Single breath counting in the assessment of pulmonary function.

Abstract

To assess the correlation of single breath counting (SBC) and peak expiratory flow rate (PEFR) to forced expiratory volume in the first second (FEV1). Prospective comparison of pulmonary function measurements. University hospital pulmonary function test (PFT) laboratory. Consenting patients scheduled to have PFTs May 1, 1992, through November 1, 1992. SBC was measured by asking patients to take a deep breath and count as far as possible in their normal speaking voice without taking another breath. Counting was timed to a metronome set at 2 counts per second. A hand-held peak flowmeter was then used to measure PEFR. Standard PFTs then were performed. Twenty-two patients were enrolled. The correlation of SBC to FEV1 (r = .68) was slightly better than of PEFR to FEV1 (r = .63). SBC was also found to correlate well with PEFR (r = .68). SBC is a reasonable alternative to PEFR. Further investigation in an emergency department setting is warranted.