Normal range 3.5-5
The symptoms usually occur at level 2.5 mmol/L. Might be sooner if rapid depletion and might be at much lower level if chronic depletion.
Depend on the causes. Not all cases need to do the similar investigation.
Depend on hospital. Certain have limited resource and need to out source and take some time.
Some of the investigation
a. Serum aldosterone and renin
b. Arterial blood gas
c. Urine potassium
d. Serum and urine osmolarity
e. FBC-hyperleucocytosis can cause pseudohypokalaemia.
Asymptomatic, no ECG changes
>2.5mmol/L : oral potassium replacement. Discharge.
<2.5mmol/L : Fast correction.
Fast correct. Similar as above.
How much to correct
Formula for correction:
Deficit (mmol) = (4 – current potassium level) X weight X 0.4
Administration: 1g in 100cc NS over 1 hour.
In most cases, hypokalemic patients are also hypomagnesemic. So Mg2+ may be added to the infusion both to optimize tubular reuptake of potassium and to contrast proarrhythmic effect of hypokalemia.