Respiratory effects of breathing down a tube

Goode, R. C.; Brown, E. B.; Howson, M. G.; Cunningham, D. J.

doi:10.1016/0034-5687(69)90033-4

Cited by 47 publications

(43 citation statements)

References 19 publications

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“…The present results demonstrated that the ventilatory response to C02-stimulation differs with different methods of increasing PETco2. In agreement with the findings by FENNER et al (1968), GOODE et al (1969), and MASUYAMA and HONDA (1984, the DS breathing exhibited larger augmentation in ventilation than did C02 inhalation. Furthermore, the present study first demonstrated that sensitivity to C02-stimulation of the regulating system, as judged by the slope of C02-ventilation response, was significantly higher in the DS breathing than in C02 inhalation when PETo 2 was concomitantly decreased.…”

Section: Discussionsupporting

confidence: 80%

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Comparison of ventilatory response between dead space and CO2 breathing in humans.

et al. 1988

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Ventilatory response during external dead space (tube) breathing and C02 inhalation for given increase in PETco2 were compared at different levels of PETo2 (hyperoxia, normoxia, and hypoxia) in human subjects. At all the PETo2 levels studied, magnitude of increment in minute ventilation (VE) and tidal volume were larger in the dead space breathing than in the C02 inhalation. The slope of C02-ventilation response line was significantly steeper in the dead space breathing only in the hypoxic condition. There was no significant difference in frequency response to C02 between the two methods. These results suggested that augmented ventilatory response to C02 in the dead space breathing occurs in the condition of peripheral chemoreceptor activation.

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Section: Discussionsupporting

confidence: 80%

“…A second possibility is that activity of the peripheral chemoreceptors is characteristically stimulated in such a manner that potentiation of afferent drives from three receptors may be exceeded in tube breathing than in C02 inhalation (GooDE et al, 1969;CUNNINGHAM et al, 1973).…”

mentioning

confidence: 99%

Comparison of ventilatory response between dead space and CO2 breathing in humans.

et al. 1988

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“…FENNER et al (1968) andGOODE et al (1969) reported that enhanced ventilatory response to C02 with tube breathing took place in normoxia or when accompanied by hypoxia. In hypoxia, the relationship between VT and the respiratory rate is a matter of con-.…”

Section: Discussionmentioning

confidence: 99%

An assessment of overall open-loop "gain" of CO2-ventilation feedback control system in hypoxia.

1985

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Overall open-loop gain of the CO2-ventilation feedback control system in hypoxia (GHco2) was determined on 8 male and one female healthy subjects. They breathed in a closed circuit, and were subjected to the progressive hypoxia test. This procedure was first conducted without dead space (DS), then with 250, 500, and finally 750 ml DS, consecutively. GHC02 was calculated by dividing the slope of the CO2 response curve (S) by that of the metabolic hyperbola (SL). GHco2 was considerably larger than the overall open-loop gain of the 02-ventilation feedback control system (Go2) previously obtained. This was ascribed to the facts that S was larger than the slope of the hypoxia response curve, and that the absolute value of SL in GHco 2 was smaller than that in G02. SEVERINGHAUS (1972) was the first to present the concept of the overall gain of the C02-feedback control system. The same idea was also proposed as the open-loop gain by MILHORN (1966). The concept of overall gain corresponds to that of open-loop gain. In the present study, we defined the overall open-loop gain as GHco2 (defined as overall gain in our previous study) by dividing the slope of the CO2-ventilation response line (S) by the slope of the metabolic hyperbola (SL) at a given end-tidal Pco2 (PETco2). When a disturbance is introduced into the system in order to change PETco2 by 4PETco2, the final change in PETC02 will be reduced to 4PETc o 2/(l + GHc o 2).In the previous communication (MASUYAMA et al., 1983), overall open-loop gain of the 02-ventilation feedback control system was evaluated and compared with that of the C02-ventilation feedback control system in normoxia. The latter was found to exceed the former, suggesting the predominant role of CO2 in the control of ventilation. However, it is known that CO2 sensitivity in regulation of respiration is affected by the presence of hypoxia (NIELSEN and SMITH, 1951).To assess the actual significance in the feedback control system in hypoxia, both

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“…Accordingly, SL' was slightly less in the DS than in the control run. FENNER et al (1968) andGOODE et al (1969) observed that enhanced ventilatory response to C02 with tube breathing took place in normoxia or when accompanied by hypoxia. This fact was thought to be ascribed to the peculiar timepattern of the Pco2 signal which possibly influenced the arterial chemoreceptors.…”

Section: Discussionmentioning

confidence: 99%

An assessment of overall "gain" of the O2-feedback control system with and without external dead space breathing.

Masuyama¹,

Hayashi²,

Honda³

1983

Jpn.J.Physiol

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Overall gain of the 02-ventilation feedback control system (G02) was determined in 9 male and one female healthy subjects. G02 progressively increased with decreasing end-tidal P02 (PETo 2). This value did not exceed the overall gain of the C02-ventilation feedback system (G002) even at a PETo 2 level of 40 mmHg, suggesting that hypoxic stimulation did not become predominant in the present experimental condition. With addition of 250 ml of external dead space, PETo 2 decrement (4PETo 2 actual) was experimentally observed. The 4PETo2.actual thus obtained was found to be in good agreement with the PETo 2 decrement deduced from G02 (4PETo 2 • expected). This result was similar to that found in the PETco2 change previously seen in normoxia.

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Respiratory effects of breathing down a tube

Cited by 47 publications

References 19 publications

Comparison of ventilatory response between dead space and CO2 breathing in humans.

Comparison of ventilatory response between dead space and CO2 breathing in humans.

An assessment of overall open-loop "gain" of CO2-ventilation feedback control system in hypoxia.

An assessment of overall "gain" of the O2-feedback control system with and without external dead space breathing.

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