Heparin infusion and haemorrhagic complications in patients treated with modified Blalock-Taussig shunt: significance of a nurse and medical audit

The modified Blalock-Taussig shunt is a surgical option in cyanotic patients. In our Institute heparin infusion therapy in the early postoperative period is used to reduce the risk of shunt thrombosis. This may produce haemorrhagic complications. Herein we describe the effect of a multidisciplinary audit to reduce the risk of haemorrhagic complications. Between January 2005 and December 2009, 49 patients received a modified Blalock-Taussig shunt and anticoagulation therapy until the second administration of an antiplatelet drug. Four patients (8.1%) experienced a haemorrhagic event. A multidisciplinary audit was organized to analyze our anticoagulation protocol. The cohort of patients was divided into group 1 and 2: patients without and with haemorrhagic events respectively. Group 2 was characterized by a low level of anticoagulation in the first postoperative day and received a dose of antithrombin III and an increase in heparin infusion. The result was excessive anticoagulation, evidenced by a significant increase in the aPTT from 44 to 138 sec (in Group 1: from 88 to 54 sec). Retrospectively the nursing staff found that these patients presented clinical signs heralding more significant bleeding. The clinical audit depicted a difference between the two groups. Group 2 was initially characterized by heparin resistance and was consequently treated. The nursing staff found that retrospectively there were clinical signs heralding bleeding and created a risk score. Finally the analysis of this data produced a change in the institutional anticoagulation protocol and created a medical and nursing combined protocol for postoperative anticoagulation screening. Since then, the haemorrhagic complications have been reduced significantly.