Association between intravenous chloride load during resuscitation and in-hospital mortality among patients with SIRS

Purpose: Recent data suggest that both elevated serum chloride levels and volume overload may be harmful during fluid resuscitation. The purpose of this study was to examine the relationship between the intravenous chloride load and in-hospital mortality among patients with systemic inflammatory response syndrome (SIRS), with and without adjustment for the crystalloid volume administered.

Methods: We conducted a retrospective analysis of 109,836 patients ≥18 years old that met criteria for SIRS and received fluid resuscitation with crystalloids. We examined the association between changes in serum chloride concentration, the administered chloride load and fluid volume, and the ‘volume-adjusted chloride load’ and in-hospital mortality.

Results: In general, increases in the serum chloride concentration were associated with increased mortality. Mortality was lowest (3.7 %) among patients with minimal increases in serum chloride concentration (0–10 mmol/L) and when the total administered chloride load was low (3.5 % among patients receiving 100–200 mmol; P < 0.05 versus patients receiving ≥500 mmol). After controlling for crystalloid fluid volume, mortality was lowest (2.6 %) when the volume-adjusted chloride load was 105–115 mmol/L. With adjustment for severity of illness, the odds of mortality increased (1.094, 95 % CI 1.062, 1.127) with increasing volume-adjusted chloride load (≥105 mmol/L).

Conclusions: Among patients with SIRS, a fluid resuscitation strategy employing lower chloride loads was associated with lower in-hospital mortality. This association was independent of the total fluid volume administered and remained significant after adjustment for severity of illness, supporting the hypothesis that crystalloids with lower chloride content may be preferable for managing patients with SIRS.