Serum K⁺ >6.5 mmol/L — What to Do When Cardiac Protection Has Not Normalised the ECG
In severe hyperkalemia — serum potassium above 6.5 mmol/L, or a symptomatic presentation with muscular weakness and/or ECG changes such as peaked T waves — initial management focuses on cardiac protection. When that step does not achieve ECG normalisation within the expected window, a defined next-line approach is required.
Clinical scenario
Serum potassium more than 6.5 mmol/L (severe), or symptomatic with muscular weakness and/or ECG changes (peaked T waves). Continuous ECG monitoring is established.
Previous step — target not reached
Cardiac protection with calcium gluconate was initiated. The target for this step is ECG normalisation within 10 minutes. When the ECG does not normalise within that window, this protocol is the next action.
Next-line approach (partial overview only)
The regimen involves a glucose-insulin combination and, where appropriate, inhaled salbutamol; concurrent metabolic acidosis, if present, is also addressed.
Patient-specific selection criteria, sequencing, and the full clinical algorithm are in the complete regimen.
Clinical goal
Reduction in serum potassium level, monitored hourly.
References
- HYPERkalaemia (Mild: 5.2–5.9 mmol/L, Moderate: 6.0–6.5 mmol/L, Severe: more than 6.5 mmol/L)
- Severe or symptomatic hyperkalaemia (e.g. muscular weakness and/or ECG changes [e.g. peaked T waves])
- Glucose and insulin – glucose 50% 50 mL with 5–10 units of insulin (e.g. Actrapid® or NovoRapid®) IV over 5 minutes; consider 5 units in patients under 50 kg or with chronic kidney disease (CKD stage 4 and 5).
- Inhaled salbutamol – nebulised salbutamol 10 mg (2 of the 5 mg/2.5 mL nebules) OR metered dose inhaler 1200 micrograms (12 puffs) via spacer
- If metabolic acidosis present, sodium bicarbonate 8.4% 50 mL IV over 5–15 minutes.
- Monitor potassium level hourly.
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