Lit Matters #2: BaSICS Trial - Type of Fluid

In critically ill adults needing fluid challenges, Plasma-Lyte 148 did not beat 0.9% saline for 90-day mortality in the BaSICS trial. This large ICU randomized trial also found no consistent signal across secondary outcomes or most subgroups, with a cautionary note around traumatic brain injury.

BaSICS Fluid Type Trial

• Primary mortality outcome: Ninety-day mortality was essentially unchanged with balanced crystalloid versus normal saline, arguing against a broad survival advantage from choosing Plasma-Lyte 148 in undifferentiated critical illness.
• Large pragmatic ICU sample: More than 10,000 patients across 75 Brazilian ICUs make this one of the biggest fluid-type trials in critical care, and the enrollment details matter when judging how far to generalize the result.
• Pre-ICU fluid exposure: Most patients had already received crystalloids before ICU enrollment, and nearly half of those got more than 1 liter, a design feature that may dilute any later between-group fluid effect.
• Illness severity snapshot: This was a genuinely sick cohort: about 61% had hypotension or vasopressor use and 44% were mechanically ventilated, which helps frame why a mortality signal would have mattered if present.
• Subgroup signal in TBI: Traumatic brain injury stood out as a possible exception, with worse outcomes seen in the balanced-fluid group, though the authors note important measurement caveats. We get into why that signal is hard to ignore in the episode.
• No subgroup rescue: Secondary and subgroup analyses did not uncover a convincing population that clearly benefited from balanced solution, reinforcing saline as a reasonable default when the indication is simply initial ICU fluid challenge.