Correction for apparent prolongation of mean transit time resulting from response time in a thermodilution system
| Autor: | Michio Arakawa, F. Ando, Tomoo Kawada, Kenjiro Kambara, T. Segawa, Hidetaka Miyazaki |
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| Rok vydání: | 1993 |
| Předmět: |
medicine.medical_specialty
Time Factors Materials science Constant flow Thermodilution Dye Dilution Technique Models Cardiovascular Biomedical Engineering Prolongation Mean and predicted response Hemodynamics Response time Transit time Mean transit time Surgery Bias Evaluation Studies as Topic Extravascular Lung Water Reaction Time medicine Mathematical Computing Mixing chamber Biomedical engineering |
| Zdroj: | IEEE Transactions on Biomedical Engineering. 40:1-7 |
| ISSN: | 0018-9294 |
| Popis: | We investigated a method of correcting an apparent prolongation in the measured mean transit time (MTT), resulting from the response time of the thermodilution system. We measured the mean response times (MRT) for five commercially available thermistor-tipped catheters by recording their step function response curves. MRT is the sum of the time from the point of step change to the point of the first detection of change in temperature (latency time) plus the time from the first detection to the point of 63.2% of full response (time constant). By using a flow loop model filled with saline through a mixing chamber, we recorded pairs of thermodilution curves simultaneously with pairs of catheters, and studied the influence of MRT on MTT over the constant flow rates of 1-6 L/min. The difference in MRT's (delta MRT, second) between a pair of thermodilution systems correlated with the difference in MTT's (delta MTT, second) between a corresponding pair of thermodilution curves, yielding an equation: delta MTT = 1.07 delta MRT = 0.04 (n = 72, r = 0.95), delta MTT/delta MRT = 1.02 +/- 0.18 (mean +/- SD). We conclude that an apparent prolongation of MTT due to response time is removable by subtracting MRT from measured MTT. |
| Databáze: | OpenAIRE |
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