The treatment of suspected stroke patients has changed significantly in the past several years. Management of hypertension by EMS providers in suspected strokes has recently been challenged. The optimal strategy for brain resuscitation remains unknown; however, treating hypertension in the stroke patient is now considered dangerous. No definitive evidence exists suggesting that emergent treatment of hypertension will improve the neurological outcome.1 In fact, numerous clinical case series have reported neurological deterioration in strokes immediately following reduction of blood pressure.2 Critical care transport providers must be familiar with the physiology of strokes and the treatments for brain resuscitation in order to provide optimal care.
Management of hypertension remains permissible in limited circumstances. During hemorrhagic strokes, an elevated blood pressure may increase the bleeding. According to Norman Kaplan, MD, clinical professor of internal medicine at the University of Texas--Southwestern, "Reducing the blood pressure in patients with either subarachnoid or intracerebral bleeding may be beneficial by minimizing further bleeding and continued vascular damage. Elevated blood pressure can worsen a subarachnoid hemorrhage, since the mechanical force across the plugged bleeding site is related to the difference between the systemic blood pressure and the cerebrospinal fluid pressure."3 Although treatment in these cases may be beneficial, it is impossible in the prehospital arena to determine the nature of the cerebral insult. Eighty to 85% of strokes are ischemic, so erring on the side of a hemorrhagic stroke is not statistically viable. Much controversy exists regarding the treatment of patients with subarachnoid hemorrhage. Some neurologists recommend withholding treatment of severe hypertension because of the potential for cerebral ischemia. Currently, there is no definite evidence proving hypertension causes enlargement of an intracerebral hemorrhage or increases the risk of rebleeding.1,2 The Brain Attack Coalition also recommends the judicious treatment of hypertension only if the patient presents symptomatic for congestive heart failure or an acute myocardial infarction.4
In patients diagnosed with intracerebral hemorrhage, the drug of choice is Trandate (labetalol hydrochloride), Nitropress (nitroprusside) or Cardene (nicardipine). Some neurologists caution that Nitropress increases cerebral blood volume and therefore increases intracranial pressure.3 Also, Nitropress is known to cause a "steal phenomenon" by shunting blood and thus causing secondary focal cerebral ischemia.1
EMS agencies choosing to treat hypertension in strokes must be acutely aware of the risks. Many prehospital protocols still recommend treating systolic pressures greater than 200 and diastolic pressures greater than 110 in the presence of suspected strokes. Generally, the drug of choice for these agencies is Trandate 20 mg intravenously to control the hypertension, while some agencies still advocate the use of nitroglycerin to lower blood pressures. Nitroglycerin is still used to lower blood pressure in the hospital setting, but is not advocated prehospital because of the inability to monitor invasive pressures and the propensity to lower pressures too quickly or cause hypotension.
Although hypertension may be a contributing factor to rebleeding in the first hour of a stroke, inadvertent overcorrection of the blood pressure will most likely exacerbate ischemia. If treatment of hypertension is going to occur, it is strongly recommended that it be cautiously lowered over 12 to 48 hours, not in the prehospital arena.