Effectiveness of short-term 6-hour high-volume hemofiltration during refractory severe septic shock

BACKGROUND: The effectiveness of a single 6-hour session of high-volume hemofiltration (HVHF) was evaluated in terms of decreased norepinephrine (NE) requirements, progressive refractory hypotension and hypoperfusion by the fourth hour, and observed versus expected hospital mortality in patients with refractory severe septic shock. METHODS: A prospective cohort study conducted at the intensive care unit with 31 patients suffering from severe septic shock (NE dose ≥0.3 μg · kg ^-1 · min ^-1 to maintain mean arterial pressure 70-80 mm Hg and lactic acidosis) and refractory to treatments recommended by Surviving Sepsis Campaign, 2008. All patients were subjected to a single short-term 6-hour HVHF with a goal-directed protocol. Changes in NE dose, hemodynamic, metabolic, and respiratory parameters were measured at the onset (t ₀), 4 (t ₄) and 6 hours (t ₆) during HVHF. Patients were considered responders if by t ₄ of HVHF, they showed a decrease in NE dose ≥50%, maintaining mean arterial pressure 80 mm Hg to 70 mm Hg. RESULTS: Twenty-five of the 31 patients responded to HVHF treatment (responders), whereas 6 did not (nonresponders). In the responders group, a decrease in NE dose was observed by t ₄ (1.3 ± 0.5 μg · kg ^-1 · min ^-1). This beneficial effect was maintained by t ₆ of treatment. Hemodynamic, metabolic, and respiratory parameters and other organic function indicators were also significantly improved by t ₄ and maintained by t ₆. Hospital mortality (45.16%) was significantly lower than that predicted by Sequential Organ Failure Assessment score (>90%): 83% for nonresponders versus 36% for responders. CONCLUSIONS: We conclude that a single session of short-term 6-hour HVHF in patients with refractory severe septic shock reduces NE dose requirements and improves organic function already by the fourth hour of treatment.