A balanced isotonic crystalloid containing sodium chloride with lactate as a bicarbonate precursor and small amounts of potassium and calcium. LR more closely approximates plasma composition than normal saline and produces less hyperchloremic acidosis with large volume resuscitation. In PA EMS protocols, LR is an optional alternative to NSS when approved by the agency medical director.

Pharmacology and Actions

LR provides isotonic volume expansion similar to NSS (approximately 25 percent intravascular retention at 1 hour) but with electrolyte composition closer to plasma. The lactate (28 mEq/L) is metabolized by the liver to bicarbonate, providing buffer effect that reduces the metabolic acidosis seen with large NSS volumes. The small amount of potassium (4 mEq/L) and calcium (2.7 mEq/L) approximates physiologic levels. The composition makes LR the preferred balanced crystalloid for many trauma resuscitation scenarios in current guidelines, though PA EMS protocols default to NSS.

Indications

Trauma resuscitation when balanced crystalloid is preferred
Burn resuscitation (Parkland and Brooke formula traditional fluid)
Postoperative volume replacement
Diabetic ketoacidosis (after initial NSS resuscitation in some protocols)
Surgical fluid management
Sepsis and septic shock resuscitation (per some protocols)

Absolute Contraindications

Severe hyperkalemia (LR contains potassium)
Crush syndrome (PA Protocol 6004 specifically advises against LR due to potassium content with rhabdomyolysis)
Severe head injury (NSS preferred over LR per PA Protocol 1000)
Severe hypercalcemia
Active blood transfusion through same IV line (calcium can react with citrate in blood products)
Severe hepatic failure (impaired lactate metabolism)

Precautions and Side Effects

Volume overload and dilutional coagulopathy are the same concerns as with NSS. Hyperkalemia risk in patients with renal impairment or already-elevated potassium. The lactate component can theoretically contribute to lactate measurements; modern lactate assays distinguish between L-lactate (which LR contains and is metabolized) and D-lactate (associated with sepsis). Cannot be used in the same IV line as ceftriaxone due to calcium-precipitation issues, or with blood products due to citrate interaction.

Adult Dosing

IV / IO

Trauma resuscitation: as ordered by protocol, generally interchangeable with NSS where the agency medical director has approved LR. Burn resuscitation per Parkland formula: 4 mL/kg/percent TBSA burned over 24 hours, half in first 8 hours from time of burn. Standard volume replacement: as ordered. Onset: Immediate (volume effect during infusion)

Pediatric Dosing

Pediatric fluid resuscitation: 20 mL/kg IV/IO bolus, similar dosing to NSS where LR is approved for use.

Pharmacokinetics

Peak Effect: IV: peak volume effect during and immediately after infusion

Duration: Approximately 25 percent intravascular retention at 1 hour; similar redistribution to NSS

Storage and Handling

Store at controlled room temperature (15 to 30 degrees Celsius). Avoid freezing. Warm to body temperature when possible for trauma resuscitation. Inspect for clarity and particulates before use.

Reconstitution:

LR is supplied as ready-to-infuse bags in volumes from 250 mL to 1000 mL. No reconstitution required. Composition per liter: Na 130 mEq, Cl 109 mEq, K 4 mEq, Ca 2.7 mEq, lactate 28 mEq.

TCCC and TECC Role

LR has historical TCCC role as a burn resuscitation fluid using the Parkland or Brooke formula. PA Burn Protocol 6071 specifies NSS rather than LR for burn resuscitation in civilian EMS. For TCCC trauma resuscitation in general, the 2026 guidelines emphasize blood products over any crystalloid; LR is acceptable when blood is not available and offers theoretical advantages over NSS in avoiding hyperchloremic acidosis. PA EMS providers may carry LR as an option per Protocol 1000 Section C.3 when the agency medical director has approved a written policy. Crush syndrome specifically contraindicates LR due to potassium content compounding rhabdomyolysis-associated hyperkalemia.

Field Context

LR is the balanced crystalloid that addresses some of NSS's metabolic shortcomings but introduces its own constraints. For PA EMS providers, LR is the optional alternative to NSS when the agency medical director has approved it via written policy. The specific protocol prohibitions matter: do not use LR in crush syndrome (potassium load) or severe head injury (NSS preferred). For burn resuscitation, classical Parkland formula uses LR, but PA Protocol 6071 specifies NSS; follow your protocol. Cannot run LR through the same line as ceftriaxone (calcium-citrate precipitation) or transfused blood products. These compatibility constraints are operationally important.

Common Mistake

Using LR in a crush syndrome patient and compounding the hyperkalemia from rhabdomyolysis. PA Protocol 6004 specifically directs NSS for crush syndrome for this reason. The other common error is running LR through the same IV line as ceftriaxone or blood products without flushing; the calcium content can cause precipitation with citrate-containing blood products and ceftriaxone.

Last Reviewed May 14, 2026

Reviewer TCCC 2026 Guidelines (01 May 2026); NREMT Paramedic Drug List; FDA labeling.

Drug Class Electrolyte / Fluid

DEA Schedule Not Controlled

Mission Impact Not Applicable - Patient Already Non-Operational

Reference Category TCCC Doctrine, Standard EMS, ALS Only

Generic Name Lactated Ringer's solution (Hartmann's solution)

Source: Tactical Combat Casualty Care (TCCC) Guidelines, 01 May 2026, Committee on Tactical Combat Casualty Care, Joint Trauma System.

Reference URL: https://penntacticalsolutions.com/pages/drug-reference/lactated-ringers

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Educational reference for trained medical providers. Not medical advice. Not a substitute for formal training, current published guidelines, or medical direction. Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances require additional storage, accountability, and documentation per DEA and state law.

In a medical emergency, call 911. This reference is not a substitute for emergency medical services.

Verify dosing, indications, and contraindications against current published guidelines and your local protocols before administration. Confirm content currency against the source citation. Penn Tactical Solutions does not provide medical direction. Clinical responsibility rests with the administering provider, their medical director, and their agency.

Lactated Ringers

Lactated Ringer's solution (Hartmann's solution)

Electrolyte / Fluid

Not Applicable - Patient Already Non-Operational

Adult Dosing

IV/IO

Pediatric

Pediatric fluid resuscitation: 20 mL/kg IV/IO bolus, similar dosing to NSS where LR is approved for use.

Contraindications

Severe hyperkalemia (LR contains potassium)| Crush syndrome (PA Protocol 6004 specifically advises against LR due to potassium content with rhabdomyolysis)| Severe head injury (NSS preferred over LR per PA Protocol 1000)| Severe hypercalcemia| Active blood transfusion through same IV line (calcium can react with citrate in blood products)| Severe hepatic failure (impaired lactate metabolism)

Common Mistake

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