Cardiac

Headache and Hypertension

  • In patients with headaches, consider hypertension as a potential cause.

  • Patients often report headaches when experiencing high blood pressure, indicating a correlation.

Understanding Hypertension

  • Hypertension is often referred to as the "silent killer" due to its potential to cause organ damage over time without noticeable symptoms.

  • Microscopic Issues: High pressure in arterioles may cause small vessels to burst, particularly behind the eyes.

  • Macroscopic Issues: Chronic hypertension can lead to organ damage, such as chronic kidney disease or renal failure due to prolonged stress on organs.

Treatment of Hypertension

  • There are multiple strategies for managing high blood pressure, focusing on controlling:

    • Heart rate

    • Stroke Volume

    • Cardiac Output: Defined as the volume of blood pumped by the heart, calculated by the formula:

      Cardiac Output=Heart Rate×Stroke Volume\text{Cardiac Output} = \text{Heart Rate} \times \text{Stroke Volume}

    • Systemic Vascular Resistance: Can be understood as the resistance to blood flow in the vessels, linked to blood pressure through the equation:

      Blood Pressure=Cardiac Output×Systemic Vascular Resistance\text{Blood Pressure} = \text{Cardiac Output} \times \text{Systemic Vascular Resistance}

Components of Cardiac Function

  • Heart Rate (HR): Measured in beats per minute, it is the frequency at which the heart contracts.

  • Stroke Volume (SV): The amount of blood ejected with each heartbeat. Measured as Ejection Fraction (EF) via echocardiogram (echo).

    • Ejection Fraction Measurement: Ejection fraction typically ranges from 50% to 70% in healthy individuals, indicating the percentage of blood ejected relative to total volume in the ventricle.

Vasoconstriction and Vasodilation

  • Vascular resistance influences blood pressure significantly:

    • Vasoconstriction: Increases pressure (e.g., from smoking or caffeine).

    • Vasodilation: Lowers blood pressure, often seen in conditions like septic shock.

    • Using the garden hose analogy, if resistance increases by closing off the end, flow decreases, analogous to vascular resistance in the body.

Medications for Blood Pressure Management

  • Beta Blockers (end in -LOL): Lower heart rate; contraindicated if heart rate < 50 bpm.

    • Examples include Atenolol, Labetalol, Propranolol.

  • ACE Inhibitors (suffix -PRIL): Cause vasodilation, examples include Lisinopril, Captopril.

  • Angiotensin Receptor Blockers (ARBs) (suffix -SARTAN): Work similarly to ACEs; examples include Losartan, Valsartan.

  • Important that patients are educated about potential orthostatic hypotension when taking these medications.

Heart Failure and Cardiac Output

  • Heart failure is defined as the heart's inability to pump sufficient blood, impacting cardiac output.

  • Right-Sided Heart Failure: Blood backs up into the right atrium, causing volume overload and resulting in edema and jugular vein distension (JVD).

  • Left-Sided Heart Failure: Leads to poor perfusion to lungs, manifesting as pulmonary edema and possible pink, frothy sputum.

    • In left-sided heart failure, we measure pulmonary arterial wedge pressure, while right-sided relies on central venous pressure.

  • Medications used in heart failure often include diuretics to manage fluid overload, noting potassium balance issues (e.g., Furosemide causes hypokalemia, Spironolactone can cause hyperkalemia).

  • Edema management correlates to diuretics, with strict management of input and output (I&O).

    • Daily weights are crucial, as 1 liter of fluid = 1 kilogram (\text{~}2.2 pounds).

Ejection Fraction and Diagnostic Tests

  • An echocardiogram is used to find ejection fraction, which is vital in diagnosing heart failure severity.

  • A normal range should be maintained for effective perfusion; low ejection fractions indicate potential heart failure.

Monitoring in ICU and Heart Failure

  • In the ICU settings, central venous pressure (CVP) monitoring is essential for evaluating right-sided heart failure.

  • The goal is a decrease in CVP with fluid management.

  • Hypotension management during heart failure is crucial to optimize cardiac output.

  • Patients can experience respiratory acidosis due to fluid overload in heart failure.

Key Concepts to Remember

  • Heart failure definitions reflect pump failure and associated cardiogenic shock.

  • B-type natriuretic peptide (BNP) levels are indicative of heart failure, with elevated values signaling worsening conditions.

  • Understand orthopnea, nocturnal dyspnea, and paroxysmal nocturnal dyspnea in heart failure cases.

    • These terms refer to varying difficulties in breathing related to position and time.

Distinguishing Between Right and Left Heart Failure

  • Right-sided failure is associated with the body (rest of body), leading to fluid back-up symptoms like JVD and edema.

  • Left-sided failure is directly related to the lungs, evident through pulmonary edema and antiflux sputum.

  • Clinical evaluations require identifying these differences during assessments for effective interventions.

Treating Angina and Myocardial Infarctions

  • Angina is a symptom of coronary artery disease; the types include stable, unstable, and variant angina, with treatment options focused on oxygenation and vasodilation.

  • EKG and cardiac biomarkers (e.g., troponin, CKMB, myoglobin) assist in evaluating suspected myocardial infarctions.

    • An STEMI (ST-elevation myocardial infarction) indicates a complete blockage of a coronary artery, leading to a lack of oxygen in the heart muscle.

  • The mnemonic MONA for treatment: Morphine, Oxygen, Nitroglycerin, Aspirin. This can also be referred to as "Old Faithful" in some contexts for its consistent use.

  • Thrombolytics can be administered when an MI is caused by a clot, aiming to dissolve the clot and restore blood flow.

    • A significant adverse reaction of thrombolytics is the risk of brain bleeds.

Shock Management

  • Various shock types require tailored treatments depending on underlying causes (e.g., cardiogenic, hypovolemic, septic).

  • Vasodilation and hypotension are common outcomes across multiple shock forms; fluid resuscitation strategies must align with shock type.

  • Neurogenic shock may present with bradycardia as an exception within the broad category.

    • Treatments focus on restoring circulation and perfusion, including the use of epinephrine in anaphylactic situations to counteract vasodilation and bronchoconstriction.

Additional Considerations in Care

  • Monitor vital signs consistently, especially during medication interventions for hypertension and cardiac conditions.

  • Seek further management in cases of worsening symptoms, especially concerning chest pain or congestive heart failure.

Peripheral Vascular Disease (PVD)

  • Involves oxygen-poor blood returning to the heart from the legs (venous insufficiency).

  • Management includes:

    • Elevating legs (legs up) to promote venous return.

    • Assessing BOTH pulses bilaterally.

    • DO NOT CROSS LEGS to avoid impeding blood flow.

    • Avoid tight socks; wear compression stockings instead to support venous return.

Peripheral Artery Disease (PAD)

  • Involves insufficient arterial blood flow to the extremities, primarily the legs.

  • Characteristics and Management:

    • Position affected leg down (dependent position) to enhance arterial flow.

    • Can cause loss of hair on the extremities, shiny skin, and thickened toenails.

    • Intermittent claudication: Leg cramping that occurs during activity (e.g., walking) but improves with rest.

    • A femoral popliteal bypass procedure can be performed to restore blood flow.

    • NO COMPRESSION STOCKINGS with PAD, as they can further impair arterial flow.