Hyperkalemia
Background
- High = >6.0meq/L
- Always consider pseudohyperkalemia (e.g. from hemolysis)
- K+ secretion is proportional to flow rate and Na delivery through distal nephron
- Mechanism for loop/thiazide diuretics causing hypokalemia
ECG
- Changes are NOT always predictable and sequential
- 6.5-7.5 - peaked Ts, incr PR, decr QT
- 7.5-8.0 - QRS widening, P flattening
- 10-12 - sine wave, V-fib, heart block
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
- Give if ECG changes or consider if K+ >7
- Calcium (only if QRS wide)
- Can give as calcium gluconate or calcium chloride
- Calcium Gluconate 2-3g
- Only 1/3 the calcium as compared to chloride
- Must give over 10min (otherwise hypotension due to osmotic shift)
- Calcium Chloride 1g
- Can be given as slow IVP over 1-2min
- 3x the amount of calcium
- Extravasation is bad - use a good IV
- Calcium Gluconate 2-3g
- Duration of action = 30-60min
- Caution in dig-toxic pts
- May require multiple doses for effect (esp w/ gluconate)
- Can give as calcium gluconate or calcium chloride
- Intracellular shift
- Insulin/Glucose
- 10 U insulin IV w/ 1-2 amp D50 IV now (unless BS already >300)
- Duration of effect = 4-6h
- Albuterol neb 5-20mg
- Response is dose-dependent
- Duration of action = 2hr
- Peak effect at 30min
- Duration of effect = 2-4hr
- Bicarb 1 amp IV (over 5 min)
- Duration of effect = 1-2hr
- Consider if pt is acidemic
- Insulin/Glucose
- Removal
- Lasix 40-80mg IV
- Volume expansion with NS if dehydrated, TLS, rhabdomyolysis, DKA, acidosis
- Kayexylate 30gm PO - unreliable and slow to work (2-6hr)
- Dialysis
See Also
Source
Tintinalli
Management Severe Hyperkalemia. Crit Care Med, 2008, 36:12
EMCrit Podcast #32