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Inspiratory gas flow induced by cardiac systole
H J Colebatch1, C K Ng, F J Maccioni
1Department of Medicine, University of New South Wales, Prince Henry Hospital, Australia.
Respiration Physiology
|August 1, 1996
Summary
Cardiac systole generates an inspiratory gas flow pulse during breathing. This study quantifies this pulse, revealing its timing, peak flow, and volume in healthy adults, offering insights into respiratory mechanics.
Area of Science:
- Physiology
- Respiratory Mechanics
- Cardiopulmonary Interactions
Background:
- Cardiac systole is known to influence intrathoracic pressure.
- The direct quantification of the resulting inspiratory gas flow pulse is not well-established.
- Understanding this phenomenon is crucial for respiratory physiology.
Purpose of the Study:
- To quantify the inspiratory gas flow pulse generated by cardiac systole.
- To determine the timing, duration, peak flow, and volume of this pulse.
- To estimate the intrathoracic pressure changes associated with the pulse.
Main Methods:
- Ten adult subjects (9 male, 1 female; age 24-65) were studied.
- Inspiratory flow was measured using a mouthpiece or nasal mask.
- External airway resistance was applied to estimate intrathoracic pressure.
Main Results:
- The inspiratory flow pulse began 50-60 ms after the ECG R wave and lasted 106 ms.
- Peak flow reached 120 ml/sec with a displaced volume of 6.6 ml.
- The effective intrathoracic pressure was estimated at -0.21 cm H2O.
Conclusions:
- Cardiac systole produces a measurable inspiratory gas flow pulse.
- This pulse is a consistent physiological event with quantifiable characteristics.
- Further research is needed to understand its contribution to gas exchange.