intubação difícil: um estudo observacional transversal
Smita Prakash, Parul Mullick, Rajvir Singh
Abstract
Background and objectives
Several anthropometric measurements have been suggested to identify a potentially difficult airway. We studied thyromental height (TMH) as a predictor of difficult laryngoscopy and difficult intubation. We also compared TMH, ratio of height to thyromental distance (RHTMD), and thyromental distance (TMD) as predictors of difficult airway.
Methods
This cross-sectional observational study was conducted in 300 adult surgical patients requiring tracheal intubation. Preoperatively airway characteristics were assessed. Standard anesthesia was administered. Degree of difficulty with mask ventilation, laryngoscopic view, duration of laryngoscopy, and difficulty in tracheal intubation (intubation difficulty scale score) were noted. Multivariate logistics regression analysis was performed to identify independent predictors for difficult laryngoscopy.
Results
Laryngoscopy was difficult in 46 of 300 (15.3%) patients; all 46 patients had Cormack-Lehane grade 3 view. Duration of laryngoscopy was 27 ± 11 s in patients with difficult laryngoscopy and 12.7 ± 3.9 s in easy laryngoscopy; p = 0.001. Multivariate analysis identified that TMH, presence of short neck, and history of snoring were independently associated with difficult laryngoscopy. Incidence of difficult intubation was 17.0%. A shorter TMH was associated with higher IDS scores; r = -0.16, p = 0.001. TMH and duration of laryngoscopy were found to be negatively correlated; a shorter TMH was associated with a longer duration of laryngoscopy; r = -0.13, p = 0.03. The cut-off threshold value for TMH in our study is 4.4 cm with a sensitivity of 66% and a specificity of 54%.
Conclusion
Thyromental height predicts difficult laryngoscopy and difficult intubation.
TMD and RHTMD did not prove to be useful as predictors of difficult airway.
Keywords
Resumo
Justificativa e objetivos: Várias medidas antropométricas têm sido sugeridas para identificar uma via aérea potencialmente difícil. Estudamos a altura tireomentoniana (ATM) como preditor de laringoscopia difícil e intubação difícil. Também comparamos a ATM, razão entre altura e distância tireomentoniana (RADTM) e distância tireomentoniana (DTM) como preditores de via aérea difícil. Métodos: Este estudo observacional transversal foi realizado em 300 pacientes cirúrgicos adultos que necessitaram de intubação traqueal. As características das vias aéreas no pré-operatório foram avaliadas. A anestesia padrão foi administrada. Grau de dificuldade com ventilação com máscara, visão laringoscópica, duração da laringoscopia e dificuldade na intubação traqueal (escore da escala de dificuldade de intubação) foram anotados. A análise de regressão logística multivariada foi realizada para identificar preditores independentes para laringoscopia difícil. Resultados: A laringoscopia foi difícil em 46 dos 300 (15,3%) pacientes; todos os 46 pacientes tinham visão grau 3 de Cormack-Lehane. A duração da laringoscopia foi de 27±11 s nos pacientes com laringoscopia difícil e 12,7±3,9 s na laringoscopia fácil; p = 0,001. A análise multivariada identificou que ATM, presença de pescoço curto e história de ronco foram independentemente associados à laringoscopia difícil. A incidência de intubação difícil foi de 17,0%. Uma ATM mais curto foi associado a pontuações mais altas de EDI; r = -0,16, p = 0,001. ATM e duração da laringoscopia foram correlacionados negativamente; um ATM mais curto foi associado a uma maior duração da laringoscopia; r = -0,13, p = 0,03. O valor limite de corte para ATM em nosso estudo é de 4,4 cm com sensibilidade de 66% e especificidade de 54%. Conclusão: A altura tireomentoniana prediz laringoscopia difícil e intubação difícil. DTM e RHTMD não se mostraram úteis como preditores de via aérea difícil.
Palavras-chave
References
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