The utility of serial peak flow measurements in the acute asthmatic being treated in the ED.
BACKGROUND
Peak flow is used extensively in emergency departments (EDs) to both assess asthma patient's status on arrival as well as to document clinical improvement during treatment. Many algorithms suggest serial peak expiratory flow (PEF) measurements during an ED stay.


OBJECTIVE
The aim of the study was to assess the contribution of serial PEF in describing the overall improvement of asthmatics over the course of an ED visit for acute exacerbation of their asthma.


METHODS
This was a prospective institutional review board-approved study of mild/moderate asthmatics presenting to an inner-city ED serving a large Latino population. Peak expiratory flow was measured before treatment (baseline PEF) and after each inhaled treatment (PEF post RX#1, PEF post RX#2, PEF post RX#3) while in the ED.


RESULTS
One hundred consecutive patients made up this study cohort. The change from baseline PEF to PEF #1 represented 86% (95% confidence interval [CI], 76%-96%) of the total improvement experienced by these patients with asthma. The change from PEF post RX#1 to PEF post RX#2 represented 7.5% (95% CI, -4.2% to 26%) of the total improvement and PEF post RX#2 to PEF post RX#3 represented 8.6% (95% CI, -1% to 34%) of the total PEF improvement seen.


CONCLUSIONS
No correlation between outcome and PEF% of predicted was made or implied.


CONCLUSIONS
The improvement in PEF seen after the first ED inhaled therapy appears to describe most of the total improvement seen in asthmatic patients. Subsequent PEFs provided little additional information.
Henderson
Sean O
SO
Department of Emergency Medicine, Keck/USC School of Medicine, Los Angeles, CA 90033, USA. sohender@hsc.usc.edu
Ahern
Terence L
TL
D000208:Acute Disease; D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy*; D016903:Drug Monitoring / Q000379:methods*; D004630:Emergencies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D011446:Prospective Studies
D000318:Adrenergic beta-Agonists