|
|
|
|
Hypertension - Contraindications HYPERTENSIVE CRISES: EMERGENCIES AND URGENCIES Hypertensive emergencies are those rare situations that require immediate blood pressure reduction (not necessarily to normal ranges) to prevent or limit target organ damage. Examples include hypertensive encephalopathy, intracranial hemorrhage, unstable angina pectoris, acute myocardial infarction, acute left ventricular failure with pulmonary edema, dissecting aortic aneurysm, or eclampsia. Hypertensive urgencies are those situations in which it is desirable to reduce blood pressure within a few hours. Examples include upper levels of stage 3 hypertension, progressive target organ complications, and severe perioperative hypertension. Elevated blood pressure alone, in the absence of symptoms or new or progressive target organ damage, rarely requires emergency therapy.Parenteral drugs for hypertensive emergencies are listed in table 10. Most hypertensive emergencies are treated initially with parenteral administration of an appropriate agent. Hypertensive urgencies can be managed with oral doses of drugs with relatively fast onset of action. The choices include loop diuretics, betablockers, ACE inhibitors, alpha 2 agonists, or calcium antagonists. The initial goal of therapy in hypertensive emergencies is to reduce mean arterial blood pressure by no more than 25 percent (within minutes to 2 hours), then toward 160/100 mm Hg within 2 to 6 hours, avoiding excessive falls in pressure that may precipitate renal, cerebral, or coronary ischemia. Although sublingual administration of fastacting nifedipine has been widely used for this purpose, several serious adverse effects have been reported with its use and the inability to control the rate or degree of fall in blood pressure makes this agent unacceptable. The routine use of sublingual nifedipine whenever blood pressure rises beyond a predetermined level in postoperative or nursing home patients is also not appropriate. Rather, the proximate causes of the elevated blood pressure, such as pain or a distended urinary bladder, should be addressed. Blood pressure should be monitored over 15 to 30minute intervals; if it remains greater than 180/120 mm Hg, one of the previously mentioned oral agents may be given. If such high levels of blood pressure are frequent, adequate doses of longacting agents should be provided. |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Read the terms under which this service is provided to you, and our privacy. guidelines.
© Copyright 1999-2000 BHC.com, LLC. All Rights Reserved.
