Cardiovascular System Overview

Cardiovascular System Overview

Primary Focus

  • Quick overview of the cardiac system.
  • Common problems associated with the system.
  • Preparation for cardiovascular assessment.
  • Specific cardiovascular assessment, focusing on circulation (C in ABC primary survey).
  • ECG recordings: performance and interpretation.
  • Examination of the clinical reasoning cycle.
  • Discussion of upcoming CPS class activities.

Overview of the Cardiovascular System

  • Main Function: Pumping blood around the body.
  • Heart: The central component, a muscular pump that contracts.
  • Purpose:
    • Delivers oxygen and nutrients to organs and tissues.
    • Returns waste products to the lungs and other excretory organs.
  • Location: Mediastinal space above the diaphragm, between the chest wall and lungs.
  • Anatomical Terms:
    • Base: Top of the heart.
    • Apex: Pointed part of the heart (bottom).
  • Circulatory System Components:
    • Arteries (typically red): Carry blood away from the heart.
    • Veins (typically blue): Return blood to the heart (except for one instance).
    • Venous blood return is aided by muscular contraction.
    • Oxygenated blood leaves the heart via contraction of the left atrium.

Heart Anatomy

  • Size: Roughly the size of your fist.
  • Chambers: Four distinct chambers, divided by septa (tissue dividing anatomical cavities).
    • Septum in the heart divides the left and right ventricles.
  • Ventricular Septal Defect (VSD): A hole between the left and right ventricles, allowing blood flow between chambers.
  • Blood Flow Through the Heart:
    • Right atrium receives deoxygenated blood from the superior and inferior vena cava.
    • Blood flows from the right atrium to the right ventricle.
    • Valves between chambers prevent backflow.
    • Tricuspid valve closes when the right ventricle contracts.
    • Blood flows out of the right ventricle through the pulmonary valve into the pulmonary artery.
    • Pulmonary artery carries deoxygenated blood to the lungs (the only artery to do so).
    • Oxygenated blood returns to the left atrium via the pulmonary vein (the only vein to do so).
    • Blood flows from the left atrium to the left ventricle and then out through the aorta.

Cardiac Output

  • Cardiac Output: Typically 4-5 liters per minute.
  • Calculation: Cardiac Output = Heart Rate eq Stroke Volume
    • Stroke Volume: Amount of blood (in milliliters) ejected from the left ventricle with each contraction.

Heart Function

  • Right Side: Primarily involved in oxygenation.
  • Left Side: Distributes oxygenated blood to organs and tissues.
  • Detailed Blood Flow:
    • Deoxygenated blood in the right ventricle is pumped out through the pulmonary artery to the lungs.
    • Blood becomes oxygenated in the lungs and returns to the left atrium via the pulmonary vein.
    • Oxygenated blood is pumped from the left atrium to the left ventricle and then out through the aorta to the body.
    • Blood returns to the right atrium via the superior and inferior vena cava, completing the cycle.
  • Pressure Systems:
    • Right side: Lower pressure, pumps blood to the lungs.
    • Left side: Higher pressure, pumps blood throughout the body.

Heart Rate Control

  • Sinoatrial (SA) Node:
    • Normal contraction control at 60-80 beats per minute.
    • Aided by the Vagus nerve and the sympathetic/parasympathetic nervous system.
  • Sympathetic Activity:
    • Flight or fight response; increases heart rate to meet oxygen and energy demands.
    • Controlled by the hypothalamus.
  • Parasympathetic Activity:
    • Recovery process; decreases heart rate to reduce oxygen and energy demands.
    • Controlled by the hypothalamus.
  • Vagus Nerve:
    • Stimulation (e.g., swallowing food, sinus massage) can cause cardiac arrhythmias.
  • Electrical Impulses:
    • SA node (pacemaker) generates electrical impulses.
    • Impulses travel to the atrioventricular (AV) node, causing a slight delay for ventricular filling.
    • Impulses then travel through the bundle of His and Purkinje fibers, which distribute the signal to cardiovascular cells.
    • Electrical stimulation causes a squeezing motion of the heart, with maximal contraction at the apex.

