Generic Name

Sodium chloride (NaCl)

Mechanism

• Isotonic osmotic agent: Restores intravascular volume by equalizing osmotic pressure with plasma.
• Electrolyte supplementation: Replaces sodium and chloride lost through hemorrhage, diuresis, or vomiting.
• Blood pressure support: Increases mean arterial pressure via intravascular volume expansion.

Pharmacokinetics

Indications

• Hypovolemia: Sepsis, major burns, trauma, hemorrhage.
• Electrolyte replacement: Sodium depletion, chloride‑deficient states.
• Maintenance fluid therapy: Pediatric and adult patients in ICU.
• Intrathecal/epidural anesthesia co‑infusions: Stabilizes cerebrospinal fluid environment.

Contraindications

• Hypernatremia: Baseline serum Na⁺ > 148 mmol/L.
• Fluid overload: Congestive heart failure, cirrhosis with ascites, renal failure (GFR < 15 mL/min).
• Severe hyponatremia requiring rapid sodium correction; use hypertonic saline cautiously instead.
• Allergy to NaCl (rare).

Warnings:
• Monitor for edema, shortness of breath, and tachycardia during administration.
• Vigilant monitoring required in patients with underlying cardiac or renal disease.

Dosing

• Intravenous (IV) normal saline (0.9 % NaCl)
• Initial volume: 20–30 mL/kg (≈1–1.5 L for an average adult) for rapid volume resuscitation.
• Maintenance: 1–2 mL/kg/h (≈60–120 mL/h) in ICU; tailor to fluid status.
• Concentration: 154 mmol/L Na⁺ / 154 mmol/L Cl⁻; 0.9 % is isotonic.
• Oral
• 5–20 mg/kg in 3–5 mL/kg water, divided into 2–4 doses/day.
• Adjust for renal or hepatic impairment.
• Intrathecal/Epidural
• Use 0.9 % or 5 % for specific indications; volumes ≤10 mL to avoid neurological complications.

Infusion rate guidelines
• 250 mL/hr: high risk for edema/CHF.

Monitoring

• Vital signs: HR, BP, respiratory rate, O₂ sat.
• Weight & I&O: Daily weight change, urine output ≥0.5 mL/kg/h.
• Serum electrolytes: Na⁺, K⁺, Cl⁻, HCO₃⁻ every 4–6 h during titration.
• Renal function: BUN, creatinine baseline and 24 h post‑infusion.
• Liver enzymes: If concomitant hepatic disease.

*Check serum sodium and chloride prior to each infusion, especially in patients with compromised renal excretion.*

Clinical Pearls

1. Isotonic “physiologic saline”: 0.9 % NaCl ~150 mmol/L Na⁺ and Cl⁻ – the gold‑standard for rapid volume expansion without altering serum osmolality.
2. “Triple‑strength” saline (3 % NaCl): Reserved for hypernatremic dehydration; use very cautiously under intensive care due to osmotic shifts.
3. Dextrose‑free solutions: NaCl alone ensures that volume expansion is not countered by insulin‑mediated intracellular shift of fluids.
4. “Stop‑the‑water” rule: In patients with heart failure, stop infusion if the patient develops dyspnea or crackles—indicate possible fluid overload.
5. Use in pediatric dosing: 5–20 mg/kg oral = 1–4 mL/kg; avoid giving more than 2 mL/kg in a 30‑minute window to prevent hypernatremia.
6. “Caution with hypovolemic shock”: In massive, ongoing blood loss, 0.9 % saline at 250 mL/h may be insufficient; consider adding colloids or blood products to maintain oncotic pressure and oxygen‑carrying capacity.
7. IV osmolarity calculations: NaCl 0.9 % → 308 mOsm/kg – matches plasma osmolarity; ensures no shift of water into or out of cells during infusion.

This drug card equips clinicians and students with a quick‑reference yet detailed overview of sodium chloride’s role in fluid‑electrolyte management and its practical application tips.