respiratory 9-14 (s + p) Flashcards
What is the main function of the respiratory system?
oxygenates blood by bringing it to close proximity of venous blood in pulmonary capillaries
What are the basic physiological roles of the respiratory system?
(Hint - CAB)
- Control of airway tone by ANS (bronchomotor tone maintained by vagal nerves)
- Airflow of lungs (slows as cross-sectional area decreases)
- Breathing - mechanical (inspiration or expiration and control of respiration)
What is respiratory failure?
Hint - not enough swapping and +/- as a result
- inadequate gas exchange in lungs
- resulting in hypoxia +/- hypercapnia (low O₂/CO₂)
What is type 1 respiratory failure?
1 problem
- hypoxia (pO2 <8kPa)
- due to ventilation-perfusion mismatch
- most commonly normal ventilation but inadequate perfusion
What is type 2 respiratory failure?
2 problems and something which affects the lungs
- hypoxia (pO2 <8kPa) and hypercapnia (pCO2 >6kPa)
- caused by a reduced lung SA or fatigue
Which tests used in the diagnosis of an obstructive airway disease?
- spirometry + peak flow → method of assessing lung function by measuring volume of air patient can expel after a maximal inspiration
- arterial blood gas (ABG)
What are spirometry and peak flow effective reliable in and what do they show?
- reliable method of distinguishing betw/ obstructive airways and restrictive disorders
- most effective way of determining disease severity in COPD
- subdivisions of lung volume
What is the healthy range for pH and what is it called when we deviate from it?
- 7.35-7.45
- acidosis ←→ alkalosis
What is the healthy range for pO2 and what is it called when we deviate from it?
(Hint - the upper limit is the most unlucky number)
- 10-13kPa
- hypoxia ←→ hyperoxia
What is the healthy range for pCO2 and what is it called when we deviate from it?
(Hint - the upper limit is the number of sides of a hexagon)
- 4.5-6kPa
- hypocapnia ←→ hypercapnia
What is the healthy range for HCO3?
22-26mmol/L
What type of respiratory problem is it if there is a:
a) problem with CO₂
b) problem with HCO₃
a) respiratory
b) metabolic
Case: An adult very stressed at work has come to A&E with acute shortness of breath and dizziness. ABG: • pH – 7.50 • pO₂ – 13 • pCO₂ – 3 • HCO₃ - 23
- pH – 7.50 alkalosis
- pO₂ – 13 normal pO₂
- pCO₂ – 3 low pCO₂
- HCO₃ – 23 normal HCO₃
Respiratory alkalosis!
Case: An 85-year-old lady with a one week history of shortness of breath, cough with green sputum and temperature. PMH – COPD. ABG: • pH – 7.42 • pO2 – 7.5 • pCO2 – 4.9 • HCO3 - 24
- pH – 7.42 normal
- pO2 – 7.5 low pO2
- pCO2 – 4.9 normal
- HCO3 – 24 normal
Type 1 respiratory failure!
Case: 69-year-old male with 2-day history worsening shortness of breath and cough. Heavy smoker. • pH - 7.22 • pO₂ – 7.2 • pCO₂ – 8.5 • HCO₃ - 26
• pH - 7.22 acidosis • pO2 – 7.2 low pO2 • pCO2 – 8.5 high pCO2 • HCO3 – 26 normal - type 2 respiratory failure/respiratory acidosis!
What does the CXR of a asthmatic patient look like?
like a normal CXR - nothings shows up
What does a COPD CXR look like?
Hint - the main vessels expands and Francis from MIC
- hyperinflated + hyperlucent lungs
- flattened diaphragm
- central pulmonary artery enlargement
- bullae