B. Faliks1,2, D. Aronowitz1,2, V. Patel1,2, J. Nicastro1,2, R. Barrera1,2 1Northwell Health,Department Of Surgery,New Hyde Park, NY, USA 2Donald and Barbara Zucker School of Medicine,Hempstead, NEW YORK, USA
Introduction: Early, effective fluid resuscitation is essential in counteracting the tissue hypoperfusion seen in severe sepsis and septic shock. However, recent evidence has shown correlation between fluid overload and adverse outcomes in critically ill patients. Fluid overload has been defined in some studies as >10% increase in admission body weight. However, there is wide variation in how fluid accumulation is recorded, reported, and interpreted, especially in relationship to body habitus.
Methods: This retrospective chart review evaluated patients in septic shock on vasopressor support with identified infective source in critically ill patients at two large tertiary centers. Total fluid accumulation and net balance at time of discontinuation of vasopressors was recorded, and reported in relationship to patient weight, BMI, and BSA. The relationships between these values and mortality, ICU days, ventilator days, and hospital days were examined. Basic statistics and linear regression analysis were performed.
Results: One hundred patients with septic shock were identified. Increasing net fluid balance at time of pressor discontinuation was significantly correlated with ICU days (R2=0.309, p=0.015), ventilator days (R2=0.250, p=0.006), and hospital days (R2=0.328, p=0.010). In addition, mortality was significantly different between those with less than the median (6L) fluid balance and those with greater than 6L balances. (30% vs 54%, respectively, p=0.015).
When looking from the lens of body habitus, obese patients (BMI>30) had significantly lower fluid balances and fluid balances per BMI (161ml/kg/m2 vs 450ml/kg/m2, p=0.0005) than nonobese patients. However, there was no significant difference between mortality in obese patients and nonobese patients (45% vs 33%, p=0.12). Although fluid balance per total body weight, per body surface area, and per BMI were all significantly correlated with ICU days, ventilator days, and hospital days as net balance was above, analyzing accumulation in this fashion did not significantly alter any of the linear regression statistics. Similarly, mortality was significantly different between those with <10% fluid balance per body weight and those in fluid overload, with >10% fluid balance per kg (31% vs 59%) but this too was not appreciably different from net balance.
Conclusion: Our data support previous studies showing that greater positive fluid balances in septic shock are associated with worse outcomes, including greater mortality, and more ICU, ventilator, and hospital days. Each of balance per BMI, balance per BSA, and balance per total body weight were similarly correlated with adverse outcomes. However, it does not appear that reporting these balances as such would give providers additional insight into risks of adverse outcome.
