Mare Nostrum

Electrolyte Imbalances — Master Correction Order Set

Properties1
tagsworkflow

9 min read

Electrolyte Imbalances — Master Correction Order Set

⚠️ SAFETY | Reference สำหรับการศึกษาและ clinical reasoning เท่านั้น ปรับตาม local protocol, renal function, cardiac status, และ attending physician ทุกครั้ง

Ⅰ. SODIUM

🔵 Hyponatremia (Na <135 mEq/L)

Classify: mild 130–134 / moderate 125–129 / severe <125 + osmolality + volume (hypo/eu/hypervolemic)

Order for One Day

🔬 Investigation

  • Serum osmolality, urine osmolality, urine Na, urine K STAT
  • Electrolytes + glucose + Cr + BUN q4h
  • Cortisol, TSH (adrenal/hypothyroid); ECG; UO q1h

💊 Medication

  • Symptomatic/severe (<125/seizure/coma): 3% NaCl 100–150 mL IV over 20 min × 3 doses จน Na ↑ ≥5/1h; limit ≤12 mEq/L/24h; high-risk ODS ≤8; NDT 2024
  • Hypovolemic: 0.9% NaCl IV → switch D5W ถ้า Na ขึ้นเร็ว
  • Hypervolemic: fluid restrict 500–1,000 mL/day + furosemide 20–40 mg IV

Order for Continue

🔬 Investigation

  • Serum Na q4–6h active; q8–12h stable; urine Na + urine Osm ซ้ำ

💊 Medication

  • SIADH: fluid restrict 500–800 mL/day → resistant: Urea oral 30 g/day (NDT 2024) หรือ Tolvaptan 7.5 mg PO OD (hospital only; ห้ามใน liver disease)
  • Overcorrection (>12 mEq/24h): D5W 3–5 mL/kg/h ± DDAVP 1–2 mcg IV/SC

🔴 Hypernatremia (Na >145 mEq/L)

FWD (L) = TBW × [(Na÷140)−1] | TBW: 0.6×IBW ♂ / 0.5×IBW ♀ / 0.45 elderly ♀

Rate: Acute <48h ≤1 mEq/L/h | Chronic ≤0.5; max ≤12/24h (KJIM 2023)

Order for One Day

🔬 Investigation

  • Na, K, Cr, BUN, glucose, osmolality STAT; urine Osm, urine Na, urine SG; Na q4h; I&O

💊 Medication

  • Hypovolemic: NSS IV ก่อน → switch 0.45% NaCl หรือ D5W เมื่อ stable
  • Euvolemic (DI): D5W IV หรือ free water PO/NG — Central: DDAVP 1–4 mcg IV/SC q12–24h — Nephrogenic: หยุด drug + NSAIDs ± HCTZ 25 mg OD
  • Hypervolemic: furosemide 20–40 mg IV + D5W; Rate = FWD÷48–72h + insensible 40–50 mL/h + UO

Order for Continue

🔬 Investigation

  • Na q6–8h จน <150 → q12–24h; Cr, BUN daily; DI: urine SG + Osm q12h

💊 Medication

  • Adjust rate ทุก 4–6h; แก้ hyperglycemia/hypoK/hyperCa; PO: free water ≥2–3 L/day

Ⅱ. POTASSIUM

🔵 Hypokalemia (K <3.5 mEq/L)

Severity: mild 3.0–3.4 / moderate 2.5–2.9 / severe <2.5

กฎเหล็ก: แก้ hypoMg ก่อน/พร้อมกัน — Mg deficiency → renal K wasting → refractory hypoK

Deficit: K 3.0–3.5 → ~100–200 mEq | K 2.5–3.0 → ~200–300 | K <2.5 → >300 mEq

Order for One Day

🔬 Investigation

  • K, Mg, Ca, Cl, HCO3, Cr, glucose STAT; ECG (U wave, T flatten, prolonged QU)
  • Urine K:Cr ratio: <13 mEq/g = extra-renal; >13 = renal loss; ABG
  • Continuous monitoring ถ้า K <3.0 หรือ ECG changes

