Ringer's Lactate Should Be Avoided in Suspected Ischemic Stroke
Ringer's Lactate (lactated Ringer's solution) should NOT be given to patients with suspected ischemic stroke; use 0.9% normal saline instead. 1, 2
Why Ringer's Lactate is Contraindicated
The critical issue is osmolality, not osmolarity. When measured as real osmolality (mosmol/kg rather than theoretical osmolality mosmol/L), Ringer's Lactate is hypotonic and should be avoided in brain injury patients including ischemic stroke. 1
Mechanism of Harm
Hypotonic solutions distribute into intracellular spaces and may exacerbate ischemic brain edema, which can worsen neurological outcomes and increase mortality. 1, 2
The Association of Anaesthetists explicitly states that "Gelatins, Ringer's lactate (compound sodium lactate) and Ringer's acetate are hypotonic when real osmolality (mosmol.kg-1) rather than theoretical osmolality (mosmol.l-1) is determined, and should be avoided." 1
In traumatic brain injury (a related brain injury condition), one multicenter study reported higher mortality in patients treated with Ringer's Lactate compared to 0.9% NaCl. 2, 3
Recommended Fluid Choice: 0.9% Normal Saline
The only commonly available isotonic crystalloid solution is 0.9% saline, and this is therefore the current crystalloid of choice in brain injury. 1
Rationale for Normal Saline
Isotonic solutions such as 0.9% saline are more evenly distributed into extracellular spaces (interstitial and intravascular) and may be better for patients with acute ischemic stroke. 1
Normal saline maintains true isotonicity (280-310 mOsm/L) and prevents increases in brain water content. 2
The American Heart Association/American Stroke Association guidelines recommend isotonic crystalloids, specifically stating that "isotonic solutions such as 0.9% saline are recommended." 1
Fluid Management Strategy in Ischemic Stroke
Initial Assessment
Most stroke patients are euvolemic at presentation and are unlikely to require volume resuscitation per se. 1
However, oral intake is often reduced after stroke, and intravenous maintenance fluids should be commenced. 1
Volume Status-Based Approach
For euvolemic patients: Initiate maintenance intravenous fluids with 0.9% saline at approximately 30 mL per kilogram of body weight daily. 1
For hypovolemic patients: Rapid replacement of depleted intravascular volume with 0.9% saline followed by maintenance fluids is reasonable. 1
Avoid hypervolemia: May exacerbate ischemic brain edema and increase cardiac stress. 1
Critical Pitfalls to Avoid
Never use hypotonic solutions (5% dextrose after glucose metabolism, 0.45% saline, Ringer's Lactate): A substantial proportion distributes into intracellular spaces and may exacerbate ischemic brain edema. 1, 2
Avoid dextrose-containing fluids unless hypoglycemia is documented (blood glucose <60 mg/dL), as excessive glucose may be injurious to stroke patients. 1
Exercise caution in patients vulnerable to volume overload (renal or heart failure). 1
Blood Pressure Considerations During Fluid Administration
Maintain systolic blood pressure >140 mmHg to avoid detrimental effects on cerebral perfusion. 1
Keep blood pressure <185/110 mmHg in patients who are candidates for or have received intravenous thrombolysis. 1
Hypotension should be avoided and treated with fluids and vasoconstrictors if necessary. 1
Special Monitoring Requirements
Monitor electrolyte levels regularly, as prolonged use of 0.9% saline can lead to hyperchloremic metabolic acidosis. 2
Maintain euvolemia by monitoring for signs of both hypovolemia (hypoperfusion, renal impairment, thrombosis risk) and hypervolemia (brain edema, cardiac stress). 1
Serum sodium and urea measurements may be useful in monitoring hydration status, with elevated osmolality (>296 mOsm/kg) associated with increased mortality. 1