PHSI N303F Cardiopulmonary Physiotherapy

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Questions and Answers

What percentage of the work of breathing (WOB) is attributed to elastic resistance?

70%

80% (correct)

90%

60%

Which of the following best describes how airflow limitation typically presents clinically?

Absent breath sounds and high fever

Increased work of breathing and wheezing (correct)

Increased heart rate and elevated blood pressure

Chest pain and productive cough

Which factor does NOT affect lung compliance?

Collagen structure

Surfactant levels

Elastic recoil

Airway resistance (correct)

In a container, what occurs to pressure when the volume is increased?

Pressure decreases Signup and view all the answers

What is the primary mechanism by which ventilation occurs?

Gas flow resulting from volume and pressure changes Signup and view all the answers

What is the term for the pressure exerted by the gases in the air?

Atmospheric pressure Signup and view all the answers

Which pressure is specifically defined as the pressure within the alveoli?

Intrapulmonary pressure Signup and view all the answers

What describes the difference between intrapulmonary pressure and intrapleural pressure?

Transpulmonary pressure Signup and view all the answers

What condition is characterized by the presence of air in the pleural space?

Pneumothorax Signup and view all the answers

Which of the following pressures would generally increase as altitude decreases?

Atmospheric pressure Signup and view all the answers

In the context of lung mechanics, which pressure is always negative?

Intrapleural pressure Signup and view all the answers

What would likely occur due to an abnormal communication between the lung and the pleural space?

Pneumothorax Signup and view all the answers

Which pressure gradient is crucial for lung expansion during breathing?

Transpulmonary pressure Signup and view all the answers

What occurs to the intra-alveolar pressure during inspiration?

It decreases as gas flows into the lungs. Signup and view all the answers

What is the relationship between intrapleural pressure and the chest wall during pre-inspiration?

Intrapleural pressure is negative, causing the chest wall to expand and the lungs to recoil. Signup and view all the answers

Which property of the lung primarily contributes to its ability to recoil?

Elastic recoil Signup and view all the answers

What happens to the intra-alveolar pressure during expiration?

It increases as gas leaves the lungs. Signup and view all the answers

Which of the following factors is NOT a property of the lung?

Tidal volume Signup and view all the answers

Which statement best describes collateral ventilation?

It allows air to bypass obstructed airways. Signup and view all the answers

What mechanism is responsible for restoring negative pressure in the lung?

The natural tendency of the lungs to recoil. Signup and view all the answers

Which physiological change signifies the start of expiration?

Increase in intra-alveolar pressure. Signup and view all the answers

What is the primary function of pulmonary surfactant in the alveoli?

Prevent surface tension collapse Signup and view all the answers

Which type of collateral ventilation involves channels that are 80 - 150 μm in size?

Channels of Martin Signup and view all the answers

What condition can result from insufficient pulmonary surfactant in premature infants?

Neonatal respiratory distress syndrome Signup and view all the answers

What is implied by the term 'compliance' in relation to lung function?

Distensibility of lung structures Signup and view all the answers

What happens to lung compliance as lung volume approaches extremes?

It becomes less compliant Signup and view all the answers

What is the consequence of airway occlusion on collateral ventilation?

Increased recruitment of collateral pathways Signup and view all the answers

What structural components contribute to the elastic recoil of the lungs?

Collagen and elastin fibers Signup and view all the answers

What is a significant clinical effect of reduced lung compliance?

Increased work of breathing Signup and view all the answers

How does aging affect lung compliance?

It leads to pulmonary fibrosis Signup and view all the answers

What is the main role of collateral ventilation during airway obstruction?

To assist in sputum clearance Signup and view all the answers

Which positioning method is recommended to expand the affected lung in an adult patient suffering from atelectasis?

Place the affected side on the upper side when side-lying. Signup and view all the answers

Which goal of interventions is primarily associated with the improvement of ventilation and perfusion matching?

Enhancing the volume of a particular lung side. Signup and view all the answers

What are the implications of supine versus prone positioning in patients with acute respiratory distress syndrome (ARDS)?

