Hypertensive Crisis

Hypertensive CrisisNURS 3305Hypertensive crisis (pp. 709-729); Ch 36 Hypertension (pp. 409-415)Copyright 2014 by Mosby, an imprint of Elsevier Inc.1Factors Influencing BPCopyright 2014 by Mosby, an imprint of Elsevier Inc.Blood PressureCardiac OutputSystemic Vascular Resistance=2Blood pressure (BP) is the force exerted by the blood against the walls of the blood vessel. It must be adequate to maintain tissue perfusion during activity and rest. The maintenance of normal BP and tissue perfusion requires the integration of both systemic factors and local peripheral vascular effects. BP is primarily a function of cardiac output (CO) and systemic vascular resistance.

Co = total blood flow through the systemic or pulmonary circulation per minute.Systemic vascular resistance (SVR) = the force opposing the movement of blood within the blood vessels. Factors Influencing BPCopyright 2014 by Mosby, an imprint of Elsevier Inc.

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Classification of Hypertension from JNC VII

CategorySystolic BPDiastolic BPNormal1004Etiology of HypertensionPrimary hypertension Also called essential or idiopathic hypertensionExact cause unknown but several contributing factors

90% to 95% of all casesCopyright 2014 by Mosby, an imprint of Elsevier Inc.5Primary (essential or idiopathic) hypertension is elevated BP without an identified cause, and it accounts for 90% to 95% of all cases of hypertension. Although the exact cause of primary hypertension is unknown, there are several contributing factors. These include increased SNS activity, overproduction of sodium-retaining hormones and vasoconstricting substances, increased sodium intake, greaterthan-ideal body weight, diabetes mellitus, tobacco use, and excessive alcohol consumption. Etiology of HypertensionSecondary hypertensionElevated BP with a specific causeClinical findings relate to underlying cause Treatment aimed at removing or treating causeIs a contributing factor to hypertensive crisis.

Copyright 2014 by Mosby, an imprint of Elsevier Inc.6Secondary hypertension is elevated BP with a specific cause that often can be identified and corrected (Table 33-3). This type of hypertension accounts for 5% to 10% of hypertension in adults. Secondary hypertension should be suspected in people who suddenly develop high BP, especially if it is severe. Clinical findings that suggest secondary hypertension relate to the underlying cause. HypertensionComplicationsTarget organ diseases occur most frequently in theHeartBrainPeripheral vascular disease KidneyEyesCopyright 2014 by Mosby, an imprint of Elsevier Inc.7Heart - Hypertension is a major risk factor for coronary artery disease (CAD). Sustained high BP increases the cardiac workload and produces left ventricular hypertrophy. Heart failure occurs when the hearts compensatory mechanisms are overwhelmed and the heart can no longer pump enough blood to meet the bodys demands (see Chapter 35). Contractility is depressed, and stroke volume and CO are decreased.

Cerebrovascular - Atherosclerosis is the most common cause of cerebrovascular disease. Hypertension is a major risk factor for cerebral atherosclerosis and stroke. Hypertensive encephalopathy may occur after a marked rise in BP if the cerebral blood flow is not decreased by autoregulation.

PVD - Hypertension speeds up the process of atherosclerosis in the peripheral blood vessels. This leads to the development of peripheral vascular disease, aortic aneurysm, and aortic dissection (see Chapter 38). Intermittent claudication (ischemic leg pain precipitated by activity and relieved with rest) is a classic symptom of peripheral vascular disease.

Kidney - Hypertension is one of the leading causes of chronic kidney disease, especially among African Americans. Renal disease results from ischemia caused by the narrowing of the renal blood vessels. This leads to atrophy of the tubules, destruction of the glomeruli, and eventual death of nephrons.

Eyes - Damage to the retinal vessels provides an indication of related vessel damage in the heart, brain, and kidneys. Manifestations of severe retinal damage include blurring of vision, retinal hemorrhage, and loss of vision.

Drug TherapyCopyright 2014 by Mosby, an imprint of Elsevier Inc.

Site and method of action of various antihypertensive drugs (bold type). ACE, Angiotensin-converting enzyme.

