Three out of four clinicians would reduce a crisis in blood pressure - with or without clinical symptoms - within an hour. This is the result of a recent survey. Nifedipine Is the preferred agent in almost all clinical conditions with excessive blood pressure increase. Scientific literature and treatment recommendations give a different and differentiated picture of the hypertensive crisis. Even a very high blood pressure, which causes no clinical symptoms, is tolerated for several hours. Here, as well as in some clinical syndromes associated with crisis pressure increase, threatens a threat rather by excessive blood pressure drop, if too fast and too much intervention.
Three years ago, a moratorium on non-delayed nifedipine was initiated in the US. After evaluating reports of serious complications, the authors called for the elimination of the fast-acting and poorly-controlled nifedipine capsules in the treatment of hypertensive crisis. The disease itself is a "stepchild" of medical research. Randomized intervention studies with clinical endpoints such as disease progression or mortality do not exist. However, taking the clinical experience and theoretical considerations documented in the literature seriously, there is virtually no indication in which the non-sustained nifedipine capsule would be the drug of choice. The discrepancy to the above-outlined practice in Germany could hardly be greater. The sparse recommendations of the German Hypertension League, in which neither indications nor target values are mentioned, do not provide sufficient decision support. We are looking forward to comments from our readers.
Hypertensive crises are potentially life-threatening events. In an emergency, however, they are not affected by the absolute level of blood pressure, but by concomitant symptoms and underlying diseases. In the Anglo-American language area, therefore, a distinction is made between hypertensive urgency and hypertensive emergency.
If there are no symptoms, or any new or progressive end organ damage, and the systolic blood pressure rises above 240 mmHg and diastolic over 140 mmHg, it is of hypertensive urgencyto go out, in which the pressure within 24 to 48 hours to lower. Usually the outpatient treatment is sufficient. Massively increased pressure with concomitant hypertonic grade III-IV and severe perioperative hypertension are among the hypertensive urgencies. Most affected are patients with long-term elevated blood pressure. Not infrequently, the event is due to irregular ingestion or abrupt discontinuation of antihypertensive drugs.
Much rarer are hypertensive emergencies, In this case, acute end organ damage (to the heart, brain, kidneys, large vessels, etc.) requires immediate hospitalization and rapid, usually intensive care treatment and monitoring, for example in hypertensive encephalopathy, acute left ventricular failure with pulmonary edema, unstable angina and myocardial infarction, aortic dissection, eclampsia, intracerebral hemorrhage and ischemic insult.
Hypertensive urgency
Because of the risk of ischemic organ damage, it is important to avoid lowering the blood pressure too quickly or bringing it into the hypotensive area. If "external" causes of hypertension such as urinary retention, pain or medication (withdrawal, comedication, interaction, etc.) can be ruled out, the blood pressure normalises for every third patient within an hour if he lies down in a quiet room. If this is not enough, antihypertensive patients will receive an additional dose of their usual medication.
In addition, oral antihypertensive drugs with moderately rapid onset of action such as ACE inhibitors, loop diuretics, alpha agonists such as clonidine (CATAPRESAN et al.) Or possibly beta-receptor blockers may be used. In case of pre-existing antihypertensive therapy, volume depletion (eg due to diuretics), old age or cerebrovascular diseases it is recommended to choose a low dose. Before taking a second dose, there is enough time to assess the effect of the first one.
The usual practice in this country of treating asymptomatically increased levels with nifedipine sublingually, is not justified. There is no need for the potentially risky rapid pressure reduction caused thereby, especially as there is a risk of pronounced reflex tachycardia.
Decisive for the choice of the extreme pressure agent and the extent of the desired pressure reduction is the underlying clinical picture. As a guideline, reduce the arterial mean pressure * within minutes to hours by a maximum of 20% to 25%. To avoid excessive blood pressure drop, the intervention should be well controllable. Efficacy, reliability and potency, manageability and potential adverse effects are further selection criteria for the antihypertensive. Familiarity with a drug can also influence the decision.
*Arterial mean pressure is roughly equivalent to diastolic blood pressure plus a third of the difference in systolic and diastolic pressures, eg, 133 at 200/100 mmHg.
US recommendations give priority to parenteral therapy, primarily with nitroprusside sodium (NIPRUSS), and therefore good controllability. Our consultants unanimously criticize the elaborate handling of nitroprusside sodium, which because of its potency requires close-meshed, possibly intra-arterial blood pressure control and thus intensive monitoring. More commonly used in this country is the less well controlled alpha blocker Urapidil (EBRANTIL).
