Written by Clay Smith
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In patients with TBI, aim for normovolemia. Positive fluid balance was associated with increased mortality and poorer neurological outcome.
Why does this matter?
Hypotension in TBI is bad. We often give a crystalloid bolus to treat hypotension. But is excessive fluid also bad for head injured patients?
Don’t drown the brain
Design: This was a combination of two prospective studies, in Europe – CENTER-TBI and in Australia – OzENTER-TBI, that enrolled patients with TBI who had a head CT and were admitted to the ICU.
Results: There were 2,125 patients included, and they found that a positive fluid balance was associated with an increase in mortality, OR 1.10 [95%CI 1.07 to 1.12] per 0.1 L increase). Also, Glasgow outcome scores were worse in those with positive fluid balance.
Implications: Aim for normovolemia in TBI patients. Of course, rapidly correct hypovolemia, just don’t overdo it. Negative fluid balance was also bad, but not as bad as positive fluid balance. See graph.
Limitations: There were so many factors that could have influenced outcome in these patients, and fluid balance was just one. Patients who had a positive fluid balance were generally sicker. Giving more fluid may have been a marker of more severe injury. They adjusted for known confounders (i.e. GCS, hypoxia, hypotension, CT severity, and more), but we can’t determine causality with this study design.
Source
Fluid balance and outcome in critically ill patients with traumatic brain injury (CENTER-TBI and OzENTER-TBI): a prospective, multicentre, comparative effectiveness study. Lancet Neurol. 2021 Aug;20(8):627-638. doi: 10.1016/S1474-4422(21)00162-9.
