Introduction:

Severe septic shock and acute kidney injury is treated with continuous renal replacement therapy (CRRT). Our default CRRT mode is continuous veno-venous haemodiafiltration (CVVHDF) using the M100 set of the Prismaflex (Baxter Corp, Deerfield, Illinois, USA) CRRT machine. We developed a new blood purification protocol using the enhanced AN 69ST membrane (oXiris) to determine if the course of severe septic shock and acute kidney injury (AKI) could be ameliorated.

Method: We electively changed oXiris 12 hourly despite normal flows and pressures. This provides fresh binding sites for endotoxin and cytokine adsorption to enhance blood purification. Vascular access was via central venous dialysis catheter. All treatments were anticoagulant-free.

Results: Two critically ill patients were treated using this newly developed frequent filter change protocol. Patient 1 was a case of alcoholic liver cirrhosis with oesophageal variceal bleeding, bacterial septicaemia and hepatic encephalopathy. The patient achieved partial renal recovery before he re-deteriorated. A total of 6 Oxiris filters were used over 3 consecutive days with good clinical response. This patient was weaned off inotropes, survived ICU but succumbed after terminal discharge from hospital with azotaemia managed conservatively without dialysis. Patient 2 suffered burns injury with a total body surface area (TBSA) > 60%. Fulminant, overwhelming septicaemia with multi-drug resistant Pseudomonas aeruginosa dominated the clinical course despite intensive medical therapy and 11 sessions of surgical debridement. A total of 19 oXiris filters were used over 13 consecutive days to augment adsorptive clearance of septic mediators. The patient died in ICU.

Conclusion: We are unable to draw any definitive conclusions except to generate the hypothesis that pulsed adsorption via frequent change of modified AN 69ST haemofilters with high affinity for septic humoral mediators may ameliorate the course of severe septic shock. More studies are however necessary.