Pulse high-volume hemofiltration in critically ill patients: a new approach for patients with septic shock

Mortality rates in septic shock remain unacceptably high despite advances in our understanding of the syndrome and its treatment. Humoral factors are increasingly recognized to participate in the pathogenesis of septic shock, giving a biological rationale to therapies that might remove varied and potentially dangerous humoral mediators. While plasma water exchange in the form of hemofiltration can remove circulating cytokines in septic patients, the procedure, as routinely performed, does not have a substantial impact on their plasma levels. More intensive plasma water exchange, as high-volume hemofiltration (HVHF)can reduce levels of these mediators and potentially improve clinical outcomes. However, there are concerns about the feasibility and costs of HVHF as a continuous modality--very high volumes are difficult to maintain over 24 hours and solute kinetics are not optimized by this regimen. We propose pulse HVHF (PHVHF)-HVHF of 85 ml/kg/hr for 6-8 hours followed by continuous venovenous hemofiltration (CVVH) of 35 ml/kg/hr for 16-18 hours-as a new method to combine the advantages of HVHFimprove solute kinetics, and minimize logistic problems. We treated 15 critically ill patients with severe sepsis and septic shock using daily PHVHF in order to evaluate the feasibility of the technique, its effects on hemodynamics, and the impact of the treatment on pathologic apoptosis in sepsis. Hemodynamic improvements were obtained after 6 hours of PHVHF and were maintained subsequently by standard CVVHas demonstrated by the reduction in norepinephrine dose. PHVHFbut not CVVHsignificantly reduces apoptotic plasma activity within 1 hour and the pattern was maintained in the following hours. PHVHF appears to be a feasible modality that may provide the same or greater benefits as HVHFwhile reducing the workload and cost.