Effect of fatiguing resistive loads on the level and pattern of respiratory activity in awake goats

Oliven, Arie; Lohda, Suresh; Adams, Merrill; Simhai, B.; Kelsen, Steven G.

doi:10.1016/0034-5687(88)90053-9

Cited by 10 publications

(8 citation statements)

References 24 publications

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“…Since training with exercise and increased dead space provided an intense respiratory challenge, it is possible that oedema had developed in the goats, thus accounting for the shift in respiratory pattern. Similar alterations in breathing patterns have been reported in goats following induction of respiratory muscle fatigue by resistive loading (Oliven, Lohda, Adams, Simhai & Kelsen, 1988). Fatigue may be a factor in the post-training changes in ventilatory pattern, but cannot explain the increase in resting ventilation observed after training since respiratory muscle fatigue reportedly decreases ventilation in goats (Oliven et al 1988).…”

Section: Effects On Resting Ventilationmentioning

confidence: 55%

“…Similar alterations in breathing patterns have been reported in goats following induction of respiratory muscle fatigue by resistive loading (Oliven, Lohda, Adams, Simhai & Kelsen, 1988). Fatigue may be a factor in the post-training changes in ventilatory pattern, but cannot explain the increase in resting ventilation observed after training since respiratory muscle fatigue reportedly decreases ventilation in goats (Oliven et al 1988). There was an insignificant trend towards tachypnoea and shallow breathing during sham training without increased dead space (Martin & Mitchell, 1992), suggesting that some of these effects are due to repeated exercise and are not necessarily specific to paired presentation of ventilatory stimuli.…”

Section: Effects On Resting Ventilationmentioning

confidence: 55%

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Long‐term modulation of the exercise ventilatory response in goats.

Martín

Mitchell

1993

The Journal of Physiology

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SUMMARY1. To test the hypothesis that repeated associations of exercise and increased respiratory dead space elicit mechanisms that augment future ventilatory responses to exercise alone, experiments were conducted on normal adult goats familiarized with experimental procedures.2. Measurements of ventilation, arterial blood gases and CO2 production were made at rest, during mild steady-state exercise (4 km h-1; 5 % grade) and with increased dead space at rest in seven goats before and after training. In Series I experiments, training consisted of fourteen to twenty exercise trials explicitly paired with increased dead space (0-8 1) over 2 days. Increased dead space predominantly represents a CO2 chemoreceptor stimulus with only mild hypoxic stimulation. Post-training measurements were made 1-6 h and 1 week after training was completed.3. The same goats repeated a slightly modified protocol several months later (Series II; 6 trials per day for 4 days) to determine if responses were both repeatable and reversible, and to investigate training effects on dynamic ventilatory responses at the onset of exercise.4. In Series I experiments, resting minute ventilation and breathing frequency were elevated 1-6 h post-training compared to baseline (44 and 74 % respectively), whereas resting tidal volume decreased (14%). One week post-training, resting values had returned to baseline. Series II training had no significant effects on resting measurements.5. Relative to baseline, arterial partial pressure of CO2 (Pa0co2) values decreased significantly more from rest to exercise 1-6 h post-training in both Series I (2-7 + 0-2 vs. 1-8 + 0 9 mmHg) and Series II (3 4 + 0-6 vs. 2-0 + 0'6 mmHg). The exercise ventilatory response increased 25-28 % 1-6 h post-training (both series), largely due to a greater exercise frequency response, but returned to baseline 1 week post-training. Training had no effect on ventilatory responses to CO2 at rest, suggesting that decreases in CO2 chemoreceptor responsiveness did not cause the greater exercise ventilatory response. Model estimates indicate that the net feedforward exercise ventilatory stimulus was increased 40-50 % by training.

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Section: Effects On Resting Ventilationmentioning

confidence: 55%

Section: Effects On Resting Ventilationmentioning

confidence: 55%

Long‐term modulation of the exercise ventilatory response in goats.

