The immediate effects of elastic loads on the breathing of man

Campbell, E. J. M.; Dinnick, O.P.; Howell, J. B. L.

doi:10.1113/jphysiol.1961.sp006674

Cited by 64 publications

(25 citation statements)

References 5 publications

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“…The increased tension developed by the diaphragm slip in response to elastic loading of breathing occurs on the first breath and supports the conclusions made previously from observations in man (Campbell, Dinnick & Howell, 1961). The progressive nature of the response suggests that it is unlikely to be a simple spinal reflex and its persistence after vagotomy indicates that it is mediated by extra-vagal pathways.…”

Section: Discussionsupporting

confidence: 87%

“…1 (Received 12 August 1963) When the inspiratory phase of breathing is hindered by an elastic load the volume inspired is reduced. Nevertheless, this volume is larger than would have been expected if the tension developed by the muscles at the end of inspiration were unchanged (Campbell, Dinnick & Howell, 1961). When expiration is hindered by the addition of a threshold expiratory load (that is, one which opposes expiration by a constant pressure), the inspiration which follows is to a larger lung volume, implying the development of greater end-inspiratory tension (Campbell, Dickinson, Dinnick & Howell, 1961 b).…”

mentioning

confidence: 99%

“…The response to threshold expiratory loads still occurs in dogs after the vagi have been cut (Campbell et al 1961 b). It seems likely, therefore, that extrapulmonary pathways are involved, probably arising from the thoracic cage, i.e.…”

mentioning

confidence: 99%

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The immediate effects of added loads on the inspiratory musculature of the rabbit

Campbell¹,

Dickinson²,

Howell³

1964

The Journal of Physiology

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Section: Discussionsupporting

confidence: 87%

mentioning

confidence: 99%

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The immediate effects of added loads on the inspiratory musculature of the rabbit

Campbell¹,

Dickinson²,

Howell³

1964

The Journal of Physiology

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“…Although lung volumes were not measured a higher functional residual capacity was suspected during expiratory loading because of the increased mean negative pressure during inspiration (Table I). Campbell et al have previously demonstrated an increased functional residual capacity with similar threshold loads to expiration (17). (b) A change in the pattern of breathing to a more rapid inspiration and a slow expiration, requiring increased effort by inspiratory muscles.…”

Section: Introductionmentioning

confidence: 99%

Respiratory Muscle Blood Flow Distribution during Expiratory Resistance

Robertson¹,

Eschenbacher²,

Johnson³

1977

J. Clin. Invest.

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A B S T R A C T When work load on the respiratory system is increased the relative increase in blood flow to each of the muscles of breathing provides an index of how the augmented effort of breathing is partitioned among the different muscles. We have used a radioactive microsphere technique to measure blood flow to each ofthe muscles ofrespiration in supine dogs during unobstructed respiration and breathing against graded expiratory threshold loads. 79% of the augmented flow went to expiratory muscles; of this increased flow to expiratory muscles 74% went to abdominal wall muscles and 26% to internal intercostals. In our earlier studies of hyperventilation induced by CO2 rebreathing where expiratory work loads were low, 44% of the increase in flow went to expiratory muscles; of this, only 39% went to abdominal wall muscles and 61% to intemal intercostals. During inspiratory resistance which produced small increases in expiratory work, 27% of the increase in blood flow went to expiratory muscles; of this, only 37% went to abdominal wall muscles and 63% to intemal intercostals. These results suggest that the internal intercostals are predominantly used for expiration when expiratory work loads are low, whereas the abdominal wall muscles are predominantly used when loads are high.For similar rates of pressure-volume work done on the lung, the total respiratory muscle blood flow is significantly greater during expiratory loads than during unobstructed hyperventilation or inspiratory loads. Thus, the abdominal wall muscles that are utilized for overcoming high pressure expiratory loads are relatively inefficient in converting metabolic energy into pressure-volume work.

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“…It is a fact, though, that the end tidal CO 2 level remained constant all through the measurements, indicating that there was some kind of compensation, possibly during the normal intervals (Threshold loads might take more than 30 seconds to be compensated for [6]), or due to a smaller relative dead-space. Again, this was not statistically confirmed from this study.…”

Section: Discussionmentioning

confidence: 96%

Transient respiratory sensitivity to small mechanical stimuli assessed by spontaneously breathing on a ventilator

Hellström

Persson

2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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-Respiratory response to repeated sequences of mild negative inspiratory pressure (NIP) was investigated. Ten healthy male subjects were spontaneously breathing on a Siemens Servo Ventilator. The ventilator delivered the NIP loading (-2 cm H 2 O during 30 seconds at 1 min interval) and was also used as a measuring device. Six transient response sequences were ensemble-averaged to discern changes in the same order as normal variation of breathing at rest. Analysis of variance showed that NIP caused a moderate reduction in ventilation (V I ), that was not compensated by increased respiratory activity (P 0.1 ). The intra-individual coefficient of variation of these two breathing parameters decreased markedly (p < 0.05), in a way that resembles restrictive lung disease. NIP loading might be an alternative test for clinical assessment of the lung and respiratory function. It is simple, and with repeated measurements, the sensitivity can be adjusted to interfere minimally with the patient.

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The immediate effects of elastic loads on the breathing of man

Cited by 64 publications

References 5 publications

The immediate effects of added loads on the inspiratory musculature of the rabbit

The immediate effects of added loads on the inspiratory musculature of the rabbit

Respiratory Muscle Blood Flow Distribution during Expiratory Resistance

Transient respiratory sensitivity to small mechanical stimuli assessed by spontaneously breathing on a ventilator

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