RESUMO
INTRODUCTION: Maximal voluntary ventilation (MVV) and flow expiratory volume in the first second (FEVi) are important spirometric parameters. They are both gender-dependent. However, estimating the MVV, which is widely practiced in cardiopulmonary function testing, by multiplying FEVi by a constant value (equal to MVV/FEVi ratio) does not seem to take this into account. The purpose of this study was to compare the MVV/FEVi ratio by gender among healthy young adults. METHODS: This cross-sectional prospective study involved 67 medical sciences students, including 36 females of the same race, height, and age group. Their ventilatory function was assessed using a computerized spirometer, according to international recommendations. Pearson's test made it possible to correlate different spirometric parameters and linear regression was established between MVV and FEVi. The nonparametric Kruskal-Wallis test was used to compare the MVV/FEVi ratio between females and males. Comparisons by gender were made also between our data and previous prediction equations. RESULTS: In both females and males, FEVi was the spirometric parameter with which MVV had the highest correlation (r = .91 in females, r = .63 in males). A comparison of the means of the MVV/FEVi ratio by gender showed a statistically significant (p < .005) decrease in females (35.68 vs. 38.87). The previous prediction equations showed statistically significant under and overestimation of MVV values when gender was not taken into account. CONCLUSION: For the same height, age, and race, the ratio MVV/FEVi was significantly lower for females. So, the use of a preset constant value in estimating the MVV without taking gender into account was methodologically questionable. This work, which could have clinical implications, would benefit from being confirmed in a larger population.
