[Evaluation of the performance of 2 mini-flow meters]

Two mini-peak flow meters, the Airmed (mini-Wright) and the Medicheck (Pulmonary Monitor), were assessed against a reference electronic spirometer (Spiromatic, based on a pneumotachograph, integrator and an Apple II computer) in a series of 10 healthy subjects and 20 patients with chronic obstructive lung disease. The devices to be tested were mounted in series with the reference instrument; each subject did five trials. It was found that the Airmed instrument overestimated the flows up to 9 l X s-1 (i.e. in patients, average difference 0.86 l X s-1, p less than 0.001; in healthy subjects, average difference 0.35 l X s-1, p less than 0.001). The correlation with the results of the reference instrument was high (r = 0.992) in healthy subjects, whose regression slope was less than unity (0.763). In patients the correlation was satisfactory (r = 0.974), and the slope close to 1 (1.05). The Medicheck overestimated slightly the results of patients (difference 0.17 l X s-1, p less than 0.01); in normal subjects the overestimation was present only below 10 l X s-1 and the difference with the reference instrument nonsignificant (average 0.19 l X s-1). The results were closely related to those of the reference spirometer in both healthy subjects (r = 0.960) and patients (r = 0.936). As for the first instrument the slope of the regression was below 1 in healthy subjects (0.751) and practically one (1.01) in patients.(ABSTRACT TRUNCATED AT 250 WORDS)