PBL Topic 2 Case 2 Flashcards
(134 cards)
What is tidal volume?
- Volume of air inspired or expired with each normal breath
What is inspiratory reserve volume?
- Volume of air that can be inspired over and above the tidal volume
What is expiratory reserve volume?
- Volume of air that can be expired after the end of normal tidal expiration
What is residual volume?
- Volume of air remaining in the lungs after the most forceful expiration
How is inspiratory capacity calculated?
- Tidal Volume + Inspiratory Reserve Volume
How is functional residual capacity calculated?
- Expiratory Reserve Volume + Residual Volume
How is vital capacity calculated?
- Inspiratory Reserve Volume + Expiratory Reserve Volume + Tidal Volume
How is total lung capacity calculated?
- Residual Volume + Vital Capacity
Outline how PEFR is calculated
- Blow out forcefully into the peak flow metre
- Best of three attempts is recorded
- Regular measurements throughout the day
Which condition is PEFR used to diagnose?
- Asthma
What are the normal values of pH?
- 7.35 - 7.45
What are the normal values of PO2?
- 80 - 100 mm Hg
- 10.5 - 13.5 kPa
What are the normal values of PCO2?
- 36 - 45 mm Hg
- 5.1 - 5.6 kPa
What are the normal values of oxygen saturation?
- Between 95% and 100%
Identify two examples of obstructive airways disorders
- COPD
- Asthma
Identify an example of a restrictive airway disorders
- Fibrosis
How can spirometry be used to diagnose an obstructive disorder?
- FEV1 is reduced
- FVC is reduced to a lesser extent than FEV1
- FEV1/FVC ratio < 0.7
How can spirometry be used to diagnose a restrictive disorder?
- FEV1 is reduced
- FVC is reduced approximately the same amount as FEV1
- FEV/FVC ratio > 0.7
Outline Henry’s Law
- Partial Pressure = [Dissolved Gas] / Solubility Coefficient
Explain why the partial pressure of CO2 is much less than that of O2
- CO2 is much more soluble than O2
Why does oxygen diffuse into the blood from the alveoli?
- Partial pressure of oxygen is greater in the gas phase than in the dissolved state
- Movement of oxygen down a pressure gradient
Why does carbon dioxide diffuse into the alveoli from the blood?
- Partial pressure of carbon dioxide is greater in the dissolved state than the gas phase
- Movement of carbon dioxide down a pressure gradient
Outline five factors that affect the rate of gas diffusion
- Partial pressure difference, ΔP
- Cross sectional area, A
- Solubility, S
- Distance, D
- Molecular weight, MW
How does alveolar air differ to atmospheric air?
- Alveolar air has less oxygen than atmospheric air
- Alveolar air has more carbon dioxide than atmospheric air