I was actually asked this on rounds once. I said, I don’t know. I received a 30-minute biochemistry lecture in response.
- 150 g/day glucose will sustain a person and spare protein from being used for metabolism. Giving D5W should not, on its own, cause hyperglycemia. It should also not dramatically increase blood glucose levels in hypoglycemic patients.
- Several organs can subsist only on glucose: the brain, the renal medulla, and RBCs.
- If patients don’t get adequate glucose, they will be “starved” for sugars and shunt to the ketone pathway. Ketones can be used by the brain and muscle, but it’s not good to rely on it for long since it has toxic side-effects.
- Giving dextrose helps patients retain fluids by promoting hyperaldosteronism (aldosterone increases sodium and water retention).