SPECIAL INDICATIONS: The hypertensive encephalopathyis now rare. Patients with long-standing, often not or only insufficiently adjusted high blood pressure are affected, as are pregnant women with pre-eclampsia and a sudden increase in pressure. Headache, nausea, vomiting, blurred vision, confusion and focal neurological deficits are typical symptoms. The blood pressure is usually massively increased. Prior to drug intervention, other causes should be excluded, especially intracerebral haemorrhage and cerebral insult, as excessively rapid and rapid reductions in blood pressure place these patients at risk.It is recommended that the mean arterial pressure be reduced by a maximum of 20% to 25% within two hours; but not below 100 mmHg to lower diastolic. However, only well controllable agents such as nitroprusside-Na, alternatively parenteral glycerol trinitrate (TRINITROSAN etc.) are suitable for this purpose. The Urapidil common in this country is less controllable. Dihydralazine (NEPRESOL et al.) Is considered the drug of choice for preeclampsia . If the blood pressure is over 160/110 mmHg, treat immediately. To prevent worsening of uteroplacental perfusion, the pressure must not be lowered excessively.
Up to 80% of all patients with ischemic stroke or intracerebral haemorrhagehave hypertensive blood pressure at the time of the event. These can be the cause as well as the consequence of the event. About every second suffers from pre-existing hypertension. The indication for pressure reduction is reserved, as enlargement of the infarcted area or worsening of cerebral blood flow is to be expected. Most patients normalize pressure within 48 hours after the event without any further therapeutic intervention. Only diastolic values above 120 to 130 mmHg are considered treatment indication. For larger intracerebral hemorrhages, some authors recommend an intervention of systolic 200 mmHg or diastolic over 120 mmHg. Within 24 hours, the mean arterial pressure should be lowered by a maximum of 20%. Caution: Patients with brain insult are particularly sensitive to antihypertensives. Therefore, it is not recommended to take antihypertensive measures in ambulant emergency aid. The few insult patients whose blood pressure must be actively lowered are to be monitored as intensively as possible or in a "stroke unit". This demand can often not be realized in the opinion of our consultants in this country. Because of good controllability nitroprusside-Na is the drug of choice, as a reserve means Urapidil is considered. For glyceryl trinitrate, restraint is considered to be more likely to increase intracerebral pressure.
Patients with subarachnoid hemorrhagebenefit from nimodipine, when survival and severity of long-term care are measured. What influence the hypotensive effect of the therapy has there remains open.
In angina or myocardial infarction , glycerol trinitrate is the drug of choice in ambulatory emergency as a spray, in the clinic parenterally. Therapeutic goal is symptom-free or decrease of mean arterial pressure by 30%, but not below 80 mmHg. The systolic value should be at least 90 mmHg, the heart rate should not increase by more than 10 beats per minute. Combination with a beta-blocker such as metoprolol. Avoids an excessive increase in frequency.
For hypertensive pulmonary edema , rapid pressure reduction is indicated within minutes. In addition to loop diuretics, glycerol trinitrate is the drug of choice in ambulatory first aid as a spray. If the effect is not sufficient, nitroprusside sodium may be appropriate. Some authors also recommend the ACE inhibitor Enalaprilat (XANEF). In terms of differential diagnosis, aortic dissection should be considered in all patients with critically elevated pressures and chest, back or abdominal pain. In acute aortic dissection , the pressure must be reduced as quickly as possible. The diastolic value must not exceed 100 mmHg. The drug of choice is nitroprusside sodium in combination with a beta-blocker. 7However, a vasodilating agent must not be used because it does not sufficiently reduce the shear forces on the aortic wall.
HIGH PRESSURE MEDICINE FOR THE TREATMENT OF HYPERTENSIVE URGENCY OR EMERGENCIES
Nitroprusside sodium (NIPRUSS) acts via the active metabolites nitric oxide (NO) formed in the smooth muscle. The strong dilating effect is almost equally pronounced on arteries and veins, the heart rate increases only slightly, the myocardial oxygen consumption decreases. The effect starts within 30 seconds after the beginning of the infusion and reaches its maximum after two minutes. Three minutes after the end of the infusion, no more blood pressure-lowering effect can be detected. Unexpected pressure drops can therefore be corrected quickly. Because of the high strength of the pressure is closely meshed, if possible to monitor intraarterial.
Nitroprusside sodium is degraded to cyanide, converted to thiocyanate by thiosulfate and excreted as such via the kidneys. Cyanide and thiocyanate intoxication is especially to be expected when the physiological thiosulphate levels are overly demanding and the renal function is impaired. The US Food and Drug Administration (FDA) recommends that you do not infuse sodium nitroprusside for more than ten minutes at maximum doses. These are rarely needed. In this country it is advised to give sodium thiosulphate for the prevention at the same time. As a direct vasodilator, nitroprusside sodium can increase cerebral perfusion and increase intracranial pressure.
The infusion solution must be protected from light. Despite repeated requests, the NO donor is still not supplied ready for use with light-protected infusion system, which makes handling unnecessarily difficult.
Glyceryl trinitrate (nitroglycerin, TRINITROSAN, etc.) also acts as a vasodilator via NO. In low doses, the effect predominates in the venous limb of the circulation; higher doses also have an effect on the arterial vascular system. Sublingual used or sprayed into the oral cavity, the effect starts after 1-3 minutes and lasts for 30-60 minutes. When administered intravenously via the perfusor, the nitrate acts within 1-2 minutes lasting 3-5 minutes.
