A 63yo male undergoes abdominal surgery. On Monday morning, 3d post-op, repeat samples confirm serum K+=7.1mmol/l. His ECG shows broad QRS complexes. Which one of the following can be used as an effective tx for this pt’s hyperkalemia?
a. Calcium chloride IV
b. Calcium gluconate IV
c. Insulin subcutaneously
d. Furosemide IV
answer: B
Treatment of Hyperkalemia
• acute therapy is warranted if ECG changes are present, or if patient is symptomatic
• tailor therapy to severity of increase in [K+] and ECG changes
[K+] <6.5 and normal ECG
treat underlying cause, stop K+ intake, (increase the loss of K+ ) via urine and/or GI tract
[K+] between 6.5 and 7.0, no ECG changes:
(shift k+ into cells) add insulin to above regimen
[K+] >7.0 and/or ECG changes:
first priority is to(protect the heart), add calcium gluconate to above
- Protect the Heart
• calcium gluconate 1-2 amps (10 mL of 10% solution) IV
• antagonizes cardiac toxicity of hyperkalemia, protects cardiac conduction system, no effect on serum [K+]
• onset within minutes, lasts 30-60 min (may require repeat doses during treatment course of hyperkalemia) - Shift K+ into Cells
• regular insulin (Insulin R) 10-20 units IV, with 1-2 amp D50W (give D50W before insulin)
onset of action 15-30 min, lasts 1-2 h
monitor capillary blood glucose q1h because of risk of hypoglycemia
can repeat every 4-6 h
caution giving D50W before insulin if hyperkalemia is severe as it can cause a serious arrhythmia
• NaHCO3 1-3 ampules (given as 3 ampules of 7.5% or 8.4% NaHCO3 in 1L D5W) onset of action 15-30 min, transient effect, drives K+ into cells in exchange for H+, more effective if patient has metabolic acidosis
• B2-agonist in nebulized form (dose = 2 cc or 10 mg inhaled) or 0.5 mg IV
onset of action 30-90 min, stimulates Na+/K+ ATPase
caution if patient has heart disease as may result in tachycardia - Enhance K+ Removal from Body
• via urine (preferred approach)
furosemide (≥40 mg IV), may need IV NS to avoid hypovolemia
• via gastrointestinal tract
cation-exchange resins: calcium resonium or sodium polystyrene sulfonate : increasingly falling out of favor due to risk of colonic necrosis; works by binding Na+ in exchange for K+, and controversial how much K+ is actually removed
lactulose PO to avoid constipation (must ensure that patient has a bowel movement after resin is administered – main benefit may be the diarrhea caused by lactulose)
kayexalate enemas with water
• dialysis (renal failure, life threatening hyperkalemia unresponsive to therapy)