1000657941.jpg
Interpret this abg
analyse_media
Reading File
Searching the Web
arterial blood gas interpretation metabolic acidosis Winter formula authoritative
Finding Sources
Searching PubMed
"metabolic acidosis" AND "systematic review"
ABG interpretation: primary normal-anion-gap metabolic acidosis with appropriate respiratory compensation.
| Value | Interpretation |
|---|---|
| pH 7.31 | Acidemia |
| HCO₃⁻ 17.9 mmol/L, base excess -7.2 | Metabolic acidosis |
| PaCO₂ 35.1 mmHg | Appropriate compensatory hypocapnia |
| Expected PaCO₂ | 1.5 × 17.9 + 8 = 34.9 ± 2 mmHg |
| Measured PaCO₂ | 35.1 mmHg, so no additional primary respiratory disorder |
This use of Winter's formula to assess compensation is consistent with metabolic-acidosis guidance.
Anion gap:
AG = Na - (Cl + HCO₃) = 138 - (115 + 17.9) = 5.1 mmol/L, which is normal/low. Thus this is hyperchloremic (normal-gap) metabolic acidosis, not high-gap acidosis. Lactate 2.08 mmol/L is only mildly raised and does not account for the acidosis.
AG = Na - (Cl + HCO₃) = 138 - (115 + 17.9) = 5.1 mmol/L, which is normal/low. Thus this is hyperchloremic (normal-gap) metabolic acidosis, not high-gap acidosis. Lactate 2.08 mmol/L is only mildly raised and does not account for the acidosis.
Associated important abnormalities
- K⁺ 2.69 mmol/L: significant hypokalemia, needs urgent clinical attention, ECG monitoring and replacement as appropriate.
- Ionized Ca²⁺ 0.88 mmol/L: low.
- Cl⁻ 115 mmol/L: elevated, supporting hyperchloremic acidosis.
- Likely causes, depending on context: diarrhea/GI bicarbonate loss, renal tubular acidosis, recent large-volume normal-saline administration, or certain medications.
Oxygenation
- PaO₂ 174 mmHg, SaO₂ 99.8%, P/F ratio approximately 829: oxygenation is more than adequate.
- However, the machine records FiO₂ 0.21 (room air), and a PaO₂ of 174 is unusual on true room air. Confirm whether the patient was receiving supplemental oxygen or whether FiO₂/sample details were entered correctly.
Bottom line: compensated hyperchloremic metabolic acidosis with marked hypokalemia, plus low ionized calcium. Clinical correlation and prompt potassium management are needed.
This is a shared conversation. Sign in to Orris to start your own chat.