Effects of Injection Site on the Accuracy of Thermal Washout: Discussion (1)
The successive EFs obtained in a washout curve are naturally fluctuating because successive stroke volumes and EFs vary in an actual heart unlike the situation in a mechanical analogue, and hence we consider that calculation of the mean EF from a few successive EFs is reasonable. However, if there were any significant relationships between successive EFs, these would not be caused by physiologic fluctuations, but by artifacts possibly derived from the measurement technique itself. We determined in this experiment that successive EFs were different; moreover, the patterns of difference were not the same between EFs obtained from ventricular injection and those from atrial injection. These findings were also seen in the artificial heart. Another finding was that EFs obtained from ventricular injection were larger than those from atrial injection, and the choice of injection site was a critical issue in this method. Cheap Diskus Advair
Why Did the Serial EFs Differ?
Theoretically, the serial EFs in a washout curve should be the same, and as far as we know, most investigators are calculating the mean value from a few EFs or are considering that the sequence of temperature steps produced by progressive dilution of the indicator is a simple exponential (unction of time.