Reduced tidal volume-inflection point and elevated operating lung volumes during exercise in females with well-controlled asthma.

INTRODUCTION: Individuals with asthma breathe at higher operating lung volumes during exercise compared with healthy individuals, which contributes to increased exertional dyspnoea. In health, females are more likely to develop exertional dyspnoea than males at a given workload or ventilation, and therefore, it is possible that females with asthma may develop disproportional dyspnoea on exertion. The purpose of this study was to compare operating lung volume and dyspnoea responses during exercise in females with and without asthma. METHODS: Sixteen female controls and 16 females with asthma were recruited for the study along with 16 male controls and 16 males with asthma as a comparison group. Asthma was confirmed using American Thoracic Society criteria. Participants completed a cycle ergometry cardiopulmonary exercise test to volitional exhaustion. Inspiratory capacity manoeuvres were performed to estimate inspiratory reserve volume (IRV) and dyspnoea was evaluated using the Modified Borg Scale. RESULTS: Females with asthma exhibited elevated dyspnoea during submaximal exercise compared with female controls (p<0.05). Females with asthma obtained a similar IRV and dyspnoea at peak exercise compared with healthy females despite lower ventilatory demand, suggesting mechanical constraint to tidal volume (VT) expansion. VT-inflection point was observed at significantly lower ventilation and V̇O2 in females with asthma compared with female controls. Forced expired volume in 1 s was significantly associated with VT-inflection point in females with asthma (R2=0.401; p<0.01) but not female controls (R2=0.002; p=0.88). CONCLUSION: These results suggest that females with asthma are more prone to experience exertional dyspnoea, secondary to dynamic mechanical constraints during submaximal exercise when compared with females without asthma.

Evaluating a Telemedicine Video Game-Linked High-Intensity Interval Training Exercise Programme in Paediatric Heart Transplant Recipients.

Paediatric heart transplant recipients (HTRs) have reduced exercise capacity, physical activity (PA), health-related quality of life (HRQoL), and self-efficacy towards PA. Exercise interventions have demonstrated improvements in exercise capacity and functional status in adult HTRs, with a specific emerging interest in the role of high-intensity interval training (HIIT). Studies of exercise interventions in paediatric HTRs have been limited and nonrandomized to date. HIIT has not yet been evaluated in paediatric HTRs. We thus seek to evaluate the safety and feasibility of a randomized crossover trial of a 12-week, home-based, video game-linked HIIT intervention using a cycle ergometer with telemedicine and remote physiological monitoring capabilities (MedBIKE) in paediatric HTRs. The secondary objective is to evaluate the impact of the intervention on (1) exercise capacity, (2) PA, (3) HRQoL and self-efficacy towards PA, and (4) sustained changes in secondary outcomes at 6 and 12 months after intervention. After a baseline assessment of the secondary outcomes, participants will be randomized to receive the MedBIKE intervention (12 weeks, 36 sessions) or usual care. After the intervention and a repeated assessment, all participants will cross over. Follow-up assessments will be administered at 6 and 12 months after the MedBIKE intervention. We anticipate that the MedBIKE intervention will be feasible and safely yield sustained improvements in exercise capacity, PA, HRQoL, and self-efficacy towards PA in paediatric HTRs. This study will serve as the foundation for a larger, multicentre randomized crossover trial and will help inform exercise rehabilitation programmes for paediatric HTRs.

La tolérance à l'effort, le niveau d'activité physique (AP), le score de la qualité de vie liée à la santé (QVLS) ainsi que l'auto-efficacité à la pratique d'une AP se trouvent diminués chez les patients pédiatriques ayant reçu une transplantation cardiaque. Il a été montré que les exercices physiques permettent d'améliorer la tolérance à l'effort ainsi que le statut fonctionnel chez les patients adultes ayant reçu une transplantation cardiaque. D'ailleurs, le rôle de l'entraînement par intervalles de haute intensité (EIHI) suscite depuis peu un nouvel intérêt à cet égard. Les études réalisées à ce jour sur les programmes d'activité physique chez les patients pédiatriques ayant reçu une transplantation cardiaque sont toutefois peu nombreuses et ne reposent pas sur une répartition aléatoire. De plus, l'EIHI n'a pas encore été évalué chez ce groupe de patients. La présente étude a donc pour objectif d'évaluer la faisabilité et l'innocuité d'un essai clinique croisé à répartition aléatoire d'une durée de 12 semaines chez des patients pédiatriques ayant reçu une transplantation cardiaque. Le programme d'activité physique prendra la forme d'un EIHI à la maison au moyen d'un jeu vidéo et d'une bicyclette ergométrique permettant une assistance et une surveillance des données physiologiques à distance (MedBIKE). Les objectifs secondaires de l'étude consistent à évaluer les effets du programme sur : 1) la tolérance à l'effort; 2) le niveau d'AP; 3) la QVLS ainsi que l'auto-efficacité à la pratique d'une AP; et 4) le maintien des améliorations relatives aux critères d'évaluation se-condaires à 6 et 12 mois. Après une évaluation initiale des critères d'évaluation secondaires, les participants seront répartis aléatoirement dans le groupe suivant le programme à l'aide du vélo MedBIKE (36 séances réparties sur 12 semaines) ou dans le groupe recevant le traitement usuel. Tous les participants changeront ensuite de groupe, et une nouvelle évaluation des critères d'évaluation se-condaires sera effectuée. Les évaluations de suivi auront lieu 6 et 12 mois après la fin du programme. On s'attend à ce que ce dernier soit sûr, facile à suivre et accompagné d'améliorations soutenues de la tolérance à l'effort, du niveau d'AP, de la QVLS et de l'auto-efficacité à la pratique d'une AP chez les patients pédiatriques ayant reçu une transplantation cardiaque. Cette étude servira de modèle à un essai clinique croisé, multicentrique, à répartition aléatoire de plus grande envergure. Elle permettra aussi de générer des renseignements utiles pour les programmes de réadaptation destinés aux patients pédiatriques ayant reçu une transplantation cardiaque.

