Asthma: acute exacerbation: emergency assessment units allowed many patients to be sent home early and safely.

The study

• aged < 18, > 55
• pO2 55 mmHg or less, pCO2 45 mmHg or more
• PEFR 80 l/min or less after first beta-agonist treatment
• factors suggesting COPD (asthma onset after 45 and 10 pack-year or more history of smoking)
• emergency-department-documented best PEFR less than their discharge criteria (usually 50% predicted)
• pregnancy
• diagnosis of pneumonia, congestive heart failure, or restrictive lung disease


Note:
• Patients could be discharged at any time if they met the following criteria:
  • high risk: PEFR >60% predicted
  • low risk: PEFR >50% predicted
  (patients were high risk if:
  • second ED visit within 10 days
  • previous ITU admission or intubation
  • hospitalised for asthma within the previous year
  • three or more ED visits within last six months
  • use of oral steroids for more than half of the previous year)


Control Group: (n = 112, 122 analysed): usual in-hospital care: nebulisers every two hours for 3 treatment, and four times daily thereafter; 60 mg iv methylprednisolone on arrival on ward and every six hours thereafter. On improvement of signs and symptoms, patients had 40 mg prednisone po twice daily
Experimental Group: (n = 110, 110 analysed): emergency diagnostic and treatment unit. Patients had further nebulisers at 4, 6, 8, 10 and 12 hours, and repeat steroids at 6 hours. Patients who failed to meet discharge criteria at 12 hours were admitted.
All patients had albuterol 2.5 mg or metaproterenol 15 mg nebulised immediately and at 30, 60, and 120 minutes. All patients had either iv methylprednisolone 120 mg or po prednisone 80 mg within the first hour. All patients were discharged home on theophylline, beta-agonist and steroid metered-dose inhalers, and 9 to 11 days of oral steroids.
85% followed for 8 weeks
Outcome notes:
• relapse : attended emergency department without an appointment; PEFR <45% predicted and patients had been symptomatic and using excessive adrenergics, or required two or more adrenergic treatments to reach 50% predicted; symptomatic and unable to complete ordinary daily activities

The evidence

Outcome	Time to outcome	CER	EER	RRR (95% CI)	ARR (95% CI)	NNT (95% CI)
relapse	8 weeks	47 (42.0%)	44 (40.0%)	5% (-31% to 31%)	1.96% (-11.0% to 14.9%)	51 (NNT = 7 to infinity; NNH = 9 to infinity)




Outcome	Control Group (SD)	Experimental Group (SD)	Mean Difference (95% CI)
cost ($): actual costs (1993 $) to hospital, plus fixed costs for services and overhead patient satisfaction	2247 (1110)	1202 (1343)	1045 (720 to 1370)
patient satisfaction level	3.33 (0.84)	3.59 (0.65)	0.26 (0.06 to 0.46)



• One patient died in the control group from a cause unrelated to asthma.
• 59% (95% CI: 50% to 68%) of patients were discharged home for the EDTU. There was no information on the number of admitted patients discharged within 12 hours.

Comments

1. No sensitivity analysis was performed on the cost analysis.



Citation

1. McDermott MF, Murphy DG, Zalenski RJ, et al: A comparison between emergency diagnostic and treatment unit and inpatient care in the management of acute asthma. Archives of Internal Medicine 1997; 157: 2055-2062
Search Terms: acute asthma in Cochrane
Contributor: Chris Ball and Clare Wotton, November 2000
Reviewer: Mitsuhiro Kamei

_{Clinical Question.}

Patient	acute severe asthma
Intervention or Exposure	emergency assessment unit
Comparison	admission to hospital
Outcome	relapse