ABG Flashcards
Respiratory acidosis findings
low pH
high PaCO2
What does respiratory acidosis suggest?
patient acutely retaining CO2
What does low PaO2 suggest?
hypoxia and respiratory failure
Type 1 respiratory failure findings
low PaO2
normal PaCO2
Type 2 respiratory failure findings
low PaO2
raised PaCO2
Causes of type 1 respiratory failure
asthma
congestive cardiac failure
PE
pneumonia
pneumothorax
What physiologically causes type 1 respiratory failure?
Ventilation-perfusion (V/Q) mismatch
volume of air passing in and out of the lungs is comparatively smaller than the volume of blood perfusing the lungs
What physiologically causes type 2 respiratory failure?
alveolar hypoventilation
lungs fail to effectively oxygenate and blow off carbon dioxide
Causes of type 2 respiratory failure
obstructive lung diseases (COPD)
restrictive lung diseases (IPF)
depression of respiratory centre (opiates)
neuromuscular disease (GBS, MND)
thoracic wall disease (rib fracture)
What does raised bicarbonate indicate?
chronic carbon dioxide retention
kidneys responded and increase bicarbonate production to balance acidic CO2
seen in COPD
Respiratory alkalosis findings
raised pH
low PaCO2
increased respiratory rate ‘blows off’ too much CO2
Respiratory alkalosis causes and how to distinguish between them
hyperventilation syndrome (eg. anxiety) = high PaCO2
Pulmonary embolism = low PaO2
Metabolic acidosis findings
low pH
low bicarbonate (HCO3-)
Metabolic acidosis causes
increased lactate (tissue hypoxia)
increased ketones (DKA)
increased hydrogen ions (renal failure, type 1 renal tubular acidosis, rhabdomyolysis)
low bicarbonate (diarrhoea, renal failure, type 2 renal tubular acidosis)
Metabolic alkalosis findings
high pH
high bicarbonate
