Plasma concentrations of Colistin sulfate in a patient with septic shock on extracorporeal membrane oxygenation and continuous renal replacement therapy: a case report

Background: Polymyxins antibiotics have become the first-line clinical drugs in the treatment of refractory gram-negative bacterial infections. Currently, there is a lack of clinical studies on the effect of extracorporeal membrane oxygenation (ECMO) combined with continuous renal replacement therapy (CRRT) on polymyxin concentrations. The purpose of this report was to investigate the changes in the plasma concentrations of Colistin sulfate during ECMO and CRRT and to provide drug administration programs for critically ill patients receiving ECMO and CRRT. Case Description: In this case report, a patient with septic shock caused by severe acute pancreatitis, with abdominal pain and dyspnea as the main manifestations, was treated with ECMO combined with CRRT for life support and multiple anti-infective drugs. However, the symptoms of infection had not got improved, the inflammatory indicators remain high and the body temperature fluctuates repeatedly 36.7-38.5 ???, was considered as carbapenem-resistant organisms (CROs) infection, and was empirically given Colistin sulfate for anti-infection treatment. Finally, the patient's condition improved and ECMO and CRRT were gradually withdrawn. At the same time, the plasma concentrations of Colistin sulfate before and after ECMO combined with CRRT, was monitored to determine the changes in the plasma concentrations of Colistin sulfate during ECMO and CRRT. Trough and peak concentrations on the 4th day of venovenous ECMO (VV-ECMO) combined with CRRT were 0.36 and 0.98 mg/L, respectively. After withdrawal of ECMO and CRRT, the concentrations were, respectively, 0.27 and 0.34 mg/L for trough concentrations, and 0.82 and 0.98 mg/L for peak concentrations. The data showed that there were no significant differences in the trough and peak concentrations of Colistin sulfate before and after ECMO and CRRT. No adverse effects occurred during follow-up. Conclusions: There were no significant differences in the trough and peak concentrations of Colistin sulfate before and after ECMO and CRRT. Therefore, no dose modification is required for Colistin sulfate in patients receiving ECMO with CRRT.