Using quality-control analysis of peak expiratory flow recordings to guide therapy for asthma.
OBJECTIVE
To compare the action points in published asthma management plans with those derived from quality-control analysis of peak expiratory flow recordings.


METHODS
Longitudinal observational study.


METHODS
An ambulatory asthma education and management program in a tertiary care hospital.


METHODS
35 adults with asthma and exacerbation of asthma.


METHODS
Peak expiratory flow diaries and symptom recordings.


RESULTS
Asthma action points from published asthma management guidelines had poor operating characteristics. The success rate was 35% when the action point was a peak expiratory flow rate less than 60% of the patient's best peak flow. The success rate improved to 88% when the action point was a peak expiratory flow rate less than 80% of the patient's best peak flow. Published action points had a high failure rate. Peak flow decreased to below the published action points during a stable period of asthma in 7% to 51% of patients studied. Action points defined using quality-control analysis did significantly better. A peak flow value less than 3 standard deviations below the patient's mean peak flow detected 84% of exacerbations and had a low failure rate (19%). Other quality-control tests had sensitivities of 91% and 71%. Quality-control action points could detect exacerbations up to 4.5 days earlier than conventional methods.


CONCLUSIONS
Individualized action points can be derived for patients with asthma by applying quality-control analysis to peak flow recordings. These action points are more sensitive in detecting exacerbations of asthma and have fewer false-positive results. Action plans developed in this manner should be more useful for the early detection of deteriorating asthma.
Gibson
P G
PG
Respiratory Medicine Unit, John Hunter Hospital, New South Wales, Australia.
Wlodarczyk
J
J
Hensley
M J
MJ
Murree-Allen
K
K
Olson
L G
LG
Saltos
N
N
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate / Q000502:physiology*; D017410:Practice Guidelines as Topic / Q000592:standards; D011786:Quality Control; D012680:Sensitivity and Specificity
D000305:Adrenal Cortex Hormones; D001993:Bronchodilator Agents