Response

Abstract

We appreciate Drs Sharma and Samuel's interest in our recently published study.1Vivodtzev I. Picard G. Cepeda F.X. et al.Acute ventilatory support during whole-body hybrid rowing in patients with high-level spinal cord injury: a randomized controlled crossover trial.Chest. 2020; 157: 1230-1240Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar However, we would like to draw attention to the fact that the main criticisms are inappropriate and to some major misstatements concerning our methods and statistical analysis. First and foremost, we did not compare the effect of training with ventilatory support (noninvasive ventilation [NIV]) but rather its acute effect on the cardiorespiratory responses to exercise. Hence, each subject performed testing both with and without NIV support in a crossover study design, meaning a block randomization has no role in this design. Randomization was used to avoid any effect of performance order (such as a learning effect, for example). It was not used, as Sharma and Asir seem to believe, to balance the characteristics of the patients between “groups”; there was only a single group of individuals. Moreover, the order of the tests was considered in our statistical analysis via a “mixed model, including order of tests, treatment, and interaction between order and treatment.”2Putt M. Chinchilli V.M. A mixed effects model for the analysis of repeated measures cross-over studies.Stat Med. 1999; 18: 3037-3058Crossref PubMed Scopus (38) Google Scholar Additionally, with a study of the acute effects of NIV, there cannot be “washout period.” However, as recommended by the exercise physiology community, we allowed a minimal recovery time of 48 hours between test-retest.3Bishop P.A. Jones E. Woods A.K. Recovery from training: a brief review: brief review.J Strength Cond Res. 2008; 22: 1015-1024Crossref PubMed Scopus (144) Google Scholar,4Dupuy O. Douzi W. Theurot D. et al.An evidence-based approach for choosing post-exercise recovery techniques to reduce markers of muscle damage, soreness, fatigue, and inflammation: a systematic review with meta-analysis.Front Physiol. 2018; 9: 403Crossref PubMed Scopus (82) Google Scholar Lastly, Sharma and Asir are mistaken in saying that we should have used a “Mann-Whitney test to compare the pattern of ventilation between the groups.” Again, there was only one group, and we did indeed compare breathing frequency and tidal volume over the entire duration of the test (four time points are clearly visible in Fig 2) for both conditions, with and without NIV, which requires a repeated measures analysis of variance. On reflection, we think these erroneous comments reflect fundamental and recurrent mistake among the clinical/scientific community regarding the difference between exercise and training studies. The requirement of a “CONSORT diagram” actually has little application to a study comparing exercise capacity. Although results from studies of acute exercise may provide insight to a possible innovative intervention, they cannot be considered as indicative of the actual effects of exercise training. Readers should pay particular attention to the design to clearly understand whether exercise (an acute effect) or training (a treatment effect) is being compared in a study. Acute Ventilatory Support During Whole-Body Hybrid Rowing in Patients With High-Level Spinal Cord Injury: A Randomized Controlled Crossover TrialCHESTVol. 157Issue 5PreviewHigh-level spinal cord injury (SCI) results in profound spinal and supraspinal deficits, leading to substantial ventilatory limitations during whole-body hybrid functional electrical stimulation (FES)-rowing, a form of exercise that markedly increases the active muscle mass via electrically induced leg contractions. This study tested the effect of noninvasive ventilation (NIV) on ventilatory and aerobic capacities in SCI. Full-Text PDF Missed Randomization and Statistical Test DetailsCHESTVol. 158Issue 4PreviewThe study by Vivodtzev et al1 published in a previous issue of CHEST (May 2020) tested the effect of noninvasive ventilation on ventilatory and aerobic capacities in patients with spinal cord injury (SCI). The authors found improvement in ventilatory efficiency during functional electrical stimulation rowing exercise in SCI, but no improvement in VO2 Peak. Full-Text PDF