Renal insufficiency: hyperkalemia

Clinical - Renal/Urine/Electrolytes

K+ outflow is responsible for phase III (repolarization) of the cardiac cycle. Insulin and beta agonists promote the influx of K+. Total body stores include 4200 mEq intracellularly, versus only 12 mEq in the plasma. Potassium excretion of K+ is determined primarily by [K+] and aldosterone levels

Decreased excretion (lowered GFR, K+ sparing diuretics, ACE-inhibitors, heparin [decreased aldosterone efficacy], and constipation), intracellular release (metabolic acidosis, beta blockers, insulin deficiency), and increased intake (blood transfusion, increased dietary intake)

Time Course of Hyperkalemia

Hyperkalemia and Induction

Duration of Neuromuscular Blockade

Signs of Hyperkalemia

(> 6 mEq/L): peaked T waves, prolonged PR interval (ex. AV block), flattened P wave, QRS widened to sine wave; (> 7 mEq/L): musculoskeletal weakness; Note that these effects are worsened by hyponatremia, hypocalcemia, and acidosis, all of which are present in the setting of renal failure

Acute Treatment of Hyperkalemia

1g CaCl2, 50g glucose, 10 U insulin, furosemide, 100 mEq bicarbonate (controversial)

Renal Failure: Hyperkalemia

  • Causes: decreased excretion (lowered GRF, ACE-inhibitors), intracellular release (metabolic acidosis), increased intake (transfusion)
  • Signs: peaked T waves, prolonged PR interval, flattened P wave, QRS widened to sine wave, musculoskeletal weakness
  • Acute Treatment: 1g CaCl2, 50g glucose, 10 U insulin, furosemide, 100 mEq bicarbonate (controversial)
  • Anesthesia Concerns: very real but may be overstated; increase in non-renal failure patients < 0.5 mEq/L with SCh. Affect on paralysis not related to K+

Sources

    Miller’s Anesthesia, 7th Edition. p 2112; Barash, PG. Clinical Anesthesia, 5th ed. (Philadelphia), p. 1020, 2006

    Anesth Analg;2002 Jul;95(1):119-22, table of contents

    [PubMed: 12088954]

    JPEN J Parenter Enteral Nutr. 1999 Jan-Feb;23(1):45-6

    [PubMed: 9527968]

    Anesth Analg;1990 Feb;70(2):172-5

    [PubMed: 2301749]

    Anaesthesia;1995 Nov;50(11):933-6

    [PubMed: 8678246]

    See also Renal failure: electrolytes

    See also...

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2009

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