Cases analysis of rational use of medicine (46)Hypertension with intracerebral hemorrhage

2011-03-16 06:43杜金山,叶咏年
天津药学 2011年2期

1.Patient'sconditions

Patient,60-year-old male,had hypertension for 10 years.BP had kept as high as 160~180/100~110 mmHg.After a heavy drink and a highly excitotary state,he had headache,nausea,vomiting,and then aphasia,disturbance of consciousness.

BP:220/115 mmHg

Cerebroscope:fundus hemorrhage

Encephalon CT scanning:high density in basal ganglion

Diagnosis:hemorrhagic apoplexy (Intracerebral hemorrhage)

2.Drugadministration

Glycerol Fructose and Sodium chloride inj 250 ml iv drop bid

Labetalol HCl inj 10 mg iv and repeating the same dose in 10 minutes later.

3.Analysis

(1)Blood pressure (BP)is frequently elevated when patients have a stroke.The highest BPs are found in patients with intracerebral hemorrhage and in patients who were previously hypertensive.Hypertension may be a stress to a stroke,a response to hypoxia,filling of bladder,increased plasma catecholamines,hypoperfusion of ischemic brain,the mental stress,intracranial hypertension,sympathic hyperfunction and so on.Elevated blood pressure also accelerates hematoma expansion and causes rebleeding.Arguments in favor of aggressive BP management in the setting of acute stroke are for reduction in the formation of cerebral edema,reduction in the risk of continuous hemorrhage and rebleeding in cases of intracerebral or subarachnoid hemorrhage.In addition,some comorbid conditions may occasionally be present,such as aortic dissection or acute myocardial ischemia,that require antihypertensive treatment in their own right.

(2)There is an association between deterioration in neurological status and large,rapid iatrogenic BP reduction in patients who present with severe hypertension and acute stroke.This complication is thought to occur if BP drops precipitously below the lower limit of cerebral blood flow autoregulation.

BP management has been thorny and important to maintain a normal brain perfusion pressure for the patients with cerebral hemorrhage.With the disturbance of autoregulation,Slight rising of Mean Arterial Pressure (MAP) may increase brain perfusim pressure leading to expansion of edema and increase of intracranial pressure,while middling droing of MAP can cause the decrease of brain perfusion pressure and cerebral ischemia.The management of MAP depends on intracranial pressure,and brain perfusion pressure should be kept at level of 60~70 mmHg.The elevated intracranial pressure can raise MAP(Cushing reflex),the treatment of only intracranial pressure may reduce MAP to reasonable level.Raised brain perfusion pressure(>80~100 mmHg) with persisting hypertension should be indicative of antihypertensive therapy.

There have been no identical views on the blood pressure management during the acute phase of stroke.Cardio-cerebral vascular specialists are arguing that antihypertensive therapy should be carefully considered during the acute phase of cerebral hemorrhage.Elevated BP resulting from brain bleeding is reflective autoregulation of elevated intracranial pressure.The rising BP may come down to original level as intracranial pressure is droping.Reduction of elevated intracranial pressure is the first important step to decrease brain edema,prevent the formation of cerebral hernia.

In view of association between the expansion of hematoma,lasting hemorrhage and excessively elevated BP,"China guide of prevention and cure of cerebrovascular disease" recommended antihypertensive therapy be not initiated until BP≥200/110 mmHg,reducing elevated BP to a level slightly higher than original one,or to 180/105 mmHg.MAP Should be kept at level <130 mmHg preventing hematoma expansion,and >90 mmHg supporting brain perfusion in patients with previous hypertension.Antihypertensive therapy should be avoided in case of SBP<165 mmHg,or DBP<95 mmHg.

(3)Excessive lowering of BP can cause latent danger,such as the decrease of brain blood flow or brain ischemia.Antihypertensive agents should be carefully selected,having short-term actions which are easily to be controlled and no influence on intracranial pressure.Some specialists recommend that Sodium nitroprusside can be given with SBP>230 mmHg,or DBP>140 mmHg,and Labetalol (in this case )can be chosen with BP of 180~230/110~140 mmHg.

Dehydrants including 20% mannitol Inj,Glycerol Fructose and Sodium chloride inj ,20% Human Albumin inj and Diuretic (Furosemide)can be used for the lowering of raised intracranial pressure which is primarily important in intracerebral bleeding.

Compared with 20% mannitol inj ,Glycerol Fructose inj seems safer in kidney,starts effects slowly and persists longer in action.