Peripheral Vascular System and Lymphatic System

Chapter Overview

The chapter delves deeper into the anatomy, physiology, and critical roles of the peripheral vascular and lymphatic systems, emphasizing their importance in overall human health and disease management.

Arteries

Major Arteries in the Body

• Temporal Arteries: These arteries are commonly assessed during a physical examination for conditions such as temporal arteritis, which can lead to vision loss if untreated.

• Carotid Arteries: These arteries not only supply blood to the brain, but they also play a vital role in carrying oxygen-rich blood. Carotid artery assessment is crucial for stroke risk evaluation.

• Brachial Arteries: Located in the upper arms, these arteries are commonly used for measuring blood pressure and are critical in assessing blood flow to the arms.

• Femoral Arteries: These large arteries supply blood to the legs and can be evaluated for conditions like peripheral artery disease (PAD). They branch into:

  • Popliteal Arteries: Found behind the knee, commonly involved in vascular assessments owing to their location.

  • Dorsalis Pedis Arteries: Important for evaluating foot oxygenation, these are located on the top of the foot, often checked for signs of ischemia.

  • Posterior Tibial Arteries: Positioned behind the shin, they supply blood to the plantar surface of the foot.

Clinical Conditions

• Ischemia: A critical condition characterized by a deficiency in oxygenated blood supply due to blood vessel obstruction. This can lead to tissue damage and, in severe cases, gangrene.

• Peripheral Artery Disease (PAD): This condition primarily affects noncoronary arteries and can cause pain during physical activity (intermittent claudication). Screening for PAD is crucial in populations at risk, such as smokers and diabetics.

Veins

Major Veins in the Body

• Jugular Veins: These veins are essential in draining blood from the head and neck back to the heart and play a role in various medical conditions affecting blood flow to the brain.

• Veins in the Arm: Split into deep and superficial systems. The deep veins correspond with major arteries and are important for efficient venous return.

• Veins in the Leg: Includes both deep and superficial veins:

  • Deep Veins: Such as the femoral and popliteal veins; their assessment is essential for diagnosing deep vein thrombosis (DVT).

  • Superficial Veins: Includes the great saphenous and small saphenous veins. These veins are critical in the context of varicose veins and venous insufficiency.

  • Perforators: These veins connect the deep and superficial venous systems and are important in maintaining venous pressure.

Venous Flow Mechanisms

Blood in the venous system is propelled by several mechanisms, which include:

• Skeletal Muscle Contraction: Muscles act as pumps, propelling blood toward the heart, especially during movement.

• Pressure Gradient from Breathing: Inhalation decreases thoracic pressure, aiding venous return, while abdominal pressure increases during exhalation.

• Intraluminal Valves: These are one-way valves that prevent backflow of blood, vital for maintaining venous blood flow toward the heart.

• Capacitance Vessels: The venous system can dilate and accommodate a larger blood volume, playing a role in managing blood pressure fluctuations.

• Incompetent Valves: This condition leads to varicose veins, where valve cusps fail to meet and cause blood pooling.

Lymphatic System

Functions of the Lymphatic System

• Fluid and Plasma Protein Conservation: The lymphatic system recaptures fluid that leaks from capillaries into tissues and returns it to the bloodstream, crucial for maintaining homeostasis.

• Immune System Role: Acts as a conduit for immune cells and plays a pivotal role in the body’s defense mechanism against pathogens.

• Lipid Absorption: The lymphatic system absorbs fats and fat-soluble vitamins from the small intestine, which are then transported to the bloodstream.

Major Components

• Right Lymphatic Duct: Drains lymph from the right arm and right side of the head and neck into the right subclavian vein, essential for upper body fluid return.

• Thoracic Duct: The largest lymphatic vessel that drains lymph from the rest of the body, playing a pivotal role in fluid homeostasis.

• Superficial Groups of Nodes: Key nodes include cervical, axillary, epitrochlear, and inguinal lymph nodes which are important in filtering lymph and responding to infections.

Organs Related to the Lymphatic System

• Spleen: A vital organ in the immune system; it destroys old red blood cells, produces antibodies, and filters microorganisms from the blood, also acting as a blood reservoir.

• Tonsils: First line of defense against pathogens entering through the mouth and nose, and play a role in developing systemic immunity.

• Thymus: This gland is crucial for the maturation of T-cells, essential for adaptive immunity, particularly during childhood.

Developmental Competence

Infants and Children

• Larger lymph nodes in children can lead to visible swelling during infections, indicating a robust immune response.

• Enlarged tonsils are often symptomatic of respiratory infections, requiring careful evaluation.

Pregnant Women

• Hormonal changes can trigger vasodilation, resulting in lower blood pressure and increased venous pressure, particularly in the lower extremities.

Aging Adults

• Aging is associated with an increased risk of arteriosclerosis, PAD, and thrombus formation; regular vascular assessments are crucial for early detection.

