Resp Failure Flashcards
1
Q
Shift o2 curve left or right
A
Left
- paco2
- temp
+ pH
right
+ Paco2
+temp
-pH
2
Q
Hypoxaemia vs hypoxia
A
- Hypoxaemia
- Low oxygen levels in the blood
- Hypoxia
- Low tissue oxygen levels
3
Q
Oxygenation delivery formula
A
DO2= (CO x ( 1.39 x Hb x SA02 + (0.003xPa02))
4
Q
Causes of hypoxaemia
A
- Decrease in available oxygen
* Boyle’s Law
* Smothering
* Increase in altitude - Alveolar Hypoventilation
* Decrease O2
* Increase CO2 - Impaired diffusion
* Fick’s law
* Thickening of the alveolar membrane
* Fibrosis - Shunting
* Most common cause of hypoxaemic respiratory failure
* Extrapulmonary shunt
* Mixing of oxygenated and deoxygenated blood
* Blood flows from right side of the heart to left without passing the alveoli
* Anatomical abnormality i.e. septal defect (arterial or ventricular)
- Intrapulmonary shunt
- Blood returns to left heart from lungs with decrease in haemoglobin saturation
- Pneumonia consolidation decreases diffusion
- VQ Mismatch
* V = Ventilation
* Q = Perfusion
* For adequate diffusion to take place, sufficient ventilation and perfusion is
needed
5
Q
Aa gradient
A
PA02-Pa02
find cause of hypoxaemia
<20mmHg
* If normal, hypoxia is due to ventilation pathology
* If elevated, indication of shunt or diffusion abnormality
PA02= PAO2 = FiO2 (Patm(760)-PH2O(47) – (PaCO2/0.8)
6
Q
acute resp failure
A
respiratory system is no longer able to meet the metabolic
demands of the body
acute + chronic
7
Q
Type 1 vs type 2
A
Type 1
<60 Pa02
Normal PC02
* Lung failure (Air can get into alveoli, but problem with diffusion)
* Due to VQ mismatch or shunt
* Caused by Pulmonary Embolis, Pneumonia, ARDS, Pulmonary oedema
Type 2
<60 Pa02
>45 PCO2
- Pump failure (Air cant get into alveoli)
- Due to hypoventilation or obstruction
- Caused by head injury, COPD, asthma, pneumothorax, drug overdose,
neuromuscular disease
