Association of mortality and neurological outcomes with hypocapnia in adult patients with acute brain injury: an updated meta-analysis.

BACKGROUND: Carbon dioxide is a key determinant of cerebral blood flow and is needed to prevent secondary damage in neurocritical care; however, optimal targets across the heterogeneous spectrum of acute brain injury (ABI) remain to be elucidated. The aim of this study was to evaluate the association between arterial hypocapnia and mortality and neurological outcomes in adult patients with ABI. METHODS: ) lower than 35 mmHg, and no-hypocapnia in adult patients with ABI-related conditions (including traumatic brain injury, subarachnoid hemorrhage, intracerebral hemorrhage, ischemic stroke, central nervous system infections, brain tumors, and post-cardiac arrest encephalopathy) were included. Random-effects meta-analyses were conducted using the restricted maximum likelihood (REML) method to pool unadjusted odds ratios (ORs). The primary outcome was all-cause mortality, and the secondary outcome was the occurrence of poor neurological outcomes defined using validated scales. Prespecified subgroup analyses and meta-regression were conducted to explore sources of heterogeneity. RESULTS: <32 mmHg). CONCLUSIONS: management and further high-quality prospective research.