5th April 2024

Investigations

Any spurious results should be repeated, particularly if there has been a delay between venepuncture and transport to the laboratory. 24-hour urine volume and electrolytes can be a reliable check of kidney function. Capillary blood and plasma glucose can reveal hyperglycaemia. 

If patients are on digoxin, blood digoxin levels should be taken alongside an arterial blood gas, looking for metabolic acidosis. Patients’ medications should be reviewed and those contributing to hyperkalaemia temporarily held. 

The ECG in hyperkalaemia may show:

• Peaked T waves
• Prolongation of PR interval 
• Widening of QRS
• Reduced amplitude or loss of P wave
• AV dissociation 
• Sine wave pattern 
• Asystole

In patients with heart disease who have an abnormal baseline ECG, bradycardia may be the only new abnormality on ECG.