Deoxygenation of inspiratory muscles during cycling, hyperpnoea and loaded breathing in health and disease: a systematic review

Abstract

Assessing inspiratory muscle deoxygenation and blood flow can provide insight into anaerobic stress, recruitment strategies and mechanisms of inspiratory muscle limitation. Therefore, this review aimed to synthesize measurements of inspiratory muscle oxyhaemoglobin (O Hb), deoxyhaemoglobin (HHb), blood volume and flow of the inspiratory muscles acquired via near-infrared spectroscopy (NIRS) during cycling, hyperpnoea and loaded breathing in healthy non-athletes, healthy athletes and patients with chronic obstructive pulmonary disease (COPD) or chronic heart failure (CHF). Searches were performed on Medline and Medline in-process, EMBASE, Central, Sportdiscus, PubMed and Compendex. Reviewers independently abstracted articles and assessed their quality using the modified Downs and Black checklist. Of the 644 articles identified, 21 met the inclusion criteria. Studies evaluated non-athletes (n = 9), athletes (n = 5), COPD (n = 2) and CHF (n = 5). The sample was 90% male and 73% were non-athletes and athletes. Interventions included cycle ergometry, hyperpnoea, loaded breathing, elbow flexor loading and combined loaded breathing and ergometry. Athletes and patients with CHF or COPD demonstrated deoxygenation of inspiratory accessory muscles that was often an opposite or exaggerated pattern compared to non-athletes. O Hb decreased and HHb increased significantly in inspiratory muscles during cycle ergometry and loaded breathing with accentuated changes during combined ergometry and loaded breathing. During different regimens of hyperpnoea or loaded breathing, comparisons of inspiratory muscles demonstrated that the sternocleidomastoid deoxygenated more than the intercostals, parasternals or scalenes. Evaluating inspiratory muscle deoxygenation via NIRS can inform mechanisms of inspiratory muscle limitation in non-athletes, athletes and patients with CHF or COPD.

More Impaired Dynamic Ventilatory Muscle Oxygenation in Congestive Heart Failure than in Chronic Obstructive Pulmonary Disease

“…The healthy subjects had higher HbO 2 , TOT, and S m O 2 , whereas the CHF group had lower HbO 2 , TOT, and HHb, and the CHF group had the lowest S m O 2 at peak exercise. We speculate that the CHF group had poor perfusion in the ventilatory muscles at peak exercise, which is compatible with previous reports [5,22,59]. Thus, this study does not support the metaboreflex or steal phenomenon of blood redistribution during heavy exercise [14,20,21,22,38,59].…”

“…Changes in HHb and HbO 2 were reported to indicate oxidative metabolism [5], i.e., that HHb represents tissue oxygen consumption and HbO 2 represents tissue oxygen perfusion or delivery, respectively. TOT was reported to indicate recruitment strategies of circulation [5], also called O 2 diffusion capacity [44,53] or to be related to vessel conductance [54] and S m O 2 was reported to indicate the balance between muscle oxygen supply and demand [55].…”

“…Thus, general linear models were used in comparison of the three groups (normal, COPD, CHF), adjusting for potential confounders such as age, body mass index, and SpO2 at each time point, respectively. For comparisons within different time points for the same variable, we did not adjust for other confounders as the measurements were from the same subject and the comparisons were planned a priori [5]. During loaded exercise, the HHb level is workload-related [35,42,50] and thus, the Hb variables were additionally corrected for peak workload.…”

“…It has been hypothesized that functional impairment is further impaired by exercise due to failure of perfusion to meet the need of increased metabolism. Patients with CHF have primarily reduced central cardiovascular function, whereas patients with COPD have secondarily reduced central cardiovascular function caused by dynamic hyperinflation [5]. Moreover, the locomotor muscles are expected to be more impaired than the inspiratory muscles (diaphragm), as inspiratory muscles are more resistant to fatigue with a higher proportion of type I fibers, despite also being impaired in strength, whereas the quadriceps have a lower proportion of type I fibers [6,7,8].…”

Oxigenación de músculos respiratorios y locomotores durante el test cardiopulmonar en pacientes con circulación de Fontan: serie de casos

“…Lo anterior provoca una disminución de la saturación de oxígeno a nivel muscular (SmO 2 ), lo que puede evaluarse a través de la interpretación de los cambios en las longitudes de onda cercana al rango infrarrojo (Near-Infrared Spectroscopy, NIRS). Así, a través de dispositivos portátiles no invasivos con tecnología NIRS y la cuantificación de la hemoglobina y mioglobina tisular local se determina la SmO 2 , aspecto que debe ser interpretado como la relación entre el suministro y utilización de oxígeno a nivel de la microcirculación muscular 11 . Utilizando esta tecnología, en PCF se ha evaluado la SmO 2 en m.Vastus-Laterallis encontrando una disminución total de la oxigenación posterior al ejercicio físico máximo (∆SmO 2 = 4.5±2.1%) 12 .…”