Potassium is the major intracellular cation.
- Hyperkalaemia is regarded as a plasma [K+] > 5.0 mmol/l
- Severe hyperkalaemia is regarded as a plasma [K+] > 6.5 mmol/l and is considered to be a medical emergency as it can lead to cardiac arrest.
- Non specific malaise
- Acute renal failure
- Cardiac arrest presentation
- Ensure it is not haemolysed and is a fresh sample
- Also look for biochemical evidence of ARF
ECG will show changes
- Tenting of T waves
- P wave amplitude reduced
- lengthened PR interval
- Broadening of QRS
- Ventricular tachycardia
- Ventricular fibrillation
- Spurious - Check no sample haemolysis and no thrombocytosis. Hyperkalaemia related to increased platelets is easy to detect by looking at a heparinised arterial or venous (blood gas) potassium or sending a lithium heparin plasma sample to the lab.
- Acute renal failure
- Obstructive nephropathy
- Cell damage - trauma, burns, rhabdomyolysis, massive blood transfusion
- Addison's disease
- K+ sparing diuretics
- Metabolic acidosis
- Excess IV or Oral K+ (Some antacids introduce a fair potassium load)
- Pseudohyperkalaemia can be caused by thrombocytosis
- Reverse pseudohyperkalaemia can be caused by heparin used to collect plasma lysing sensitized blood cells.
- Remove underlying cause.
- Calcium (either as gluconate or chloride) gives cardioprotection (but does not lower K+)
- Insulin + glucose to shift K+ back into cells
- Most evidence based on 10 international units insulin and 25g of 50% glucose
- Provides too little insulin to achieve maximal hypokalaemic effect possible with the hormone and too little glucose to avoid hypoglycaemia
- Lowers blood glucose by about 1.5 mmol/L at 1 hour
- This is not appropriate in diabetic ketoacidosis
- It will tend to induce hypos, especially in advanced renal failure
- So monitor blood glucose
- Weight based regimes are safer (eg 0.1 units/kg up to 95kg
- In non-diabetics a glucose load alone will cause almost a good drop in the potassium
- Salbutamol nebuliser (or infusion if you are where its available) will also shift K+ back into cells
- Binding resins such as calcium resonium
- Haemofiltration and dialysis
- The definitive treatment
Cochrane has published a systematic review on emergency interventions for hyperkalaemia . They conclude that inhaled or nebulised, or IV insulin-and-glucose are the first-line therapies for the management of emergency hyperkalaemia that are best supported by the evidence. In combination they may be more effective than either alone, and should be considered when hyperkalaemia is severe. In the presence of arrhythmias anecdotal evidence suggests that IV calcium is effecting in treating arrhythmia. Bicarbonate has a very limited role, but interestingly may have some efficacy in the hyperkalaemic cardiac arrest situation
Guidelines for the treatment of hyperkalaemia in adults.
- ↑ Vereijken TL, Bellersen L, Groenewoud JM, Knubben L, Baltussen L, Kramers C. Risk calculation for hyperkalaemia in heart failure patients. The Netherlands journal of medicine. 2007 Jun; 65(6):208-11.
- ↑ Indermitte J, Burkolter S, Drewe J, Krähenbühl S, Hersberger KE. Risk factors associated with a high velocity of the development of hyperkalaemia in hospitalised patients. Drug safety : an international journal of medical toxicology and drug experience. 2007; 30(1):71-80.
- ↑ Harel Z, Kamel KS. Optimal Dose and Method of Administration of Intravenous Insulin in the Management of Emergency Hyperkalemia: A Systematic Review. PloS one. 2016; 11(5):e0154963.(Epub) (Link to article – subscription may be required.)
- ↑ Packham DK, Rasmussen HS, Lavin PT, El-Shahawy MA, Roger SD, Block G, Qunibi W, Pergola P, Singh B. Sodium zirconium cyclosilicate in hyperkalemia. The New England journal of medicine. 2015 Jan 15; 372(3):222-31.(Link to article – subscription may be required.)
- ↑ Wang CH, Huang CH, Chang WT, Tsai MS, Yu PH, Wu YW, Hung KY, Chen WJ. The effects of calcium and sodium bicarbonate on severe hyperkalaemia during cardiopulmonary resuscitation: A retrospective cohort study of adult in-hospital cardiac arrest. Resuscitation. 2016 Jan; 98:105-11.(Link to article – subscription may be required.)