Lactated Ringer’s Solution
Lactated Ringer’s is an electrolyte replacement fluid with metabolizable lactate buffer; fluid plans must distinguish resuscitation, deficit replacement and maintenance.
Group
Balanced isotonic crystalloid
Mechanism of Action
Expands extracellular fluid and supplies electrolytes; metabolism of lactate supplies an alkalinizing effect.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Moderate dehydration | Reference only | IV | Historical replacement rate 15-30 mL/kg/hour; reassess frequently and adjust to current deficits and losses. | |
| Severe dehydration | Reference only | IV | Historical replacement rate 50 mL/kg/hour, requiring close reassessment; not a routine ongoing rate. | |
| Maintenance infusion | Reference only | IV | 2-6 mL/kg/hour in dogs or 2-3 mL/kg/hour in cats; a separate daily recommendation is 55-65 mL/kg/day, not necessarily numerically identical. | |
| Daily maintenance | Reference only | IV, SC, IP | 55-65 mL/kg/day; route suitability and absorption depend on clinical status. Do not use SC or IP for shock resuscitation. | |
| Anaesthetic fluid support | Reference only | IV | Initial 5 mL/kg/hour in dogs; increase towards 10 mL/kg/hour only if losses and response justify it. | |
| Shock resuscitation | Reference only | IV | Historical total 90 mL/kg in dogs. Published guidance describes half in the first 30 minutes and 10 mL/kg reassessment increments every 15 minutes; individualize rather than delivering the total automatically. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Moderate dehydration | Reference only | IV | Historical replacement rate 15-30 mL/kg/hour; reassess frequently and adjust to current deficits and losses. | |
| Severe dehydration | Reference only | IV | Historical replacement rate 50 mL/kg/hour, requiring close reassessment; not a routine ongoing rate. | |
| Maintenance infusion | Reference only | IV | 2-6 mL/kg/hour in dogs or 2-3 mL/kg/hour in cats; a separate daily recommendation is 55-65 mL/kg/day, not necessarily numerically identical. | |
| Daily maintenance | Reference only | IV, SC, IP | 55-65 mL/kg/day; route suitability and absorption depend on clinical status. Do not use SC or IP for shock resuscitation. | |
| Anaesthetic fluid support | Reference only | IV | Initial 3 mL/kg/hour in cats; increase towards 10 mL/kg/hour only if losses and response justify it. | |
| Shock resuscitation | Reference only | IV | Historical total 60-70 mL/kg in cats. Published guidance describes half in the first 30 minutes and 10 mL/kg reassessment increments every 15 minutes; individualize rather than delivering the total automatically. |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Maintenance | Reference only | IV | 40-50 mL/kg/day. | |
| Moderate dehydration | Reference only | IV | 15-30 mL/kg/hour with frequent reassessment. | |
| Severe dehydration | Reference only | IV | 50 mL/kg/hour with frequent reassessment. | |
| Neonatal dehydration | Reference only | IV | Calves/foals: moderate deficit 45 mL/kg, severe deficit 80-90 mL/kg, delivered at 30-40 mL/kg/hour; the published guidance describes up to 80 mL/kg/hour for severe cases. Reassess carefully. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Maintenance | Reference only | IV | 40-50 mL/kg/day. | |
| Moderate dehydration | Reference only | IV | 15-30 mL/kg/hour with frequent reassessment. | |
| Severe dehydration | Reference only | IV | 50 mL/kg/hour with frequent reassessment. | |
| Neonatal dehydration | Reference only | IV | Calves/foals: moderate deficit 45 mL/kg, severe deficit 80-90 mL/kg, delivered at 30-40 mL/kg/hour; the published guidance describes up to 80 mL/kg/hour for severe cases. Reassess carefully. |
Pigs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Maintenance | Reference only | IV | 40-50 mL/kg/day. | |
| Moderate dehydration | Reference only | IV | 15-30 mL/kg/hour with frequent reassessment. | |
| Severe dehydration | Reference only | IV | 50 mL/kg/hour with frequent reassessment. |
Indications
- Fluid deficits and maintenance
- Selected hypovolaemia resuscitation
- Compatible intravenous drug delivery
Contraindications
- Fluid overload risk, especially with impaired cardiac or renal reserve, requires individualized administration.
Interactions
- Calcium can cause incompatibility with chelating drugs or other calcium-incompatible admixtures.
- Do not add medicines unstable at pH 6-7.4.
Adverse effects
- Volume overload and pulmonary oedema
- Electrolyte imbalance when the fluid plan is inappropriate
Toxicity
Reduce or stop excess fluid and assess respiration, perfusion, electrolytes and renal function.
Monitoring and Administration
Reassess perfusion after each resuscitation increment. Historical full shock volumes are not one unmonitored bolus.
Monitor fluid balance, respiratory signs, body weight and sodium, potassium and chloride.
Typical example composition per litre: sodium 130 mmol, chloride 112 mmol, potassium 4 mmol, lactate 28 mmol and calcium 1.36 mmol; osmolarity approximately 273 mOsm/L. Actual bag composition can vary.
Maintain asepsis; after puncture or transfer, sterility cannot be assumed.