Ventilatory efficiency in children and adolescents born extremely preterm

Abstract

Purpose: Children and adolescents born extremely preterm (EP) have lower dynamic lung volumes and gas transfer capacity than subjects born at term. Most studies also report lower aerobic capacity. We hypothesized that ventilatory efficiency was poorer and that breathing patterns differed in EP−born compared to term−born individuals.Methods: Two area−based cohorts of participants born with gestational age ≤28 weeks or birth weight ≤1000 g in 1982−85 (n = 46) and 1991-92 (n = 35) were compared with individually matched controls born at term. Mean ages were 18 and 10 years, respectively. The participants performed an incremental treadmill exercise test to peak oxygen uptake with data averaged over 20 s intervals. For each participant, the relationship between exhaled minute ventilation (V E ) and carbon dioxide output (VCO 2 ) was described by a linear model, and the relationship between tidal volume (V T ) andV E by a quadratic model. Multivariate regression analyses were done with curve parameters as dependent variables, and the categories EP vs. term−born, sex, age, height, weight and forced expiratory volume in 1 s (FEV 1 ) as independent variables.Results: In adjusted analyses, the slope of theV E −VCO 2 relationship was significantly steeper in the EP than the term-born group, whereas no group difference was observed for the breathing pattern, which was related to FEV 1 only.Conclusion: EP-born participants breathed with higherV E for any given CO 2 output, indicating lower ventilatory efficiency, possibly contributing to lower aerobic capacity. The breathing patterns did not differ between the EP and term−born groups when adjusted for FEV 1 .

The effect of test modality on dynamic exercise biomarkers in children, adolescents, and young adults

“…) that are less effort‐dependent than the traditional O 2 max and, arguably, more acceptable in children and adolescents, particularly those with chronic diseases or conditions (Stein et al, ; Cooper et al, ). Dynamic relationships among CPET variables (such as HR, E, CO 2 , and O 2 ) reveal novel insights into cardiorespiratory function in health and disease (Cooper et al, ; Troutman et al, ; Moser et al, ; Chen et al, ; Elbehairy et al, ; Hestnes et al, ), and can be obtained in both CE and TM modalities without necessarily measuring work rate. The effect of exercise modality on submaximal physiologic output variables has not been adequately studied in children and adolescents.…”