Calculated versus Measured MVV-Surrogate Marker of Ventilatory CPET.

Colwell KL(1), Bhatia R

Med Sci Sports Exerc. 2017 Oct;49(10):1987-1992.

INTRODUCTION: Maximum voluntary ventilation (MVV), a surrogate marker of maximum
ventilatory capacity, allows for measuring ventilatory reserve during
cardiopulmonary exercise testing (CPET), which is necessary to assess ventilatory
limitation. MVV can be measured directly during a patient maneuver or indirectly
by calculating from forced expiratory volume in 1 s (FEV1 × 40). We investigated
for a potential difference between calculated MVV and measured MVV in pediatric
subjects, and which better represents maximum ventilatory capacity during CPET.

METHODS: Data were collected retrospectively from CPET conducted in pediatric
subjects for exercise-induced dyspnea from January 2014 to June 2015 at Akron
Children’s Hospital. Subjects with neuromuscular weakness, morbid obesity, and
suboptimal effort during the testing were excluded from the study.

RESULTS: Thirty-five subjects (mean ± SD, age = 13.8 ± 2.7 yr, range = 7-18 yr)
fulfilled the criteria. Measured MVV was significantly lower than calculated MVV
(89.9 ± 26.4 vs 122.4 ± 34.5 L·min; P < 0.01). The ventilatory reserve based on
measured MVV was also significantly lower than ventilatory reserve based on
calculated MVV (12.4% ± 19.6% vs 36.1% ± 13.2%; P < 0.01). Calculated MVV (as
well as ventilatory reserve based on calculated MVV) was significantly correlated
with ventilatory parameters. By contrast, no significant correlations were found
between measured MVV (or ventilatory reserve based on measured MVV) and
ventilatory parameters except for peak ventilation (peak V˙E).

CONCLUSIONS: The measured MVV was significantly lower than the calculated MVV in
our pediatric subjects. The calculated MVV was a better surrogate of maximum
ventilatory capacity as shown by significant correlation to other ventilatory
parameters during CPET.