There are two types of angiotensin inhibitors. The first type is angiotensin-converting enzyme (ACE) inhibitors. These prevent the conversion of angiotensin I to A-II and thus reduce A-II-mediated vasoconstriction and sodium and water retention. The second type is A-II receptor blockers (ARBs). These prevent A-II from binding to its receptors in the blood vessel walls. 8

Case Study C.S. is referred to his health care provider to follow up on his high blood pressure screening. His blood pressure is 225 /141 mmHg when checked in the physicians office.

What does this blood indicate? What are the potential effects of this blood pressure?Fuse/ThinkstockCopyright 2014 by Mosby, an imprint of Elsevier Inc.9Hypertensive CrisisHypertensive UrgencyHypertensive EmergencyOccurs over days to weeksBP > 180/110No evidences of target organ disease

Develops over hours to daysSeverely elevated BP (often >220/140 mmHg)Evidence of target organ diseaseCause target organ damage Heart (AMI) Brain (encephalopathy or stroke[SAH]), kidney (renal failure), Aorta (dissection), Eyes (retinopathy)Copyright 2014 by Mosby, an imprint of Elsevier Inc.10Hypertensive Crisis - EtiologyUntreated or uncontrolled hypertensionRenal dysfunctionPregnancyEndocrine disordersAcute aortic dissectionPostoperative complications after surgeryBurns

11Hypertensive CrisisClinical Manifestations/End organ damageHypertensive encephalopathyHeadache, n/v, seizures, confusion, comaRenal insufficiencyCardiac decompensationMI, HF, pulmonary edemaAortic dissectionCopyright 2014 by Mosby, an imprint of Elsevier Inc.12HypertensionNursing AssessmentCardiovascularVital signs BP in both arms initially, monitor frequently, arterial line may be indicated especially with IV vasodilatorsChest pain (AMI or Aortic dissection), dysrhythmiasNeurologicMental status changes, HA, blurred vision, papilledema, stroke, comaRenalSudden decrease/absence of UOP, renal failure

Copyright 2014 by Mosby, an imprint of Elsevier Inc.13HypertensionNursing AssessmentCatecholamine excess PheochromocytomaMAOI in combination with other drugs or foodsAbrupt withdrawal of of antihypertensive agents

Copyright 2014 by Mosby, an imprint of Elsevier Inc.14Hypertensive CrisisNursing/Collaborative ManagementHospitalizationIV drug therapy: titrated to MAPTitrate IV meds to lower pressure cautiouslyInitial goal: reduce by no more than 25% in first 2-6 hoursIschemic stroke (BP lowered slowly by 15-20%Aortic dissection (SBP < 100 mmHg)Copyright 2014 by Mosby, an imprint of Elsevier Inc.15Hypertensive CrisisNursing/Collaborative ManagementIV drug therapy: IV VasodilatorsNitrates NTG vasodilation (venous > arterial) decreases LVEDV (preload), decreases chest pain

Nitroprusside (Nipride) peripheral vasodilation (arterial & venous smooth muscle), decreases preload and afterloadNursing considerations avoid long term use due to cyanide toxicityCopyright 2014 by Mosby, an imprint of Elsevier Inc.16Hypertensive CrisisNursing/Collaborative ManagementOther Drug TherapyAce Inhibitors enalaprilDiuretics furosemideBeta blockers labetolol (alpha, beta blockade effect), esmolol (short acting beta blocker)Calcium channel blockers nicardipine, cardizem, verapamilDopamine receptor antagonist fenoldopamAlpha blocker phentolamineHydralazine

Copyright 2014 by Mosby, an imprint of Elsevier Inc.17Hypertensive CrisisNursing/Collaborative ManagementMonitor for possible complicationsMonitor cardiac and renal functionPerform Neurologic checksDetermine cause of hypertensive crisis after resolvedEducation to avoid future crisisCopyright 2014 by Mosby, an imprint of Elsevier Inc.18Discharge Teaching

DietLow sodium, low fat diet. Lower cholesterol levels to < 200 mg/dL total and LDL