💊 Medication

  • Mild (3.0–3.4) + PO: KCl oral 40–80 mEq/day q6–8h
  • Moderate (2.5–2.9) / ECG / NPO: KCl 20 mEq in 100 mL NSS IV over 1h peripheral (max 10 mEq/h); CVC: 20–40 mEq/h (pump; ห้าม bolus)
  • Severe (<2.5) / arrhythmia: KCl 20 mEq in 100 mL NSS IV over 1h CVC; continuous monitoring
  • Concurrent hypoMg: MgSO4 2 g in 100 mL NSS IV over 20–30 min → 1 g/h × 6–8h

Order for Continue

🔬 Investigation

  • K, Mg q4–6h IV; q12h K >3.5; daily oral maintenance

💊 Medication

  • K >3.5: KCl PO 20–40 mEq/day; หยุด K-wasting drugs
  • Primary hyperaldosteronism: spironolactone 25–100 mg OD
  • Target K ≥4.0 ใน cardiac patients

🔴 Hyperkalemia (K >5.0 mEq/L)

Severity: mild 5.0–5.5 / moderate 5.5–6.0 / severe >6.0 หรือ ECG changes

กฎเหล็ก: ECG changes > ตัวเลข — peaked T / wide QRS / sine wave = emergency ทันที

Order for One Day

🔬 Investigation

  • ECG STAT (peaked T → PR ↑ → P absent → wide QRS → sine wave → VF)
  • K, electrolytes, Cr, Ca, glucose; pseudohyperK check (lithium-heparin tube); ABG
  • Continuous cardiac monitoring

💊 Medication

  • Step 1 — Membrane stabilization (ECG changes): Ca gluconate 10% 1–2 g IV over 5–10 min; repeat × 3 — Digoxin: ให้ช้า over 20–30 min — CVC: CaCl 10% (3× potency; cardiac arrest/hypotension)
  • Step 2 — Shift: Insulin 10 units IV + 50% dextrose 50 mL (BG <250); glucose q1h × 4h — Salbutamol 10–20 mg neb — NaHCO3 50–100 mEq ถ้า pH <7.2 เท่านั้น
  • Step 3 — Eliminate: Furosemide 40–80 mg IV — SZC (Lokelma) 10 g PO q8h × 3 doses (preferred; onset ~1h; UKKA 2023) — Patiromer 8.4 g OD — ❌ ห้าม Kayexalate
  • Step 4: Hemodialysis STAT (ESRD/oliguric AKI/refractory)

Order for Continue

🔬 Investigation

  • K, Cr, glucose q2–4h; ECG q4–6h; UO q1h

💊 Medication

  • หยุด ACEi/ARB/K-sparing/NSAIDs/TMP-SMX/heparin; low K diet <40–60 mEq/day
  • Maintenance: SZC 5 g OD หรือ patiromer 8.4 g OD (CKD/HF)
  • Hypoaldosteronism/type 4 RTA: fludrocortisone 0.1 mg OD

Ⅲ. MAGNESIUM

🔵 Hypomagnesemia (Mg <1.7 mg/dL)

Severity: mild 1.2–1.7 / moderate 0.8–1.2 / severe <0.8 หรือ symptomatic

สำคัญ: Mg ↓ → PTH suppression → hypoCa + renal K wasting → refractory hypoK/hypoCa

Order for One Day

🔬 Investigation

  • Mg, K, Ca, Phos STAT; ECG (QTc → torsades); Cr; FEMg: <2% extra-renal / >4% renal
  • Continuous monitoring ถ้า Mg <1.0 หรือ QTc >500 ms

💊 Medication

  • Mild + PO: Mg oxide 400–800 mg PO BID
  • Moderate–severe / symptomatic: MgSO4 2–4 g in 100 mL NSS IV over 15–30 min → 1–2 g/h IV × 6–24h (max 50 mEq/24h); target ≥2.0 mg/dL; Monitor DTR q1–2h; หาย DTR = หยุดทันที
  • Antidote: Ca gluconate 1–2 g IV over 5 min (ถ้า hyperMg)
  • Torsades: MgSO4 2 g IV over 1–2 min

