Bedside Snapshot

Use It For
Hypovolemia and shock; sepsis with TBI or raised ICP; DKA/HHS initial fluid; hypovolemic hyponatremia or hypernatremia (volume first), severe hypercalcemia; blood transfusion lines and drug dilution
Adult Dose
  • Shock: 500 mL IV/IO bolus, reassess, repeat (up to 30 mL/kg)
  • Sepsis: ≥30 mL/kg crystalloid in 3 hr (balanced default; 0.9% saline with TBI or raised ICP)
  • DKA/HHS: 500–1,000 mL/hr IV for the first 2–4 hr
Pediatric Dose
Shock: 10–20 mL/kg bolus, reassess (up to 40–60 mL/kg with intensive care). Newborn volume expansion: 10 mL/kg IV/IO over 5–10 min, repeat if inadequate. Maintenance: isotonic with dextrose and KCl
Onset / Duration
IV/IO: immediate / volume-based; much of a bolus moves into the interstitium over minutes to hours, faster with capillary leak
Do Not Give / Hold If
Hypernatremia without hypovolemia (in shock: isotonic volume first, free water later); fluid overload, new crackles or falling SpO₂; SIADH (Na⁺ can fall); bacteriostatic saline in neonates or as replacement fluid
Watch For
Fluid overload (crackles, falling SpO₂); hyperchloremic acidosis after liters (Cl⁻ up, HCO₃⁻ down); Na⁺ overcorrection in chronic hyponatremia (serial Na⁺, urine surge)
Reversal / Rescue
No antidote: stop the infusion. Overload: sit up, oxygen, CPAP or ventilation, diuretic. Persistent shock: vasopressor or blood. Na⁺ rising too fast: stop and notify the prescriber
Must Remember
Pick the fluid on purpose: balanced crystalloid is the default in sepsis, but 0.9% saline stays first choice for TBI or raised ICP, hypovolemic hyponatremia (not SIADH), chloride-loss alkalosis and blood lines

Indications

Emergency & Prehospital

  • Hypovolemia and hypovolemic shock: Vomiting, diarrhea, heat illness, burn losses and other extracellular fluid deficits. It is the crystalloid most EMS agencies carry.
  • Sepsis-induced hypoperfusion or septic shock: Balanced crystalloid is the default, lactated Ringer's or Plasma-Lyte A. Use 0.9% saline when sepsis and traumatic brain injury or raised ICP coexist.
  • Traumatic brain injury (TBI) or raised intracranial pressure (ICP): Isotonic crystalloid is the preferred fluid. Its job is to prevent hypotension. Avoid hypotonic fluids.
  • Hemorrhagic shock: Use a small-volume bridge only when blood products are not available.
  • Crush injury: Start potassium-free fluid before the trapped limb is released.

ED / ICU / Transport

  • Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS): The initial resuscitation fluid is 0.9% saline or a balanced crystalloid. Balanced crystalloid is linked to faster DKA resolution and less hyperchloremic acidosis.
  • Hypovolemic hyponatremia: Restoring volume raises sodium. Not for SIADH (syndrome of inappropriate antidiuretic hormone).
  • Hypovolemic hypernatremia: Isotonic saline restores circulating volume first. Free-water replacement comes after that. Then lower Na⁺ slowly, no more than about 10 mEq/L in 24 hr.
  • Hypochloremic metabolic alkalosis: Vomiting or nasogastric losses. The saline supplies the chloride the kidney needs to excrete bicarbonate.
  • Severe hypercalcemia: Hydration comes first, while antiresorptive drugs take effect.
  • Blood product transfusion: Saline is the standard solution for blood tubing. Use another fluid only if it is FDA-approved for use with blood (e.g., Plasma-Lyte A pH 7.4). Never lactated Ringer's (calcium) or dextrose.
  • Pediatric maintenance fluid: It is the base of isotonic maintenance fluid, with dextrose and potassium, for most children 28 days to 18 years.

Other Uses

  • Drug diluent, carrier and line flush: Most IV drugs are compatible with it. Check each drug label.
  • Priming solution: Hemodialysis circuits (FDA-labeled) and transfusion sets get primed with it.

