Study objectives: To assess the correlation of single breath counting (SBC) and peak expiratory flow rate (PEFR) to forced expiratory volume in the first second (FEV1).
Design: Prospective comparison of pulmonary function measurements.
Setting: University hospital pulmonary function test (PFT) laboratory.
Type of participants: Consenting patients scheduled to have PFTs May 1, 1992, through November 1, 1992.
Interventions: 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.
Measurements and main results: 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).
Conclusion: SBC is a reasonable alternative to PEFR. Further investigation in an emergency department setting is warranted.