Purpose: To investigate the effects of physiologic and mechanical aging on peak flowmeters. Materials and methods: Eight each of MiniWright (MW; Clement Clark; Harlow, UK), Personal-Best (PB; HealthScan Products; Cedar Grove, NJ), Vitalograph (V; Vitalograph Ltd; Buckingham, UK), and Breath- Taker (BT; Medical Development Australia; Melbourne, Australia) peak flowmeters were assessed for accuracy and repeatability before and after aging using a computer-driven syringe to deliver peak flows from 100 to 700 L/min. Four of each type of flowmeter were physiologically aged by normal subjects performing up to six peak flows daily for 1 year. The remaining four of each flowmeter were mechanically aged using an accelerated aging device to deliver 2,000 exponential waveforms with a peak flow of 600 L/min over a period of 3 h. Results: The V and BT flowmeters were linear and accurate over the range 100 to 700 L/min, while the PB overread at high flows. The MW was alinear throughout. The SD of the difference between readings before and after aging ranged from 8.6 to 40.6 L/min (mean, 9.2). Comparing the slopes of the relationship of actual against reference peak expiratory flow (PEF) showed that 16 flowmeters-5 BTs, 6 MWs, 4 PBs, and 1 V had no significant change in slope after aging. Mechanical aging caused a consistent underreading in PEF at high flow rates. Physiologic aging showed a more variable pattern both within and between flowmeter types. The MW was the most affected by physiologic aging, producing overestimates of PEF by as much as 100 L/min at 500 L/min. Conclusions: We conclude that the effects of physiologic and mechanical aging are different, and that while mechanical aging may provide a guide to the effects of aging, studies using physiologic aging would be more appropriate.

Item Type:	Refereed Article
Research Division:	Medical and Health Sciences
Research Group:	Cardiorespiratory Medicine and Haematology
Research Field:	Respiratory Diseases
Objective Division:	Health
Objective Group:	Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:	Respiratory System and Diseases (incl. Asthma)
Author:	Johns, DP (Associate Professor David Johns)
Author:	Walters, EH (Professor Haydn Walters)
ID Code:	35877
Year Published:	1998
Web of Science® Times Cited:	1
Deposited By:	Medicine (Discipline)
Deposited On:	2005-09-12
Last Modified:	2011-09-29
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