• A decrease in the number and size of lymph nodes can affect immune response efficiency.

Culture and Genetics

• Smoking: This is a significant risk factor for PAD and coronary artery disease (CAD), with increased prevalence in certain demographics.

• Diabetes, Dyslipidemia, Hypertension: These conditions are critical in evaluating the risk for PAD, especially noted in non-Hispanic black populations.

• Recommended Screenings: Individuals over 70 or aged 50-69 with risk factors should be screened regularly to assess vascular health.

Assessment Parameters

Key aspects to observe include:

• Leg Pain or Cramps: Often indicative of vascular insufficiency, particularly during exertion.

• Skin Changes: Changes on arms or legs can signal underlying vascular issues.

• Swelling in Limbs: Unexplained edema should prompt further investigation for potential venous obstruction or heart failure.

• Enlargement of Lymph Nodes: Persistent enlargement may indicate systemic infection or malignancy.

Review Medical History

Focus areas include:

• Current medications and their potential vascular side effects.

• Smoking habits and exposure to secondhand smoke, which can exacerbate vascular conditions.

Terms and Measurements

• Claudication Distance: Measures how far a patient can walk before experiencing pain due to ischemia, important for assessing the severity of PAD.

• Profile Sign: Assesses for early clubbing of fingers, which may indicate chronic hypoxia.

• Capillary Refill: Measures circulatory effectiveness; ideally should take no more than 1-2 seconds in healthy individuals.

• Modified Allen Test: Used to evaluate collateral circulation in the hand prior to radial artery cannulation.

Edema Assessment

Pitting Edema Grading:

• 1+: Mild, slight indentation that disappears quickly.

• 2+: Moderate, subsides rapidly but visible.

• 3+: Deep, indentation remains briefly after pressure is released.

• 4+: Very deep, long-lasting indentation that may require further investigation.

• Unilateral Edema: May indicate deep vein obstruction or localized issues.

• Bilateral Pitting Edema: Commonly associated with systemic conditions, such as heart failure or liver disease.

Leg Assessment

Critical observational points:

• Skin Color Changes: Linked to arterial insufficiency and potential ischemia.

• Doppler Examination: Utilized for assessing weak or absent pulses, indicating possible vascular compromise.

• Ankle-Brachial Index (ABI): A non-invasive test to assess PAD, with results interpreted as:

  • 0.90 or less: Indicative of PAD, graded further based on severity:

    • 0.90 to 0.71: Mild PAD.

    • 0.70 to 0.41: Moderate PAD.

    • 0.40 to 0.30: Severe PAD.

    • <0.30: Indicates ischemia requiring immediate attention.

Abnormal Findings in Pulses

Understanding pulse qualities is essential in diagnosing various conditions:

• Weak, Thread Pulse (1+): Difficult to palpate; may indicate poor circulation.

• Strong, Bounding Pulse (3+): Easily felt and may indicate hyperdynamic circulation or anxiety.

• Water-Hammer Pulse: Characterized by a sudden collapse following a strong impulse, often indicative of aortic regurgitation.

• Pulsus Bigeminus, Alternans, Paradoxus, and Bisferiens: These complex pulse patterns suggest significant cardiovascular pathology that requires a detailed assessment.

Peripheral Vascular Disease (PVD) in Arms

• Raynaud's Phenomenon: Characterized by tricolor changes in the fingers (white, blue, red) often triggered by cold or stress, necessitating lifestyle modifications and treatment strategies.

• Lymphedema: Can occur post-cancer treatment, leading to high-protein limb swelling that requires careful management to enhance quality of life.

Leg Ulcers Analysis

Types of Leg Ulcers:

• Arterial (Ischemic) Ulcer: Resulting from inadequate blood supply, these ulcers tend to occur on the feet or toes, requiring urgent vascular intervention.

• Venous (Stasis) Ulcer: Commonly associated with history of DVT or chronic venous insufficiency, typically located around the ankles and manageable with appropriate care.

• Neuropathic Ulcer: Frequently seen in diabetic patients, these ulcers arise from reduced sensation and can lead to significant complications if untreated.

Other Conditions

• Superficial Varicose Veins: Often appear as tortuous, dilated veins on the legs due to chronic venous pressure increase, leading to potential symptoms of discomfort and cosmetic concerns.

• Deep Vein Thrombophlebitis: The presence of a thrombus in deep veins leads to inflammation, pain, and potential embolic complications, emphasizing the need for prompt diagnosis.

Peripheral Artery Disease Details

Key Conditions

• Aneurysms: Defined as a localized dilation of the arterial wall, these can rupture and lead to life-threatening hemorrhage.

• Occlusions: Often secondary to atherosclerosis, these lead to significant morbidity by restricting blood flow and necessitating surgical intervention in severe cases.