Extracorporeal circulatory support systems require blood product management due to the large vascular access caliber cannulas of at least 14 F and the exposure of blood components and cells to the artificial surfaces of tubings, rotor and oxygenator. As a main complicating feature, complex derangements of blood components can occur during implantation and the operational period of such systems. To increase patient safety by strengthening the body's own reserves, it is therefore necessary to characterize the extend of blood product substitution as precisely as possible.

METHODS

We included consecutive patients over a 5 - year - period (2016 to 2021) who received an extracorporeal circulatory support system (Impella, veno-arterial extracorporeal membrane oxygenation (VA - ECMO), ECMO in combination with an Impella (ECMella)). Associated amounts of blood products, costs and various clinical parameters were obtained. Assessment of the local findings of the vascular access site was described according to the criteria of the Bleeding Academic Research Consortium (BARC) and the Global Utilization of Streptokinase and tPA for Occluded Coronary Arteries (GUSTO). Hemolysis was characterized by serum free hemoglobin (fHb [µmol / L]).

RESULTS

370 patients were included in our study (Table 1). A median of 7 (3 - 12) red blood cell (RBC) transfusions were used in the total collective (VA-ECMO: 7 (3 - 12); ECMella: 12.5 (6.7 - 27.5); Impella: 3 (1 - 5); p < 0.05). The majority of the RBC - requirement within the first 24 hours of operation was relevantly associated with VA – ECMO patients (VA - ECMO: 67%, ECMella: 42%; Impella: 33%, p < 0.05). During ICU – treatment, a positive correlation could be found between the duration of mechanical support and absolute number of RBC - transfusions (Figure 1). Overall blood product substitution was especially high in ECMella - patients (Figure 2) as well as associated costs (VA – ECMO: 497.5 EUR (0 – 1259.9) vs. ECMella: 1642.4 EUR (1079.1 – 3660.3) vs. 341.3 EUR (0 – 849.3); p < 0.01; (median and interquartile range)). Moderate bleeding complications in the groin area occurred in 45% of patients of the entire collective (GUSTO criteria) of which VA - ECMO patients presented the most cases (58%; p < 0.05) and when implanted during ongoing CPR. Regarding further bleeding characterization (BARC criteria), type 3a was the most common type (31.7%) in the study population. Hemolysis was present during the first 48 hours in all three subgroups, particularly for Impella patients due to their initial high flow rates > 3 liters / minute (VA – ECMO: 14.2 (7.2 – 23.3) vs. ECMella: 18.4 (8.8 – 72.5) vs. Impella 49.8 (21.3 – 113.1); p < 0.01). However elevated levels of fHb mainly persisted for ECMella patients albeit not significantly (VA – ECMO: 9.3 (6.2 – 17.1) vs. ECMella: 14.1 (7.3 – 20.9) vs. Impella 8.8 (6.2 – 21.4); p > 0.05).

CONCLUSION

Despite the technical advances of extracorporeal circulation support systems, a relevant amount of resources is necessary during the operational period to maintain coagulation homeostasis particularly in ECMella patients which reflects the invasiveness of the procedure outperforming other causes like hemolysis. Complications at the insertion site are common. Bleeding is to be expected, especially when using a VA - ECMO in emergency situations. Standardized follow-up protocols for early detection of peripheral complications should be established by interdisciplinary teams.