Intercostal and forearm muscle deoxygenation during respiratory fatigue in patients with heart failure: potential role of a respiratory muscle metaboreflex

Abstract

The purpose of this study was to determine the effect of respiratory muscle fatigue on intercostal and forearm muscle perfusion and oxygenation in patients with heart failure. Five clinically stable heart failure patients with respiratory muscle weakness (age, 66±12 years; left ventricle ejection fraction, 34±3%) and nine matched healthy controls underwent a respiratory muscle fatigue protocol, breathing against a fixed resistance at 60% of their maximal inspiratory pressure for as long as they could sustain the predetermined inspiratory pressure. Intercostal and forearm muscle blood volume and oxygenation were continuously monitored by near-infrared spectroscopy with transducers placed on the seventh left intercostal space and the left forearm. Data were compared by two-way ANOVA and Bonferroni correction. Respiratory fatigue occurred at 5.1±1.3 min in heart failure patients and at 9.3±1.4 min in controls (P<0.05), but perceived effort, changes in heart rate, and in systolic blood pressure were similar between groups (P>0.05). Respiratory fatigue in heart failure reduced intercostal and forearm muscle blood volume (P<0.05) along with decreased tissue oxygenation both in intercostal (heart failure, -2.6±1.6%; controls, +1.6±0.5%; P<0.05) and in forearm muscles (heart failure, -4.5±0.5%; controls, +0.5±0.8%; P<0.05). These results suggest that respiratory fatigue in patients with heart failure causes an oxygen demand/delivery mismatch in respiratory muscles, probably leading to a reflex reduction in peripheral limb muscle perfusion, featuring a respiratory metaboreflex.

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

“…In three of four studies that compared CHF patients to healthy participants, SA O 2 Hb consistently decreased during incremental cycle ergometry in patients compared to no change in healthy subjects. IC StO 2 decreased during inspiratory resistive loading in CHF patients compared to no change in healthy participants (Moreno et al ., ). In the three studies that examined the response to cycle ergometry, SA tHb did not change in either group during cycle ergometry.…”

“…In the three studies that examined the response to cycle ergometry, SA tHb did not change in either group during cycle ergometry. In contrast, IC tHb decreased during inspiratory resistive loading in CHF patients compared to no change in the healthy group (Moreno et al ., ).…”

“…Whether optode measures of IC represent only ICs was not described in most reports. Of note, the positioning of NIRS optodes over the IC was described similarly in eight reports as the 7th intercostal space at the midaxillary line (Guenette et al ., , ; Vogiatzis et al ., , ; Athanasopoulos et al ., ; Shadgan et al ., ; Henderson et al ., ; Moreno et al ., ), and another report described the optode position as placement over the left sixth intercostal space at the anterior axillary line (Katayama et al ., ). Of these nine articles, only an early report described this location to be at the apposition of the costal diaphragm (Guenette et al ., ).…”

Neural control of circulation and exercise: a translational approach disclosing interactions between central command, arterial baroreflex, and muscle metaboreflex

“…With the use of nearinfrared spectroscopy, deoxygenation of the serratus anterior muscle during cycling maximal exercise in heart failure without concomitant arterial blood oxygen desaturation has been shown (58). During a protocol with progressive inspiratory pressure, respiratory muscle fatigue was induced in subjects with heart failure at rest, revealing deoxygenation not only in intercostal muscles but also in resting forearm, an effect not seen in healthy controls, suggesting underperfusion of respiratory muscles in those patients (73).…”

Effects of High-Intensity Inspiratory Muscle Training in Rugby Players

“…[4][5][6][7][8] The feature responsible for the athlete's performance limitation is the so-called metaboreflex, in which metabolites accumulation during fatiguing muscle exercise promotes an increase in muscle sympathetic nerve activity and consequently peripheral vasoconstriction. [9][10][11] The IMT with linear pressure loading equipment has been considered a potential modifying agent of strength and inspiratory muscle strength, as well as attenuatingthe metabolic accumulation during inspiratory muscle work, resulting in the decrease of diaphragmatic muscle fatigue, dyspnea and increase of physical performance. [12][13][14][15] Therefore, the inspiratory muscle training with high pressure loads on rugby players need be elucidated.…”