Myoglobin adsorption and saturation kinetics of the cytokine adsorber Cytosorb® in patients with severe rhabdomyolysis: a prospective trial

Background Rhabdomyolysis is a serious condition that can lead to acute kidney injury with the need of renal replacement therapy (RRT). The cytokine adsorber Cytosorb (R) (CS) can be used for extracorporeal myoglobin elimination in patients with rhabdomyolysis. However, data on adsorption capacity and saturation kinetics are still missing. Methods The prospective Cyto-SOLVE study (NCT04913298) included 20 intensive care unit patients with severe rhabdomyolysis (plasma myoglobin > 5000 ng/ml), RRT due to acute kidney injury and the use of CS for myoglobin elimination. Myoglobin and creatine kinase (CK) were measured in the patient's blood and pre- and post-CS at defined time points (ten minutes, one, three, six, and twelve hours after initiation). We calculated Relative Change (RC, %) with: 1 - (concentration(pre - post) / concentration (pre)) * 100. Myoglobin plasma clearances (ml/min) were calculated with: (bloodflow * (1 - hematocrit)) * (concentration (pre - post) / concentration (pre)) Results There was a significant decrease of the myoglobin plasma concentration six hours after installation of CS (median (IQR) 56,894 ng/ml (11,544; 102,737 ng/ml) vs. 40,125 ng/ml (7879; 75,638 ng/ml) (p < 0.001). No significant change was observed after twelve hours. Significant extracorporeal adsorption of myoglobin can be seen at all time points (p < 0.05) (ten minutes, one, three, six, and twelve hours after initiation). The median (IQR) RC of myoglobin at the above-mentioned time points was - 79.2% (-85.1; -47.1%), -34.7% (-42.7;-18.4%), -16.1% (-22.1; -9.4%), -8.3% (-7.5; -1.3%), and - 3.9% (-3.9; -1.3%), respectively. The median myoglobin plasma clearance ten minutes after starting CS treatment was 64.0 ml/min (58.6; 73.5 ml/min), decreasing rapidly to 29.1 ml/min (26.5; 36.1 ml/min), 16.1 ml/min (11.9; 22.5 ml/min), 7.9 ml/min (5.5; 12.5 ml/min), and 3.7 ml/min (2.4; 6.4 ml/min) after one, three, six, and twelve hours, respectively. Conclusion The Cytosorb (R) adsorber effectively eliminates myoglobin. However, the adsorption capacity decreased rapidly after about three hours, resulting in reduced effectiveness. Early change of the adsorber in patients with severe rhabdomyolysis might increase the efficacy. The clinical benefit should be investigated in further clinical trials.