Order for Continue

🔬 Investigation

  • Mg, K, Ca q6–8h IV; recheck K+Ca หลัง Mg replete

💊 Medication

  • Mg >1.7: Mg oxide 400 mg PO BID; หยุด PPI/loop diuretics
  • Renal wasting: amiloride 5–10 mg OD; แก้ hypoK + hypoCa ร่วม

🔴 Hypermagnesemia (Mg >2.5 mg/dL)

Mg (mg/dL)อาการ
2.5–4.0Nausea, flushing
4.0–6.0Drowsiness, hyporeflexia, hypotension
6.0–12.0Paralysis, respiratory depression
>12.0Heart block, cardiac arrest

Order for One Day

🔬 Investigation

  • Mg, Ca, Cr STAT; Mg q2–4h; ECG (PR ↑, wide QRS, AV block); ABG; continuous monitoring

💊 Medication

  • หยุด Mg preparations ทันที
  • Ca gluconate 10% 2 g IV over 5 min; repeat q30 min × 4
  • NSS + furosemide 40 mg IV; MV ถ้า RR <10
  • Emergent HD ถ้า severe/ESRD (ปรึกษา nephrology STAT)

Order for Continue

🔬 Investigation

  • Mg q4–6h; DTR + RR + BP q1h

💊 Medication

  • Avoid all Mg-containing products throughout admission

Ⅳ. CALCIUM

🔵 Hypocalcemia (iCa <1.12 หรือ Ca <8.5 mg/dL)

กฎเหล็ก: iCa เสมอใน critically ill — Corrected Ca = Ca + 0.8 × (4.0 − albumin)

Severity: mild iCa 1.0–1.12 / moderate 0.75–1.0 / severe <0.75 หรือ symptomatic

Order for One Day

🔬 Investigation

  • iCa, total Ca, Mg, Phos, K, albumin, Cr STAT; ECG (QTc ↑)
  • PTH, 25-OH VitD, 1,25-OH VitD, PTHrP; Chvostek + Trousseau; ABG
  • Continuous monitoring ถ้า iCa <1.0

💊 Medication

  • Severe/symptomatic (iCa <0.75): Ca gluconate 10% 2–3 g IV over 10–20 min → Ca gluconate infusion 1–2 g/h × 6–12h — ❌ ห้ามผสมกับ NaHCO3 — Cardiac arrest: CaCl 10% via CVC (3× potency)
  • Mild–Moderate: CaCO3 500–1,000 mg elemental PO TID — Calcitriol 0.25–0.5 mcg PO BID (hypoparathyroidism/CKD) — Cholecalciferol 50,000 IU/week (VitD deficiency)
  • แก้ hypoMg ก่อน/ร่วมเสมอ (Mg → PTH resistance)

Order for Continue

🔬 Investigation

  • iCa, Mg, Phos q6–8h IV; 24h urine Ca; PTH + 25-OH VitD

💊 Medication

  • Switch PO เมื่อ iCa >1.0; calcitriol 0.25 mcg BID (hypoparathyroidism)
  • Hungry bone syndrome: IV+PO Ca + high-dose calcitriol; iCa q4h; duration weeks

🔴 Hypercalcemia (Ca >10.5 หรือ iCa >1.30 mmol/L)

Severity: mild 10.5–12.0 / moderate 12.0–14.0 / crisis >14.0

Order for One Day

🔬 Investigation

  • Ca, iCa, albumin, Phos, Cr, Mg, ALP, K STAT; ECG (QTc ↓, J wave)
  • PTH, PTHrP, 25-OH VitD, 1,25-OH VitD; SPEP/IPEP, LDH; urine Ca:Cr ratio
  • Ca q4–6h; I&O

