An Improved Thermal Dilution Method for Measuring Jugular Venous Flow

The local thermal dilution method of performing serial bilateral measurements of internal jugular venous flow is significantly improved by injecting a bolus of saline rather than by using a continuous injection of saline. New thermistor catheter designs maintain the proper separation between the sites of injection and of sampling and require only a single insertion per side. The method measures mean flow rates over a two-second to three-second interval. Measurements were made in 14 patients with cerebrovascular disease. Studies of five patients are presented to illustrate the value of the method for assessing internal jugular venous hemodynamics. Positive response to injection of acetazolamide was noted in four of these five patients. Cyclic variations in jugular flow were observed in one patient with Cheyne-Stokes respiration. Occasional retrograde flow in one jugular vein was recorded in another patient.