Extracorporeal blood purification in refractory septic shock: A case study

Abstract

Background : Systemic inflammatory states such as severe sepsis and septic shock result in immunologic disturbances with the release of numerous inflammatory mediators. The systemic inflammatory response, though a result of innate immunity, can become deleterious when excessive or uncontrolled, leading to the development of multi-organ failure syndrome and death. Extracorporeal blood purification therapies have been proposed to improve outcomes for patients with severe sepsis. These therapies are based on the principle that removal of inflammatory mediators or bacterial toxins (or both) from the blood will favorably modulate the host inflammatory response. Recently, significant technological progress has greatly broadened the spectrum of techniques available for blood purification. However, these techniques have not entered into mainstream clinical practice around the world. Hemoadsorption places sorbents in direct contact with blood via an extracorporeal circuit. Polymyxin B is a cyclic basic polypeptide that disrupts the permeability of the cell membrane of Gram-negative bacteria. Polymyxin B-immobilized polystyrene-derived fibres (Toramyxin, Toray Industries, Inc., Tokyo, Japan) have been developed for use in extracoporeal therapy as a means to remove endotoxin from the blood. There are not many studies showing the efficacy of extracorporeal blood purification in paediatric population in India or around the world. Methods : A six years old girl with Salmonella typhi sepsis was retrieved on day 6 of illness in a state of fluid refractory shock on ventilatory support with oxygenation index (OI) of 16.2 and Vasoactive Inotropic Score (VIS) after 2 hours of admission was 50 with a diastolic blood pressure (DBP) of 35mmHg. She had multi-organ dysfunction with SGOT 3745U/L, SGPT 1353U/L, Arterial Lactate 11mmol/L, Creatinine 1.0mg/dl, CRP 108mg/ dl, Bicytopenia - Platelet 56000/cu.mm, WBC 2200/cu.mm (with 76% Neutrophils). She was on appropriate antibiotics since past 2 days at the referral centre. Over a period of 24 hours, her VIS increased to 53 with Fluid Overload percent (FO%) reaching 12% and her kidney injury progressed to AKIN Stage 3. We started her on Continuous Veno-venous Hemo-diafiltration (CVVHDF) which resulted in improvement in her renal parameters, Creatinine 0.4mg/dl, but she continued to have very low DBP (30 -35mmHg) despite high VIS and her inflammatory markers increased CRP 132mg/dl, with persistent Bicytopenia - Platelet 23000/cu.mm, WBC 2700/cu.mm (with 80% Neutrophils). As the child was already on CRRT, a decision to start the child on extracorporeal blood purification using Toramyxin cartridge was made and initiated at 40 hours after admission and continued for 36 hours. Results : With this, the child showed improvement with VIS decreasing to 35 after twelve hours, 25 after thirty six hours and 11 after twelve hours of stopping extracorporeal blood purification. Her inflammatory markers decreased with CRP 90mg/L after twelve hours and 54mg/L twenty four hours later. Blood counts also improved with WBC rising to 9100 (80% Neutrophils) forty eight hours of starting hemoadsorption, while she received platelet transfusion for thrombocytopenia. Her OI also improved to 8.7 after forty eight hours. The patient was off inotropes within 72 hours of starting extracorporeal blood purification and was extubated within 96 hours. Conclusion : We conclude that the use of an extracorporeal blood purification device (Toramyxin) may have helped in the removal of circulating endotoxin by adsorption, thus preventing progression of the biological cascade of sepsis and resulted in improvement in our patient’s hemodynamic status and decrease in inflammatory response leading to clinical improvement. The major limitation of our report is our inability to measure endotoxin levels of our patient to demonstrate decrease in their level pre- and post- hemoadsorption. We also cannot comment on the efficacy of extracorporeal blood purification devices based on this single case. But we wish to emphasise that many new modalities exist in treatment of septic shock and can be considered when dealing with refractory septic shock.