Hyperkalemia in the OR

Renal · Hepatic · Endocrine · 7 min read

Recognize the ECG progression, treat in the right order: stabilize the membrane, shift K+ intracellular, remove K+ from the body. Speed matters; sequence matters more.

Recognize early — the ECG is your friend

Normal K+ 3.5-5.0; hyperK+ defined > 5.0; severe > 6.5 or symptomatic. ECG progression as K+ climbs: K 5.5-6.5 → PEAKED T WAVES (narrow base, tall, symmetric). K 6.5-7.5 → flattened/lost P, prolonged PR, WIDENED QRS. K 7.5-8.5 → SINE WAVE (broad QRS merging with T — the classic 'death rhythm' shape). K >8.5 → VF, asystole. Classic perioperative scenarios: succinylcholine in chronic SCI/burns/disuse (extrajunctional AChR upregulation → massive K release), older PRBC units in massive transfusion, ESRD on dialysis, severe acidosis (each 0.1 ↓ pH = ~0.5 mEq/L K shift out of cells), tumor lysis post-chemo, rhabdo from prolonged supine hypotension or compartment syndrome.

Hyperkalemia algorithm →

Step 1 — STABILIZE the membrane

If ECG changes or K >6.5, give CALCIUM FIRST. CaCl 1 g IV (10 mL of 10% solution — central line preferred — sclerosing) OR Ca-gluconate 3 g IV (peripherally OK — gentler) over 5-10 min. Onset 1-3 min. Lasts 30-60 min. Calcium does NOT lower K+ — it antagonizes the membrane effects (raises threshold for arrhythmia). REPEAT every 30-60 min until K+ is reduced. Don't wait for shifts to take effect — the next 5 min after stabilization is when you build toward removing K from the body.

Step 2 — SHIFT K+ intracellular

Three workhorses, often given together. INSULIN 10 units regular IV + DEXTROSE 50% 25 g (one amp D50W) — onset 15-30 min, lasts 4-6 h; insulin activates Na/K-ATPase → cellular K uptake. Don't forget the dextrose unless glucose >250. BICARBONATE 50-100 mEq (1-2 amps) IV — most effective when patient is acidotic; less effective in non-acidotic. ALBUTEROL 10-20 mg nebulized (4-5× standard dose) — β2 → cellular K uptake; 15-30 min onset; useful especially when IV access is limited. NEVER mix bicarb + calcium in same line — they precipitate. Two separate lines.

Step 3 — REMOVE K+ from the body

Stabilizing + shifting buys time but doesn't solve the problem. FUROSEMIDE 40-80 mg IV (or higher in CKD) — requires functional kidney; onset 15-30 min. SODIUM POLYSTYRENE SULFONATE (Kayexalate) PO/PR — slow + variable + GI necrosis risk; modern alternatives PATIROMER + SODIUM ZIRCONIUM CYCLOSILICATE (Lokelma) — better tolerated. HEMODIALYSIS for severe + refractory — especially ESRD; immediate effect during procedure. If K >7 with ECG changes that don't resolve with stabilize + shift, get nephro on the phone for emergent dialysis.

Perioperative — prevent the spike

(1) AVOID SUCCINYLCHOLINE in patients with: chronic hyperkalemia, denervation/SCI/CVA >24-72 h, burns >24-72 h, prolonged ICU immobility, muscular dystrophy, severe sepsis. Use rocuronium 1.0-1.2 mg/kg + sugammadex backup. (2) MASS TRANSFUSION: monitor K closely; use fresh PRBC units when possible; older units have higher K from cell lysis during storage. (3) FLUID CHOICE in known hyperK+: prefer NS over LR (LR has 4 mEq/L K, plasma-lyte 5; NS 0); modest absolute amount but matters in severe cases. (4) DIALYSIS PATIENTS: dialyze pre-op when feasible; check K within 24 h of major surgery; K >5.5 pre-op should prompt urgent dialysis or aggressive medical treatment.

Pearl — think in seconds, not minutes

Calcium first, then everything else. Don't waste 10 min hunting for the right insulin order if the ECG is wide. Calcium → 5-10 min to act → membrane stabilized → now you have time to set up the rest. The biggest perioperative mistake is treating mildly elevated K (5.5-6.0) as urgent vs treating severe + ECG-changes hyperkalemia methodically. Order the K, look at the ECG, treat the patient — not the number.

References

· AHA ACLS 2020
· KDIGO Guidelines for Acute Kidney Injury
· Miller's Anesthesia 9e Ch 16