Blood Pressure Management

The accurate assessment of the hemodynamic state in ICH patients is of primary importance during their early management. The vast majority of acute stroke patients present with elevated blood pressure as clinical manifestation of a long-standing premorbid condition, as a physiologic response to the acute neurologic insult, or as a combination of both. In the unusual situation in which hypotension occurs, etiologic causes, such as hypovolemia, neuro/cardio-genic cardiac dysfunction, or significant bleeding at a remote site, must be investigated and treated aggressively, once demonstrated. Vascular access must be adequate for all diagnostic and therapeutic interventions. Central venous access should be considered for patients who require administration of vasoactive drugs or who have inadequate peripheral vein caliber to accommodate the large-bore catheters that are necessary for resuscitation. Insertion of an arterial catheter should be considered in patients in whom measurement of beat-to-beat blood pressure or frequent measurement of arterial blood gases is necessary. Adequate management of the elevated blood pressure that follows the ictus in patients with ICH remains a controversial subject, mainly due to the paucity of clear evidence supporting well-defined targets of care. Hematoma growth (Fig. 1) has been found to occur in 38% of patients in the first 20 hr after the bleed and has been attributed to the acute and poorly controlled hypertension that is

Figure 1 Admission brain CT of a patient with spontaneous ICH showing a left basal ganglia hemorrhage with intraventricular extension (A). Eight hours following admission, the patient developed worsening level of consciousness. Follow-up brain CT demonstrated significant hematoma enlargement as well as worsening intraventricular hemorrhage (B).

Figure 1 Admission brain CT of a patient with spontaneous ICH showing a left basal ganglia hemorrhage with intraventricular extension (A). Eight hours following admission, the patient developed worsening level of consciousness. Follow-up brain CT demonstrated significant hematoma enlargement as well as worsening intraventricular hemorrhage (B).

common in these patients (9). Thus, the intuitive response to this clinically meaningful threat has been the attempt to aggressively treat hypertension in this group of patients, though it is now unclear if a true correlation exists between these two events. Furthermore, overaggressive treatment of blood pressure could decrease blood supply to viable perihematoma tissue (perihematoma ischemia) and, in a more global setting, critically reduce cerebral perfusion pressure (global ischemia), especially if the ICP is already elevated. This biologically plausible mechanism of secondary brain injury found a clinical correlate when worse clinical outcome was documented in ICH patients who underwent early rapid and aggressive blood pressure lowering following the ictus (10). Another study using positron-emission tomography, found stable perihematomal cerebral blood flow and oxygen extraction ratio during a 15% to 20% reduction in mean arterial blood pressure of hypertensive patients with small- to moderate-sized hemorrhages. These results suggest that perihematoma ischemia, if present, is far from a universal occurrence in these patients during moderate blood pressure lowering (11,12 ).

Based on limited clinical evidence that is available in the literature, a Writing Group of the Stroke Council for the AHA recommended maintaining mean arterial blood pressure below 130 mmHg in ICH patients with a history of hypertension (2). Recommended drugs include sodium nitroprusside (0.5-10 |g/kg/min) in the treatment of systolic blood pressure greater than 230 mmHg or diastolic blood pressure greater than 140 mmHg (Table 1). Nevertheless, treating practitioners should be aware of the potential of this agent to further raise ICP. For systolic blood pressure between 180 and 230 mmHg, recommended drugs include intravenous labetalol, hydralazine, esmolol, and enalapril. The choice of agents to treat acute hypertension following ICH is derived from preexisting guidelines for the treatment of hypertension following acute ischemic stroke (13). The availability of intravenous nicardipine and its relative ease of use make it another suitable alternative in the treatment of elevated blood pressure in these patients.

Current research in the field aimed at assessing outcomes in ICH patients who are randomized following the ictus to different target blood pressure goals is being driven by both the lack of prospective studies that address clinically meaningful blood pressure targets and the results of recent clinical investigations that suggest that aggressive pharmacologic treatment of acute hypertension in patients with ICH could lead to a low rate of neurologic deterioration due to hematoma expansion (14 ).

Table 1 Blood Pressure Management in intracerebral Hemorrhage

Elevated blood pressure (suggested medications) Labetalol

5-100 mg/hr by intermittent bolus doses of 10 - 40 mg or

Enalapril Labetalol

Esmolol

Nitroprusside

Hydralazine continuous drip (2-8 mg/min) 500 |jg/kg as a load; maintenance use, 50-200 |jg kg-1 min 0.5-10 jg kg min 10-20 mg every 4-6 hr 0.625-1.2 mg every 6 hr as needed 5-100 mg/hr by intermittent bolus doses of 10 - 40 mg or continuous drip (2-8 mg/min) The following algorithm adapted from guidelines for antihypertensive therapy in patients with acute stroke may be used in the first few hours of ICH (level of evidence V, grade C recommendation):

  1. If systolic blood pressure (BP) is >230 mmHg or diastolic BP > 140 mmHg on 2 readings 5 min apart, institute nitroprusside.
  2. If systolic BP is 180 to 230 mmHg, diastolic BP 105 to 140 mmHg, or mean arterial BP > 130 mmHg on

2 readings 20 min apart, institute intravenous labetalol, esmolol, enalapril, or other smaller doses of easily titratable intravenous medications, such as diltiazem, lisinopril, or verapamil.

  1. If systolic BP is <180 mmHg and diastolic BP < 105 mmHg, defer antihypertensive therapy, choice of medication depends on other medical contraindications (e.g., avoid labetalol in patients with asthma).
  2. If ICP monitoring is available, cerebral perfusion pressure should be kept at >70 mmHg. Low blood pressure:

Volume replenishment is the first line of approach. Isotonic saline or colloids can be used and monitored with central venous pressure or pulmonary artery wedge pressure. If hypotension persists after correction of volume deficit, continuous infusions of pressors should be considered, particularly for low systolic blood pressure, such as < 90 mmHg.

Source: From Ref. 95.

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