Top of Respiratory Table - ABG + O2 delivery Flashcards
When do you do ABG
Any deteriorating patient Acute exacerbation of chest Impaired consciousness Poor resp effort Signs of hypercapnia Certain conditions - DKA Sats <92%
What do you comment on
Is it a type 1 or type 2 resp failure
Is patient retaining CO2
What info is provided
pH pCO2 and pO2 Electrolyes - Na / K Lactate Hb Base excess
Why is VBG useful
Accurate for pH and pCO2
Less pain and less risk
Useful in cardiac arrest (diff reference values)
What is not accurate
O2
When do you do ABG
Patient in shock / critical state
Shows pO2 accurately
What is the base excess (used instead of bicarb)
The amount of acid needed to restore blood to original pH
Increases alkalosis
Decreases acidosis
How do you analyse blood gas
What is patient's condition Is patient acidotic or alkalemic Is patient hypoxic What has happened to PaCO2 What has happened to BE / bicarbonate
What do you want to know about patients condition
Is it acute or chronic
e.g. resus will have mixed metabolic and resp acidosis due to inadequate ventilation + lactic acid
What is acidotic
pH <7.35
What is alkaloid
pH >7.45
Is patient hyperaemic
O2 10.5-13.5
If on supplementary O2 PaO2 should be 10% of this
What should CO2 be
4.5-6
If CO2 increased
Suggest respiratory acidosis
OR
Resp compensating for metabolic alkalosis
If CO2 decreased
Resp alkalosis
OR
Resp compensation for metabolic acidosis
If CO2 decreased what will patient be doing
Hyperventilating
Rare if normal RR / spontaneous breathing
More common in mechanical ventilation
Acidosis high CO2
Resp acidosis
Acidosis low Co2
Hyperventilating to compensate for metabolic acidosis
Aklaosis + low CO2
Resp alkalosis
Alkalosis + high CO2
Don’t get