Predicting recovery from acute asthma in an emergency diagnostic and treatment unit.
OBJECTIVE
Optimal use of emergency diagnostic and treatment unit (EDTU) resources for treatment of acute asthma should be facilitated by the selection of patients with a high probability of discharge from the EDTU. The study goal was to identify characteristics of the patient or exacerbation that could be used to predict recovery of pulmonary function within 12 hours.


METHODS
Comprehensive cohort design in an urban public hospital. The subjects were 269 patients with moderately severe asthma exacerbations. Data were collected for historical and presenting features and response to treatment over 12 hours. Two outcomes were examined: 1) discharge from the EDTU and 2) achieving 50% predicted peak expiratory flow rate (PEFR) within 12 hours.


RESULTS
The two outcomes showed good concordance. The third-treatment PEFR was found to be predictive of both discharge and reaching 50% predicted PEFR within 12 hours. Since the objective measure of reaching 50% predicted PEFR is more readily defined and thus more generalizable, the authors focused on this outcome when describing prediction zones. Patients with 40% or higher PEFR after third treatment had an 89% probability of reaching 50% predicted in 12 hours, while those with a third-treatment PEFR lower than 32% predicted had only a 22% probability.


CONCLUSIONS
A simple objective measure of pulmonary function early in treatment discriminated among those with high, low, and intermediate probabilities of achieving a specified level of PEFR within 12 hours. Awareness of this probability could assist clinicians attempting to predict discharge from the EDTU and facilitate decision making regarding utilization of EDTU resources.
McCarren
M
M
Center for Health Services Research, and Department of Epidemiology, School of Public Health, University of Illinois at Chicago, USA. mccarren@research.hines.med.va.gov
Zalenski
R J
RJ
McDermott
M
M
Kaur
K
K
D000328:Adult; D001249:Asthma / Q000503:physiopathology / Q000628:therapy*; D002641:Chicago; D002985:Clinical Protocols; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006305:Health Status Indicators; D006786:Hospitals, Urban; D006801:Humans; D008297:Male; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care; D018579:Patient Selection; D010366:Peak Expiratory Flow Rate; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic