TY - JOUR
T1 - Quantification of the temperature gradient through a catheter in continuous infusion thermodilution for coronary flow measurements
AU - van de Steeg, Melissa G.M.
AU - van de Vosse, Frans N.
AU - Pijls, Nico H.J.
AU - van 't Veer, Marcel
PY - 2020/7
Y1 - 2020/7
N2 - OBJECTIVE: Quantifying the absolute coronary blood flow can be done using continuous infusion thermodilution requiring a dedicated infusion catheter. Up to now, there has been little insight into the effect of small variabilities in the physical parameters on the temperature gradient along this catheter. The key goal of this study is to develop and validate a computer model that predicts the temperature of the infusion fluid at the infusion site of the infusion catheter. A secondary goal is to gain insight into the influence of physical variations for the individual patient on the calculated blood flow rate. APPROACH: A numerical model of the temperature in the catheter was built using the convection-diffusion equation and validated using an in vitro setup. A sensitivity analysis was performed to investigate the influence of the catheter path inside the body and the temperature of the infusion fluid at different infusion rates. These results were compared to in vivo measurements of 94 patients. Finally, the variation in the computed blood flow rate is estimated considering an average patient, using small variations in the physical parameters. MAIN RESULTS: The computed temperature corresponded well with the in vitro measurements, since a maximal difference of 1.5% was observed. The length of the catheter path inside the body had the most influence on the temperature of the infusion fluid at the infusion site. Moreover, temperatures from the numerical model were similar to the results from in vivo measurements. By varying the length of the catheters with 0.04 m, the largest deviation in the calculated blood flow was 33.3 ml/min. SIGNIFICANCE: Insight is gained into the influence of physical variations on the temperature of the infusion fluid at the infusion site of the catheter using thermodilution. The developed numerical model can possibly be used to reduce time in estimating the blood flow rate.
AB - OBJECTIVE: Quantifying the absolute coronary blood flow can be done using continuous infusion thermodilution requiring a dedicated infusion catheter. Up to now, there has been little insight into the effect of small variabilities in the physical parameters on the temperature gradient along this catheter. The key goal of this study is to develop and validate a computer model that predicts the temperature of the infusion fluid at the infusion site of the infusion catheter. A secondary goal is to gain insight into the influence of physical variations for the individual patient on the calculated blood flow rate. APPROACH: A numerical model of the temperature in the catheter was built using the convection-diffusion equation and validated using an in vitro setup. A sensitivity analysis was performed to investigate the influence of the catheter path inside the body and the temperature of the infusion fluid at different infusion rates. These results were compared to in vivo measurements of 94 patients. Finally, the variation in the computed blood flow rate is estimated considering an average patient, using small variations in the physical parameters. MAIN RESULTS: The computed temperature corresponded well with the in vitro measurements, since a maximal difference of 1.5% was observed. The length of the catheter path inside the body had the most influence on the temperature of the infusion fluid at the infusion site. Moreover, temperatures from the numerical model were similar to the results from in vivo measurements. By varying the length of the catheters with 0.04 m, the largest deviation in the calculated blood flow was 33.3 ml/min. SIGNIFICANCE: Insight is gained into the influence of physical variations on the temperature of the infusion fluid at the infusion site of the catheter using thermodilution. The developed numerical model can possibly be used to reduce time in estimating the blood flow rate.
KW - coronary blood flow
KW - convection-diffusion equation
KW - thermodilution
KW - sensitivity analysis
KW - numerical discretisation
UR - http://www.scopus.com/inward/record.url?scp=85089424753&partnerID=8YFLogxK
U2 - 10.1088/1361-6579/ab979d
DO - 10.1088/1361-6579/ab979d
M3 - Article
C2 - 32464612
AN - SCOPUS:85089424753
SN - 0967-3334
VL - 41
JO - Physiological Measurement
JF - Physiological Measurement
IS - 7
M1 - 075006
ER -