Hyperkalemia

*KDIGO's lower bound is 5.0 or the laboratory upper limit of normal. KDIGO bands are expert opinion (Clase 2020, Fig. 4: 5.0–5.9, 6.0–6.4, ≥ 6.5; ECG changes raise the level by one). UKKA adopts the European Resuscitation Council threshold of 5.5. The K⁺ is rounded to one decimal before banding. Up to half of patients with hyperkalemia have a normal ECG, including some with extreme values — a normal ECG is not reassuring (KDIGO).

1. Protect the heart — IV calcium when the ECG shows hyperkalemic changes: 30 mL 10% calcium gluconate over 10 min, or 10 mL 10% calcium chloride over 5 min (both ≈ 6.8 mmol Ca²⁺). Chloride is preferred in cardiac arrest or peri-arrest; gluconate for everyone else. Repeat ECG; consider a further dose after 5 min if changes persist, or when the effect (≈ 60 min) wears off in refractory hyperkalemia. The July 2026 update downgraded the evidence grade after the 2025 ILCOR review; the recommendation stands. KDIGO differs: its algorithm (Clase 2020, Fig. 5) gives IV calcium at K⁺ > 6.5 even with a normal ECG, and the ED summary suggests calcium above 6.5 when an ECG is not yet possible. The tool shows both positions.
2. Shift K⁺ into cells — insulin–glucose for moderate (suggested) and severe (recommended) hyperkalemia: 10 units soluble insulin with 25 g glucose over 15–30 min. If pre-treatment glucose is < 7.0 mmol/L (126 mg/dL), follow with 10% glucose at 50 mL/h for 5 h (25 g), target 4–7 mmol/L. Nebulized salbutamol 10–20 mg as an adjunct (recommended in severe, may be used in moderate), never alone. Sodium bicarbonate is not routine.
3. Remove K⁺ — sodium zirconium cyclosilicate 10 g three times daily for up to 72 h (severe: recommended; moderate: consider) or patiromer 8.4 g once daily (≥ 6.0). Calcium resonium is no longer recommended acutely. Stop binders when K⁺ ≤ 5.0 and watch for rebound. Consider dialysis if K⁺ stays ≥ 6.5 despite medical therapy; hemodialysis patients with K⁺ ≥ 6.5 need urgent dialysis. KDIGO (Fig. 5): with AKI or CKD, consider dialysis; without, consider it if repeat K⁺ is > 6.0.
4. Monitor — K⁺ at 1, 2, 4, 6 and 24 h after treatment of moderate or severe hyperkalemia; glucose at 0, 30, 60, 90, 120, 180, 240, 300 and 360 min after insulin–glucose. Continuous ECG monitoring for K⁺ ≥ 6.5, ECG changes, or 6.0–6.4 in an unwell patient or with an expected rise.
5. Prevent — find and treat the cause; review drugs.

UKKA keeps 10 units: four reports showed a dose-dependent effect (10 units more effective than 5), and it prevents hypoglycemia with the glucose follow-on instead of a smaller insulin dose. The KDIGO ED summary cites US studies in which 5 units lowered K⁺ as much as 10 units with less hypoglycemia, and its algorithm footnote lists 5 units + 25 g glucose. Hypoglycemia risk factors (UKKA Table 21): low pre-treatment glucose, renal impairment (AKI, CKD G4–5, kidney failure), low body weight, older age, no diabetes, insulin ≥ 10 units, glucose ≤ 25 g. Follow your institutional protocol; whichever insulin dose you use, the glucose co-prescription and the check schedule do not change.

KDIGO notes that with glucose > 200 mg/dL (11.1 mmol/L) insulin may be given without additional glucose. This tool still pairs every insulin dose with glucose, per UKKA.

Glucose volume for 25 g: 50 mL of 50% (large vein; phlebitis risk), 125 mL of 20%, or 250 mL of 10%. Choose by venous access and volume status.

The fear that calcium causes "stone heart" in digoxin toxicity rests on case reports. In a 17-year cohort, 23 of 161 patients with digoxin toxicity received IV calcium with no life-threatening dysrhythmia within 1 h and identical mortality (22% vs 22%) (Levine 2011); a 2025 study found no effect on short-term mortality. UKKA still lists digoxin as a caution for IV calcium. Give calcium when the ECG demands it; if digoxin toxicity is suspected, treat the toxicity — the DigiFab label lists K⁺ > 5.5 mEq/L with rapidly progressive toxicity as a life-threatening feature.

US labels state that none of the three should be used as emergency treatment for life-threatening hyperkalemia because of delayed onset; UKKA nevertheless recommends SZC alongside shift therapy in severe hyperkalemia.