Sleep Apnoea and Respiratory Failure Flashcards
1
Q
What happens on inspiration?
A
- rib cage moves up and out
- intercostal muscles contract
- diaphragm contracts and moves down
- pressure in lungs decreases so less than outside and air rushes in
2
Q
What happens on expiration?
A
- intercostal muscles relax
- diaphragm relaxes and moves up
- elastic recoil of lungs forces them to contract
- pressure inside lungs greater than outside so air gets pushed out
3
Q
What are the peripheral chemoreceptors?
A
- carotid and aortic bodies
4
Q
Hypoxic pulmonary vasoconstriction
A
- if alveolus has no oxygen supply = hypoxic
- vasoconstriction occurs = no perfusion = no more oxygen = won’t be inflated
5
Q
Type 1 respiratory failure
A
- PaO2 <8 kPa
6
Q
Type 2 respiratory failure
A
PaO2<8kPa AND PaCO2 >6.5kPa
7
Q
Mechanisms of hypoxia
A
- hypoventilation
- diffusion abnormality
- ventilation/perfusion mismatch
- right to left cardiac shunt bypassing lungs
- low inspired oxygen = high altitude/air flight
8
Q
Example of ventilation perfusion mismatch
A
Lobar pneumonia Asthma = mucus plugs so obstructs airflow Lobar collapse PE Pneumothorax
9
Q
Example of diffusion abnormality
A
Sarcoidosis
Pulmonary fibrosis
COPD
10
Q
Example of hypoventilation
A
Kyphoscoliosis Thoracoplasty for TB COPD Motor Neurone Disease Muscular Dystrophy Morbid obesity
11
Q
Example of right to left shunt
A
Eisenmenger syndrome
12
Q
Types of Resp Failure
A
Acute and chronic for type 1 and 2
13
Q
LTOT
A
- improves survival for COPD with hypoxia
- reduces hypoxia complications = polycythaemia, cor pulmonale
- at least 15 hours per day
14
Q
Define COPD with hypoxia
A
PaO2<7.3kPa
15
Q
Chronic Type 1 Resp Failure Consequences
A
- Pulmonary hypertension
- Cor pulmonale = peripheral oedema
- 2ndry polycythaemia = stroke
- symptoms from ischaemic heart/peripheral vascular diseases
- poor sleep/fatigue