Prone position may improve oxygenation and lung mechanics. Signup and view all the answers

What is a primary property of lung structures contributing to compliance?

Surface tension of the alveolar fluid. Signup and view all the answers

Which statement correctly describes the mechanics of breathing related to pressure changes?

Inhalation is facilitated by an increase in intrathoracic volume and a decrease in pressure. Signup and view all the answers

What is a key indication for the technique known as huffing?

To clear obstructed airways. Signup and view all the answers

Which of the following would NOT be a goal of positioning a patient during physiotherapy?

To improve muscle strength. Signup and view all the answers

In the context of increasing lung compliance, which factor is most significant?

The structural integrity of the alveoli. Signup and view all the answers

What is one of the key phenomena associated with forced expiration in patients with emphysema?

Dynamic compression of airways Signup and view all the answers

What does the Equal Pressure Point (EPP) indicate during forced expiration?

Transition from central to peripheral airways Signup and view all the answers

Which measurement is primarily used to differentiate between restrictive and obstructive lung diseases?

Forced vital capacity (FVC) Signup and view all the answers

What occurs when the closing volume of the lungs is reached?

Inspiration requires significantly higher pressure Signup and view all the answers

What is the primary purpose of the huffing technique in respiratory therapy?

To facilitate the movement of secretions Signup and view all the answers

How does aging affect closing volume in the lungs?

Closing volume increases Signup and view all the answers

Which property of the lungs is characterized by the ability to return to its original shape after being stretched?

Elastic recoil Signup and view all the answers

What is a major factor contributing to the turbulence in expiratory flow in patients with severe obstructive lung disease?

Dynamic airway compression Signup and view all the answers

During forced expiration from high lung volumes, what is the main outcome of coughing?

It clears secretions from the upper airway Signup and view all the answers

What role does surfactant play in respiratory mechanics?

Reduces surface tension in the alveoli Signup and view all the answers

Study Notes

Cardiopulmonary Physiotherapy - Review of Respiratory Physiology I

Course: PHSI N303F Cardiopulmonary Physiotherapy
Topic: Review of Respiratory Physiology I: Mechanics of Breathing
Lecturer: Ms Eva Chan, Senior Lecturer, Department of Physiotherapy, HKMU
Date: 3 Sept 2024

Learning Objectives

Recognize the properties of pulmonary structures and their functions
Illustrate factors contributing to airflow resistance
Describe inspiration and expiration, explaining pressure changes during the respiratory cycle
Explain regional differences in lung volume
Apply breathing mechanics to pulmonary physiotherapy practice, including airflow assessment, decision-making regarding interventions (positioning, breathing exercises, secretion clearance)

Revision on Breathing

A video demonstrating pulmonary ventilation (breathing) is available.

Properties of the Lung

Include: airway resistance, collateral ventilation, compliance, elastic recoil, surfactant
Key terms: respiratory mechanics; clinical implications for physiotherapists

Airway Resistance

Resistance of the respiratory tract to airflow during inhalation and exhalation
Calibre of the airways is inversely proportional to the 4th power of the radius (resistance is 16 times greater if radius is halved).
Narrowed airways increase resistance
Factors affecting calibre: bronchial smooth muscle (parasympathetic causes constriction, sympathetic causes dilation), secretion, mucosal oedema, tumour/mass, inhaled foreign body, loss of radial traction.

Bronchial Smooth Muscle

Balanced activity between parasympathetic nervous system (bronchoconstriction) and sympathetic nervous system (bronchodilation)

Collateral Ventilation

Airflow through interalveolar pores (Kohn), bronchiole-alveolar canals (Lambert), and interbronchial channels (Martin).
Microscopic pathways for collateral air distribution.

Clinical Importance

Gas can bypass obstructed airways through collateral pathways.
Increasing lung volume aids in recruiting collateral ventilation and re-expanding collapsed alveoli.
This helps propel sputum more proximally.
Interventions include deep breathing with holds and secretion removal.

