Abstract
Several methods are available for measuring the circulation time from the antecubital veins through the pulmonary bed to the capillaries of the systemic circuit. One method is the decholin method proposed by Winternitz, Deutsch, and Bruell, 1 and recently studied by Tarr, Oppenheimer and Sager. 2 Another is described by Fishberg, Hitzig, and King, 3 in which saccharin injected into an antecubital vein is detected in the tongue. No method has been devised clinically applicable for measuring circulation time from the peripheral veins to the capillaries of the lung. This may be obtained by introducing ether into an antecubital vein and determining the time that elapses before the patient perceives its odor. Ether is peculiarly adapted to this purpose because: 1. Its volatility at blood temperature is so great that when a small quantity is injected, a sufficient amount volatilizes in the pulmonary capillaries during the first circuit of the blood to be invariably perceptible by smell. 2. The small volume needed permits rapid intravenous introduction, the advantage of this being that it will flow in a small blood volume, resulting in a sharp definition of both the time of injection and the time of arrival in the pulmonary capillaries. 3. It is harmless in the quantities used. In over 200 injections, no untoward constitutional reactions were encountered. The subject is usually aware of a “creeping” feeling along the course of the vein. About 25% of the patients complain of transient pain in this location. In 28 cases in which the veins were carefully followed, thrombosis developed on 3 occasions. Paravenous infiltration causes no necrosis. In many instances, the measurement was carried out 2 and even 3 times within a few minutes without causing unpleasant reactions. 4. Because of its volatility, the measurement can be repeated as soon as desired.
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