Respiration physiology
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Respiration physiology · May 1985
Transient PO2 and PCO2 differences between end-tidal gas and arterial blood during rebreathing in awake dogs.
O2 and CO2 partial pressures in end-tidal gas (PA) and carotid artery blood (Pa) were measured during non-steady-state gas exchange in unanesthetized dogs. In 5 experiments (A), low O2 breathing in open circuit preceded prolonged rebreathing during maintained normoxia. ⋯ This behavior of (PA-Pa)O2 could be explained by a lung model with unequal distribution of alveolar ventilation and perfusion to alveolar volume. The negative (Pa-PA)CO2 values observed during rebreathing with rapidly increasing PACO2 were in part attributable to such unequal distribution effects, in part to lung-to-carotid artery transit time effects.