Comparison of Peak Expiratory Flow Rate and FEV1 in Assessing Bronchomotor Tone after Challenges with Occupational Sensitizers

Bronchial responses to occupational sensitizers measured by peak expiratory flow rate (PEFR) and forced expiratory volume in 1 s (FEV1) during late reactions (between 90 minutes and 8 hours after exposure) were compared in two groups of 88 subjects who had undergone specific inhalation challenges in the laboratory. The first group had what was considered a positive reaction (a fall of at least 15 percent in FEV1) whereas the second group's reaction was interpreted as negative (fall in FEV1 0.80) in only 32/88 subjects (36 percent). No subject who was considered to have a negative challenge according to FEV1 had a change in PEFR >20 percent. We therefore conclude that changes in PEFR are far less sensitive than changes in FEV1 in detecting responses during late reactions to occupational sensitizers.