Blood Gases Flashcards
How is blood pH controlled
CO2 levels
Excretion of acid
Acidaemia vs acidosis
Acidemia changes pH
Acidosis is accumulation of acid but doesn’t always result in pH change
Base excess definition
Volume of base needed to return to normal pH
Bicarbonate role in the blood
Excreted from kidneys used as a buffer in maintain normal pH
Lactate use in ABG
produced from anaerobic respiration and shows poor tissue perfusion
Respiratory compensation
Low CO2
increased rate and depth of respiration
Metabolic respiration
HCO3 retention in kidneys
What is the best way to interpret an ABG
- Look at patient, review examination findings
- PO2
3.pH
4.PCO2 - HCO3
- Patient compensation
- Other ABG values
Type 1 respiratory failure
Low O2
Low or normal CO2
Common causes of type 1
Asthma
Pneumonia
Pulmonary embolus
Common causes of type 2
COPD
Opiates
Myasthenia gravis
Pneumonia
What is type 2 respiratory failure
Low PaO2
High PaCO2
How are blood gases measured
Blood taken from artery and haemoglobin saturation is measured
Spectrometry Clip
Dysfunction of which nerve can be implicated in respiratory failure
Phrenic nerve
Where are peripheral chemoreceptors for CO2 O2 and pH located
Carotid and aortic bodies