Composition
ComponentPer LiterComparison to Plasma
NaCl
9 g (0.9 g per 100 mL)
—
Na⁺
154 mEq
135–145 mEq/L: higher
Cl⁻
154 mEq
96–106 mEq/L: about 50% higher
K⁺, Ca²⁺, Mg²⁺
None
Potassium-free; no calcium to clot citrated blood
Buffer
None
Plasma HCO₃⁻ 22–28 mEq/L; saline dilutes it
Glucose, calories
None (0 kcal)
Add dextrose for maintenance or after DKA glucose falls
Osmolarity
308 mOsm/L (calculated)
Serum osmolality 275–295 mOsm/kg
pH
5.0 (range 4.5–7.0)
7.35–7.45; saline acidosis comes from its chloride, not the bag pH
Tonicity
Isotonic
No free water: does not shift water into brain cells
  • Chloride load: Equal Na⁺ and Cl⁻ (154 mEq/L each) dilute plasma bicarbonate. Several liters cause a hyperchloremic, normal anion gap metabolic acidosis.
  • Free water: None. That is why saline is the fluid for TBI, raised ICP and hypovolemic hyponatremia. In SIADH, though, the kidney excretes the salt in concentrated urine and keeps the water, so Na⁺ can fall.
  • Where it goes: It spreads through the whole extracellular space. Plasma is about one-quarter of extracellular fluid. So a common teaching estimate says roughly one-quarter of a bolus stays in the vessels of a euvolemic adult. Hypovolemia keeps more in, and capillary leak keeps less in.
  • Products: These are US label values (Baxter). Other makers sell the same strength. Bacteriostatic 0.9% saline vials add 0.9% benzyl alcohol, so they are a different product.

Dosing & Administration

Doses vary by protocol; follow local protocols and medical direction.

Available Forms

  • 0.9% Sodium Chloride Injection, USP (9 mg/mL): Single-dose flexible bags of 25, 50, 100, 150, 250, 500 and 1,000 mL. EMS and transport usually carry the 1,000 mL bag. The small bags are drug-diluent minibags.
  • Preservative-free vials and prefilled flush syringes: Use them for drug dilution and line flushing.
  • Bacteriostatic 0.9% saline (multiple-dose vials, 0.9% benzyl alcohol): Drug dilution only. Do not use it for fluid replacement, and never in neonates.
  • Look-alikes: 0.45% saline, 3% and 5% hypertonic saline, dextrose-saline combinations and saline irrigation. Read the percentage before you spike the bag.

