CCM Notes
ICU Essentials · Electrolytes
Electrolyte Correction Protocols
K⁺ · Mg²⁺ · Ca²⁺ · Na⁺ · PO₄ — Correction Formulas & IV Protocols
K⁺
Potassium
Normal: 3.5–5.0 mEq/L
Hypokalemia
K+ 3.0–3.5: 20–40 mEq PO
K+ 2.5–3.0: 40 mEq IV over 4h (peripheral)
K+ <2.5 or Sx: 10–20 mEq/h IV (central)
Max peripheral rate: 10 mEq/h
Max central rate: 20 mEq/h
Hyperkalemia
K+ >5.5 + ECG: Calcium gluconate 1g IV (membrane stabilization)
Insulin 10U IV + D50 25g
Albuterol 10–20mg nebulized
Kayexalate / Patiromer PO
Dialysis if refractory
ECG Changes (Hypo)
Flattened T waves
Prominent U waves
ST depression
Risk: VF/VT — replace Mg first
K 0.1 ↓ ≈ 100 mEq total deficit
Mg²⁺
Magnesium
Normal: 1.8–2.4 mg/dL
Hypomagnesemia
Mild (1.2–1.8): MgSO₄ 2g IV over 2h
Severe (<1.2 or Sx): 4–8g IV over 4–12h
Oral: Mg oxide 400–800mg/day
Always replace before K+ in hypokalemia
Torsades: 2g IV push over 2min
Hypermagnesemia
Mild: Discontinue Mg supplements/antacids
>4 mg/dL: Calcium gluconate 1g IV (antagonist)
Severe: IV fluids + loop diuretic
>8 mg/dL: Dialysis
Caution in renal failure
Symptoms by Level
4–5 mg/dL: Hyporeflexia
5–7 mg/dL: Respiratory depression
>7 mg/dL: Cardiac arrest
Antidote: Calcium gluconate
Ca²⁺
Calcium
iCa²⁺: 1.12–1.32 mmol/L
Hypocalcemia
Symptomatic: Calcium gluconate 1–2g IV over 10min, then infusion
Calcium gluconate: 90 mg elemental Ca/g
Calcium chloride: 270 mg elemental Ca/g
Asymptomatic: PO Calcium carbonate + Vit D
Corrected Calcium
Corrected Ca = Measured Ca + 0.8 × (4 − albumin)
OR: Use ionized calcium for accuracy
Symptomatic hypoCa: tetany, Chvostek's, Trousseau's signs, QTc prolongation
Hypercalcemia
IV NS 200–500 mL/h hydration
Calcitonin 4–8 IU/kg q6–12h (acute)
Zoledronic acid 4mg IV (sustained)
Glucocorticoids if granulomatous
Ca >14 = medical emergency
PO₄
Phosphorus
Normal: 2.5–4.5 mg/dL
Hypophosphatemia
Mild (2–2.5): PO supplementation
Moderate (1–2): PO₄ 15 mmol IV over 2h
Severe (<1): 30–45 mmol IV over 6h
Refeeding syndrome: anticipate and prevent
Symptoms
Respiratory failure (diaphragm weakness)
Hemolytic anemia
Rhabdomyolysis
Encephalopathy, seizures
Critical: <1 mg/dL
Rate Limits
Max IV rate: 7.5 mmol/h
Caution: may precipitate with Ca2+
Use separate IV line
Monitor Ca²⁺ during infusion
💧 Sodium Correction (Na⁺ Normal: 135–145 mEq/L)
Hyponatremia (Acute, Sx)
3% NaCl 1–2 mL/kg/h
Goal: ↑ Na by 1–2 mEq/L/h until Sx resolve
Max correction rate
8–10 mEq/L/24h
Risk of osmotic demyelination syndrome (ODS) if too fast
Hypernatremia
D5W or 0.45% NS
Correct at ≤0.5 mEq/L/h; max 10–12 mEq/L/24h (risk cerebral edema)
Free Water Deficit (FWD)
TBW × (Na/140 − 1)
TBW = 0.6 × wt (M), 0.5 × wt (F)
SIADH Management
Fluid restriction 800–1000 mL/d
Salt tabs; Tolvaptan if refractory (severe SIADH)
Adrogue-Madias Formula
ΔNa = (Inf Na − Serum Na) ÷ (TBW + 1)
Change in serum Na per 1L infused