Arteries and Veins

  • Blood vessels form a closed system.
  • Great vessels: Aorta, vena cava, carotid arteries, iliac vessels.
  • Saphenous vein: Large vein often used for coronary artery bypass grafts.
  • Blood Distribution:
    • 65% in veins.
    • 13% in arterioles.
    • 7% in lungs.
    • 3% in heart.
  • Blockage of major vessels can cause circulation problems.

Cardiovascular Health Problems

  • Color Changes:
    • Cyanosis (blueness of lips or fingers) indicates potential cardiac failure.
    • Results from inadequate oxygenation by the right side of the heart or insufficient pressure from the left side.
  • Chest Discomfort:
    • Pressure, pain, or angina indicate insufficient perfusion to coronary vessels.
  • Palpitations:
    • Feeling one's own heartbeat.
  • Sweating:
    • Increased sympathetic nervous response.
  • Lightheadedness/Syncope:
    • Caused by insufficient blood supply to the brain due to inadequate pressure from the left side of the heart.
  • Shortness of Breath:
    • May result from right-sided heart failure, leading to inadequate oxygenation.
  • Edema:
    • Indicates failure of the venous system, leading to fluid buildup.
  • Extremity Symptoms:
    • Pain, numbness, or tingling suggest decreased blood supply.
  • Fatigue:
    • Associated with right-sided heart failure and insufficiently oxygenated blood.
  • Feeling of Doom:
    • Sometimes experienced during major cardiac events or with certain drugs (e.g., atropine).
  • Self-Care Restrictions:
    • Result from chronic symptoms affecting overall bodily functions.

Physical Assessment Preparation

  • Introduction:
    • Introduce yourself and explain the assessment process.
    • Inform the patient that the assessment involves assessing the chest and that they are required to take their upper half of the clothes off.
    • Explain the steps, purpose, and duration of the assessment.
    • Address any patient questions or concerns.
  • Privacy and Comfort:
    • Maintain patient privacy (e.g., draw curtains, provide appropriate covering).
    • Ensure patient comfort; allow bathroom breaks if needed.
  • Environment:
    • Adjust bed height to avoid strain.
    • Ensure adequate lighting and ambient temperature.
  • Patient Control:
    • Allow the patient to stop if they become fatigued or uncomfortable.

Physical Assessment Procedure

  • Systematic Approach:
    • Use a head-to-toe approach.
    • Start at the base of the heart and move to the apex.
    • When assessing circulation, move from jugular pulses down to radial and popliteal pulses.
  • Documentation:
    • Record all findings to ensure continuity of care.
  • Equipment:
    • Blood pressure monitor.
    • Weighing scale.
    • Stethoscope.
    • Timing device (for heart rate).
    • Measurement tools (e.g., for ankle or chest circumference).
  • Environment Considerations:
    • Adjust privacy, duration, temperature, and lighting to optimize assessment.
  • Communication:
    • Obtain consent and explain each step of the examination.
    • Recognize and respond to both verbal and non-verbal cues.
  • Positioning:
    • Use appropriate positions, such as supine, prone, high Fowler's (90 degrees), semi-Fowler's (45 degrees), or reclining (30 degrees).
    • Understand how position affects cardiac assessment (e.g., pressure needed to pump blood against gravity).

General Observations and Primary Survey

  • Primary Survey Focus:
    • Circulation (C in ABCDE) is primary focus
  • Components:
    • Vital signs, manual blood pressure, radial pulse, etc.
    • Color changes.
    • Palpation assessing temperature.
    • Auscultation listening to heart and apical heart sounds.
    • Electrocardiogram (ECG/EKG).
    • Urine output and any fluid losses.
  • Data Types:
    • Objective: Measurable data (e.g., temperature of 39.3°C).
    • Subjective: Patient-reported data (e.g.,