Compliance

Distensibility (flexibility) of an elastic structure
Measured as change in pulmonary volume over change in pressure
Less compliant (stiff) at extremes of lung volume.

Elastic Recoil of the Lung

Elastic fibers of elastin and collagen at alveolar walls and around vessels and bronchi help with lung recoil.
Recoil helps to maintain lung shape and return to resting volume after inspiration.

Pulmonary Surfactant

Mixture of phospholipids and apoproteins
Synthesized and secreted by type II alveolar cells between 23 and 24 weeks gestation.
Reduces surface tension of fluid lining alveoli, preventing their collapse.
Clinical significance: insufficient surfactant reduces compliance leading to alveolar atelectasis and risk of pulmonary edema; neonatal Respiratory Distress Syndrome (RDS) is common in premature infants due to insufficient surfactant.

Reduced Compliance

High pressure required to increase volume, due to: increased fibrous tissue (pulmonary fibrosis/alveolar edema), lung not being ventilated for long (atelectasis), reduced pulmonary surfactant.

Increased Compliance

Pulmonary emphysema, aging,

Extrapulmonary Structures - Reduced Chest Wall Compliance

Thoracic deformity, raised intra-abdominal pressure

Work of Breathing

Work is done to move the lung and chest wall to overcome elastic and resistive forces in the airways, lungs, and chest wall.
Approximately 80% of the work of breathing is elastic resistance.
Approximately 20% of the work of breathing is airflow resistance.

How Do Patients Present Clinically If There Is Airflow Limitation?

Increased work of breathing
Shortness of Breath (SOB)
Wheezing
Lowered oxygen saturation (SpO2)

How Does Ventilation Happen?

Ventilation involves a sequence of volume change -> pressure change -> gas flow.

Human Lung Model

A model demonstrating the structure of the lungs is referenced.

Boyle's Law

States that pressure and volume of a gas have an inverse relationship (P1V1 = P2V2).

Pulmonary Ventilation

Movement of air into and out of the lungs.

Understanding the Terms

Atmospheric pressure: pressure exerted by gases in the air
Intrapulmonary pressure: pressure within the alveoli
Intrapleural pressure: pressure within the pleural cavity
Transpulmonary pressure: difference between intrapulmonary and intrapleural pressures

Clinical Significance–Pneumothorax

Presence of air in the pleural space due to abnormal communication between the lung and pleural space or the atmosphere.
Leads to lung collapse.
Intervention: insertion of drains to restore negative pressure.

Forced Expiration Technique - Huffing

Active Cycle Breathing Technique (ACBT) component
Clearing peripheral airway secretions using mid to low lung volumes
Clearing upper airway secretions with high lung volumes using coughing technique

Closing Volume

Inspiration falls below a lower inflection point on the pressure/volume curve when closing volume is reached
Large pressure needed to open airways/alveoli
Closing volume increases with age, smoking, lung disease, and position (supine > upright).

Positioning

Enhance lung volume, improve ventilation/perfusion matching, and achieve secretion drainage by manipulating patient position.

Forced Expiration at Mid to Low Lung Volumes

Equal pressure point (EPP) shifts distally into smaller peripheral airways as lung volumes decrease.

Using More Effort

Dynamic compression of airways due to increased effort for expiration.

Measurement of Expiratory Flow Rate

Spirometric measurements like FEV1, FVC (forced vital capacity) are used.
Differentiate between restrictive and obstructive lung diseases.

Positions of Equal Pressure Points

Forced expiration at volumes above functional residual capacity (FRC) or at decreasing capacities involving lower volumes in the smaller segmental and peripheral airways.

Pre-inspiration

Negative intrapleural pressure results from the chest wall tendency to pull outward versus the lungs tendency to pull inward.

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Description

This quiz covers the fundamental concepts of respiratory physiology as it relates to cardiopulmonary physiotherapy. You'll explore mechanics of breathing, airflow resistance, and the physiological changes that occur during inspiration and expiration. Perfect for students seeking to enhance their understanding of respiratory functions in clinical settings.