Clinical course and outcome of patients admitted to an ICU for status asthmaticus

Study objectives: To describe the prognostic factors, clinical course, and outcome of patients with status asthmaticus treated in a medical ICU (MICU). Design: Analysis of prospective data. Setting: A multidisciplinary MICU of an inner-city university hospital. Patients: We collected data on 132 hospital admissions of 89 patients with status asthmaticus treated in our MICU from August 1995 through July 1998. Measurements: APACHE (acute physiology and chronic health evaluation) II scores were among the parameters measured. Results: Seventy-nine percent of the patients were female, and 67% were African American (mean SD age, 42.4 +/- 15.1 years). Patients in 48 of the 132 hospital admissions (36%) required invasive mechanical ventilation; sepsis developed in patients during 17 hospital admissions (13%), nonpulmonary organ failure developed during 16 hospital admissions (12%), and ARDS developed during 2 hospital admissions (2%). Pneumothorax developed in four patients and required tube thoracostomy in all four patients. The median APACHE II score was 11. Predicted mortality and actual mortality were 6.7% and 8.3%, respectively. The two most common immediate causes of death were pneumothorax (n = 3) and nosocomial infection (n = 3). All the deaths occurred in female patients. Compared with survivors, nonsurvivors had higher APACHE II scores (median, 26 vs 15; p < 0.0001), Paco(2) (63.8 +/- 21.3 mm Hg vs 47.8 +/- 19.1 mm Hg, p = 0.0101), and lower arterial pH (7.09 +/- 0.12 vs 7.27 +/- 0.12, p < 0.0001), respectively. Patients in 10 of 48 hospital admissions (21%) who required mechanical ventilation died. Conclusions: The hospital mortality of patients admitted to an MICU for status asthmaticus is higher than expected. Higher APACHE II score and Paco(2) and lower arterial pH within 24 h of hospital admission are associated with increased mortality. Sepsis and nonpulmonary organ failure are more likely to develop in nonsurvivors than survivors.