Complex Acid-Base & Electrolyte Crises

12-Lead ECG & Continuous Telemetry
• Attach limb/precordial leads immediately.
• Obtain simultaneous point-of-care VBG/ABG with ionized calcium (iCa²⁺), K⁺, Na⁺, glucose, and lactate [1,2].

• 12-Lead ECG machine
• Heparinized blood gas syringe
• 2x large-bore IVs (16G–18G)

Detect lethal cardiac membrane instability (sine-wave K⁺, Torsades de Pointes, or QRS widening from Na⁺ channel blockade) before laboratory confirmation returns [1,2].

Myocardial Membrane Stabilization (If Severe Hyperkalemia / Sine-Wave QRS)
• Calcium Gluconate 10%: 30 mL (3 g = 13.95 mEq elemental Ca²⁺) IV over 2–5 min via peripheral IV [1,2].
• OR Calcium Chloride 10%: 10 mL (1 g = 13.6 mEq elemental Ca²⁺) IV over 2–5 min via central line (or secure large-bore peripheral vein in cardiac arrest) [1,2].

• Prefilled 10 mL ampules
• Dedicated IV line (flush thoroughly before giving NaHCO₃ to prevent CaCO₃ precipitation)

Restores the transmembrane voltage gradient by shifting the threshold potential (Vₜ) less negative (from −75 mV back toward −65 mV), restoring fast voltage-gated Na⁺ channel (Naᵥ1.5) availability without changing serum [K⁺] [2].

Seizure / Brainstem Herniation Arrest (If Severe Hyponatremic Encephalopathy)
• 3% Hypertonic Saline (NaCl): 100 mL to 150 mL IV bolus over 10–20 min (may repeat up to twice at 10-min intervals until seizures cease) [3,4].
Torsades / Severe Hypomagnesemia Stabilization
• Magnesium Sulfate (MgSO₄): 2 g (16.2 mEq) diluted in 50 mL D5W/NS IV push over 2–5 min (push over 1–2 min if pulseless Torsades) [1].

• 500 mL bag 3% NaCl (513 mEq/L)
• Infusion pump or manual syringe bolus

3% NaCl: acutely raises serum tonicity by 4–6 mEq/L, creating an osmotic gradient across the intact blood-brain barrier (BBB) that pulls free water out of edematous astrocytes within minutes (Monro-Kellie doctrine) [3,4].
MgSO₄: suppresses early afterdepolarizations (EADs) by inhibiting L-type Ca²⁺ influx during Phase 2 of the cardiac action potential [1].

Intracellular Potassium Shift (Hyperkalemia)
• Regular Insulin: 10 Units IV push (5 Units if eGFR < 30 mL/min or ESRD) preceded by Dextrose 50% (D50W) 50 mL (25 g) IV (or 250 mL D10W) if serum glucose < 250 mg/dL (13.9 mmol/L) [1,2].
• Nebulized Albuterol (Salbutamol): 10–20 mg continuous nebulization over 15 min [1,2].

• Insulin syringe + D50W ampule / D10W bag
• High-output nebulizer mask (4x to 8x standard bronchodilator dose)

Activates sarcolemmal Na⁺/K⁺-ATPase pumps via insulin receptor substrate-1 (IRS-1)/PI3K signaling and β₂-adrenergic receptor Gs-cAMP-PKA cascades, driving K⁺ into skeletal muscle cells within 15–30 min [2].

Severe Acidemia Rescue (pH < 7.10 or AKI + pH < 7.20) & Definitive Elimination
• Isotonic Sodium Bicarbonate: Infuse 1.26% or 1.4% NaHCO₃ (150 mEq/L) 250–500 mL IV over 30–60 min [5].
• Definitive K⁺ Clearance: Furosemide 40–80 mg IV (if hypervolemic/euvolemic with intact renal function) + Sodium Zirconium Cyclosilicate (SZC) 10 g PO + Emergent Nephrology consult for Hemodialysis [1,2].

• Isotonic NaHCO₃ infusion
• High-flow dialysis catheter (12–14 Fr) if anuric/ESRD

Buffers extracellular [H⁺] via the Henderson-Hasselbalch carbonic anhydrase equilibrium, restores vascular α₁-receptor catecholamine responsiveness, and initiates total body K⁺ removal via the distal nephron or extracorporeal clearance [2,5].