Crystalloids vs. colloids for fluid resuscitation in the Intensive Care Unit: A systematic review and meta-analysis

Guidelines recommend crystalloids for fluid resuscitation in sepsis/shock and switching to albumin in cases where crystalloids are insufficient. We evaluated hemodynamic response to crystalloids/colloids in critically ill adults.

The primary research question was: "Are crystalloids sufficient for volume replacement in severe indications (intensive care unit [ICU]/critical illness)?" Randomized, controlled trials (RCTs) were identified using PubMed and EMBASE, and screened against predefined inclusion/exclusion criteria. Meta-analyses were performed on extracted data.

Fifty-five RCTs (N = 27,036 patients) were eligible. Central venous pressure was significantly lower with crystalloids than with albumin, hydroxyethyl starch (HES), or gelatin (all p < .001). Mean arterial pressure was significantly lower with crystalloids vs. albumin (mean difference [MD]: -3.5 mm Hg; p = .03) or gelatin (MD: -9.2 mm Hg; p = .02). Significantly higher volumes of crystalloids were administered vs. HES (MD: +1775 mL); volume administered was numerically higher vs. albumin (MD: +1985 mL). Compared with the albumin group, cardiac index was significantly lower in the crystalloid group (MD: -0.6 L/min/m², p < .001). All mortality and 90-day mortality were significantly lower for crystalloids compared with HES (relative risk 0.91; p = .009 and 0.9; p = .005, respectively).

Crystalloids were less efficient than colloids at stabilizing resuscitation endpoints; guidance on when to switch is urgently required.