💊 Medication

  • Ca >12 / symptomatic: NSS 200–500 mL/h IV → furosemide 20–40 mg IV หลัง volume repleted เท่านั้น — Calcitonin 4–8 IU/kg SC/IM q6–12h (bridge ≤48h) — Zoledronic acid 4 mg IV over 15 min (most potent; Cr <4.5) — Pamidronate 60–90 mg IV over 2–4h (Cr 2.5–4.5) — Denosumab 120 mg SC (AKI/refractory) — Dexamethasone 4 mg IV q6h (VitD-mediated/myeloma)
  • Crisis (Ca >14): ICU; emergent HD ถ้า AKI

Order for Continue

🔬 Investigation

  • Ca q6–12h; BMP, Cr daily; workup: CT, bone scan, PTH/PTHrP

💊 Medication

  • ❌ ห้าม thiazide, Ca supplement, VitD
  • Oral hydration ≥2–3 L/day; cinacalcet 30–90 mg OD ถ้า secondary hyperPTH ใน ESRD

Ⅴ. PHOSPHATE

🔵 Hypophosphatemia (Phos <2.5 mg/dL)

Severity: mild 1.5–2.5 / moderate 1.0–1.5 / severe <1.0

4 associations: Refeeding | DKA recovery | Alcoholism | Acute respiratory alkalosis

Order for One Day

🔬 Investigation

  • Phos, iCa, Mg, K, Cr, albumin STAT; ABG; BG; CK (rhabdo)
  • FEPhos = (uPhos × sCr)/(sPhos × uCr) × 100: >5% renal / <5% transcellular/GI

💊 Medication

  • Mild + PO: Na/K phosphate PO 16–32 mmol TID (stagger ≥2h จาก Ca)
  • Moderate–severe / NPO: K <4.0 → Potassium phosphate 15–30 mmol in 250 mL NSS IV over 4–6h — K ≥4.0 → Sodium phosphate 15–30 mmol in 250 mL NSS IV over 4–6h — Severe (<1.0): 30–45 mmol; recheck 4h; total 60–90 mmol — ⚠️ monitor iCa (rapid → hyperPhos → hypoCa)

Order for Continue

🔬 Investigation

  • Phos, iCa, Mg q4–6h IV; CK daily (severe)

💊 Medication

  • Switch PO เมื่อ Phos >1.5
  • Refeeding: Thiamine 100–200 mg IV ก่อน + hypocaloric ≥2d + daily lytes
  • แก้ hypoMg ร่วมเสมอ; X-linked/TIO: Burosumab → ปรึกษา endocrinology

🔴 Hyperphosphatemia (Phos >4.5 mg/dL)

Order for One Day

🔬 Investigation

  • Phos, Ca, Cr, PTH, ALP, K, uric acid, LDH STAT; ECG ถ้า Ca×Phos >70; CK; LDH

💊 Medication

  • แก้ hypoCa ก่อน; IV hydration + furosemide
  • Phosphate binders (with meals เสมอ): Sevelamer carbonate 800–1,600 mg PO TID — CaCO3 500–1,500 mg PO TID — Lanthanum carbonate 1,500 mg/day TID — Cinacalcet 30–90 mg OD (secondary hyperPTH ใน ESRD)
  • Phos restriction <800–1,000 mg/day; TLS → IV hydration + rasburicase ± HD

Order for Continue

🔬 Investigation

  • Phos, Ca, Cr, PTH weekly; binder timing (with meals)

💊 Medication

  • Low Phos diet; limit dairy/processed food/colas; dialysis adequacy review ถ้า ESRD

⚡ ICU Quick Reference — “2–3–4 Rule”

ElectrolyteGoalIV Quick-doseExpected ↑
Mg≥2.0 mg/dLMgSO4 1 g IV↑ 0.2 mg/dL
Phos≥3.0 mg/dLNa-Phos 15 mmol IV↑ 0.4 mg/dL
K≥4.0 mEq/LKCl 10 mEq IV↑ 0.05–0.1 mEq/L
CaiCa ≥1.12Ca-gluconate 1 g IV↑ 0.5 mg/dL (total)

⚠️ Reference only — ปรับตาม local protocol, renal function, cardiac status, และ attending physician ทุกครั้ง

Graph View

Backlinks