BACKGROUND: Although the use of nose clips (NC) during forced expiratory spirometry is encouraged by both the American Thoracic Society (ATS) and the European Respiratory Society (ERS), few data support this practice. METHOD & SUBJECTS: We performed a prospective, single-masked, cross-over study in children and adults to determine whether the use of NC significantly affected spirometric values. Eighty adults (46% with airways obstruction) and 81 children (22% with airways obstruction) performed spirometry both with and without (w/o) NC in random order. RESULTS: For children, no significant differences were found between spirometric values (FVC, FEV1, FEF25-75%, and PEFR) obtained with and w/o NC. For adults, there were no significant differences in FVC or PEFR. The difference in FEV1, although only 1% of the mean value, was statistically significant; the mean (SD) for FEV1-NC was 3.03 (1.14) L versus 3.00 (1.12) L w/o NC, p = 0.001. No children and 1 adult had a > 10% improvement in FEV1 with NC, and 2 patients (both children) had a > 10% improvement w/o NC. The mean differences were similar and not statistically significantly different for obstructed and unobstructed patients. We found that the use of NC did not alter values obtained by forced expiratory spirometry in a clinically important manner. CONCLUSION: Our results suggest that the routine use of NC during forced expiratory spirometry should be questioned.
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