Fluid resuscitation in septic shock: the effect of increasing fluid balance on mortality

Purpose: To determine whether progressively increasing fluid balance after initial fluid resuscitation for septic shock is associated with increased mortality.

Methods: A retrospective review of the use of intravenous fluids in patients with septic shock in a large university affiliated hospital with 56 medical-surgical intensive care unit beds. We analyzed the data of 350 patients with septic shock who were managed according to the Surviving Sepsis Campaign guidelines. Based on net fluid balance at 24 hours, we examined the results of increase in positive fluid balance on the risk of in-hospital mortality. Patients were divided into 4 groups based on the amount of fluid balance by 24 hours, based on 6-L aliquots.

Results: At 24 hours, the average fluid balance was +6.5 L. After correcting for age and sequential organ failure assessment score, a more positive fluid balance at 24 hours significantly increased the risk of in-hospital mortality. Using Cox proportional hazard analysis, excess 12-, 18-, and 24-L positive fluid balance had higher risk of mortality than those patients with a neutral to positive 6-L fluid balance (reference group). Adjusted hazard ratios, 1.519 (95% confidence interval [CI], 1.353-1.685), 1.740 (95% CI, 1.467-2.013), and 1.620 (95% CI, 1.197-2.043), respectively, P < .05.

Conclusion: In patients with septic shock resuscitated according to current guidelines, a more positive fluid balance at 24 hours is associated with an increase in the risk of mortality. Optimal survival occurred at neutral fluid balance and up to 6-L positive fluid balance at 24 hours after the development of septic shock.