Revista Brasileira de Terapia Intensiva (Sep 2007)
Teste de permeabilidade de vias aéreas pré-extubação: comparação entre três métodos em ventilação espontânea Cuff leak test preextubation: comparison between three methods in spontaneous ventilation
Abstract
JUSTIFICATIVA E OBJETIVOS: O teste de permeabilidade avalia obstrução de via aérea superior e é classicamente realizado em modo assistido-controlado de ventilação mecânica. O objetivo deste estudo foi analisar este teste em ventilação espontânea, através de três diferentes métodos e compará-los. MÉTODO: Vinte pacientes intubados foram submetidos a três diferentes formas do teste de permeabilidade, todos em ventilação espontânea: com o ventilômetro e o paciente conectado ao ventilador (teste 1); através do display do ventilador mecânico (teste 2); e com o ventilômetro e o paciente desconectado do ventilador (teste 3). O vazamento ao redor do tubo traqueal (TT) foi definido como a porcentagem decorrente da diferença entre o volume-corrente inspirado (balonete insuflado) e expirado (balonete desinsuflado). Foram avaliadas as diferenças entre os três testes, bem como correlacionado a porcentagem de vazamento entre os testes com três variáveis: pressão do balonete, diâmetro do TT e tempo de intubação. RESULTADOS: Houve diferença significativa (p BACKGROUND AND OBJECTIVES: The cuff leak test aims to evaluate the presence of airway obstruction and normally is carried through in the controlled mode of mechanical ventilation. The objective of this study was to evaluate the cuff leak in patients breathing spontaneously, across three different methods, and to compare them. METHODS: Twenty intubated patients had been submitted to three different forms of cuff leak test, all of them in spontaneous respiration: measuring air leak buy using a ventilometer and with the patient connected to the mechanical ventilator (test 1); through the display of the mechanical ventilator (test 2); and with ventilometer and the patient detached from the mechanical ventilator (test 3). The air leak around the tracheal tube (TT) was defined as the percentage difference between the inspired tidal volume (insufflated cuff) and exhaled (deflated cuff). The air leak differences between the three tests were evaluated, as well as their correlations to three variables: cuff pressure, TT diameter and intubation time. RESULTS: Statistically significant (p < 0.05) air leak difference was observed between the tests 1 and 2 in relation to the test 3 in the general and regarding time intubation below 48h and cuff pressure below 20 cmH2O. Regarding the tube diameter, it had been difference only between tests 2 and 3 for 8.5 mm tubes. CONCLUSIONS: The cuff leak test in spontaneous ventilation seems to be more accurate when the patient is connected to the mechanical ventilator, and that additional studies are needed to determine the real contribution of the test in this ventilation mode to predict laryngeal edema.
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