Exploring the Promise of Telemedicine Exercise Interventions in Children and Adolescents With Congenital Heart Disease.

Youth with congenital heart disease (CHD) have reduced exercise capacity via various physical and psychosocial mechanisms. In addition to limited physiologic exercise capacity, these patients experience lower levels of physical activity, physical activity self-efficacy, health-related quality of life, and endothelial function. The study of exercise interventions and cardiac rehabilitation programs in pediatric CHD populations remains limited, particularly home-based interventions that incorporate real-time physiologic monitoring. Home-based interventions provide improved access and convenience to patients. This is principally important for patients from geographically disperse regions who receive their care at centralized subspecialty centres, as is the case for Canadian pediatric cardiac care. These programs, however, have traditionally not permitted the supervision of safety, technique, and adherence that are afforded by hospital/facility-based programs. As such, telemedicine is an important evolving area that combines the benefits of traditional home and facility-based cardiac rehabilitation. An additional key area lacking study surrounds the types of exercise interventions in youth with CHD. To date, interventions have often centred around moderate-intensity continuous exercise. High-intensity interval training might offer superior cardiorespiratory advantages but remains understudied in the CHD population. In this review, we highlight the existing evidence basis for exercise interventions in youth with CHD, explore the promise of incorporating telemedicine home-based solutions, and highlight key knowledge gaps. To address identified knowledge gaps, we are undertaking a 12-week randomized crossover trial of a home-based telemedicine high-intensity interval training intervention in youth with repaired moderate-severe CHD using a video game-linked cycle ergometer (known as the MedBIKE; https://spaces.facsci.ualberta.ca/ahci/projects/medical-projects/remote-rehab-bike-projects).

A single breath of nitric oxide does not alter pulmonary perfusion pressure.

NEW FINDINGS: What is the central question of this study? Is the amount of inhaled nitric oxide (NO) used during a diffusing capacity for inhaled NO manoeuvre sufficient to reduce pulmonary artery systolic pressure (PASP)? What is the main finding and its importance? These findings suggest that a single breath of inhaled NO does not change PASP, and combined with previous correlational work, further validates the use of the diffusing capacity for NO manoeuvre as a technique to determine pulmonary capillary blood volume and membrane diffusing capacity. ABSTRACT: The measurement of diffusing capacity is an important pulmonary function test to evaluate gas exchange. Using both carbon monoxide and nitric oxide (NO), the diffusing capacity for nitric oxide (DL,NO ) technique allows for the partitioning of capillary blood volume and membrane diffusing capacity. However, inhaled NO is known to dilate pulmonary arterioles in both health and disease and therefore could alter the outcomes that the DL,NO technique aims to quantify. The purpose of the study was to determine if a DL,NO manoeuvre alters pulmonary perfusion pressure. Nine participants completed 12 simulated 10-s breath-hold DL,NO manoeuvres (n = 6 placebo inhalations and n = 6 with 40 ppm NO; order randomized) during which tricuspid regurgitant jet velocity was recorded continuously using Doppler ultrasound to estimate pulmonary artery systolic pressure (PASP) as a surrogate for pulmonary perfusion pressure. The PASP was not different between the placebo and NO conditions (P = 0.742). These data indicate that a single DL,NO manoeuvre does not alter PASP and therefore would not be expected to acutely alter pulmonary capillary blood volume or membrane diffusing capacity.

Systemic vascular health is compromised in both confirmed and unconfirmed asthma.

INTRODUCTION: Asthma is associated with increased risk of cardiovascular diseases. Despite many presenting with symptoms of asthma, asthma cannot always be confirmed by physiological assessment. It is thus far unknown if the heightened cardiovascular risk applies to this group. The purpose of this study was to examine markers of cardiovascular risk, including endothelial function, arterial stiffness, and systemic inflammation, in individuals with confirmed asthma, unconfirmed asthma, and healthy controls. As short-acting beta agonist (SABA) use is associated with increased cardiovascular risk, a secondary analysis was conducted to investigate the impact of regular SABA use on vascular outcomes. METHODS: Individuals with confirmed asthma (n = 26), unconfirmed asthma (n = 15), and healthy controls (n = 26) were recruited for this cross-sectional study. Asthma was confirmed by FEV1 reversibility, methacholine challenge, or exercise challenge. Endothelial function was assessed using flow-mediated dilation (FMD), arterial stiffness using pulse wave velocity (PWV), and systemic inflammation by C-reactive protein (CRP) levels. RESULTS: FMD was significantly lower in both asthma groups compared to controls (confirmed: 7.7 ± 3.6%, unconfirmed: 7.3 ± 3.5%, controls: 10.4 ± 3.6%, p = 0.02). No difference was found in PWV nor CRP. Asthma participants who used SABA had increased arterial stiffness compared to those without SABA (9.2 ± 2.7 m/s, 7.7 ± 1.1 m/s respectively, p = 0.03). No difference was seen in FMD or CRP between SABA groups. CONCLUSION: Individuals with a clinical history of asthma symptoms demonstrate vascular impairments regardless of physiological confirmation of disease. Regular SABA use increases arterial stiffness. Avoiding potentially inappropriate SABA use among people without physiologically confirmed asthma may thus be beneficial in curbing cardiovascular risk.