Alveolar to arterial transmission of oxygen fluctuations due to respiration in anesthetized dogs

Summary The amplitudes of respiratory oxygen fluctuations in the alveoli obtained by calculation were compared with those of the arterial blood measured by a catheterP _{O 2} electrode in vivo in anesthetized and artificially ventilated dogs. It is shown that there is a significant correlation between them in general in bothP _{O 2} andS _{O 2} though the latter correlates better. Amplitude ratio of arterial to alveolar O₂ fluctuations was calculated from two factors, i.e., dispersion of circulation time in the pulmonary vein and mixing in the left heart. The results of calculation agree satisfactorily with those obtained experimentally. The reduction of the amplitude of respiratory fluctuations of oxygen seems to be quite small in the aorta.