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# Normal Saline (0.9% Sodium Chloride)
## Overview
Normal Saline (NS) is an isotonic crystalloid solution containing 154 mEq/L each of sodium and chloride. It is commonly used for fluid resuscitation and electrolyte replacement.
## Primary Indications
* Extracellular fluid replacement
* Treatment of metabolic alkalosis with fluid volume deficit
* Mild sodium depletion
* Vehicle for medication administration
* Wound/device irrigation
## Adult Dosing
* **Resuscitation:** Typically 500 mL to 1,000 mL bolus, repeated based on clinical response (hemodynamic status, urine output).
* **Maintenance:** Generally 1.5–2 mL/kg/hour, but highly dependent on clinical status and local institutional protocol.
## Pediatric Dosing
* **Resuscitation:** 20 mL/kg IV bolus, administered rapidly. Repeat as needed based on perfusion and clinical assessment. In septic shock, follow PALS guidelines (may require multiple early boluses).
* **Maintenance:** Calculated via the Holliday-Segar method (100 mL/kg for first 10 kg; 50 mL/kg for next 10 kg; 20 mL/kg for every kg above 20), typically provided as a continuous hourly rate.
## Dose Adjustments
* **Renal/Hepatic Impairment:** Reduce volume and rate in patients with heart failure or renal failure to prevent fluid overload and pulmonary edema.
* **Hypernatremia:** Use caution or contraindicate; isotonic saline may worsen hypernatremia compared to hypotonic alternatives.
## Contraindications
* Hypernatremia
* Fluid overload states (e.g., congestive heart failure, severe edema)
* Conditions where large volume infusions are clinically contraindicated
## Adverse Effects
* **Hyperchloremic metabolic acidosis:** Risk with large-volume administration due to high chloride content (leads to non-anion gap metabolic acidosis).
* **Fluid overload:** Pulmonary edema, peripheral edema, hypertension.
* **Dilutional coagulopathy:** Occurs with massive volume resuscitation.
## Key Drug Interactions
* **Incompatibilities:** Always verify physical compatibility before adding drugs to an NS infusion. Do not use as a vehicle for drugs that precipitate in a saline environment (e.g., phenytoin).
## Monitoring
* **Volume status:** Blood pressure, heart rate, urine output, lung sounds (crackles), and peripheral edema.
* **Labs:** Serum electrolytes (especially sodium and chloride), acid-base status (BUN/Cr ratio as an indicator of perfusion).
## Clinical Pearls
* **Chloride Load:** Prolonged or high-volume administration of NS is increasingly associated with acute kidney injury (AKI) compared to balanced crystalloids (like Lactated Ringer’s or Plasma-Lyte) due to the risk of renal vasoconstriction from hyperchloremia.
* **Hypertonicity:** NS is technically slightly hypertonic compared to human plasma, but clinically categorized as isotonic.
* **Consistency:** Always adhere to local institutional fluid stewardship protocols, especially in the ICU setting.
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**Educational Disclaimer:** This information is for educational purposes only. Drug dosing, contraindications, and compatibility can change. Always verify current prescribing information using local institutional protocols, package inserts, and evidence-based clinical reference software (e.g., Lexicomp, UpToDate) before administering medication.