Adult Dosing

IndicationDose & RouteRepeat / MaxNotes
Hypovolemia or shock (EMS)
500 mL IV/IO bolus, pressure-infused over <15 min, reassess after each
Repeat to MAP 65 mmHg, up to 30 mL/kg; stop for pulmonary edema
Smaller boluses in heart failure, dialysis or older adults. Persistent shock: vasopressor (norepinephrine) or blood, not endless fluid
Sepsis-induced hypoperfusion or septic shock
≥30 mL/kg IV/IO crystalloid within the first 3 hr, as boluses with reassessment after each
No fixed max: stop for overload or no response; then liberal or restrictive strategy per patient
Default fluid: balanced crystalloid (lactated Ringer's or Plasma-Lyte A), including in sepsis (Surviving Sepsis Campaign 2026 suggests balanced fluid over 0.9% saline). Use 0.9% saline instead with traumatic brain injury or raised ICP (individual-patient meta-analysis of 6 ICU trials, BEST-Living: in-hospital death 19.1% with balanced fluid vs 14.7% with saline in TBI), in crush injury (NASEMSO 2022: avoid lactated Ringer's), in hypovolemic hyponatremia, and when hyperkalemia is a risk (lactated Ringer's label: avoid). Dosing weight: actual, or adjusted or ideal if BMI >30
Hemorrhagic shock (no blood available)
500 mL IV/IO bolus to a target SBP 90 mmHg (radial pulse, alert)
Contact medical direction after 2 L total crystalloid
Blood products first whenever available; excess crystalloid worsens coagulopathy. Tranexamic acid per protocol
Moderate or severe TBI (age >10 yr)
500 mL IV/IO boluses to keep SBP ≥110 mmHg
No fixed max: prevent hypotension, stop for overload
Do not wait for hypotension to treat. Avoid hypotonic fluids. SBP ≥110 mmHg: NASEMSO 2022, p.234
DKA or HHS
500–1,000 mL/hr IV for the first 2–4 hr (no renal or cardiac compromise)
Then rate per protocol; add 5–10% dextrose when glucose <250 mg/dL
0.9% saline or balanced crystalloid. Consider smaller boluses (e.g., 250 mL) in older adults and people with heart or kidney failure. K⁺ <3.5 mEq/L: replace K⁺ and delay insulin
Crush injury
1,000 mL IV bolus before release; then 500–1,000 mL/hr IV
No fixed max: titrate to urine output; stop for overload
Start before the limb is freed. Monitor ECG for hyperkalemia at release
Burns, not in shock (over 40 kg)
Initial rate by TBSA ("Rule of 10"): TBSA % rounded to the nearest 10 × 10 = mL/hr IV for 40–80 kg; add 100 mL/hr for every 10 kg over 80 kg
Rate, not bolus; then titrate per burn protocol and urine output. Burn patient in shock: use the shock row
Lactated Ringer's or 0.9% saline per NASEMSO 2022, p.219 (Rule of 10 rate on that page); see lactated Ringer's for burn formulas. Under 40 kg: burn fluid chart with length-based weight. Consider trauma or cyanide if in shock
Severe hypercalcemia (e.g., of malignancy)
1–2 L IV bolus, then 200–500 mL/hr
Titrate to urine output 100–150 mL/hr; stop or slow for overload
Regimen from the Endocrine Society 2023 hypercalcemia-of-malignancy guideline; extrapolated to other causes. Bridge until the antiresorptive works. Tailor volume to cardiac and renal function and assess for overload; older adults and heart or kidney failure need smaller volumes. Loop diuretics are not routine; use only to treat volume overload
Hypovolemic hyponatremia
Isotonic saline boluses or infusion per protocol, with serial Na⁺
Na⁺ rise ≤10 mEq/L in 24 hr; ≤8 mEq/L in 24 hr in high osmotic demyelination risk (alcoholism, malnutrition, hypokalemia, liver disease)
Once volume is restored, a brisk water diuresis can raise Na⁺ fast. See sodium
Drug diluent, carrier, flush; blood transfusion
Volume per drug label and institutional policy; prime and flush transfusion sets with 0.9% saline
No fixed max: count all carrier volume in the fluid balance
0.9% saline is the standard solution for blood tubing; other fluids only if FDA-approved for use with blood (e.g., Plasma-Lyte A pH 7.4). Never lactated Ringer's (calcium) or dextrose

