A cerebral perfusion pressure (CPP) ≤ 60 mmHg correlated with favorable outcome in adult severe traumatic brain injury patients - a retrospective study

Background: Current guidelines for the treatment of severe TBI recommend maintaining a cerebral perfusion pressure (CPP) above 60 mmHg. However, the rationale for this target is not supported by high-level evidence demonstrating improved outcomes. In our institution, as well as others, an alternative algorithm—originally named the Lund concept—has been used. This approach employs metoprolol and clonidine to limit CPP, allowing levels below 60 mmHg, with the aim of reducing cerebral edema. Previous reports on this algorithm have suggested better outcomes compared to contemporary practices, but no population-based studies have been conducted to validate these findings. Research Question: Does allowing CPP levels lower than 60 mmHg improve outcome in severe TBI? Methods: The study included all adult patients (n=171) treated for severe traumatic brain injury (TBI) over a ten-year period in the southern Swedish healthcare region. Baseline data, intracranial pressure (ICP), CPP, treatment duration, surgical interventions, and administered drugs were correlated to the Glasgow Outcome Scale Extended (GOSE). Results: The 30-day and 6-month mortality rates were 16% and 20%, respectively. Good outcome (GOSE 7-8) was achieved in 29% of patients. Ordinal and linear regression analyses indicated that a CPP of 51-60 mmHg correlated with survival, while age and a CPP > 60 mmHg were associated with worse outcome. Conclusion: The application of CPP levels lower than those currently recommended appears to result in better outcomes compared to relevant population-based reports. However, it is possible that the use of metoprolol and clonidine may have additional effects beyond simply reducing CPP.