Perfusion, Hypertension, and Coronary Artery Disease: Key Concepts and Interventions

Perfusion

The flow of blood through arteries and capillaries delivering nutrients and oxygen to cells.

Central perfusion

Force of blood movement generated by cardiac output; requires adequate cardiac function, blood pressure, and blood volume.

Cardiac output

Stroke volume x heart rate.

Stroke volume

Impacted by preload, afterload, and contractility.

Preload

Degree of stretching of the ventricular muscle at the end of diastole.

Afterload

Resistance of pressure that the ventricle needs to overcome to eject blood into the circulation.

Contractility

Force that the myocardium generates during contraction.

Tissue perfusion

Volume of blood to the target tissues; requires patent vessels, adequate hydrostatic pressure, and capillary permeability.

Impaired central perfusion

Occurs when cardiac output is inadequate, leading to reduced oxygenated blood reaching body tissues.

Impaired tissue perfusion

Associated with loss of vessel patency or permeability or inadequate central perfusion.

Labs and diagnostics

Includes creatine, kinase, dehydrogenase, natriuretic peptides, troponin, homocysteine, C-reactive protein, serum lipids, platelets, prothrombin time, partial thromboplastin time, international normalized ratio, EKG, cardiac stress tests, and radiographic studies.

Clinical management

Treatment strategies depend on underlying condition, including diet modification, increased activity, smoking cessation, and pharmacotherapy.

Pharmacotherapy

Includes antihypertensives, antiarrhythmics, inotropics, antianginal agents, vasodilators, and vasopressors.

Tissue perfusion pharmacotherapy

Includes anticoagulants, thrombolytics, lipid-lowering agents, vasodilators, and antiplatelet agents.

Collaborative intervention for central perfusion

Includes pacemaker, electrical cardioversion, ablation therapy, intra-aortic balloon pump, cardiac valve surgery, and cardiac transplant.

Collaborative intervention for impaired tissue perfusion

Includes bypass and graft surgery, stent or angioplasty, and endarterectomy.

Cardiac monitoring

One large box is 0.2 seconds; one small box is 0.04 seconds.

Sinus bradycardia

Causes include sleep, vagal stimulation, hypothyroidism, and increased intracranial pressure.

Sinus tachycardia

Causes include exercise, excitement, heart failure, hyperthyroidism, caffeine, nitrates, and nicotine.

Sinus rhythm with PVC

Characterized by wide and bizarre QRS complexes; causes include heart disease and electrolyte imbalance.

Hypertension classification

Blood pressure > 130/80 for 2 or more assessments at least 2 weeks apart.

Essential hypertension

Most common type, results in damage to vital organs.

Secondary hypertension

Causes include kidney disease, primary aldosteronism, and Cushing disease.

Assessment for hypertension

Includes history, physical assessment, psychological assessment, and diagnostic tests.

Implementation for hypertension

Includes health teaching, promoting adherence to the plan of care, and nutrition.

Pharmacology for hypertension

Includes diuretics, specifically thiazide, which inhibit water and sodium.

Thiazine diuretics

Inhibit water and sodium reabsorption and increase potassium excretion.

Loop diuretics

Decrease sodium reabsorption and increase potassium excretion.

Potassium-sparing diuretics

Affect the distal tubule and prevent reabsorption of sodium in exchange for potassium.

Nursing actions for diuretics

Monitor potassium levels; Thiazide and loop diuretics can cause hypokalemia; Potassium-sparing can also lead to hypokalemia.

Calcium channel blockers

Alter the movement of calcium ions through the cell membrane, leading to vasodilation and decreased blood pressure.

Nursing actions for calcium channel blockers

Avoid grapefruit juice, monitor for hypotension and changes in heart rate, and change position slowly.

Angiotensin converting enzyme inhibitors

Prevent the conversion of angiotensin I to angiotensin II, which prevents vasoconstriction.

Nursing actions for ACE inhibitors

Monitor for hypotension and edema; report dry cough as a common side effect.

Angiotensin receptor blockers

Block the effects of angiotensin II at the receptor and decrease peripheral resistance.

Nursing actions for angiotensin receptor blockers

Monitor for angioedema, heart failure, and hyperkalemia.

Beta blockers

Block the sympathetic nervous system, producing a slower heart rate and decreased blood pressure.

Nursing actions for beta blockers

Monitor for hypotension and bradycardia; do not stop suddenly.

Central alpha-2 agonists

Reduce peripheral vascular resistance and decrease blood pressure by inhibiting reuptake of norepinephrine.

Nursing actions for central alpha-2 agonists

Monitor blood pressure and pulse; not first-line medication for hypertension.

Alpha adrenergic antagonists

Cause vasodilation to decrease blood pressure.

Nursing actions for alpha adrenergic antagonists

Monitor for postural hypotension and closely monitor at initiation of treatment.

Hypertensive crisis causes

Not taking medication or not taking it correctly.

IV hypertensives monitoring

Monitor blood pressure every 5-15 minutes before, during, and after administration.

Coronary artery disease (CAD)

Atherosclerosis where plaques start in childhood and continue throughout adulthood, causing narrowing and occlusion of arteries.

Risk factors for CAD

Modifiable: High BP, high cholesterol, smoking, obesity, sedentary lifestyle, diet, chronic stress, alcohol consumption; Non-modifiable: Advanced age, family history, sex, race/ethnicity.

Manifestations of CAD in males

Nausea/vomiting, jaw, neck or back pain, pressure or pain in chest, shortness of breath.

Manifestations of CAD in females

Nausea/vomiting, jaw, neck and upper back pain, sometimes chest pain, pressure or pain in lower chest or upper abdomen, shortness of breath, fainting, indigestion, extreme fatigue.

Diagnostics for CAD

Labs: cholesterol, homocysteine, inflammatory markers; ECG, echocardiogram, stress tests, cardiac catheterization.

Nursing interventions for CAD

Obtain clear history, head-to-toe assessment, cardiac rehab.

Patient education for CAD

Smoking cessation, DASH diet, physical activity, maintain healthy weight, social determinants of health.

Complications of CAD interventions

Medications, cardiac catheterization, coronary artery bypass graft surgery; quicker intervention reduces complications.

Peripheral vascular disease pathophysiology

Veins are damaged from infection or injury, occluded from blood clot, or altered due to congenital defect.

Diagnostics for peripheral vascular disease

Ankle brachial index, plethysmography, Doppler flow studies, ultrasound, d-dimer tests.