Pediatric Dosing

IndicationDose (per kg) & RouteMax Single / Max TotalNotes
Septic shock (intensive care available)
10–20 mL/kg IV/IO bolus, reassess after each
Up to 40–60 mL/kg in the first hr; stop if shock resolves or overload appears (crackles, hepatomegaly)
Balanced crystalloid is the default for children with septic shock (Surviving Sepsis Campaign Children 2026, conditional). PRoMPT BOLUS (9,041 children, 47 emergency departments) found no kidney-outcome difference: major adverse kidney event at 30 days 3.4% with balanced fluid vs 3.0% with 0.9% saline (RR 1.10, 95% CI 0.88 to 1.40); hyperchloremia 31.4% vs 49.0%. Use 0.9% saline when raised ICP (for example CNS infection) is a concern.
Septic shock (no intensive care)
Hypotension: 10–20 mL/kg IV/IO bolus. No hypotension: no bolus; maintenance fluid only
Up to 40 mL/kg in the first hr
Boluses without hypotension in this setting are recommended against (strong recommendation)
Hypovolemic or hemorrhagic shock
20 mL/kg IV/IO bolus, reassess after each (10 mL/kg if cardiogenic shock is suspected)
Max single 20 mL/kg (adult-size adolescents: adult 500 mL boluses). Total: medical shock fluid goal up to 60 mL/kg or 1 L; trauma: contact medical direction after 60 mL/kg
Bleeding: blood products as soon as available. See pediatric shock
DKA
No shock (dehydration, glucose >250 mg/dL): 10 mL/kg IV bolus, reassess. Shock: 20 mL/kg IV/IO boluses per pediatric shock dosing, reassess after each
No shock: repeat to a total of 40 mL/kg, then deficit replacement per pediatric DKA protocol. Shock: per pediatric shock limits (medical direction after 60 mL/kg)
Protocol-dependent: bolus volume and rate vary between EMS and pediatric DKA protocols. Watch neurologic status for cerebral edema. Check K⁺ and glucose
Moderate or severe TBI (age 10 yr and under)
Isotonic IV/IO boluses (20 mL/kg per pediatric shock dosing), reassess after each, to keep SBP above the age threshold
Prevent SBP <60 mmHg (<1 month), <70 mmHg (1–12 months) or <70 + 2 × age in years (1–10 yr); stop for overload
Do not wait for hypotension to treat. Avoid hypotonic fluids. Thresholds: NASEMSO 2022, p.234; NASEMSO gives no TBI volume, so 20 mL/kg is borrowed from shock dosing
Crush injury
10 mL/kg/hr IV after extrication
No fixed max: titrate to urine output; stop for overload
Start fluid before release where possible. NASEMSO 2022 p.222 gives no pediatric pre-release volume (its 1,000 mL pre-release bolus is not weight-based) and 10 mL/kg/hr after extrication. Monitor ECG for hyperkalemia
Maintenance (28 days to 18 yr)
Isotonic fluid with appropriate dextrose and potassium chloride (e.g., D5 0.9% saline with KCl), volume by weight-based formula
Hourly rate per maintenance formula; check Na⁺, K⁺ and glucose at least daily
Replaces hypotonic fluids per the AAP 2018 guideline. Not covered: neurosurgical disorders, cardiac disease, hepatic disease, cancer, renal dysfunction, diabetes insipidus, voluminous watery diarrhea, severe burns, neonates <28 days or in the NICU, and adolescents >18 yr
Neonatal resuscitation: volume expansion
0.9% saline or blood 10–20 mL/kg IV/IO (umbilical venous catheter or IO) over 5–10 min; repeat if the response is inadequate (2025 AHA Part 5, COR 2b, C-EO)
Repeat if response is inadequate
For evidence of hypovolemia or known or suspected blood loss with heart rate under 60/min despite ventilation, compressions and epinephrine: volume expansion may be reasonable (2025 AHA Guidelines for CPR and ECC, Part 5). Normal saline is the crystalloid of choice; uncrossmatched type O, Rh-negative blood (or crossmatched, if immediately available) is preferred when blood loss is substantial (Part 5 synopsis)
Neonates: bacteriostatic saline
Contraindicated (benzyl alcohol)
Use preservative-free 0.9% saline only
Benzyl alcohol preservative; preservative-free products only for any neonatal flush, dilution or volume

Very low birth weight infants: any sodium chloride injection given too fast or in excess can raise serum osmolality. That raises the risk of intracerebral hemorrhage. See weight-based dosing.

Preparation & Administration

  • Line: peripheral IV or IO; the largest practical catheter for rapid boluses
  • Air embolism: use a non-vented set (or close the vent), never connect bags in series, remove all air from the bag before using a pressure bag, and stop the pump before the bag empties
  • Blood products: prime and flush the transfusion set with 0.9% saline (other fluids only if FDA-approved for use with blood); never lactated Ringer's (calcium clots citrated blood) or dextrose in the same tubing
  • Additives: check compatibility first, mix thoroughly, inspect for precipitate and discoloration, and do not store admixed bags
  • Pump: run maintenance fluids, children's fluids and DKA infusions on a pump with a volume limit
  • Inspection: squeeze the inner bag for leaks and use only clear solution

