Airway and Respiratory System Basics and Cardiovascular Physiology

Pulmonary Function

• Purpose: Measures air and blood flow in the lungs.
• Use: Detects pulmonary embolism or uneven blood distribution.

Afterload

• Definition: The resistance the heart must overcome to eject blood during contraction.
• High afterload means more work for the heart.

Systemic Circulation Return

• Deoxygenated blood from the body returns to the right atrium.
• This initiates the pulmonary circulation for reoxygenation.

Inotropes and Vasopressors

• Inotropes: Strengthen heart contractions.
• Vasopressors: Constrict blood vessels to raise blood pressure.
• Used for patients with dangerously low blood pressure.

Positive Inotropes

• Action: Increase calcium in heart muscle cells or make cells more sensitive to calcium.
• Effect: Stronger cardiac contraction.
• Examples: Dobutamine, digoxin.

Mucous Plugging

• Definition: A blockage in the airway due to thick secretions.
• Effects: Leads to alveolar hypoinflation, air trapping, atelectasis, decreased gas exchange, and increased airway resistance.

Macrophages

• Function: Immune cells in the alveoli that clear debris via phagocytosis.
• Important for preventing infection and maintaining clean airways.

Breath Sounds

• Bronchovesicular sounds: Heard over the main bronchus and upper right lung.
• Rhonchi: Deep, low-pitched sounds, usually on exhalation, indicating secretion in larger airways.

Bronchial Hygiene Therapy

• Includes: Deep breathing, coughing, postural drainage, chest physiotherapy (CPT), and positive pressure therapies.
• Purpose: Helps remove secretions and improve lung function.

Chest Physical Therapy (CPT)

• Method: Manual percussion and vibration on the chest wall.
• Goal: Dislodge mucus to aid in secretion clearance.

Trendelenburg Position

• How: Head lower than feet (can be done by raising foot of bed or lowering head).
• Use: Enhances postural drainage for secretion clearance in specific lung lobes.

Bronchiectasis

• Definition: Permanent widening of airways due to chronic inflammation/infection.
• Symptoms: Chronic cough, excessive mucus, frequent infections.

Alveolar Hypoxia

• Definition: Low oxygen levels in the alveoli.
• Causes: Poor ventilation, obstruction, or lung disease.

Pulmonary Blood Flow Pathway

• Sequence: Right ventricle → pulmonary artery → arterioles → alveolar capillaries → venules → pulmonary veins → left atrium.
• Function: Brings deoxygenated blood to lungs, oxygenates it, and returns it to the heart.

V/Q Scan (Ventilation/Perfusion Scan)

• Assesses lung ventilation and perfusion.