Have an Extremely High Threshold in Giving Antihypertensives in Head Trauma
M. Craig Barrett PharmD
Ronald F. Sing DO
Blood pressure control in the intensive care unit (ICU) can result in controversial and difficult management decisions because of the paucity of data. This seems especially apparent in patients with traumatic brain injury (TBI). Hypertension can be the body’s natural response to TBI in an attempt to autoregulate cerebral blood flow as the body may require an elevated blood pressure to maintain adequate cerebral blood flow. Hypertension after TBI may also be the result of a nonspecific reflex pressor response or triggers of a catecholamine response, such as pain and agitation.
Once the primary trauma to the brain has occurred, minimizing secondary insults is the primary objective to achieve maximal neurologic recovery. Avoiding hypotension (systolic blood pressure <90mm Hg) and hypoxia (oxygen saturation <90% or PaO2 <60 mm Hg) in TBI patients is essential to prevent cerebral ischemia, since both independently predict a worse outcome. The Brain Trauma Foundation recommends the mean arterial blood pressure (MAP) be maintained above 90 mm Hg in an attempt to maintain a cerebral perfusion pressure (CPP) greater than 70 mm Hg.
What to Do
In the event that the MAP is excessively elevated beyond that required to maintain an adequate CPP, sedation and analgesia should be optimized prior to consideration of antihypertensive administration. No antihypertensive therapy should be instituted without consultation with a senior member of the treatment team. In the very unlikely event that blood pressure reduction is warranted, the most desirable agent would have a smooth dose-response relationship providing a predictable and controllable onset. The drug would also be a short-acting, titratable infusion to allow the specific blood pressure targets to be achieved while avoiding hypotension. Additionally, the drug would have few adverse effects and would not cause intracranial pressure (ICP) elevation.