Contraindications & Precautions

Contraindications

  • No contraindication is known for 0.9% Sodium Chloride Injection, per the FDA label.
  • Bacteriostatic saline (benzyl alcohol): Do not use it in neonates, for fluid or sodium replacement, or for epidural or spinal use.
  • Hypernatremia without hypovolemia, or fluid overload (relative: the label advises avoiding it unless use cannot be avoided, then monitoring Na⁺). In hypovolemic shock with hypernatremia, restore volume with isotonic fluid first. Then correct the free-water deficit slowly.
  • Euvolemic hyponatremia from SIADH (relative: saline can push Na⁺ lower still).

Precautions

  • Sodium and fluid retention: heart failure, cirrhosis, kidney disease, primary or secondary hyperaldosteronism, pre-eclampsia, corticosteroid therapy.
  • Severe renal impairment: Hypernatremia and overload are the risks. If saline cannot be avoided, monitor closely.
  • Chronic hyponatremia: Too fast a correction risks osmotic demyelination syndrome (ODS).
  • Hyponatremia risk: children, older adults, postoperative patients, SIADH, cardiac or pulmonary failure, drugs such as diuretics, antiepileptics and psychotropics.
  • Large volumes: They bring hyperchloremic acidosis and dilute clotting factors in hemorrhage.

Hold / Reassess If

  • New crackles, falling SpO₂, rising work of breathing or oxygen need: stop, reassess volume.
  • No rise in blood pressure, perfusion or urine output after a bolus: reassess before more fluid; consider vasopressor or blood.
  • Na⁺ rising more than 10 mEq/L in 24 hr (≤8 mEq/L in 24 hr in high osmotic demyelination risk), or a sudden large urine output in hyponatremia: stop and notify the prescriber.
  • Na⁺ >145 mEq/L, or Cl⁻ rising with HCO₃⁻ falling after several liters: switch fluid per prescriber.
Pressure Bags and Air: Air embolism has happened with pressurized flexible bags. Pull all the air out of the bag before you pressurize it. Use a non-vented set. Never connect bags in series.

Adverse Effects & Toxicity

Common

  • Infusion-site reactions: erythema, streaking, burning, urticaria at the site
  • Peripheral and tissue edema after large volumes
  • Hyperchloremia and a fall in bicarbonate after several liters
  • Frequencies are not established. The reports come from postmarketing use only.

Serious / Life-Threatening

EffectRecognitionManagement
Fluid overload and pulmonary edema
Crackles, falling SpO₂, edema, raised jugular venous pressure
Stop; sit up; oxygen, CPAP or ventilation; furosemide if not hypovolemic
Hyperchloremic metabolic acidosis
Falling HCO₃⁻ with rising Cl⁻ and a normal anion gap after several liters
Switch to a balanced crystalloid unless TBI, raised ICP or hyperkalemia risk still needs saline; check lactate and anion gap before blaming ongoing shock
Hypernatremia
Thirst, confusion, Na⁺ >145 mEq/L; high risk in renal failure
Stop; replace free water per prescriber; correct gradually
Hyponatremic encephalopathy
Headache, nausea, vomiting, lethargy, seizures; SIADH or postoperative patients given large volumes
Stop; STAT Na⁺; severe symptoms: 3% saline per protocol
Osmotic demyelination (overcorrection)
Days later: dysarthria, dysphagia, weakness, altered consciousness after a rapid Na⁺ rise
Prevent: serial Na⁺, stop saline if Na⁺ climbs too fast; the prescriber may relower Na⁺
Hypersensitivity or infusion reaction (postmarketing, frequency unknown)
Hypotension, fever, tremor, chills, urticaria, rash, pruritus; tachycardia, chest pain, dyspnea, flushing
Stop the infusion immediately; treat per anaphylaxis protocol if severe (epinephrine IM)
Air embolism
Sudden dyspnea, hypotension, stroke or arrest during a pressurized infusion
Stop and clamp; high-flow oxygen; resuscitate

