Abstract： Objective To describe the clinical features of invasive pulmonary aspergillosis(IPA) in critically ill patients with chronic respiratory diseases(CRD)and to estimate its value for early diagnosis and treatment. Methods Retrospective study of critically ill CRD patients with Dositive Aspergillus from sputum or bronchial alveolar lavage fluid in a respiratory ICU of a teaching hospital.Results There were 149 CRD patients admitted between October 2004 and February 2007. Among these patients,16 cases of IPA(11 COPD,4 COPD with asthma,1 bronchiectasis)were collected.Three cases fulfilled the criteria of proven IPA,10 of probable and 3 of possible IPA.Corticosteroids and multiple broad-spectrum antibiotics had been administered to 12 and 15 patients respectively. Fifteen patients experienced worsening of bronchospasm leading to acute respiratory failure.Nine patients failed to improve on noninvasive ventilation,and 14 patients required invasive ventilation.Twelve patients had infiltrates on chest X-ray.Before the appearance of infiltrates,bronchoscopy showed tracheobronchial inflammatory changes with severe bronchospasm.With the rapid progression of infiltrates,bronchial pseudomembrane was observed,with increased white blood cell count and exacerbated radiology findings.The rate of positive isolation of Aspergillus from airway samples during early stage was lower than late stage(2/12 vs 10/12).Early treatment was started before the appearance of infiltrates in 4 patients,all of whom survived.Although antifungal treatment was started when IPA was suspected after the appearance of infiltrates,11 of 12 patients died in septic shock or multiple-organ failure.Conclusions IPA occurring in critieally ill CRD patients is not rare and has a poor prognosis. Early diagnosis and empirical antifungal treatment based on certain clinical features may improve the outcome.