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The effect of using a heparin-free flush system for central venous and pulmonary artery catheters on a general medical and surgical intensive care unit

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Heparin flush systems prevent thrombus formation on invasive monitoring devices. Unfractionated heparin increases the risk of thrombocytopenia, and drug interactions in lines. Low dose heparin, given to most patients on the unit to prevent deep vein thrombosis (DVT), decreases thrombus formation on central venous catheters (CVC). Pulmonary artery catheters (PAC) can be maintained with non-heparinised solutions but evidence for arterial lines is conflicting. Due to the high incidence of thrombocytopenia in our patients and the routine use of low molecular weight heparin to prevent DVT, we decided to investigate the use of a heparin-free flush system.


The study took place over two 4 week periods: one of heparin-free flush and one using a heparin flush. All patients on the unit were recruited into the study. Line care was according to unit practice. Duration of catheter patency and complications were recorded. Results were analysed using Chi squared and Fisher exact 2 tailed tests.


The numbers of catheters in each group were: (see Table 1)

The numbers of thrombus associated problems were: (see Table 2)

There was no statistical difference in the thrombus-associated complication rates between the two groups.


This study demonstrated that the removal of heparin from the flush systems of invasive monitoring lines does not lead to an increase in thrombus-associated complications, prevents the exposure to the risks of unfractionated heparin, which include thrombocytopenia and drug interactions, thereby improving patient care.

Table 1
Table 2

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  • Heparin
  • Thrombocytopenia
  • Deep Vein Thrombosis
  • Central Venous Catheter
  • Thrombus Formation