Overdose & Toxicity Management

  • Signs: fluid overload with pulmonary or peripheral edema; hypernatremia; hyperchloremic acidosis
  • Management: stop the infusion, support oxygenation and ventilation, give a loop diuretic for overload, and monitor fluid balance, electrolytes and acid-base status
  • Antidote: none

Monitoring
ParameterWhen / How OftenTarget / Act If
Clinical: perfusion
Before and after every bolus
Heart rate, blood pressure (MAP ≥65 mmHg in adult shock; SBP ≥110 mmHg in TBI, NASEMSO 2022 p.234), capillary refill, mental status; no response: reassess before more fluid. ICU and transport: use dynamic measures where available (passive leg raise or fluid challenge with stroke volume or pulse-pressure variation) with capillary refill and lactate trend to decide on more fluid, as SSC 2026 suggests
Clinical: lungs and SpO₂
Every assessment, especially during boluses
Crackles, falling SpO₂ or rising work of breathing (children: hepatomegaly): stop, reassess volume
Clinical: urine output
Hourly in shock, DKA, crush injury and hypercalcemia
Adults <0.5 mL/kg/hr or children <1 mL/kg/hr: reassess volume. Hyponatremia with a sudden large urine output: check Na⁺ now
Clinical: fluid balance and weight
Running total during resuscitation; daily after
Large positive balance once stable: stop maintenance, consider active fluid removal
Laboratory: Na⁺
Baseline; every 2–4 hr while correcting hyponatremia; every 4 hr with electrolytes in DKA/HHS; daily on maintenance
Rise >10 mEq/L in 24 hr or Na⁺ >145 mEq/L: stop, notify prescriber. High osmotic demyelination risk (alcoholism, malnutrition, hypokalemia, liver disease): limit the rise to 8 mEq/L in 24 hr and check Na⁺ more often (sodium)
Laboratory: Cl⁻, HCO₃⁻, anion gap
Baseline and after each 2–3 L
Rising Cl⁻ with falling HCO₃⁻ and normal gap: hyperchloremic acidosis; change fluid (chloride, bicarbonate)
Laboratory: K⁺, glucose, creatinine, lactate
Baseline. DKA/HHS: glucose every 1–2 hr; K⁺ 2 hr after insulin starts, then every 4 hr; electrolytes every 4 hr; HHS: serum osmolality every 4 hr (protocols may check more often)
K⁺ <3.5 mEq/L in DKA: replace and delay insulin; use lactate trend with clinical signs (potassium, glucose, lactate)
Infusion Safety: bag, line and rate
Start, bag change, handoff
Right strength (0.9%, not 0.45% or 3%), preservative-free product, pump rate matches order, no air in pressurized bags

Interactions & Compatibility

Clinically Significant Interactions

Drug / ClassEffectWhat To Do
Corticosteroids, corticotropin
Sodium and fluid retention; higher risk of hypernatremia and overload
Label advises avoiding saline in patients receiving these drugs; if it must be used, limit volume and monitor Na⁺, fluid balance and acid-base status
Lithium
0.9% saline increases renal lithium clearance; levels fall
Monitor lithium levels during large-volume saline
Diuretics, some antiepileptic and psychotropic drugs
Higher risk of hyponatremia
Label advises avoiding where possible; if used, monitor Na⁺
Drugs that increase vasopressin effect
Reduced free-water excretion; hyponatremia risk with IV fluids
Monitor Na⁺

IV Compatibility

  • Diluent of choice: 0.9% saline is the standard diluent and flush for most IV drugs. A few drugs need D5W instead (e.g., amphotericin B products precipitate in saline). Follow each drug's label.
  • Blood components: 0.9% saline is the standard solution for blood tubing. Use another fluid only if it is FDA-approved or documented safe for that use (e.g., Plasma-Lyte A pH 7.4 is labeled compatible with blood). Never lactated Ringer's or dextrose.
  • Additives: may be incompatible; mix thoroughly, inspect for precipitate and consult pharmacy.
  • Verify with an institutional compatibility resource.

