There are significant differences in the practice of fluid management in intensive care unit (ICU) patients with traumatic brain injury, with a new study published in Lancet Neurology suggesting that positive fluid balance is associated with worse outcomes.
While most patients with traumatic brain injury are given intravenous fluids to maintain adequate blood flow and oxygen supply to organ tissues, the recommended fluid management for these patients is controversial. The aim of the current study was to quantify the variability of fluid management strategies in patients with traumatic brain injury in intensive care units in Europe and Australia and to determine the relationship between different fluid therapy strategies and outcomes.
The study used data from patients with at least 16 years of traumatic brain injury who required a head CT and who were enrolled in the intensive care unit from 2 observation cohorts: CENTER-TBI (Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury), an ongoing multicenter, prospective Observational cohort study conducted in 18 countries across Europe and OzENTER-TBI (Australia-Europe NeuroTrauma Effectiveness Research in Traumatic Brain Injury), a study that included data from patients admitted to intensive care units at 2 major trauma centers in Australia became.
The study researchers gathered detailed information on demographics, injury characteristics, clinical characteristics, laboratory results, monitoring, treatment intensity, and outcomes. They recorded the average daily fluid intake and calculated the average fluid balance, defined as the difference between fluid intake and loss, to determine the relationship between fluid management and ICU mortality and functional outcome at 6 months.
A total of 2125 patients (median age 50 years; 74% men) from 55 hospitals in 18 countries were eligible for the data analysis, including 1928 patients from the CENTER-TBI study and 197 patients from the OzENTER-TBI study.
Across the centers, the median mean daily fluid balance ranged from -0.85 L to 1.13 L and the median mean daily fluid intake ranged from 1.48 L to 4.23 L.
In the adjusted analysis, an average daily positive fluid balance was associated with a higher mortality rate in the intensive care unit (odds ratio [OR], 1.10 [95% CI, 1.07-1.12] per 0.1 l increase) and poorer functional result (OR, 1.04 [95% CI, 1.02-1.05]). On the other hand, there was no association between negative mean daily fluid balance and ICU mortality or functional outcome.
A higher mean daily intake was associated with a higher ICU mortality, with a 5% increased risk of death per 0.1 L increase (OR 1.05 [95% CI, 1.03-1.06]) and with poorer functional results (OR, 1.04 [95% CI, 1.03-1.04] per 1-point decrease in the Glasgow Outcome Scale Extended per 0.1 L increase).
Due to the possible residual mix-up due to indication, an instrumental variable analysis was also carried out, which is less sensitive to mix-ups according to indication. This analysis confirmed the relationship between a higher fluid balance and increased mortality in the intensive care unit (OR 1.17.). [95% CI, 1.05-1.29]) and poorer functional result (OR, 1.07 [95% CI, 1.02-1.13]). However, increased hydration was not associated with ICU mortality or poorer functional outcome.
The study had several limitations, including the observational design, lack of data on key variables, a potential overestimation of fluid balance as imperceptible fluid losses were not taken into account.
“Our results, combined with previous evidence, suggest a stricter normovolemia policy, carefully avoiding both hypervolaemia and hypovolemia, as indicated by average neutral fluid balances, given the harm associated with both medium negative and positive fluid balances connected, ”concluded the study researchers.
Wiegers EJA, Lingsma HF, Huijben JA, et al. Fluid balance and outcome in critically ill patients with traumatic brain injury (CENTER-TBI and OzENTER-TBI): a prospective, multicenter, comparative efficacy study. Lancet Neurol. 2021; 20 (8): 627-638. doi: 10.1016 / S1474-4422 (21) 00162-9