Recognise concurrent primary disturbances.
Clues
- • Normal pH with abnormal CO₂ and HCO₃
- • Compensation outside expected range
- • Delta-gap ratio <1 or >2 (HAGMA)
Classic examples
- • Salicylate: respiratory alkalosis + HAGMA
- • DKA + vomiting: HAGMA + metabolic alkalosis (ratio >2)
- • COPD on diuretic: chronic respiratory acidosis + metabolic alkalosis
- • Severe sepsis + opioid: lactic acidosis + respiratory acidosis
