Characteristics, Weaning Strategy, and Outcome of Patients Receiving Extracorporeal Life Support following Cardiogenic Shock

Objectives: Extracorporeal life support (ECLS) represents the last therapy option in refractory cardiogenic shock (CS). Nevertheless the outcome differs between patients with post-cardiotomy CS and those who suffered a cardiac arrest followed by mechanical resuscitation and subsequent ECLS therapy (eCRP). Aim of this study was to analyze the outcome of ECLS according to the pathologic entity and history of CS.

Methods: Registry data of 105 consecutive patients who received an ECLS due to CS between 05/2008 and 05/2017 were reviewed retrospectively. 25 patients were excluded cause of cannulation problems, inadequate ECLS-function or incomplete data. Finally 80 patients (64% male, mean age 60 ± 16 years, BMI 28.9 ± 6.5), were included and divided in two groups: n = 29 (36%) with previous cardiac surgery (post-cardiotomy group) and n = 51 (64%) without cardiac surgery (eCPR-group). Low-flow-time, blood gases at implantation, ECLS-time, weaning- and 30-day-survival rates were compared between groups.

Results: ECLS was implanted in emergency situation via the femoral vein and artery (n = 72; 90%) or right axillary artery (n = 8; 10%). Later implantation of a distally-projected 8 Fr arterial cannula for leg/arm perfusion was performed additionally in n = 44 (55%). Mean low-flow-time prior to ECLS implantation was 53 ± 27 minute, being shorter in the post-cardiotomy-group (40 ± 23 minute versus 57 ± 28 minute, p = 0.001). At implantation lactate (13 ± 5 versus 11 ± 7 mmol/l), pH- (7.1 ± 0.3 versus 7.2 ± 0.2) and base excess values (−8.9 ± 14.4 versus −8.7 ± 6.3 mmol/l) were more pathologic in the eCPR group. Mean over all ECLS-time was 91 ± 128 hours with a weaning rate of 37% (n = 30). In six of these patients (20%) weaning was performed by intermediate switching from V-A to V-VA perfusion mode, adding a third cannula in the jugular vein. Finally these patients were weaned in a progredient VV mode by reducing the flow through the arterial line. Post-cardiotomy patients presented higher weaning- (45% versus 33%) and 30-day-survival rates (41% versus 21%) in the post-cardiotomy group. Patients with an extended low-flow time showed lower weaning- and survival rates.

Conclusions: ECLS increases the survival chances in post-cardiotomy CS. A weaning strategy with a mode-switch from V-A- to V-VA-mode seems to be beneficial. In patients destined for ECLS the low-flow time prior to full eCRP should be minimized to increase the survival chance. This may be achieved by considering eCRP even in an out-of-hospital scenario.