Is Mallampati classification a good screening test? A prospective cohort evaluating the predictive values of Mallampati test at different thresholds
A classificação de Mallampati é um bom teste de triagem? Coorte prospectiva avaliando os valores preditivos do teste de Mallampati em diferentes limiares
Clístenes C. de Carvalho, Danielle M. da Silva, Marina S. Leite, Flávia A. de Orange
Abstract
Background
There is currently some discussion over the actual usefulness of performing preoperative upper airway assessment to predict difficult airways. In this field, modified Mallampati test (MMT) is a widespread tool used for prediction of difficult airways showing only a feeble predictive performance as a diagnostic test. We therefore aimed at evaluating if MMT test would perform better when used as a screening test rather than diagnostic.
Methods
An accuracy prospective study was conducted with 570 patients undergoing general anesthesia for surgical procedures. We collected preoperatively data on sex, age, weight, height, body mass index (BMI), ASA physical status, and MMT. The main outcome was difficult laryngoscopy defined as Cormack and Lahane classes 3 or 4. Bivariate analyses were performed to build three different predictive models with their ROC curves.
Results
Difficult laryngoscopy was reported in 36 patients (6.32%). Sex, ASA physical status, and MMT were associated with difficult laryngoscopy, while body mass index (BMI) was not. The MMT cut-off with the highest odds ratio was the class II, which also presented significantly higher sensitivity (94.44%). The balanced accuracy was 67.11% (95% CI: 62.78–71.44%) for the cut-off of class II and 71.68% (95% CI: 63.83–79.54) for the class III.
Conclusion
MMT seems to be more clinically useful when the class II is employed as the threshold for possible difficult laryngoscopies. At this cut-off, MMT shows the considerable highest sensitivity plus the highest odds ratio, prioritizing thus the anticipation of difficult laryngoscopies.
Keywords
Resumo
Justificativa: Atualmente existe alguma discussão sobre a real utilidade da avaliação pré-operatória das vias aéreas superiores para prever vias aéreas difíceis. Neste campo, o teste de Mallampati modificado (MMT) é uma ferramenta amplamente utilizada para predição de vias aéreas difíceis, mostrando apenas um fraco desempenho preditivo como teste diagnóstico. Portanto, nosso objetivo foi avaliar se o teste MMT teria melhor desempenho quando usado como teste de triagem em vez de diagnóstico. Métodos: Foi realizado um estudo prospectivo de acurácia com 570 pacientes submetidos à anestesia geral para procedimentos cirúrgicos. Coletamos dados pré-operatórios sobre sexo, idade, peso, altura, índice de massa corporal (IMC), estado físico ASA e MMT. O desfecho principal foi a laringoscopia difícil definida como classes 3 ou 4 de Cormack e Lahane. Análises bivariadas foram realizadas para construir três modelos preditivos diferentes com suas curvas ROC. Resultados: Laringoscopia difícil foi relatada em 36 pacientes (6,32%). Sexo, estado físico ASA e MMT foram associados à laringoscopia difícil, enquanto o índice de massa corporal (IMC) não foi. O ponto de corte do MMT com maior odds ratio foi a classe II, que também apresentou sensibilidade significativamente maior (94,44%). A acurácia balanceada foi de 67,11% (IC 95%: 62,78–71,44%) para o ponto de corte da classe II e 71,68% (IC 95%: 63,83–79,54) para a classe III. Conclusão: O MMT parece ser mais útil clinicamente quando a classe II é empregada como limiar para possíveis laringoscopias difíceis. Neste ponto de corte, o MMT apresenta a maior sensibilidade consideravelmente mais a maior razão de chances, priorizando assim a antecipação de laringoscopias difíceis
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References
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