Fluid Choice for Nausea and Vomiting
For patients with nausea and vomiting requiring intravenous fluid resuscitation, lactated Ringer's solution (or other balanced crystalloids) is superior to normal saline and should be used as first-line therapy.
Primary Recommendation
Balanced crystalloids such as lactated Ringer's solution are recommended over 0.9% normal saline for fluid resuscitation in patients with nausea and vomiting, as they reduce the risk of acute kidney injury, avoid hyperchloremic metabolic acidosis, and potentially decrease mortality. 1
For severe dehydration from hyperemesis, administer 20 mL/kg boluses of Ringer's lactate solution until pulse, perfusion, and mental status normalize. 1
Replace ongoing vomiting losses with 2 mL/kg of fluid for each episode of emesis. 1
Why Balanced Crystalloids Over Saline
Lactated Ringer's contains near-physiological concentrations of electrolytes with lower chloride content than normal saline (108 mmol/L vs 154 mmol/L), which reduces the risk of hyperchloremic metabolic acidosis. 1
When large volumes are required (>1-1.5 L), lactated Ringer's is strongly preferred over normal saline to avoid hyperchloremic acidosis, coagulopathy, and potential worsening of kidney function. 1
The 2024 perioperative fluid management guidelines from the British Journal of Anaesthesia recommend buffered crystalloid solutions over 0.9% saline in the absence of hypochloraemia. 2
The 2013 Surviving Sepsis Campaign guidelines recommend crystalloids as the initial fluid of choice for resuscitation, with no benefit demonstrated for colloids. 2
Critical Exception: Traumatic Brain Injury
Avoid lactated Ringer's in patients with severe traumatic brain injury or head trauma—use 0.9% saline instead. 3, 1
Lactated Ringer's has an osmolarity of 273-277 mOsm/L, making it slightly hypotonic compared to plasma (275-295 mOsm/L), which can worsen cerebral edema and increase intracranial pressure. 3
For patients with TBI or demonstrably injured brain, 0.9% saline should be chosen as the initial fluid. 2
Additional Clinical Considerations
Monitor electrolytes, particularly potassium and magnesium, as vomiting causes losses that may need supplementation beyond what lactated Ringer's provides (which contains 4 mmol/L potassium). 1
Assess volume status and clinical response within 6 hours of initiating fluid resuscitation. 1
Monitor for volume overload carefully, especially in patients with underlying cardiovascular disease, heart failure, or chronic kidney disease. 1
The potassium content in lactated Ringer's (4 mmol/L) should not be considered a contraindication in patients with mild-to-moderate hyperkalemia or renal dysfunction, except in rhabdomyolysis or crush syndrome. 3
What to Avoid
Avoid using normal saline as the primary resuscitation fluid if significant volumes are anticipated, as it causes hyperchloremic acidosis, electrolyte derangements, and potentially worsens kidney function. 1
Avoid synthetic colloids, as they offer no mortality benefit over crystalloids, are more expensive, and have been associated with harm in ICU settings. 2, 1
Avoid routine use of albumin for fluid resuscitation in nausea and vomiting. 2
Supporting Evidence for Crystalloid Preloading
- One study comparing fluid preloading strategies for postoperative nausea and vomiting found that preloading with lactated Ringer's (crystalloid) resulted in the lowest incidence of PONV (25%) compared to various colloid solutions (35-75%), suggesting intravascular volume deficits may be a factor in nausea and vomiting. 4