ICU Vivas · Acid–base
Data viva — a systematic read of a mixed acid–base dataset
A data-interpretation viva in which the candidate is given a blood gas and a biochemistry panel and must work through the six-step method — pH, primary disorder, Winter's-formula compensation, the albumin-corrected anion gap, the delta-delta, and the cause — arriving at a septic lactic high anion-gap metabolic acidosis.
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Prompt
A blood-gas and biochemistry panel from a 58-year-old man in septic shock, with the pH, the PaCO2, the bicarbonate, the sodium, chloride, albumin, lactate, glucose and urea — to be interpreted in full.
Stimulus
You are shown the blood gas and biochemistry of a 58-year-old man who is day one into a septic shock from a pneumonia:
| Variable | Value | (normal) |
|---|---|---|
| pH | 7.30 | (7.35–7.45) |
| PaCO2 | 30 mmHg | (35–45) |
| HCO3 | 15 mmol/L | (22–26) |
| Base excess | −11 | (−2 to +2) |
| Lactate | 5.5 mmol/L | (0.5–1.6) |
| Sodium | 140 mmol/L | (135–145) |
| Chloride | 104 mmol/L | (98–107) |
| Albumin | 40 g/L | (35–50) |
| Glucose | 6.0 mmol/L | (3.5–7.8) |
| Urea | 8.0 mmol/L | (2.5–6.5) |
| Creatinine | 90 micromol/L | (60–110) |
Interpret the acid–base disorder in full.[4]
References4ShowHide
- [1]Adrogué HJ, Madias NE. Management of life-threatening acid-base disorders. First of two parts. New England Journal of Medicine, 1998.PMID 9414329
- [2]Kraut JA, Madias NE. Serum Anion Gap: Its Uses and Limitations in Clinical Medicine. Clinical Journal of the American Society of Nephrology, 2007.PMID 17699401
- [3]Kraut JA, Madias NE. Lactic acidosis. New England Journal of Medicine, 2014.PMID 25494270
- [4]Bersten AD, Soni N (eds) Oh's Intensive Care Manual. 8th edition, Elsevier, 2018.