Hyperkalemia: Difference between revisions

Revision as of 22:50, 14 July 2011

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
1. Hemolysis of specimen
2. Pronged tourniquet use prior to blood draw
3. Thrombocytosis/leukocytosis
Redistribution
1. Acidemia (DKA)
2. Cellular breakdown
  1. Rhabdomyolysis/crush injury
  2. Hemolysis
  3. Tumor lysis syndrome
Increased total body potassium
1. Inadequate excretion
  1. Renal caused (acute or chronic renal failure-must have GFR<10)
  2. Hypoaldo
  3. Drug-induced
    1. K sparing diuretics (spironolactone), ACEI, NSAIDs
2. Excessive intake
  1. Diet
  2. Blood transfusion
Misc
1. Sux, Dig, B-blockers

1. 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

2. 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

3. 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

@@ Line 40: / Line 40: @@
 ##Sux, Dig, B-blockers
-<span class="Apple-style-span" style="font-size: 18px;">Treatment</span>
-<div style="font-family: Arial, Verdana, sans-serif; color: rgb(34, 34, 34); background-color: rgb(255, 255, 255);">
 *1. Membrane Stabilization
 **Calcium gluconate 1-3 amp IV or chloride 1amp IV
-***<span style="font-family:arial,helvetica,sans-serif;">Give if ECG changes/hypotension or >7</span>
+***Give if ECG changes/hypotension or >7
-***<span style="font-family:arial,helvetica,sans-serif;">Gluconate requires hepatic metabolism to free Ca moiety</span>
+***Gluconate requires hepatic metabolism to free Ca moiety
-***<span style="font-family:arial,helvetica,sans-serif;">Gluconate slower onset than Ca-chloride</span>
+***Gluconate slower onset than Ca-chloride
-***<span style="font-family:arial,helvetica,sans-serif;">Chloride extravasation is very bad - use a good IV</span>
+***Chloride extravasation is very bad - use a good IV
-***<span style="font-family:arial,helvetica,sans-serif;">Duration of effect = 30-50min</span>
+***Duration of effect = 30-50min
-***<span style="font-family:arial,helvetica,sans-serif;">Caution in dig-toxic pts</span>
+***Caution in dig-toxic pts
-***<span style="font-family:arial,helvetica,sans-serif;">May take more than one round of calcium</span>
+***May take more than one round of calcium
-***<span style="font-family:arial,helvetica,sans-serif;">May require repeat dosing as effects are transient</span>
+***May require repeat dosing as effects are transient
-&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
 *2. Intracellular shift