The Annals of Thoracic Surgery, Vol 32, 506-509, Copyright © 1981 by The Society of Thoracic Surgeons
Accuracy in coronary graft flow measurement
JM Moran, DW Burke, JM Loeb, AJ Roberts, JH Sanders Jr and LL Michaelis
A blood flow calibration apparatus is described for use with
electromagnetic flow probes. It is an automatic gravity-flow system, which
provides a constant level and therefore constant flow at any preset rate.
On several occasions, the use of this device has helped to determine
whether flow probes require simple adjustment, factory repair, or
replacement. Using this system, a systematic error in the manufacturer's
"precalibration" averaging +22% (range, 9 to 50%) has been discovered, and
appropriate corrections have been made. The accuracy of these corrections
has been confirmed by a rapid, in vivo method of calibration, which also is
described and which can be carried out during the conduct of aortocoronary
bypass operation. It is recommended that all groups measuring coronary
graft flow become familiar with their electromagnetic flowmeter and probes
by means such as those described, in the interest of accurate flow
measurement after bypass operation.