Nursing 160 W8D2

Types of Perfusion

• Central Perfusion

  • Generated by Cardiac Output

    • Amount of blood pumped by the heart each minute.

    • Results from electrical and mechanical factors aiding blood movement from the heart to body vessels.

  • Impaired Central Perfusion

    • Conditions causing decreased cardiac output, such as:

      • Altered myocardial contraction (heart not pumping strongly).

      • Inadequate heart valve function (valves not closing properly).

      • Congenital heart defects.

    • Leads to reduced oxygenated blood flow to organs, potentially causing ischemia (less than normal blood flow), tissue injury, and death.

      • Example: Occlusion of coronary artery (heart attack leads to myocardial infarction - MI).

Tissue Perfusion

• Refers to blood flow through arteries and capillaries to target tissues.

• Determined by Arterial Blood Pressure, affected by cardiac output and Systemic Vascular Resistance (SVR) (peripheral vascular resistance).

  • Blood vessels can constrict (decrease diameter) or dilate (increase diameter) to regulate blood pressure and oxygen delivery.

• Impaired Tissue Perfusion

  • Results from interference or reduced blood flow to capillaries, preventing adequate oxygen delivery.

  • Causes include arterial blockage or excessive edema (swelling that compresses blood vessels).

• Factors affecting cardiac output include heart rate, arrhythmias, blood volume, heart muscle contractility, medications, and heart disease.

Preload and Afterload

• Preload:

  • Amount of blood in the ventricle at the end of diastole.

  • End diastolic pressure correlates with stroke volume and cardiac output.

  • Greater preload leads to stronger myocardial contraction.

• Afterload:

  • Pressure the heart must work against to eject blood.

  • Influenced by vessel diameter: narrower vessels create higher afterload, increasing heart's workload.

  • Example: Hypertension increases afterload.

Risk Factors for Impaired Perfusion

• Anyone can be at risk, but some modifiable factors include:

  • Diet (high sodium, high fat).

  • Physical activity (inactivity contributes to hypertension).

  • Smoking (nicotine constricts blood vessels).

• Older adults more vulnerable:

  • Decreased coronary artery blood flow, stroke volume, cardiac output.

  • Stiffening and thickening of heart muscle and blood vessels.

• Other factors:

  • Environmental (low income, limited access to healthcare).

  • Genetic predispositions (higher risk in certain ethnic groups).

  • Lifestyle factors (obesity, sedentary lifestyle).

Symptoms of Impaired Perfusion

• Pain: Chest pain (due to ischemia), leg pain (intermittent claudication in PAD).

• Syncope (fainting): Often due to inadequate cerebral perfusion.

• Dizziness: Often from blood pressure drops (orthostatic hypotension).

• Shortness of Breath (Dyspnea): Common in heart failure.

• Edema: Pitting edema indicates fluid overload in legs.

• Fatigue: Can indicate inadequate tissue oxygenation.

Assessment and Diagnosis

• Gather history including:

  • Present health status, family history, chronic diseases (hypertension, diabetes).

  • Medications (including over-the-counter and illicit drugs).

  • Lifestyle habits (diet, exercise, smoking, alcohol use).

• Conduct physical exams and monitor vital signs (check for hypertension, tachycardia).

• Diagnostic tests include:

  • Electrocardiograms (EKG) for heart rhythm.

  • Stress tests to evaluate cardiac perfusion under exertion.

  • Echocardiogram for structural/functional heart analysis.

  • Blood tests for lipid levels, CBC to assess red blood cell status.

Treatment Approaches

• Primary Prevention:

  • Lifestyle modifications (diet, exercise, smoking cessation).

• Secondary Prevention:

  • Regular screenings (blood pressure, lipid levels).

• Tertiary Prevention:

  • Cardiac rehabilitation post-heart event (rehab to strengthen heart).

• Medications:

  • Vasopressors, diuretics, anti-dysrhythmic agents, blood thinners, anti-lipid medications.

• Surgical interventions:

  • Pacemakers, defibrillators, heart valve replacements, CABG (coronary artery bypass grafting).

Complications of Hypertension

• Can lead to coronary heart disease, stroke, heart failure, kidney failure, and damage to the eyes.

• Hypertension is a leading global cause of death.

Special Considerations

• Symptoms differ by gender; women may present atypically during heart attacks (e.g., breathlessness rather than chest pain).

• Importance of recognizing signs of inadequate perfusion and acting quickly.