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The Impact of Extracorporeal Removal Techniques on Outcome of Sepsis

　　Jonathan Cohen, MD,[10] of Brighton and Sussex Medical School in Falmer, United Kingdom, discussed the extent to which extracorporeal removal techniques affect the outcome of sepsis and reviewed general concepts as well as the results of clinical trials. These therapies attempt to counteract the physiologic response to sepsis mediators by removing those that are toxic or harmful from the circulation. Therapies can be viewed as nonselective (eg, hemofiltration, hemoperfusion, plasmapheresis/exchange) or selective (eg, leukopheresis, endotoxin removal). General issues to consider include the potential for a detrimental effect from removal of beneficial factors in addition to those considered harmful, as well as safety concerns related to hemodynamic stability and infection. A recently published prospective, randomized, controlled trial suggested that decreased mortality from plasma exchange was possible in severe sepsis and septic shock.[11] However, differences in baseline demographics (age) and clinical variables (site of infection, percent of patients requiring mechanical ventilation) were present. Correcting for these variables reduced the significance of treatment with plasmapheresis on mortality; and although a trend still existed favoring plasma exchange, it was no longer a statistically significant effect. Clinical information regarding the role of more selective modalities, such as the use of endotoxin adsorbers, is limited,[12] although the experimental techniques to target the removal of superantigens or potent immunostimulating toxins represent an area of active investigation. In aggregate, experimental studies to date are perceived as encouraging, but clinical data remain fragmentary and incomplete.