Potassium
Normal Range: 3.6-5.0 mEq/L
Hypokalemia:
Goal: in general >3.5, in cardiac patients >4.0; use caution when repleting in patients with renal dysfunction
Always replete magnesium first if Mg++<2.0mg/dl
Note: when repleting via IV: 10mEq/hr via peripheral line or 20meq/hr central line
- Every 10 mEq of K given is expected to raise the K by 0.1 (i.e. if you give 40mEq of K to a patient with K of 3.4, expect the repeat K to be approximately 3.8)
If rechecking, do so 3 hours after dose
| Level | Oral | IV |
|---|---|---|
| <3.3 | Kdur 60mEq | KCl 60mEq |
| 3.3-3.5 | Kdur 40mEq | KCl 20mEq |
| 3.6-4.0 | Kdur 20mEq | KCl 20mEq |
Hyperkalemia:
check if sample was hemolyzed or sent off IV running potassium; if either is true, order stat plasma K and recheck
if renal failure: patient may require immediate medical management and urgent dialysis
Hyperkalemic emergency:
clinical manifestations of hyperkalemia (muscle weakness, paralysis, cardiac conduction abnormalities or arrhythmias)
serum K > 6.5 meq/L
serum K > 5.5 meq/L with significant renal impairment and ongoing tissue breakdown (rhabdo, TLS, etc.)
treat with rapidly acting therapies (calcium gluconate 1g IV, insulin IV + D50) and removal (dialysis, GI cation exchangers if no contraindication, diuretics)
Phosphorus
Oral: Phospha 250 neutral (Neutra-phos)
IV: Potassium/Sodium Phosphate 15mmol
| Level | Oral | IV |
|---|---|---|
| <1.5 | 0.5mmol/kg sodium phos | |
| 1.5-2.0 | Neutraphos 0.25mmol/kg | 0.25mmol/kg sodium phos |
| 2.1-2.4 | 0.15mmol/kg sodium phos |
Magnesium
Goal > 2.0
| Level | IV |
|---|---|
| <1.0 | Magnesium Sulfate 1g x 4 doses @ 1g/hr |
| 1.0-1.4 | Magnesium Sulfate 1g x 3 doses @ 1g/hr |
| 1.5-2.0 | Magnesium Sulfate 1g x 2 doses @ 1g/hr |
Calcium
Replete if ionized Calcium < 1.0
- Calcium gluconate: 1g Calcium gluconate IV over 1 hour
- Calcium chloride: 13.6 mEq of elemental calcium; DO NOT give peripherally, risk of thrombophlebitis