A 38-year-old man with type1 diabetes has been vomiting for 8 hours. He is clinically dehydrated with a blood pressure of 90/60 mmHg. His capillary blood glucose is 18.5mmol/l. What is the single most relevant initial investigation?
A. Arterial blood gases
B. Full blood count
C. Hemoglobin A/C
D. Liver function tests
E. Serum urea concentration
Ans. The key is A. Arterial blood gases. [Dx is diabetic keto-acidosis. Initial investigation is arterial blood gases which will demonstrate acidosis