Utilization analysis of an observation unit for children with asthma

Pediatr Emerg Care. 1999 Apr;15(2):79-83. doi: 10.1097/00006565-199904000-00001.


Background: Short-stay observation unit (OU) care for children with asthma has the potential to reduce hospitalization rates for this common pediatric condition. In the effort to increase the efficiency of such a unit, knowledge of predictive factors for successful discharge is important.

Objectives: 1) To define clinical predictive factors determined at the time of initial presentation in the emergency department (ED) that would identify which children with asthma are most likely to be successfully discharged from an OU. 2) To compare the management provided in the initial 3 hours upon arrival at the ED between the children who are eventually successfully discharged from an OU to those who require an inpatient admission. 3) To compare the length of stay in the OU between the patients who eventually go home to those who require an inpatient admission.

Design: Case control study.

Setting: Urban, tertiary-care pediatric ED.

Participants: From a collected database of all patients with asthma 1 to 18 years of age, presenting to the ED from July 1, 1993 to June 30, 1994 (n = 2248), a random sample of 350 patients was identified. All children meeting the definition of "case" or "control" from this sample were included. Cases were defined as children with asthma who were successfully discharged after a stay in the OU. Controls were defined as children with asthma who were not successfully discharged; that is, children who required subsequent inpatient admission.

Results: Of the 350 children with asthma in the randomly selected subset sample, 47 cases and 21 controls were identified. In both cases and controls, patients had similar characteristics regarding mean age, sex, mean weight, previous history of asthma, and mean length of illness. The use of medications in the 24 hours prior to presentation to the ED was similar between both groups. No differences were found in the mean respiratory rate upon presentation between the cases and the controls (40/min vs. 44/min; P = 0.2), mean oxygen saturation (95 vs. 94%; P = 0.4). However, there was a significant difference in the requirement of supplemental oxygen between cases and controls (15 vs. 43%; P = 0.01; OR = 0.23:0.07 to 0.76). No further differences were found in the first 3 hours of ED management. The number of albuterol and ipratropium nebulizations was similar. The use, dosage, and timing of systemic steroids were also similar between the groups. The cases remained in the OU for a shorter period of time (8.7 hours vs 9.2 hours; 95% C.I.: -2.8 to 1.8) than the controls.

Conclusion: No clinical predictive factors determined at the time of arrival to the ED were identified for children with asthma who were successfully discharged from the OU except for a lesser need of oxygen supplementation. The patients observed in the OU had similar management in the initial 3 hours of arrival and similar length of stay in the OU, regardless of their disposition outcome. Maximal OU efficiency remains limited by the lack of clear predictive factors for successful discharge. Further study in this area is indicated.

Publication types

  • Comparative Study

MeSH terms

  • Acute Disease
  • Adolescent
  • Asthma / metabolism
  • Asthma / physiopathology
  • Asthma / therapy*
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Emergency Service, Hospital / organization & administration
  • Emergency Treatment
  • Female
  • Forecasting
  • Hospital Units / statistics & numerical data*
  • Hospitalization / statistics & numerical data*
  • Humans
  • Infant
  • Male
  • Observation
  • Ontario
  • Oxygen / therapeutic use


  • Oxygen