Ventilatory muscle recruitment in exercise with O2 in obstructed patients with mild hypoxemia

Criner, GJ; Celli, B. R.

doi:10.1152/jappl.1987.63.1.195

Cited by 69 publications

(30 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Firstly, the contribution of hypoxaemia to the exercise limitation is still uncertain, and the mechanisms by which oxygen affects exercise performance are complex [6][7][8][9][10][11]. The present study confirmed previous reports showing that the acute effects of oxygen, as well as the effects of training, correlated poorly with lung function parameters or blood gas values at rest or during exercise [5,6,17].…”

Section: Effects Of Oxygen-supplemented Exercise Trainingsupporting

confidence: 86%

“…These acute effects of oxygen have been observed both in normoxic patients and in patients who are hypoxaemic at rest or during exercise. Several mechanisms may be involved, including reduction in ventilatory response to exercise (reduced ventilatory equivalent for carbon dioxide (V'E/V'CO 2 )) [6], ventilatory muscle recruitment [7] and delayed ventilatory muscle fatigue [8,9], improved aerobic capacity of the working muscles [10] and a reduction in breathlessness [11].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise

Rooyackers

Dekhuijzen²,

Herwaarden³

et al. 1997

Eur Respir J

148

121

View full text Add to dashboard Cite

Supplemental oxygen has acute beneficial effects on exercise performance in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate whether oxygen-supplemented training enhances the effects of training while breathing room air in patients with severe COPD.A randomized controlled trial was performed in 24 patients with severe COPD who developed hypoxaemia during incremental cycle exercise (arterial oxygen saturation (Sa,O 2 ) <90% at peak exercise). All patients participated in an in-patient pulmonary rehabilitation programme of 10 weeks duration. They were assigned either to general exercise training while breathing room air (GET/RA group: forced expiratory volume in one second (FEV1) 38% of predicted; arterial oxygen tension (Pa,O 2 ) 10.5 kPa at rest; Pa,O 2 7.3 kPa at peak exercise), or to GET while breathing supplemental oxygen (GET/O 2 group: FEV1 29% pred; Pa,O 2 10.2 kPa at rest; Pa,O 2 7.2 kPa at peak exercise). Sa,O 2 was not allowed to fall below 90% during the training. The effects on exercise performance while breathing air and oxygen, and on quality of life were compared.Maximum workload (Wmax) significantly increased in the GET/RA group (mean (SD) 17 (15) W, p<0.01), but not in the GET/O 2 group (7 (25) W). Six minute walking distance (6MWD), stair-climbing, weight-lifting exercise (all while breathing room air) and quality of life significantly increased in both groups. Acute administration of oxygen improved exercise performance before and after training. Training significantly increased Wmax, peak carbon dioxide production (V'CO 2 ) and 6MWD while breathing oxygen in both groups. Differences between groups were not significant.Pulmonary rehabilitation improved exercise performance and quality of life in both groups. Supplementation of oxygen during the training did not add to the effects of training on room air.

show abstract

Section: Effects Of Oxygen-supplemented Exercise Trainingsupporting

confidence: 86%

mentioning

confidence: 99%

Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise

Rooyackers

Dekhuijzen²,

Herwaarden³

et al. 1997

Eur Respir J

148

121

View full text Add to dashboard Cite

show abstract

“…The PTPoes, PTPdi and PTPga have been used to assess respiratory muscle activity [8,9,13,18], and correlate well with measurements of the oxygen consumption of contracting respiratory muscles [19]. Alternative approaches include assessment of electromyographic activity [20,21] or the Poes:Pga ratio [22,23]. It should be noted that the PTP is not synonymous with work, which is the product of pressure and flow.…”

Section: Critique Of the Methodsmentioning

confidence: 99%

Respiratory muscle activity in patients with COPD walking to exhaustion with and without pressure support

Kyroussis¹,

Polkey²,

Hamnegärd³

et al. 2000

Eur Respir J

115

View full text Add to dashboard Cite

The function of the diaphragm and other respiratory muscles during exercise in chronic obstructive pulmonary disease (COPD) remains controversial and few data exist regarding respiratory muscle pressure generation in this situation.The inspiratory pressure/time products of the oesophageal and transdiaphragmatic pressure, and the expiratory gastric pressure/time product during exhaustive treadmill walking in 12 patients with severe COPD are reported. The effect of noninvasive positive pressure ventilation during treadmill exercise was also examined in a subgroup of patients (n=6).During free walking, the inspiratory pressure/time products rose early in the walk and then remained level until the patients were forced to stop because of intolerable dyspnoea. In contrast, the expiratory gastric pressure/time product increased progressively throughout the walk. When patients walked the same distance assisted by noninvasive positive pressure ventilation, a substantial reduction was observed in the inspiratory and expiratory pressure/time products throughout the walk. When patients walked with positive pressure ventilation for as long as they could, the pressure/time products observed at exercise cessation were lower than those observed during exercise cessation after free walking.It is concluded that, in severe chronic obstructive pulmonary disease, inspiratory muscle pressure generation does not increase to meet the demands imposed by exhaustive exercise, whereas expiratory muscle pressure generation rises progressively. Inspiratory pressure support was shown to substantially unload all components of the respiratory muscle pump. Eur Respir J 2000; 15: 649±655.

