ABGs

Question 1

What are the causes of respiratory acidosis?

Answer 1

COPD
decompensation in other respiratory conditions e.g. life-threatening asthma / pulmonary oedema
neuromuscular disease
obesity hypoventilation syndrome
sedative drugs: benzodiazepines, opiate overdose

Question 2

What are the causes of respiratory alkalosis?

Answer 2

anxiety leading to hyperventilation
pulmonary embolism
salicylate poisoning*
CNS disorders: stroke, subarachnoid haemorrhage, encephalitis
altitude
pregnancy

*salicylate overdose leads to a mixed respiratory alkalosis and metabolic acidosis. Early stimulation of the respiratory centre leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis