REPLETING ELECTROLYTES
Before repleting, always ask yourself: how’s the patient’s renal function?
For decreased renal function: Always error on
the side of UNDER replacement.
MNEMONIC
To remember how to replete, remember: 4-3-2
K (goal around 4.0): usually 10 mEq will give you a rise of 0.1 mEq/L; IV and PO have an equivalent effect. Fastest infusion time is 10 mEq/hr through a peripheral line, or 20 mEq/hr for a central line if on a monitored bed.
– Examples:
– 3.0 – 100mEq
– 3.5 – 60mEq
– 3.8 – 20mEq
Phos (goal around 3.0): choose KPhos or NaPhos. If the patient needs K as well, they will get 4.4 mEq of K for every 3 mmol of Kphos. Be careful in the setting of hypercalcemia.
– Examples:
– >2.0 – oral neutraphos 2 tabs po TID x 3 doses
– 1.5- 2.0 – 0.08 mmol/kg IV over 6 hrs
– 0-1.5 – 0.16 mmol/kg IV over 6 hrs
Mg (goal around 2.0): usually 1 gm for each 0.1 mEq/L. Magnesium oxide can be used PO (4 tabs being equal to 1 gm) but it is not absorbed well.
– Examples:
– 1.6–4gmIV
– 1.8–2gmIV
Things to keep in mind about Mag:
1. If you give it PO, so get ready for some diarrhea
2. If Mag is low, you’ll need to replete that so that your K can also rise
REFERENCE:
“Intern Survival Guide.” Anonymous