PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-4 (poor performance status brain tumor patients specifically eligible) Life expectancy: At least 2 months Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Pulmonary: No history of adult asthma No emphysema No pulmonary insufficiency No pulmonary edema Other: No AIDS or positive HIV serology No pregnant women