Asthma: acute exacerbation: signs and symptoms improved before PEFR.

Clinical bottom line (level 4)

  1. Improvement in signs and symptoms in patients with asthma did not correlate well with improvements in peak expiratory flow rate.
McFadden et al: New England Journal of Medicine 1973; 288 (5): 221-225
Expires November 2002

The study

Setting: university hospital, USA

22 patients (aged mean 26 years, 82% female) acute asthma (PEFR 20% predicted)
All patients received 2.5 mg isoproterenol with intermittent positive pressure breathing for 15 minutes, repeated every hour for up to five hours.
Independent unblinded reference standard, applied in all patients from a consecutive ?appropriate spectrum.
Reference standard:
  • peak expiratory flow rate (PEFR)
Diagnostic test: clinical signs and symptoms

The evidence

  • symptom: baseline: PEFR 70 l/min: 20% predicted
  • symptom: retractions gone: PEFR 140 l/min
  • symptoms gone: 170 l/min
  • signs gone: PEFR 210 l/min: 54% predicted
  • symptoms: best: PEFR 340 l/min
  • When 90% of patients felt better, 40% still had expiratory wheeze.

Citation

  1. McFadden E, Kiser R, De Groot WJ: Acute bronchial asthma: correlations between clinical and physiologic manifestations. New England Journal of Medicine 1973; 288 (5): 221-225
Search Terms: reference from acute asthma chapter: Lee, Hsu, Stasior; Quick Consult Manual to Evidence-Based Medicine: publ. Lippincott-Raven 1997
Contributor: Chris Ball and Clare Wotton, June 2000
Reviewer:

Clinical Question.
Patient acute asthma
Intervention or Exposure symptom improvement
Outcome prediction of PEFR