What is included in hemodynamic management in patients with vertebrobasilar stroke?

Updated: Mar 03, 2020
  • Author: Vladimir Kaye, MD; Chief Editor: Stephen Kishner, MD, MHA  more...
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Answer

Answer

Hemodynamic management should be aimed at minimizing the ischemic injury. Cerebral ischemia impairs the brain’s ability to autoregulate its circulation through vasoconstriction and vasodilatation. Therefore, under ischemic conditions, the cerebral blood flow becomes blood pressure–dependent. [29] An increase in the mean arterial pressure (MAP) results in vasoconstriction. This response limits the perfusion pressure and the blood volume. A decrease in the MAP results in vasodilatation.

In normotensive patients, the limits of autoregulation are within the range of 50-150 mm Hg of the MAP. In chronic hypertensive patients, the curve of autoregulation is shifted upward. In the patients with severe cerebral vascular occlusive disease, the MAP and the cerebral perfusion pressure (CPP) become critical in maintaining the cerebral blood flow. CPP is equal to MAP less intracranial pressure (ICP) (ie, CPP = MAP-ICP). Therefore, overzealous treatment of hypertension should be avoided, because it can decrease the cerebral perfusion pressure and exacerbate the ongoing ischemia.

No existing information from randomized trials indicates whether treating hypertension is better than not treating it. Based on evidence from experimental models and on data from clinical experience, hypertension should not be treated unless there is evidence of end-organ damage, such as hypertensive encephalopathy, unstable angina, acute myocardial infarction, heart failure, or acute renal failure.

Hypertension should be treated when the diastolic blood pressure is greater than 120 mm Hg or when the systolic blood pressure is over 200 mm Hg. Otherwise, when thrombolysis is a strong consideration, the treatment parameters become 110 mm Hg or more for diastolic blood pressure or greater than 180 mm Hg for systolic blood pressure.

Commonly used antihypertensives are labetalol and nitroprusside. When diastolic blood pressure is greater than 140 mm Hg, nitroprusside is the preferred drug, provided that no contraindications exist.

Patients with hypotension need to be treated to optimize the MAP and, consequently, the blood pressure–dependent cerebral blood flow. Maximal effort should be made to maintain a normal intravascular volume using isotonic solutions. If the MAP continues to be low despite fluid management, vasopressors, such as dopamine, dobutamine, and phenylephrine, should be used.

In patients with unknown intravascular volume status or those with complications, such as congestive heart failure and pulmonary edema, a pulmonary artery catheter should be placed to monitor the central venous pressure and the pulmonary capillary wedge pressure. This approach would improve monitoring of the intravascular volume to avoid overload.


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