I am thankful for the opportunity to comment on the interesting letter from Dr. Pivalizza and Dr. Warters. They, too, have demonstrated that aprotinin affects the thromboelastograph trace even when kaolin is used as the activator. We did not mention their work in our article as our submission to Anesthesiology preceded their abstract. Unlike our results, they have not noted a difference in the R times and maximum amplitudes with celite and kaolin activation. This may relate to the concentrations of these activators. As the kaolin and celite concentrations are increased, there is a decrease in the R times and a slight increase in the maximum amplitudes of the thromboelastograph traces. We used 37 μl of 1% kaolin and 1% celite solutions per milliliter of blood. Perhaps the kaolin or celite concentration used by Dr. Pivalizza and Dr. Waters was different. This illustrates one of the potential problems with near patient tests, such as thromboelastography. It is difficult to assure quality control and to standardize results among centers.
Michael S. Avidan, F.C.A.S.A.
© 2002 American Society of Anesthesiologists, Inc.