ABGs Flashcards
What biochemical changes are seen in respiratory acidosis?
high H+ high CO2
Describe the changes seen in compensated resp acidosis.
normal H+ high CO2 high HCO3-
List some causes of respiratory acidosis.
COPD, asthma, Guillain Barre, opioid toxicity
Describe the ABG changes seen in diabetic ketoacidosis. And list other causes of the same changes.
high H+ low HCO3-
lactic acidosis, aspirin overdose, diarrhoea, ileostomy, renal tubular acidosis, Addison’s disease
What is the anion gap and what is its significance in metabolic acidosis?
Na+ - (HCO3- + Cl-)
normal = 4-12 mmol/L
excessive H+ = increased anion gap e.g. DKA
loss of HCO3- = decreased anion gap e.g. diarrhoea
Describe the mechanism causing the following ABG results: normal H+ low HCO3- low CO2
compensated metabolic acidosis
Describe the ABG picture seen in metabolic alkalosis.
low H+ high HCO3-
If an ABG result shows normal H+ ions, high HCO3- and high CO2 levels, which mechanism is occuring?
compensated metabolic alkalosis
Causes of metabolic alkalosis can be divided into three sections: GI loss, renal loss and iatrogenic. Can you give an example of each?
GI loss: vomiting/diarrhoea
Renal loss: diuretics, heart failure, nephrotic syndrome, cirrhosis, Conn’s syndrome
Iatrogenic: Milk-Alkali syndrome
What is the mechanism behind the ABG results low H+ and low CO2?
respiratory alkalosis
Describe the ABG changes seen in compensated respiratory alkalosis.
normal H+ low CO2 low HCO3-
What are some of the causes of respiratory alkalosis?
panic attack, pain, pneumonia, PE, pneumothorax
How would the picture of mixed resp/met acidosis display on ABG results?
high H+ high CO2 low HCO3-
What causes a mixed resp/met acidosis?
cardiac arrest, multi-organ failure
What would cause the following ABG results?
low H+ low CO2+ high HCO3-
mixed resp/met alkalosis
hyperemesis gravidarum, liver cirrhosis with diuretic use, excessive ventilation in COPD
