Specimen Name Result Units Range
ABG pH 7.28 (7.36-7.44)
PaO2 65 mmHg (70-100)
PaCO2 48 mmHg (35-45)
HCO3- 22 mmol/L (21-26)

28yo female in 3rd trimester of pregnancy.

What is the acid-base disorder?
Respiratory Acidosis - Severe Acute

Normal levels in mid-late pregnancy:

  • pH : 7.40-7.45 (high-normal )
  • PCO2 : 28-32 mmHg
  • HCO3- : 18-20 mmol/L
  • Progesterone-driven hyperventilation → chronic resp. alkalosis

Presented with hyper-acute asthma attack:

  • pH : acidosis
  • PCO2 : respiratory acidosis (*late event in acute asthma)
  • HCO3- : consistent with acute