TY - JOUR
T1 - Continuous infusion thermodilution for assessment of coronary flow: Theoretical background and in vitro validation
AU - Veer, van 't, M.
AU - Geven, M.C.F.
AU - Rutten, M.C.M.
AU - Horst, van der, A.
AU - Aarnoudse, W.H.
AU - Pijls, N.H.J.
AU - Vosse, van de, F.N.
PY - 2009
Y1 - 2009
N2 - Direct volumetric assessment of coronary flow during cardiac catheterization has not been available so far. In the current study continuous infusion thermodilution, a method based on continuous infusion of saline into a selective coronary artery is evaluated. Theoretically, volumetric flow can be calculated from the known infusion rate (Qi), the temperatures of the blood (Tb), the saline (Ti), and the mixture downstream to the infusion site (T). We aimed to validate and optimize the measurement method in an in vitro model of the coronary circulation. Full mixing of infusate and blood was found to be the main prerequisite for accurate determination of the coronary flow. To achieve full mixing the influence of catheter design, infusion rate, and location of temperature measurement were assessed. We found that continuous infusion thermodilution slightly overestimated coronary flow determined by directly measured reference flow by 7 ± 8%, over the entire physiological flow range of 50-250 ml/min. These results were found using a specially designed infusion catheter (infusion mainly through distally located sideholes), a high enough infusion rate (25 ml/min), and measurement of the mixing temperature between 5 and 8 cm distal from the tip of the infusion catheter. Absolute coronary flow rate can be measured reliably by the continuous infusion method when full mixing is present, under the conditions mentioned above. © 2009 IPEM.
AB - Direct volumetric assessment of coronary flow during cardiac catheterization has not been available so far. In the current study continuous infusion thermodilution, a method based on continuous infusion of saline into a selective coronary artery is evaluated. Theoretically, volumetric flow can be calculated from the known infusion rate (Qi), the temperatures of the blood (Tb), the saline (Ti), and the mixture downstream to the infusion site (T). We aimed to validate and optimize the measurement method in an in vitro model of the coronary circulation. Full mixing of infusate and blood was found to be the main prerequisite for accurate determination of the coronary flow. To achieve full mixing the influence of catheter design, infusion rate, and location of temperature measurement were assessed. We found that continuous infusion thermodilution slightly overestimated coronary flow determined by directly measured reference flow by 7 ± 8%, over the entire physiological flow range of 50-250 ml/min. These results were found using a specially designed infusion catheter (infusion mainly through distally located sideholes), a high enough infusion rate (25 ml/min), and measurement of the mixing temperature between 5 and 8 cm distal from the tip of the infusion catheter. Absolute coronary flow rate can be measured reliably by the continuous infusion method when full mixing is present, under the conditions mentioned above. © 2009 IPEM.
U2 - 10.1016/j.medengphy.2009.01.006
DO - 10.1016/j.medengphy.2009.01.006
M3 - Article
C2 - 19237308
SN - 1350-4533
VL - 31
SP - 688
EP - 694
JO - Medical Engineering & Physics
JF - Medical Engineering & Physics
IS - 6
ER -