A comparison of low and standard anti-coagulation regimens in extracorporeal membrane oxygenation

Abstract

Background: Bleeding and need for blood products are major complications associated with extracorporeal membrane oxygenation (ECMO) use. This study evaluated bleeding complications with low and standard heparinization protocols in the maintenance of venoarterial (VA)-ECMO.

Methods: A retrospective comparison was performed of 2 methods of heparinization in a contemporaneous series of adult patients supported with VA-ECMO at Rush University Medical Center, between November 2011 and November 2016. CentriMag (Thoratec, Pleasanton, CA) pumps, Quadrox (Maquet, Wayne, NJ) oxygenators, and heparin-bonded circuitry were used in all patients. Group 1 was a control group of 50 patients who had ECMO support with an initiation dose of 5,000 U of heparin, followed by standard heparinization at a goal activated clotting time of 180 to 220 seconds. Group 2 comprised 52 adult patients supported with a "low heparin protocol" ECMO, receiving a standard heparin bolus of 5,000 U for cannulation but without subsequent, ongoing heparin administration. Acuity of illness was similar in both groups as assessed by the Mortality Probability Model (59% in Group 1 vs 62.9% in Group 2, p = 0.08). Data were submitted to the Extracorporeal Life Support Organization prospectively. Clots in the circuit, limb ischemia, oxygenator failure, and embolic complications were recorded.

Results: Weaning off ECMO was successful in 26 patients (50%) in Group 2 compared with 18 (36%) in Group 1 (p = 0.05). Hemorrhage from the cannulation site occurred in 11 (21%) in Group 2 vs 21 (42%) in Group 1 and from the surgical site in 11 (21%) in Group 2 vs 18 (36%) in Group 1. Severe bleeding complications were higher in the control group (Group 1, 32%) compared with Group 2 (11.5%; p = 0.012).

Conclusions: Maintenance with low heparin is safe in patients supported by VA-ECMO. This strategy may reduce risk of severe bleeding and associated complications.

Keywords: ECMO; anti-coagulation; bleeding complications; low heparin; thromboembolic complications.