A New Device for Intraoperative Renal Blood Flow Measurement during Open-Heart Surgery: An Experimental Study and the Clinical Pilot Study

Renal blood flow (RBF) may vary during cardiopulmonary bypass
and low flow may cause insufficient blood supply of the kidney
triggering renal failure postoperatively. Still, a valid intraoperative
method of continuous RBF measurement is not available. A new catheter
combining thermodilution and intravascular Doppler was developed, first
calibrated in an in vitro model, and the catheter specific constant was
determined. Then, application of the device was evaluated in a pilot
study in an adult cardiovascular population. The data of the clinical
pilot study revealed high correlation between the flow velocities
detected by intravascular Doppler and the RBF measured by thermodilution
(Pearson’s correlation range: 0.78 to 0.97). In conclusion, the RBF can
be measured excellently in real time using the new catheter, even under
cardiopulmonary bypass.