Significant undesirable effects include headache and increased intracranial pressure increase compared to nitroprusside sodium. The extent of possible reflex tachycardia depends on the filling state of the heart chambers. If pre-existing volume depletion angina pectoris attacks are possible. Tolerance develops with long-term use.
Urapidil (EBRANTIL) is mainly recommended in Germany. In Denmark, Sweden, Canada and the US, the product is not authorized. It blocks postsynaptic alpha-1 receptors and stimulates central serotonin receptors. The peripheral resistance decreases without the heart rate rising. The effect starts within 5 minutes after starting the infusion and lasts for 4-6 hours. It is therefore less well controlled.
The intracranial pressure should not affect Urapidil. Severe hypotension is expected in approximately 4% of patients. 24 headache, dizziness, nausea, vomiting, feeling of pressure behind the breastbone can occur, among others, and are mainly due to too rapid lowering of blood pressure.
Enalaprilat(XANEF) is the only available intravenous ACE inhibitor. The effect begins after 15-30 minutes and lasts for about 6 hours (difficult to control). Excessive pressure reduction is expected, especially in patients with pre-existing volume depletion or kidney-induced hypertension. For hypertensive urgency, captopril per os is considered. The effect begins 20-30 minutes after ingestion and lasts for 8-12 hours. We do not see the benefits of a sometimes suggested sublingual application.
The alpha and beta receptor blocker Labetalol frequently recommended in American literatureis no longer available in Germany, but in Switzerland (TRANDATE). He was taken off the market in this country because of severe liver damage. The beta-blocker used is predominantly metoprolol. About 1 minute after iv injection, the effect begins and lasts for 6-8 hours.
The loop diuretic Furosemide Reduces pressure by increasing sodium chloride secretion as well as reducing blood volume and smooth muscle responsiveness to vasoconstrictor stimuli. The natriuretic effect begins 5 minutes after iv injection and lasts about 2 hours. After ingestion per os is expected to begin within one hour and lasting 6-8 hours.
Indications for otherwise obsolete because of pronounced immunoallergenic interferences vasodilator dihydralazine is the parenteral acute treatment of pronounced hypertension in the last trimester of pregnancy. In early pregnancy it is contraindicated for teratogenic effects. The effect starts after 5-10 minutes and lasts 4-6 hours. Reflex tachycardia and hypotension occur.
Clonidine Is not suitable for hypertensive emergency due to poor controllability and sedative properties that may complicate assessment of a patient's neurological status. In case of urgency, the 30-60 minute alpha agonist is the reserve agent. The antihypertensive effect lasts for 6-8 hours.
Diazoxide (HYPERTONALUM) is increasingly considered obsolete due to excessive blood pressure drop and pronounced reflex tachycardia in hypertensive crisis. cave fluid retention. It must not be used for angina pectoris, myocardial infarction, aortic aneurysm or pulmonary edema.
Nifedipine sublingual Is still widely used in this country for acute treatment. The effect begins after 5-10 minutes, reaches the maximum after 20-30 minutes and lasts for 2-5 hours. There is danger of overreaction. Reflex tachycardia carries the risk of cardiac ischemia. Therefore, calcium antagonists from the dihydropyridine (nifedipine) group with rapid onset of action should not be prescribed for unstable angina pectoris and acute myocardial infarction. 16 reports of serious side effects of sublingual nifedipine are mainly cerebrovascular and cardiac ischemia, two patients died after heart attack. Because of poor controllability and possible life-threatening consequences, the use of nifedipine in hypertensive emergencies or urgencies is therefore prohibited.
CONCLUSIONS: A hypertensive crisis can be life-threatening if the increase in blood pressure causes clinical symptoms or organ damage. Rapid reduction of pressure, regardless of clinical circumstances, may endanger patients. The distinction between hypertensive urgency and hypertensive emergency prevails in this country more and more. In the case of hypertensive urgencies, ie the absence of symptoms or acute end organ damage, it is possible to first wait while the patient lies down in a quiet room. If the blood pressure remains high, an additional dose of continuous medication or other oral antihypertensive drugs with moderately rapid onset of action such as captopril may be taken. It is enough to reduce the pressure within 24 to 48 hours.
Hypertension associated with acute end-organ damage such as heart attack or pulmonary edema is a hypertensive emergency. Patients must go to the clinic immediately. How fast, how strong and with what means the pressure is reduced, depends on the clinical circumstances. In order to avoid excessive reactions, the therapy should be well controllable. Apart from outpatient first aid measures, therefore, parenteral treatment is required, primarily with nitroprusside sodium (NIPRUSS) or glyceryl trinitrate (TRINITROSAN etc.). The more commonly used alpha-blocker Urapidil (EBRANTIL) is easy to handle, but due to its lasting effect up to six hours, it is less effective to control.
Contrary to the widespread practice of treating critically elevated blood pressure with non-sustained nifedipine, We do not see any therapeutic need at the current level of knowledge of the drug. The rapid and sustained calcium antagonist endangers patients by uncontrollable excess blood pressure drop with ischemic complications.