A 72-year-old female is admitted to ICU after decortication of her left lung, due to empyema. Her background history includes insulin dependent diabetes mellitus, rheumatoid arthritis and hypertension. She was previously hospitalised 2 weeks ago for a methicillin sensitive Staphylococcus aureus bacteremia, and is on high dose intravenous flucloxacillin. She is persistently febrile.
Parameter | Patient Value | Adult Normal Range | ||||||||||
FiO2 | 0.6 | |||||||||||
pH | 6.94* | 7.35 – 7.45 | ||||||||||
pO2 | 85.0 mmHg (11.3 kPa) | |||||||||||
pCO2 | 43.0 mmHg (5.7 kPa) | 35.0 – 45.0 (4.6 – 6.0) | ||||||||||
SpO2 | 98% | |||||||||||
Bicarbonate | 9.0 mmol/L* | 22.0 – 26.0 | ||||||||||
Base Excess | -15 mmol/L* | -2.0 – +2.0 | ||||||||||
Lactate | 4.0 mmol/L* | 0.5 – 1.6 | ||||||||||
Sodium | 141 mmol/L | 135 – 145 | ||||||||||
Potassium | 5.0 mmol/L | 3.5 – 5.0 | ||||||||||
Chloride | 92 mmol/L* | 95 – 105 | ||||||||||
Glucose | 3.8 mmol/L | 3.5 – 6.0 | ||||||||||
Urea | 18.0 mmol/L* | 3.0 – 8.0 | ||||||||||
Creatinine | 145 μmol/L* | 45 – 90 |
a) List the abnormalities on the blood gas analysis. (15% marks)
b) Outline how you would investigate this further. (15% marks)
Not available.
Let us dissect these results systematically:
So, on this gas, there is:
So: wherever the stem volunteers a history of flucloxacillin or MSSA, the expectation is that the trainees will mention pyroglutamic acidosis in their list of differentials. However, this is a diabetic and she has renal failure. So: relevant investigations should include: