Formula Basis
Na Deficit (mEq) = TBW × (Target Na − Current Na)
TBW (Total Body Water) = Weight × factor (♂ adult 0.6 · ♀ adult 0.5 · ♂ elderly 0.5 · ♀ elderly 0.45). The deficit tells how much sodium must be infused to raise serum Na to target — but it must not all be given in 24h (ODS risk).
Safe 24h Target
The maximum serum Na value you should aim for within the first 24 hours, calculated as Current Na + 8 mEq/L (with absolute ceiling 10 mEq/L/24h). Faster correction risks Osmotic Demyelination Syndrome (ODS), especially in chronic hyponatremia.
Total Volume (full deficit)
The fluid volume that would deliver the entire calculated Na deficit. Shown for reference only — do NOT infuse all at once. Use it to plan multi-day correction (typical chronic hyponatremia needs 2–3 days).
Safe 24h Volume
The fluid volume that delivers exactly enough Na to raise serum Na by ≤8 mEq/L in 24h. This is what you actually order on Day 1. On Day 2 and beyond, repeat the same regimen until target reached, rechecking Na q4–6h.
Rate (24h)
Safe 24h Volume ÷ 24 hours. The infusion rate in mL/h to give continuously. For NaCl 3% this typically runs at 25–50 mL/h via infusion pump; never push hypertonic saline at maintenance fluid rates.
Adrogué-Madias ΔNa
ΔNa per L = (Infusate Na − Serum Na) / (TBW + 1)
Predicts how much serum Na will rise after infusing 1 L of the chosen fluid. Useful sanity check — if 1 L of NaCl 3% would raise Na by 12 mEq/L, you should not give a full liter in 24h. Cross-check against the rate calculation.
Formula Basis
K Deficit (mEq) = (Target K − Current K) × Weight × 0.4
The 0.4 factor approximates the extracellular fluid space affected by acute repletion. This is the practical IV dose — NOT the entire total body deficit (which can be 200–400 mEq/L drop and is restored over days via oral/diet). For 70 kg, K 2.5 → 4.0: 1.5 × 70 × 0.4 = 42 mEq ≈ 1 vial KCl 7.46% (50 mL).
PIV (Peripheral IV)
Peripheral Intravenous line — a standard cannula in a forearm/hand vein. Safer to place but limits how concentrated and how fast you can infuse KCl. Maximum: 40 mEq/L concentration, 10 mEq/h rate (consensus safety limit to avoid endothelial injury and arrhythmia).
Textbook safe · 40 mEq/L max
The international consensus upper limit for peripheral KCl infusion: dilute to ≤40 mEq/L (e.g., 20 mEq in 500 mL NS) and infuse at ≤10 mEq/h. This causes minimal venous irritation and is the published guideline standard (Kruse, UpToDate, NEJM).
Common Indonesian practice · 100 mEq/L · large-bore PIV
In Indonesian ED/ICU practice, KCl 50 mEq in NS 500 mL (= 100 mEq/L) is widely used via large-bore peripheral cannula (18G in cubital/forearm vein) when CVC is unavailable. This exceeds textbook safety but is accepted clinically with caution. Trade-off: faster correction vs. risk of pain, phlebitis, and infiltration. Use only if: large-bore IV, frequent site monitoring, patient can communicate pain, and no severe arrhythmia.
Custom Rate / Slow Infusion
If the patient cannot tolerate the standard infusion rate (KCl burning, pain, phlebitis), use the "Slow rate" input on the recommended card to extend the per-bag duration. Example: change 50 mEq + NS 500 mL from 8 jam → 24 jam. This drops mL/h flow from 62 → 21 (less venous irritation) but slows mEq/h to 2.1. Useful when: KCl-induced pain at site, small/fragile veins, oral supplementation also given in parallel, or non-urgent correction.
All calculations are for clinical decision support only. Always verify against current guidelines and the patient's full clinical picture.