Flow velocity profile of the pulmonary artery measured by the continuous cardiac output monitoring catheter.

The KATS catheter (continuous arterial thermodeprivation system catheter) measures the blood flow velocity of the pulmonary artery (PA) by thermodeprivation which enables continuous determination of cardiac output. The accuracy of this system may depend on the degree of uniformity of flow velocity in the PA, because small movements of the catheter within the PA are inevitable with a beating heart. We evaluated the flow velocity profile of the PA in seven anaesthetized open-chest dogs to assess these potential errors. A custom-made stiff catheter, at the tip of which was incorporated the flow velocity sensor of the KATS catheter, was used to penetrate the main PA in the short axis direction (perpendicular to flow direction) or the long axis direction (along flow direction). The stiff catheter was moved in increments of 2.5 mm, and flow velocity was recorded. The wall-to-wall distance of the PA along each direction was divided into five sections (S1 to S5 for the short axis, and L1 to L5 for the long axis). Flow velocity data for each section were averaged and presented as relative values against the control mid-point velocity. Along the short axis, flow velocity was 0.41 +/- 0.20 (SD), 1.00 +/- 0.10, 1.03 +/- 0.10, 1.08 +/- 0.13 and 0.49 +/- 0.26 from S1 to S5, i.e., lower in S1 and S5 which were close to the vascular walls (P < 0.05) but uniform in other areas. Along the long axis, flow velocity was 0.28 +/- 0.28, 0.88 +/- 0.09, 0.94 +/- 0.08, 1.06 +/- 0.25 and 1.28 +/- 0.50 from L1 to L5.(ABSTRACT TRUNCATED AT 250 WORDS)