Martín

Mitchell

1993

The Journal of Physiology

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“…This concept is supported by animal studies that suggest that when fatiguing loads are applied, EMG di activity falls prior to the development of muscle fatigue. 122,123 In studies of healthy subjects undergoing fatiguing loads, respiratory muscle fatigue can be induced, but half of the loss in muscle function was due to a reduction in diaphragmatic neural activation. 31 If overt respiratory muscle fatigue is not present in COPD patients and baseline central drive to the respiratory muscles is not reduced, the question of whether respiratory muscle dysfunction contributes to respiratory failure in COPD patients needs to be raised.…”

Section: Effect Of Respiratory Muscle Dysfunction On Fatigue and Respmentioning

confidence: 99%

Respiratory Muscle Function in Chronic Obstructive Pulmonary Disease

Ferguson¹

1993

Semin Respir Crit Care Med

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“…The diaphragm is the most important muscle of inspiration. Diaphragmatic fatigue has been demonstrated in experiments in animals and humans during breathing with added inspiratory loads (Bazzy & Haddad 1984, Rochester 1984, Aubier et al 1985, Aldrich & Appel 1985, Oliven et al 1988) and in animals during septic and cardiogenic shock (Aubier et al 1981, Hussain et al 1985.…”

mentioning

confidence: 99%

“…A central component of diaphragmatic fatigue has been found during increased inspiratory loads in humans (Bellemare & Bigland-Ritchie 1987), awake monkeys (Watchko et al 1988) and rabbits (Aldrich 1988) and anaesthetized dogs (Roussos & Macklem 1986), whereas central fatigue was not found in anaesthetized rabbits (Osborn & Road 1993). In most studies demonstrating diaphragm fatigue, the central inspiratory activity was not recorded (Bazzy & Haddad 1984, Aldrich & Appel 1985, Levine & Henson 1988, Oliven et al 1988). In the present study we examined peripheral and central components of dia-phragmatic fatigue in the same experiment.…”

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confidence: 99%

Central and peripheral components of diaphragmatic fatigue during inspiratory resistive load in cats

Aleksandrova

Isaev

1997

Acta Physiologica Scandinavica

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The development of fatigue was investigated in the diaphragm of anaesthetized, tracheostomized, spontaneously breathing cats during restricted air flow. Ventilation, transdiaphragmatic pressure (Pdi), integrated electrical activity of diaphragm (Edi) and phrenic nerve (Eph) were measured simultaneously and expressed as a percentage of values at unloaded breathing. Inspiratory loads were 60, 70 and 80% of Pdi max. The Pdi max was measured by airway occlusion at functional residual capacity. The duration of loads was 40-60 min. The diaphragmatic fatigue developed only during heavy inspiratory loading (80% Pdi max). During the first 10 min of heavy load Pdi, Edi and Eph increased to 905 +/- 60%, 248 +/- 20% and 229 +/- 24%, respectively (P < 0.01), and then began to fall gradually. Ventilation declined to 39 +/- 3% after 60 min of heavy load (P < 0.01), resulting in acute hypercapnia and hypoxia. Initial fatigue appeared as a decrease in Pdi (to 781 +/- 63%) and parallel decline in Edi (to 233 +/- 21%) after 30 min of load (P < 0.05). Phrenic nerve activity did not change during this stage. These data suggest a peripheral basis of diaphragmatic fatigue, related to disorders in neuromuscular transmission. After 60 min of heavy load, Pdi fell to 675 +/- 49%, Edi declined to 209 +/- 28% and Eph decreased to 189 +/- 25%. We interpret the decrease in phrenic nerve activity as a weakening of central inspiratory drive and development of the central component of diaphragmatic fatigue in the last stage.

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Effect of fatiguing resistive loads on the level and pattern of respiratory activity in awake goats

Cited by 10 publications

References 24 publications

Long‐term modulation of the exercise ventilatory response in goats.

Long‐term modulation of the exercise ventilatory response in goats.

Respiratory Muscle Function in Chronic Obstructive Pulmonary Disease

Central and peripheral components of diaphragmatic fatigue during inspiratory resistive load in cats

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