Control of heparinisation during cardiopulmonary bypass. Experience with the activated clotting time method.

A rational approach to the control of heparinisation during open heart surgery is advocated. Some of the possible and potential shortcomings of the time-based heparin protocols in current use are presented. The use of a recent, simple automated device 'Hemochron' to estimate the Activated Clotting Time is described and it is found to be an economical and efficient method to monitor heparinisation during cardiopulmonary bypass.