A new method for measuring venous blood flow with the aid of an electromagnetic flowmeter.

Using a silicone elastometer sheath, wrapped around the portal vein, with an external probe for electromagnetic flowmetry, and with the aid of an outside depression, the authors succeeded in measuring portal vein blood flow with great precision, both under normal conditions and during vasoconstriction induced by drug administration. The above system allows variations synchronous with respiration and cardiac contractions to be seen. The reproducibility of a "no flow" point further enables registrations to be continued for hours for physiological and pharmacological studies. The sheath probe system described for the registration of portal vein blood flow is applicable to all other veins.