show abstract

“…First, the impaired pulmonary gas exchange characterizing many of these patients often results in reduced hemoglobin saturation [arterial O 2 saturation by pulse oximetry (Sp O 2 )] compared with age-matched healthy control subjects at rest and especially during exercise (1,17,46,53). Second, patients with COPD experience expiratory flow limitation, hyperinflation, and greater respiratory muscle work (W r ) at any given level of exercise (65), which may or may not lead to inspiratory and/or expiratory muscle fatigue (36,38,42,56,57).…”

mentioning

confidence: 99%

Impact of pulmonary system limitations on locomotor muscle fatigue in patients with COPD

Amann

Regan

Kobitary

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

129

145

View full text Add to dashboard Cite

We examined the effects of respiratory muscle work [inspiratory (W r-insp); expiratory (W r-exp)] and arterial oxygenation (SpO 2 ) on exerciseinduced locomotor muscle fatigue in patients with chronic obstructive pulmonary disease (COPD). Eight patients (FEV, 48 Ϯ 4%) performed constant-load cycling to exhaustion (Ctrl; 9.8 Ϯ 1.2 min). In subsequent trials, the identical exercise was repeated with 1) proportional assist ventilation ϩ heliox (PAV); 2) heliox (He:21% O 2); 3) 60% O 2 inspirate (hyperoxia); or 4) hyperoxic heliox mixture (He: 40% O 2). Five age-matched healthy control subjects performed Ctrl exercise at the same relative workload but for 14.7 min (Ϸbest COPD performance). Exercise-induced quadriceps fatigue was assessed via changes in quadriceps twitch force (Q tw,pot) from before to 10 min after exercise in response to supramaximal femoral nerve stimulation. During Ctrl, absolute workload (124 Ϯ 6 vs. 62 Ϯ 7 W), W r-insp (207 Ϯ 18 vs. 301 Ϯ 37 cmH 2O·s·min Ϫ1 ), Wr-exp (172 Ϯ 15 vs. 635 Ϯ 58 cmH 2O·s·min Ϫ1 ), and SpO 2 (96 Ϯ 1% vs. 87 Ϯ 3%) differed between control subjects and patients. Various interventions altered W r-insp, W r-exp, and SpO 2 from Ctrl (PAV: Ϫ55 Ϯ 5%, Ϫ21 Ϯ 7%, ϩ6 Ϯ 2%; He:21% O 2: Ϫ16 Ϯ 2%, Ϫ25 Ϯ 5%, ϩ4 Ϯ 1%; hyperoxia: Ϫ11 Ϯ 2%, Ϫ17 Ϯ 4%, ϩ16 Ϯ 4%; He:40% O 2: Ϫ22 Ϯ 2%, Ϫ27 Ϯ 6%, ϩ15 Ϯ 4%). Ten minutes after Ctrl exercise, Q tw,pot was reduced by 25 Ϯ 2% (P Ͻ 0.01) in all COPD and 2 Ϯ 1% (P ϭ 0.07) in healthy control subjects. In COPD, ⌬Q tw,pot was attenuated by onethird after each interventional trial; however, most of the exerciseinduced reductions in Q tw,pot remained. Our findings suggest that the high susceptibility to locomotor muscle fatigue in patients with COPD is in part attributable to insufficient O 2 transport as a consequence of exaggerated arterial hypoxemia and/or excessive respiratory muscle work but also support a critical role for the well-known altered intrinsic muscle characteristics in these patients.work of breathing; arterial oxygenation; blood flow; chronic obstructive pulmonary disease PATIENTS WITH chronic obstructive pulmonary disease (COPD) are characterized by endurance exercise intolerance, a characteristic consequence of the disease that impairs their capability for physical rehabilitation and contributes to their poor quality of life. Given the pathophysiological heterogeneity of COPD including various comorbidities (31), controversy exists about the prevailing determinants of the impaired capability for exercise in patients with COPD (2, 18, 54). The traditional view of perceived respiratory difficulty (dyspnea) as a critical factor restricting exercise is important and certainly plays a significant limiting role in many patients with COPD (34, 50). However, substantial exercise-induced locomotor muscle fatigue also occurs in many of these patients (34, 39 -41), and their susceptibility to peripheral muscle fatigue is greater than in age-matched healthy control subjects exercising at the same work rate (39, 40). Peripheral muscle fatigue ha...

show abstract

Ventilatory muscle recruitment in exercise with O2 in obstructed patients with mild hypoxemia

Cited by 69 publications

References 0 publications

Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise

Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise

Respiratory muscle activity in patients with COPD walking to exhaustion with and without pressure support

Impact of pulmonary system limitations on locomotor muscle fatigue in patients with COPD

Contact Info

Product

Resources

About