Special Populations
  • Pediatrics: Use rests on clinical practice. Children run a higher risk of hyponatremia and hyponatremic encephalopathy, and of overload from repeated boluses. Reassess after every bolus. For maintenance, the AAP recommends isotonic fluid with dextrose and potassium for most patients 28 days to 18 years. See the Pediatric Dosing table.
  • Neonates: Preservative-free saline only, with no benzyl alcohol. In very low birth weight infants, rapid or excessive saline can raise serum osmolality and the risk of intracerebral hemorrhage. Neonatal volume expansion uses 0.9% saline or blood.
  • Pregnancy: There are no controlled studies. Sodium chloride and water are normal body constituents, and saline is used routinely in pregnancy and labor. The label says to give it only when the potential benefit justifies the potential risk to the fetus. Pre-eclampsia raises the risk of overload, so limit the volume and reassess.
  • Lactation: The label advises caution in nursing women, because transfer into milk has not been studied. Sodium chloride is a normal milk constituent, and clinically meaningful infant exposure is not expected.
  • Older Adults: They face a higher risk of electrolyte imbalance and overload. Start at the low end, give smaller boluses and check renal function. Saline is not on the AGS Beers Criteria.
  • Renal Impairment: In severe renal impairment the label advises avoiding saline, because of hypernatremia and overload. If it is used, monitor Na⁺ and fluid balance.
  • Hyperkalemia Risk: Saline is the choice when hyperkalemia is a risk, since the lactated Ringer's label says avoid it. Large volumes cause hyperchloremic acidosis, though, and that can shift K⁺ out of cells. Monitor K⁺.
  • Hepatic Impairment: Cirrhosis drives sodium and water retention, and large volumes worsen ascites and edema. Use the smallest effective volume.
  • Obesity / Dosing Weight: For sepsis volumes, adjusted or ideal body weight may be used when BMI >30.
  • Heart Failure: Give smaller boluses and check the lungs and SpO₂ often.
  • Traumatic Brain Injury: Isotonic crystalloid is preferred. Prevent hypotension early, not late. Keep SBP ≥110 mmHg over 10 yr (NASEMSO 2022, p.234). In children, keep SBP above 60 mmHg (<1 month), 70 mmHg (1–12 months) or 70 + 2 × age in years (1–10 yr).

Field & Transport Considerations
  • Scope: Starting IV or IO fluid is typically an AEMT, Paramedic, RN and critical-care transport (Paramedic/RN/CCT) skill. Scope varies by state and agency protocol.
  • Storage & Stability: Keep it at room temperature (25°C (77°F)) in the overwrap. A brief exposure up to 40°C (104°F) does not harm the product. Avoid excessive vehicle heat.
  • Carried Concentration: Confirm 0.9% on every bag. 0.45% saline and hypertonic saline bags look similar. Do not use bacteriostatic vials to flush neonates.
  • Pressure Infusion: remove all air from the bag before using a pressure bag; never connect bags in series.
  • Infusions in Transport: pump for maintenance, DKA and pediatric fluids; carry enough volume for the trip plus delays; reassess lungs and SpO₂ after each bolus and after moves.
  • Handoff Essentials: indication, total volume and time of each bolus, current rate, response (blood pressure, perfusion, urine output), lung findings, last Na⁺ and glucose in DKA or hyponatremia, and any blood given through the line.

