Factors associated with outcomes of patients on extracorporeal membrane oxygenation support: a 5-year cohort study

Abstract

Introduction: Mortality of patients on extracorporeal membrane oxygenation (ECMO) remains high. The objectives of this study were to assess the factors associated with outcome of patients undergoing ECMO in a large ECMO referral centre and to compare veno-arterial ECMO (VA ECMO) with veno-venous ECMO (VV ECMO).

Methods: We reviewed a prospectively obtained ECMO database and patients' medical records between January 2005 and June 2011. Demographic characteristics, illness severity at admission, ECMO indication, organ failure scores before ECMO and the ECMO mode and configuration were recorded. Bleeding, neurological, vascular and infectious complications that occurred on ECMO were also collected. Demographic, illness, ECMO support descriptors and complications associated with hospital mortality were analysed.

Results: ECMO was initiated 158 times in 151 patients. VA ECMO (66.5%) was twice as common as VV ECMO (33.5%) with a median duration significantly shorter than for VV ECMO (7 days (first and third quartiles: 5; 10 days) versus 10 days (first and third quartiles: 6; 16 days)). The most frequent complications during ECMO support were bleeding and bloodstream infections regardless of ECMO type. More than 70% of the ECMO episodes were successfully weaned in each ECMO group. The overall mortality was 37.3% (37.1% for the patients who underwent VA ECMO, and 37.7% for the patients who underwent VV ECMO). Haemorrhagic events, assessed by the total of red blood cell units received during ECMO, were associated with hospital mortality for both ECMO types.

Conclusions: Among neurologic, vascular, infectious and bleeding events that occurred on ECMO, bleeding was the most frequent and had a significant impact on mortality. Further studies are needed to better investigate bleeding and coagulopathy in these patients. Interventions that reduce these complications may improve outcome.

Figure 1

Primary indications of the 158 extracorporeal membrane oxygenation (ECMO) procedures. AMI, acute myocardial infarction; ARDS, acute respiratory distress syndrome; CABG, coronary artery bypass surgery; CM/FM, cardiomyopathy/myocarditis; PE, pulmonary emboli; Tx, transplantation.

Figure 2

Comparison of the number of red blood cell (RBC) units transfused during extracorporeal membrane oxygenation (ECMO) procedures between survivors and non-survivors in different types of ECMO. VA ECMO, veno-arterial ECMO; VV ECMO, veno-venous ECMO.