hyperkalemia Flashcards
What is the guideline for patients aged greater than or equal to 12 years with suspected hyperkalaemia?
Monitor cardiac rhythm continuously and acquire a 12 lead ECG.
What should be determined after acquiring a 12 lead ECG in suspected hyperkalaemia?
Determine the severity of ECG changes.
What are the treatments for mild to moderate ECG changes in hyperkalaemia?
Administer continuous nebulised salbutamol.
What treatments are administered for severe ECG changes in hyperkalaemia?
- Continuous nebulised salbutamol
- 6.8 mmol (1 g) of calcium chloride IV
- Large flush of 0.9% sodium chloride IV
- 100 ml of 8.4% sodium bicarbonate IV
- 500 ml of 0.9% sodium chloride IV if signs of hypovolaemia
What should be done if severe ECG changes persist or recur after initial treatment?
Repeat calcium chloride and sodium bicarbonate after 20 minutes.
treatment of bradycardia despite treatment?
adrenaline infusion
What is the definition of hyperkalaemia?
A serum potassium concentration greater than 5.5 mmol/L.
At what serum potassium concentration do adverse cardiovascular effects from hyperkalaemia usually occur?
Greater than 6 mmol/L.
What are common symptoms associated with hyperkalaemia?
Usually asymptomatic; symptoms related to reduced cardiac output due to dysrhythmia.
What factors influence the level at which hyperkalaemia is associated with abnormal cardiac conduction?
- Patient’s usual potassium concentration
- Rate of potassium concentration increase
What are mild to moderate ECG changes associated with hyperkalaemia?
- Peaked T waves
- Mild to moderate broadening of the QRS complex without bradycardia
What are severe ECG changes associated with hyperkalaemia?
- Severe broadening of the QRS complex
- Bradycardia
What is the most common cause of hyperkalaemia?
End stage renal failure, especially if the patient is on dialysis.
List other causes of hyperkalaemia.
- Rhabdomyolysis associated with prolonged immobility
- Metabolic acidosis associated with severe sepsis
- Very severe diabetic ketoacidosis
- Haemolysis associated with blood transfusion
Which medications increase the likelihood of developing hyperkalaemia?
- Angiotensin converting enzyme inhibitors (pril)
- Angiotensin receptor blockers
- NSAIDs
- Potassium-sparing diuretics
What ECG features are typically seen as potassium concentration increases?
- Peaked T waves
- Flat P waves or loss of P waves
- Mild to moderate broadening of the QRS complex (0.12-0.16 seconds)
- Severe broadening of the QRS complex (greater than 0.16 seconds)
- Bradycardia
- Fusion of the QRS complex with the T wave forming sine waves
Why is a flush of 0.9% sodium chloride required between calcium and sodium bicarbonate administration?
To prevent the ions becoming insoluable which occurs when these electrolytes are mixed.
What is the effect of calcium ions in the treatment of hyperkalaemia?
Provide electrical stabilisation of cardiac cells but do not reduce potassium concentration.
How does sodium bicarbonate affect potassium concentration?
Causes hydrogen ions to leave the intracellular space, replaced by potassium ions, reducing concentration temporarily.
What is the effect of continuous nebulised salbutamol on potassium concentration?
Stimulates beta 2 receptors, causing potassium to move into the intracellular space, reducing concentration.
If a patient is hypotensive without bradydysrhythmia, what is likely the cause?
Hypovolaemia and/or sepsis.
What concurrent condition is likely in a patient with rhabdomyolysis associated with prolonged immobility?
Concurrent hypovolaemia.
