Hand-Held Personal Digital Assistant Program for the HEMOCHRON® RxDx® Heparin and Protamine Dosing System

Abstract

The use of in vitro dosing assays for heparin and protamine during cardiac surgery has significantly improved overall postoperative patient outcome. The HEMOCHRON® RxDx® system (International Technidyne Corp, Edison, NJ) is widely used for anticoagulation management. Based on a series of consecutive in vitro tests, the RxDx system is used to quantify the patient's heparin requirement (heparin response test, HRT), measure the activated clotting time (ACT), calculate the blood heparin concentration and the required protamine dose (protamine response test, PRT), as well as determine the efficacy of heparin reversal (protamine dose assay, PDA-O). A hand-held personal digital assistant (PDA) program has been developed that performs the RxDx calculations used for anticoagulation management during cardiac surgery. The Palm™ m505 hand-held device (Palm, Inc., Santa Clara, CA) is used in concert with any standard Hemochron blood coagulation system. The Palm m505 device has been programmed to perform all the calculations required for the RxDx test system. Patient's body weight, height, and gender are entered into the program using the on-screen keypad and the template provided in the Hemochron program. The calculator automatically provides the patient's blood volume and the recommended heparin dose upon entering the baseline ACT and HRT values and a target ACT. At the end of the case, the optimal protamine dose is determined, and the total heparin level is calculated and displayed upon entry of ACT and PRT clotting times. Following protamine administration, the program calculates any additional protamine required to neutralize residual heparin using the data from a PDA-O test. The RxDx hand-held PDA is accurate, quick, simple, and easy to use, patient data are saved and can be retrieved. The inclusion of this rapid computing technology into the Hemochron RxDx system serves to expand the applications of the Hemochron RxDx system during cardiac interventions.