Does pulmonary air embolism affect the pulsatility of pulmonary capillary blood flow in dogs?
Iwao, Y.; Masuda, J.; Ochiai, R.; Higa, S.; Takeda, J.; Sekiguchi, H.; Nagano, M.
Nihon Kyobu Shikkan Gakkai Zasshi 29(3): 338-344
1991
ISSN/ISBN: 0301-1542 PMID: 2067154 Document Number: 377733
The difference in the uptake rate through the lungs between nitrous oxide and oxygen has been shown to represent the pulmonary capillary blood flow (.ovrhdot.Qc). The pulsatility of .ovrhdot.Qc, defined as the ratio of maximum .ovrhdot.Qc and mean .ovrhdot.Qc (.ovrhdot.Qc max/Qc), the ratio of .ovrhdot.Qc max and stroke volume (.ovrhdot.Qc max/SV), and the ratio of systolic .ovrhdot.Qc and SV (Vsyst/SV), has been also shown to indicate the pulmonary vasodilation as well as vasoconstriction. We measured .ovrhdot.Qc by means of body plethysmography in dogs with pulmonary air embolism, in order to evaluate its effect on the pulmonary vasculature. Ten adult dogs were anesthetized with pentobarbital and pancuronium, and were mechanically ventilated. A volume of air (0.5 ml/kg) was injected into the central vein. Although there was no significant change in systemic blood pressure, cardiac output, heart rate, and airway pressure after the injection of air, pulmonary arterial pressure and pulmonary vascular resistance increased significantly. Qc, .ovrhdot.Qc max, .ovrhdot.Qc max/Qc, and .ovrhdot.Q max/SV decreased significantly after the air injection. Since these findings suggest that the pulmonary air embolism provoked pulmonary vasoconstribtion, and attenuated the pulsatility of .ovrhdot.Qc, optimal pulmonary vasodilation therapy would be recommended to improve the pulmonary hypertension secondary to pulmonary air embolism.