Functions of the respiratory system
- Gas exchange
- Immunological
- Biological
What is hypoventilation?
Where less air enters the alveoli, resulting in reduced oxygen and increased carbon dioxide in the blood
What is a shunt?
Can be intrapulmonary or intracardiac. Both forms of shunting result in blood entering the leftsided circulation without an increase in oxygen content
Dead space
The conducting airways (trachea, bronchi, respiratory bronchioles) are non-gas exchange areas, therefore, are termed anatomical dead space (normally about 150ml per breath)
V/Q mismatch
V/Q mismatch is in between the 2 extremes of shunt and dead space, ie, where there is either
- Blood flow (Q) with reduced ventilation (V) (low V/Q)
- Ventilation (V) with reduced blood flow (Q) (high V/Q)
What is the pump?
To move air in & out of the lung, it requires the neuro, musculo and skeletal components to be intact. If there is disruption to any part of this pathway it will lead to impairment of the respiratory system. Pump failure or disruption can lead to impairment
What are the functions of the lung?
- Gas movement = Through the conducting airways to alveoli. Between the alveolus and capillary
- Secretion movement in the airways = Clearance of secretions
What are the divisions of gas movement?
O2 and CO2 movement
What are the divisions of secretion movement?
Mucociliary clearance (mucus or cilia) and cough
What is respiratory load?
What the muscles have to work against to
- Move the chest wall (chest wall compliance)
- Move air through the airways (airway resistance)
- Expand the alveoli (lung compliance)
What is a symptom?
A new feeling or a departure from normal feelings which is noticed by the patient. Is ‘subjective’ or self reported.
What is dyspnoea?
Breathlessness. The most common cardiorespiratory symptom but can also be caused by other disorders such as musculoskeletal (impaired respiratory muscles), anemia (decreased oxygen carrying capacity of the blood)
What is a sign?
Is something that can be
demonstrated physically, tested for using an objective test or noticed by other people
Common respiratory symptoms
Dyspnoea, wheeze or chest tightness, cough (+/- sputum), pain in chest region.
Common respiratory signs
General appearance, chest wall characteristics, breathing pattern, abnormalities of breathing rate, abnormality on auscultation, cough and secretions, haemoptysis, limb abnormalities, digital clubbing, respiratory investigations, reduced exercise tolerance, reduced QOL
What is a relevant finding?
Something that you need to consider, which:
- May influence hypothesis generation and/or treatment choice/implementation
- Is often found in the patient’s history
May or may not have a cause
