Hemolysis in pediatric patients receiving centrifugal-pump extracorporeal membrane oxygenation: prevalence, risk factors, and outcomes.

OBJECTIVES

To explore the prevalence and risk factors for hemolysis in children receiving extracorporeal membrane oxygenation and examine the relationship between hemolysis and adverse outcomes.

DESIGN

Retrospective, single-center study.

SETTING

Tertiary PICU.

PATIENTS

Two hundred seven children receiving extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma-free hemoglobin was tested daily and hemolysis was diagnosed based on peak plasma-free hemoglobin as mild (< 0.5 g/L), moderate (0.5-1.0 g/L), or severe (> 1.0 g/L). Gender, age, weight, diagnosis, oxygenator type, cannulation site, mean venous inlet pressure, mean pump speed, mean flow, and visible clots in the extracorporeal membrane oxygenation circuit were entered into the ordered logistic regression model to identify risk factors of hemolysis. Complications and clinical outcomes were compared across four hemolysis groups. Of the 207 patients, 69 patients (33.3%; 95% CI, 27.0-40.2%) did not have hemolysis, 98 patients (47.3%; 95% CI, 40.4-54.4%) had mild hemolysis, 26 patients (12.5%; 95% CI, 8.4-17.9%) had moderate hemolysis, and 14 patients (6.8%; 95% CI, 3.7-11.1%) had severe hemolysis with a median peak plasma-free hemoglobin of 1.51 g/L (1.18-2.05 g/L). The independent risk factors for hemolysis during extracorporeal membrane oxygenation were use of Quadrox D (odds ratio, 7.25; 95% CI, 3.10-16.95; p < 0.001) or Lilliput (odds ratio, 37.32; 95% CI, 8.95-155.56; p < 0.001) oxygenators, mean venous inlet pressure (odds ratio, 0.95; 95% CI, 0.91-0.98; p = 0.002), and mean pump speed (odds ratio, 2.89; 95% CI, 1.36-6.14; p = 0.006). Patients with hemolysis were more likely to experience a longer extracorporeal membrane oxygenation run and require more blood products. After controlling for age, weight, pediatric index of mortality 2, and diagnosis, patients with severe hemolysis were more likely to die in the ICU (odds ratio, 5.93; 95% CI, 1.64-21.43; p = 0.007) and in hospital (odds ratio, 6.34; 95% CI, 1.71-23.54; p = 0.006).

CONCLUSIONS

Hemolysis during extracorporeal membrane oxygenation with centrifugal pumps was common and associated with a number of adverse outcomes. Risk factors for hemolysis included oxygenator types, mean venous inlet pressure, and mean pump speed. Further studies are warranted comparing pump types while controlling both physical and nonphysical confounders.