Driving cerebral perfusion pressure with pressors: how, which, when?
In traumatic brain injury, cerebral hypoperfusion is associated with adverse outcome, particularly in the early phases of management. This has resulted in the increased use of drugs such as adrenaline, noradrenaline, dopamine and phenylephrine to augment or maintain systemic blood pressures at near normal levels. This is now part of standard practice and is endorsed by the Brain Trauma Foundation guidelines. It probably matters little which agent is used, provided appropriate monitoring is in place and those reversible causes of hypotension are promptly excluded and treated. However, blindly applying management guidelines to all patients may negate these early benefits. The time has come move away from artificially separated concepts of "intracranial pressure" versus "cerebral perfusion pressure" based strategies. These should be considered in parallel and applied to an individual patient, rather than making the patient fit into an all-encompassing treatment algorithm. . A paradigm shift from a "set and forget" philosophy to one of "titration against time" to achieve appropriate therapeutic targets is now required. In this context the rational use of vasoactive agents to optimise cerebral perfusion pressure may be employed. On the basis of limited animal and human evidence, noradrenaline appears to be the most appropriate catecholamine for traumatic brain injury, although definitive, targeted trials are required.
Department of Intensive Care Medicine, The St George Hospital, Sydney, NSW 2217, Australia j.myburgh@unsw.edu.au.
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