Abstract: The objective was to analyze the pneumothorax and mediastinal emphysema occurred after the non-invasive and invasive mechanical ventilation(MV)and to discuss relevant strategy in respiratory treatment in patients with critical severe acute respiratory syndrome(SARS).Altogether 31 serious cases of SARSundergoing MV were analyzed,retrospectively,in comparison with 89 cases of acute respiratory distress syndrome(ARDS)undergoing MV in surgical intensive care unit during the last two years.Re-sults:Pneumothorax and mediastinal emphysema occurred in 9 of 31serious cases of SARS with MV,and mediastinal emphysema in 1 of 189 cases of SARS without MV.Pneumothorax occurred in 1 of 89cases of ARDS with MV.The incidence of pneumothorax and mediastinal emphysema in serious cases of SARS with MV was significantly higher(P<0.01)than those in cases of SARS without MV and ARDS with MV.The peripheral blood oxygen saturation level and modified respiratory index didn't change significantly after reasonable adjustment of ventilation pressure and increase of oxygen concentration inhaled.Eight cases of pneumothorax and mediastinal emphysema improved gradually,thoracic closed drainage was performed in one case.Conclusions:The incidence of pneumothorax and mediastinal emphysema in serious SARS patients with MV is significantly higher than that in SARS patients without MV and that of ARDS patients with MV.It might be associated with SARS related pulmonary injuries,intense cough and high mechanical ventilative pressure.The pneumothorax and mediastinal emphysema improve gradually in most of the cases after reasonable adjustment of mechanical ventilative pressure.So when MV is used in the treatment of serious SARS patients to improve hypoxemia,optimized mechanical ventilative pressure should be obtained in order to avoid pneumothorax and mediastinal emphysema.

Key words: severe acute respiratory syndrome, pneumothorax, mediastinal emphysema, mechanical ventilation, non-invasive positive pressure ventilation