Usefulness of routine laboratory parameters in the decision to treat refractory cardiac arrest with extracorporeal life support.

Aim: To evaluate the usefulness of routine laboratory parameters in the decision to treat refractory cardiac arrest patients with extracorporeal life support (ECLS).

Methods: Sixty-six adults with witnessed cardiac arrest of cardiac origin unrelated to poisoning or hypothermia undergoing cardiopulmonary resuscitation without return of spontaneous circulation (duration: 155 min [120-180], median, [25-75%-percentiles]) were included in a prospective cohort-study. ECLS was implemented under cardiac massage, using a centrifugal pump connected to a hollow-fiber membrane-oxygenator, aiming to maintain ECLS flow ≥ 2.5 l/min and mean arterial pressure ≥ 60 mm Hg.

Results: Forty-seven of 66 patients died within 24 h from multiorgan failure and massive capillary leak. Of 19/66 patients who survived ≥ 24 h with stable circulatory conditions permitting neurological evaluation, four became conscious and were transferred for further cardiac assistance, while three became organ donors. Ultimately, one patient survived without neurologic sequelae after cardiac transplantation. Using multivariate analysis, only pre-cannulation peripheral venous oxygen saturation (SpvO₂, 28% [15-52]) independently predicted inability to maintain targeted ECLS conditions ≥ 24 h (odds ratio for each 10%-decrease [95%-confidence interval]: 1.65 [1.21; 2.25], p=0.002). The area under the receiver-operating-characteristics curve was 0.78 [0.63; 0.93]. SpvO₂ cut-off value of 33% was associated with a sensitivity of 0.68 [0.50; 0.83] and specificity of 0.81 [0.54; 0.96]. SpvO₂ ≤ 8%, lactate concentration ≥ 21 mmol/l, fibrinogen ≤ 0.8 g/l, and prothrombin index ≤ 11% predicted premature ECLS discontinuation with a specificity of 1.

Conclusion: SpvO₂ is useful to predict the inability of maintaining refractory cardiac arrest victims on ECLS without detrimental capillary leak and multiorgan failure until neurological evaluation.