Abstract: Objective  To discuss the diagnosis method in critical patients with mechanical ventilation and pneumothorax by ultrasound in emergency intensive care unit（EICU）.Methods  For 57 patients with highly suspicious of mechanical ventilation combined with pneumothorax admitted to EICU， the diagnosis was performed by bedside pultrasound， bedside chest Xray and chest CT. Analysis of various inspection methods were performed in the time needed for diagnosis， diagnostic sensitivity， specificity and accuracy. Results  The diagnostic time in bedside ultrasound， bedside chest Xray and chest CT was (5.05±1.91) min， (16.04±3.73) min and (22.55±3.52) min， respectively; the shortest diagnosis time was done by bedside ultrasound （P<0.01）. Kappa value by bedside pulmonary ultrasound and bedside chest CT was 0.930， Kappa value by bedside chest Xray and bedside chest CT was 0.444， bedside ultrasound was obviously better than bedside chest Xray. Conclusion  The bedside ultrasound has a  high value and efficiency in the diagnosis of mechanical ventilation combined with pneumothorax in EICU patients.

Key words: pneumothorax；ultrasonography；respiration, artificial