Cardiovascular System: Blood Flow, Pressure, and Shock Management

What is the function of arteries?

Carry oxygenated blood away from the heart under high pressure; assess pulses, color, and refill to evaluate perfusion.

What is the function of veins?

Return deoxygenated blood to the heart under low pressure; promote mobility and compression to enhance venous return.

What do capillaries do?

Connect arteries and veins for oxygen, nutrient, and waste exchange; slow refill or cyanosis signals poor perfusion.

What is Mean Arterial Pressure (MAP)?

Average pressure driving blood through systemic circulation; maintain ≥65 mm Hg to ensure organ perfusion.

What does Systemic Vascular Resistance (SVR) represent?

The opposing force to blood flow; high in hypertension, low in sepsis; guides afterload management.

What defines hypertension?

Chronic high blood pressure that damages arterial walls and organs; managed with lifestyle change and medications.

What is atherosclerosis?

Plaque buildup in arteries causing narrowing and reduced elasticity; base of most coronary and carotid disease.

What is Peripheral Artery Disease (PAD)?

Narrowing of peripheral arteries causing leg pain with exertion relieved by rest; protect feet and encourage walking to tolerance.

What is an aneurysm?

Localized dilation of an arterial wall; monitor size and BP, report sudden back or abdominal pain.

What is Deep Vein Thrombosis (DVT)?

Clot formation in deep veins causing swelling and warmth; avoid massage and use anticoagulants.

What is a Pulmonary Embolism (PE)?

Embolus obstructs pulmonary arteries; sudden dyspnea, chest pain, tachycardia; give oxygen and anticoagulants.

What causes varicose veins?

Valve incompetence leading to dilated, twisted veins; improve with elevation and compression.

What is Chronic Venous Insufficiency?

Venous valve failure causing stasis and skin changes; promote ambulation, elevation, compression.

How do ACE inhibitors like lisinopril work?

Block angiotensin II formation → vasodilation and lower BP; monitor BP, potassium, renal function, cough.

How do ARBs such as losartan work?

Block angiotensin II receptors to lower vascular tone; monitor potassium and renal function.

What is the effect of calcium channel blockers?

Relax arterial smooth muscle to reduce BP; monitor for hypotension and edema; avoid grapefruit juice.

How do beta-blockers lower blood pressure?

Slow HR and contractility; hold if HR < 60 bpm; avoid abrupt withdrawal.

What is the action of thiazide diuretics?

Promote sodium and water loss to reduce volume; monitor electrolytes and orthostatic hypotension.

What are loop diuretics used for?

Rapid volume removal in overload; monitor potassium, urine output, and hearing.

Why are statins prescribed?

Lower LDL cholesterol and stabilize plaques; take at night, report muscle pain, monitor liver function.

What do antiplatelet drugs do?

Prevent platelet aggregation and clot formation; monitor for bleeding.

What is the purpose of anticoagulants like warfarin or heparin?

Inhibit clotting factors to prevent thrombosis; monitor INR/aPTT and teach bleeding precautions.

How do vasodilators such as hydralazine or nitroglycerin help?

Relax smooth muscle and reduce afterload; monitor for hypotension and teach slow position changes.

What is the main nursing goal in maintaining perfusion?

Keep MAP ≥ 65 mm Hg by adjusting fluids or antihypertensives; observe pulses and skin color.

How can nurses prevent thrombus formation?

Encourage mobility, compression stockings, and anticoagulant therapy; assess for swelling or tenderness.

What lifestyle modifications reduce vascular risk?

Follow DASH diet, exercise regularly, and stop smoking to improve BP and lipid profile.

How can vascular complications be prevented?

Protect skin, avoid leg crossing, manage wounds; maintain intact skin and perfusion.

What happens in hypovolemic shock?

Circulating volume loss decreases preload and cardiac output; caused by bleeding, burns, dehydration; treat with rapid fluids.

What defines cardiogenic shock?

Pump failure lowers cardiac output; caused by MI or heart failure; treat with inotropes and afterload reduction.

What occurs in distributive shock?

Widespread vasodilation and capillary leak cause relative hypovolemia; treat with fluids, vasopressors, and underlying cause.

What is obstructive shock?

Blood flow is physically blocked (e.g., tamponade, PE, pneumothorax); relieve obstruction.

What fluids are used to restore preload?

Normal saline or lactated Ringer's; warm fluids, monitor lungs and urine output.

What are vasopressors used for?

Constrict vessels to raise MAP; administer via central line, titrate, monitor perfusion.

What do inotropes such as dobutamine do?

Increase contractility and cardiac output; monitor ECG and ensure adequate volume first.

How do vasodilators aid shock management?

Decrease afterload and oxygen demand; require continuous BP monitoring.

Why are antibiotics given in septic shock?

To eliminate infection source; obtain cultures before giving first dose.

What is the role of corticosteroids in shock?

Restore vascular tone and reduce inflammation; monitor glucose and infection risk.

What does epinephrine do physiologically?

Acts on alpha and beta receptors to increase HR, contractility, and vascular tone; first-line for anaphylaxis.

What is a normal Mean Arterial Pressure (MAP)?

65-105 mm Hg; indicates adequate organ perfusion.

What does Central Venous Pressure (CVP) measure?

2-8 mm Hg; reflects preload—low in hypovolemia, high in overload.

What is normal Cardiac Output (CO)?

4-8 L/min; low in pump failure, high in early sepsis.

What is normal Systemic Vascular Resistance (SVR)?

800-1200 dyn·s/cm⁵; high = vasoconstriction, low = vasodilation.

What does Mixed Venous O₂ Saturation (SvO₂) indicate?

60-80 %; low = poor oxygen delivery, high = inefficient use (sepsis).

What does elevated serum lactate mean?

>1.6 mmol/L indicates anaerobic metabolism and poor perfusion; falling levels show improvement.

What is the minimum urine output goal in shock?

≥ 0.5 mL/kg/hr; indicates adequate renal perfusion and volume status