<i>Oxygen Cost of Breathing</i>

Bartlett, R. G.; Brubach, H. F.; Specht, H.

doi:10.1152/jappl.1958.12.3.413

Cited by 72 publications

(24 citation statements)

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“…We also calculated the respiratory muscle oxygen consumption from changes in total body oxygen consumption during each increment in work load (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) in these same animals (Table VI): The total body oxygen consumption at resting ventilation is subtracted from total body oxygen consumption at increased work of breathing, and the difference is assumed to be due to the increased oxygen consumption in respiratory muscles necessary for the increased work of breathing (difference between resting work and increased work).…”

Section: Resultsmentioning

confidence: 99%

“…Seven healthy mongrel dogs weighing [16][17][18][19][20][21][22][23][24][25][26][27] kg were anesthetized with sodium pentobarbital 25 mg/kg intravenously; small increments were given subsequently to sustain adequate anesthesia but maintain the comeal reflex. A tracheostomy was performed and the tracheostomy tube connected to a one-way Otis-McKerrow valve.…”

Section: Methodsmentioning

confidence: 99%

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The relationship of respiratory failure to the oxygen consumption of, lactate production by, and distribution of blood flow among respiratory muscles during increasing inspiratory resistance.

Robertson¹,

Foster²,

Johnson³

1977

J. Clin. Invest.

170

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A B S T R A C T An animal model was developed to determine if blood flow to the respiratory muscles limits oxygen delivery and thus work output during inspiratory resistance. With incremental increases in the rate of work of breathing to 15 times the resting level, blood flow to the diaphragm rose exponentially 26-fold. Blood flow to other inspiratory and a few expiratory muscles increased to a much smaller extent, often only at the greater work loads. Cardiac output and blood pressure did not change. Arterial-venous oxygen content difference across the diaphragm became maximal at low work rates and thereafter all increases in oxygen delivery during higher work rates were accomplished by increments in blood flow. Oxygen consumption of the respiratory musculature calculated by blood flow times oxygen extraction increased exponentially with increasing work of breathing and was less than the increase in total body oxygen consumption at each work load. Hypoxemia and respiratory acidosis occurred when the animals inspired through the highest resistance; blood flow and oxygen consumption were even higher than that observed during previous resistances and there was no evidence of a shift to anaerobic metabolism in blood lactate and pyruvate levels. Respiratory failure did not appear to be a consequence of insufficient blood flow in this model.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The relationship of respiratory failure to the oxygen consumption of, lactate production by, and distribution of blood flow among respiratory muscles during increasing inspiratory resistance.

Robertson¹,

Foster²,

Johnson³

1977

J. Clin. Invest.

170

View full text Add to dashboard Cite

show abstract

“…The lines describing these slopes, although parallel, do not meet when projected through the period of increased respiratory work but are separated by a distance equivalent to the additional oxygen consumed by the increased work (6,7). When the oxygen consumption of the second control period differs from the first, the lines describing each are not parallel and the distance between them can no longer be used to determine the increase of oxygen uptake during the period of increased respiratory work.…”

Section: Methodsmentioning

confidence: 99%

“…The efficiency of the combined chest and lung for external resistance work, assessed in three studies (6,7,10), gave results of 1 to 10 per cent. In two studies (8,9), respiratory mechanical work estimates during unobstructed hyperventilation were derived from the area of loops obtained by plotting esophageal pressure against respiratory volume, as in the present study.…”

Section: Fig 3 the Relationship Of Oxygen Cost To Respiratory Mechamentioning

confidence: 99%

The Relationship of Oxygen Cost of Breathing to Respiratory Mechanical Work and Respiratory Force

McGregor¹,

Becklake²

1961

J. Clin. Invest.

169

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“…Liljestrand (19) showed that activation of the normal control processes was essential for reproducible measurement of the oxygen cost of breathing, with voluntary hyperventilation leading to unreliable measurements because of inefficient activation of respiratory and other muscles. Errors in the measurement of the oxygen cost of breathing historically have been a matter of concern (20)(21)(22)(23)(24)(25). Reliability has been an issue because with the hyperventilation of ventilatory loading, the inspired to expired oxygen difference is small; errors in the measurement of FEO2 lead to large errors in calculated oxygen consumption.…”

Section: Discussionmentioning

confidence: 99%

Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

Casán

Villafranca

Kearon

et al. 1997

Canadian Respiratory Journal

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During exercise, the sustainable activity of large muscle groups is limited by oxygen delivery. The purpose of this study was to see whether the oxygen consumption of the respiratory muscles reaches a similar critical value under maximal resistive loading and hyperventilation. A secondary objective was to see whether dyspnea (estimated discomfort experienced with breathing using the Borg 0-10 scale) and the oxygen consumption of the respiratory muscles are closely related across conditions. This would be expected if intramuscular sensory nerve fibres stimulated as a consequence of metabolic events contributed to this sensation. In six normal subjects the respiratory muscles were progressively activated by the addition of incremental inspiratory resistive loads to a maximum of 300 cm H20×s/L (SD=66.4), and incremental dead space to a maximum of 2638 mL (SD=452), associated with an increase in ventilation to 75.1 L/min (SD=29.79). Each increment was maintained for 5 mins to allow the measurement of oxygen uptake in a steady state. During resistive loading total oxygen consumption increased from 239 mL/min (SD=38.2) to 299 mL/min (SD=52.3) and dyspnea increased to 'very severe' (Borg scale 7.5, SD=1.55). During dead space loading total oxygen consumption increased from 270 mL/min (SD=20.2) to 426 mL/min (SD=81.9) and dyspnea increased to 'very severe' (7.1, SD=0.66). Oxygen cost of inspiratory muscle power was 25 mL/watt (95% confidence limits 16.7 to 34.3) with dead space loading and 91 mL/watt (95% confidence limits 54 to 128) with resistive loading. Oxygen consumption did not reach a critical common value in the two types of loading, 60 mL/min (SD 22.3) during maximal resistive loading and 156 mL/min (SD 82.4) during maximal dead space loading (P<0.05). Physiological factors limiting the respiratory muscles are not uniquely related to oxygen consumption and appear to be expressed through the activation of sensory structures, perceptually manifested as dyspnea.

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Oxygen Cost of Breathing

Cited by 72 publications

References 0 publications

The relationship of respiratory failure to the oxygen consumption of, lactate production by, and distribution of blood flow among respiratory muscles during increasing inspiratory resistance.

The relationship of respiratory failure to the oxygen consumption of, lactate production by, and distribution of blood flow among respiratory muscles during increasing inspiratory resistance.

The Relationship of Oxygen Cost of Breathing to Respiratory Mechanical Work and Respiratory Force

Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

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