Stroke: Management of Adverse Effects Presented by: F. Covert RN, BSN

Vasodilator Therapy

Review: Blood Pressure Blood pressure is the amount of force (pressure) applied to the artery walls. Systolic: The force applied to arterial walls during ventricular systole. Diastolic: The force applied to arterial walls during ventricular diastole.

Hypertension Chronic hypertension aggravates atherosclerosis and increases vascular resistance (vasoconstriction) within the brain. Positive effects: Increased vascular resistance protects the brain from the damaging effects of systemic hypertension. Negative effects: Predisposes the brain to cerebral ischemia by impairing vasodilator responsiveness. When diastolic BP exceeds 120mmHg, the ischemic brain is at high risk of hemorrhage.

Acute on Chronic Hypertension Acute increases in blood pressure superimposed on a chronic hypertensive state. Approximately 50% of all patients positive for an acute ischemic stroke will have a history of preexisting hypertension. On average these individuals will have higher blood pressures post acute stroke than those who were previously normotensive.

Blood Pressure Management Treatment of hypertension should be done very cautiously. Neurological deterioration has been associated with precipitous decreases in blood pressure induced by emergency antihypertensive treatment. When blood pressure drops below the lower limit of cerebral blood flow auto-regulation it causes more widespread cerebral hypoperfusion.

Blood Pressure Monitoring Ischemic Stroke: Post tPA Vital Signs: Every 15 minutes for 2 hours from start of tPA then, Every 30 minutes for 6 hours then, Hourly for the next 16 hours Temperature is monitored every 4 hours for 24 hours.

Blood Pressure Monitoring Hemorrhagic Stroke: Intra-cerebral Bleed Vital Signs: Hourly for 24 hours then, Every 4 hours ongoing

Utilized in Ischemic and Hemorrhagic Stroke Standing Orders Labetalol (Trandate) Potent alpha and beta blocker Slows heart rate and decreases peripheral vascular resistance Use cautiously in patients with constrictive airway diseases IVP: Given over 1-2 minutes in 10mg increments, can be repeated every 10-20 minutes (max dose 300mg) Drip: Give a 10mg bolus, followed by a drip started at 2-8mg/min Can be administered in ICU/CCU, ED, PACU, AMB Surgery, Radiology, Cardiology Utilized in Ischemic and Hemorrhagic Stroke Standing Orders

Nicardipine (Cardene) Calcium channel blocker Decreases systemic vascular resistance and blood pressure Administered as an IV infusion, started at 5mg/hour and may be increased by 2.5mg/hour every 15 minutes (max 15mg/hour) Contraindicated for patient’s with conduction deficits (i.e. Second/Third degree heart blocks) Can be administered in ICU/CCU and ED Utilized in Ischemic and Hemorrhagic Stroke Standing Orders

Nitroprusside (Nipride) Potent vasodilator used in emergent hypertensive conditions Acts directly on venous and arterial smooth muscle Administer as an IV drip beginning at 0.3mcg/kg/min, titrate by 0.2mcg/kg/min to desired MAP (max 10mcg/kg/min) Monitor closely for cyanide toxicity Can be administered in ICU/CCU and ED Utilized in the Hemorrhagic Stroke Standing Orders, recommended for consideration in Ischemic Strokes.

Cyanide Toxicity Signs and Symptoms: Nausea, vomiting, diaphoresis, apprehension, headache, restlessness, muscle twitching, dizziness, palpitations, retrosternal pain and/or abdominal pain. If this occurs, stop the infusion and symptoms should resolve within 10 minutes, if not then effects are from another source.

Utilized in the Hemorrhagic Stroke Standing Orders. Enalapril (Vasotec) An ACE-inhibitor that prevents the conversion angiotensin I to II, preventing vasoconstriction Decreases peripheral arterial and venous resistance Administered IVP at 0.625-1.25mg every 6 hours as needed Contraindicated in patients with hypersensitivity or allergy to ACE-inhibitors Can be administered in ICU/CCU, ED, PACU, 2CN, AMB Surgery, Radiology, Cardiology Utilized in the Hemorrhagic Stroke Standing Orders.

Hydralazine (Apresoline) Potent vasodilator with direct vasodilating effects on the arterioles Administered IVP in doses of 5-20mg every six hours as needed Contraindicated in patient’s with Rheumatic Heart disease Can be administered in ICU/CCU, PACU, ED, AMB Surgery, 2CN, Birthing Center, Radiology, Cardiology Utilized in Hemorrhagic Stroke Standing Orders.

Volume Expansion

Post-Hemorrhagic Stroke Patients are at an increased risk for cerebral vasospasm after spontaneous subarachnoid hemorrhage Medically induced hypertension has proven to reduce vasospasm post bleed Methods: Intra-vascular volume expansion: Used to stabilize vessel walls from spasm/collapse Vasopressor support: Vessels are less likely to spasm while acutely constricted Administration of anti-diuretics: Assist in the retention of fluids to stabilize vessel walls

Cerebral Ischemia Utilization of intra-vascular volume expansion and induced hypertension are effective in reversing ischemic deficits from vasospasm, provided that the treatment commences before the cerebral infarction occurs. If not, ultimately it can be used to prevent further ischemic damage to the cerebrum post infarct.

References Phillips, S. (2004). Pathophysiology and management of hypertension in acute ischemic stroke. Hypertension, 23, 131-136. Miller, E.L., Murray, L., Richards, L., et al. (2010). Comprehensive overview of nursing and interdisciplinary rehabilitation care of the stroke patient. Stroke, 41, 2402-2448. I.V. Push Medication Guidelines. Garden City Hospital department of pharmacy (2010).