J. A. Bernards

Effects of pulmonary gas embolism on circulation and respiration in the dog

SummaryMongrel dogs weighing 15–25 kg and anesthetized with thiopental-gamma-hydroxybutyric acid were used to investigate the effects of pulmonary gas embolism on pulmonary arterial pressure (Pap), systemic arterial pressure (Pa) and cardiac output (

Capnostat and oxystat. Electronic devices to automatically maintain the end-tidal\(P_{CO_2 } \) and\(P_{O_2 } \) of a subject connected to a closed respiratory circuit at adjustable levels

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Ventilation estimated from efferent phrenic nerve activity in the paralysed cat

). Pulmonary gas embolism was produced either by venous injection or by venous infusion. The most marked effect of pulmonary gas embolism on circulation was an increase inPap which returned to the original level after stopping the gas administration. 1.After gas injectionPap rose to a maximum within 30\2-60 s. The extent of this rise inPap showed a positive correlation with the volume of the injected gas. The kind of gas (oxygen, helium, neon, nitrogen, air), however, did not influence the extent of the rise inPap, but did influence the time of return ofPap to the original level. Carbon dioxide showed an exceptional behavior in that it had almost no effect onPap at all.Pa hardly changed with the volume of the gas injections (20\2-60 ml injected within 1 s);

The role of the fusimotor system with respect to the contribution of the diaphragm and the intercostal muscles to the respiratory tidal volume

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Effects of pulmonary gas embolism on circulation and respiration in the dog. V. Effect of changing breathing gas composition on pulmonary gas embolization.

was not measured after gas injections (the direct Fick method is not usable in this situation).2.Gas infusion caused a slow rise ofPap, its steep-ness and extent depending on the rate of infusion and on the physical properties of the infused gas. When the right ventricle was able to maintain its output, a constant level ofPap was reached after 10\2-15 min. In this circulatory steady statePap appeared to be a measure of the degree of embolization. However, this relationship no longer held when the right ventricle failed as evidenced by a fall inPap,Pa and