Clinical Pearls
Saline Can Lower Sodium: Salt is not a cure for every low sodium. In SIADH the kidney holds the water and sends the salt out in concentrated urine. Infused saline can push Na⁺ lower. Saline is for hypovolemic hyponatremia. It is not for euvolemic SIADH.
Watch the Urine in Hyponatremia: Restore the volume and antidiuretic hormone shuts off. The kidney then dumps water, and a sudden big urine output can drive Na⁺ up dangerously fast. Recheck Na⁺ now and call the prescriber.
Exam Discriminator, Which Fluid Runs With Blood: Blood tubing runs on 0.9% saline by default. Another fluid needs FDA approval for use with blood (e.g., Plasma-Lyte A pH 7.4). Lactated Ringer's is out, since its calcium can clot citrated blood. Dextrose is out too.
New Acidosis After Liters of Saline: Bicarbonate falling, chloride climbing, anion gap normal? After liters of saline, that is usually the fluid talking, not shock getting worse. Check the anion gap and lactate before you give more.
What the Big Trials Show: In ICU adults, balanced crystalloid meant slightly fewer major adverse kidney events (SMART). BaSICS and PLUS showed no mortality difference. In children, PRoMPT BOLUS found no kidney-outcome gap (3.4% vs 3.0%).
Crystalloids Compared (Na⁺ / Cl⁻ / K⁺ / Ca²⁺ mEq/L; osmolarity):
  • 0.9% saline: 154 / 154 / 0 / 0, 308 mOsm/L, no buffer. Pick it for TBI, hypovolemic hyponatremia and blood lines.
  • Lactated Ringer's: 130 / 109 / 4 / 2.7, 273 mOsm/L. The buffer is lactate.
  • Plasma-Lyte A: 140 / 98 / 5 / 0, 294 mOsm/L. Acetate and gluconate are the buffers.

Pharmacology

Mechanism of Action

  • Replacing water and sodium chloride expands the extracellular volume, and briefly the intravascular volume too. That restores preload and perfusion.
  • Sodium stays mainly outside cells, so the bolus spreads through the interstitium within minutes to hours. A common teaching estimate says about one-quarter stays intravascular, which is plasma's share of extracellular fluid. Actual retention varies with volume status and capillary leak.
  • Equal Na⁺ and Cl⁻ give a strong ion difference of zero. That dilutes plasma bicarbonate. Large volumes produce a hyperchloremic, normal anion gap acidosis.
  • It supplies chloride, which lets the kidney excrete bicarbonate. That corrects chloride-responsive (vomiting) alkalosis.

Pharmacokinetics

RouteOnsetPeakDuration
IV or IO infusion
Immediate
End of the bolus
Volume-based: the plasma volume gain fades as fluid moves into the interstitium, faster with capillary leak
  • Half-life: There is no meaningful drug half-life. The effect follows volume, rate and capillary leak.
  • Metabolism: None. Sodium and chloride are body electrolytes.
  • Elimination: The kidneys excrete sodium and chloride mainly. The renin-angiotensin-aldosterone system and antidiuretic hormone regulate that. Saline can induce diuresis.

Names & Classification
Generic Name
0.9% Sodium Chloride Injection, USP; normal saline (NS), isotonic saline
Brand Names
Generic; US makers include Baxter, B. Braun, Fresenius Kabi and ICU Medical
Pharmacologic Class
Isotonic crystalloid (unbuffered electrolyte solution)
Therapeutic Class
IV fluid; volume and electrolyte replacement; drug diluent
Controlled Substance
Not controlled
ISMP High-Alert
No (hypertonic sodium chloride greater than 0.9% is ISMP high-alert)
Look-Alike / Sound-Alike
None commonly reported as a named pair; in practice 0.9%, 0.45% and 3% saline bags, and preservative-free vs bacteriostatic vials, look alike

Related

References
  1. Baxter Healthcare Corporation. (2024). Sodium Chloride Injection, USP, in VIAFLEX plastic container: Prescribing information (rev. July 2024). DailyMed, U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f55bd888-5e01-474d-871b-24654c070178
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  4. Umpierrez, G. E., Davis, G. M., ElSayed, N. A., et al. (2024). Hyperglycemic crises in adults with diabetes: A consensus report. Diabetes Care, 47(8), 1257–1275. https://doi.org/10.2337/dci24-0032
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  11. El-Hajj Fuleihan, G., Clines, G. A., Hu, M. I., et al. (2023). Treatment of hypercalcemia of malignancy in adults: An Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology & Metabolism, 108(3), 507–528. https://doi.org/10.1210/clinem/dgac621
  12. Hospira, Inc. (2019). Bacteriostatic sodium chloride injection, USP: Prescribing information (rev. February 2019). DailyMed, U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=376093e7-e09e-4a57-3199-195e45251866

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