Hyperkalemia
Background
High = >5.5meq/L
High! = >6.5meq/L
Diagnosis
Always consider pseudohyperkalemia (e.g. from hemolysis)!
ECG
- 6.5-7.5 - peaked Ts, inc PR, dec QT
- 7.5-8.0 - QRS widening, P flattening
- 10-12 - sine wave, v-fib, heart block
changes are not always predictable and may progress quickly on ECG
Differential Diagnosis
- Pseudohyperkalemia
- Hemolysis of specimen
- Pronged tourniquet use prior to blood draw
- Thrombocytosis/leukocytosis
- Redistribution
- Acidemia (DKA)
- Cellular breakdown
- Rhabdomyolysis/crush injury
- Hemolysis
- Tumor lysis syndrome
- Increased total body potassium
- Inadequate excretion
- Renal caused (acute or chronic renal failure-must have GFR<10)
- Hypoaldo
- Drug-induced
- K sparing diuretics (spironolactone), ACEI, NSAIDs
- Excessive intake
- Diet
- Blood transfusion
- Inadequate excretion
- Misc
- Sux, Dig, B-blockers
Treatment
- Membrane Stabilization
- Calcium gluconate 1-3 amp IV or chloride 1amp IV
- Give if ECG changes/hypotension or >7
- Gluconate requires hepatic metabolism to free Ca moiety
- Gluconate slower onset than Ca-chloride
- Chloride extravasation is very bad - use a good IV
- Duration of effect = 30-50min
- Caution in dig-toxic pts
- May take more than one round of calcium
- May require repeat dosing as effects are transient
- Calcium gluconate 1-3 amp IV or chloride 1amp IV
- Intracellular shift
- 10 U insulin IV w/ 1 amp D50 IV now and 1 amp in 15 min
- Duration of effect = 4-6h
- Albuterol neb 2.5mg x 3 or 20mg over 1hour
- Duration of effect = 2-4hr
- Higher doses more effective
- Dose 20mg over 1 hour dropped K by 0.6mEq
- Prior Bet-agonist use makes pts resistant to effects
- NaBicarb 1 amp IV (over 5 min)
- Duration of effect = 1-2hr
- 10 U insulin IV w/ 1 amp D50 IV now and 1 amp in 15 min
- Removal
- Dialysis
- Lasix 40-80mg IV
- Volume expansion with NS if dehydrated, TLS, rhabdomyolysis, DKA, acidosis
- Kayexylate 30-60gms PO - unreliable and slow to work
Source
Tintinalli
Management Severe Hyperkalemia. Crit Care Med, 2008, 36:12