How to Choose IV Fluid
For most hospitalized patients requiring IV fluids, use balanced crystalloid solutions (Ringer's Lactate or Plasmalyte) as first-line therapy rather than 0.9% normal saline, as they reduce major adverse kidney events and mortality while maintaining better acid-base balance. 1, 2
General Approach: Balanced Crystalloids First
Balanced crystalloids (Ringer's Lactate, Plasmalyte) should be your default choice for IV fluid therapy across most clinical scenarios. 3, 1, 2 These solutions have electrolyte compositions closer to plasma and consistently demonstrate superior outcomes compared to normal saline. 2, 4
Why Balanced Crystalloids Are Superior
The SMART study of 15,802 ICU patients demonstrated that balanced solutions reduced major adverse kidney events (death, renal replacement therapy, or persistent renal dysfunction) compared to normal saline (14.3% vs 15.4%, P=0.04). 5
High-volume administration of chloride-rich solutions (>5000 mL) is associated with increased mortality, postoperative hyperchloremia, and worse renal outcomes. 3, 2
Balanced solutions consistently provide better acid-base balance and prevent hyperchloremic metabolic acidosis. 3, 6, 4
Lower transfusion requirements have been reported in patients at high hemorrhagic risk receiving balanced solutions versus normal saline. 3
Clinical Scenario-Specific Recommendations
Hemorrhagic Shock
Use balanced crystalloids (not 0.9% NaCl) as first-line fluid therapy in hemorrhagic shock to reduce mortality and adverse renal events. 3
Crystalloid solutions should be preferred over synthetic colloids due to risks of renal failure and hemostasis disorders. 3
Do NOT use albumin in hemorrhagic shock—it provides no benefit and is more expensive. 3
Do NOT use hypertonic saline (3% or 7.5%) as first-line therapy—it shows no mortality benefit. 3, 1
Exception: In hemorrhagic shock combined with severe traumatic brain injury and focal neurological signs, a bolus of hypertonic saline may be beneficial due to its osmotic effect. 3, 1
Acute Brain Injury
Use isotonic crystalloids (osmolarity 280-310 mOsm/L) as first-line fluid therapy in acute brain injury. 3
Acceptable isotonic solutions include 0.9% NaCl, Plasmalyte, and Isofundine. 3
Avoid hypotonic solutions (<280 mOsm/L) including Ringer's Lactate in traumatic brain injury—one study showed higher mortality with Ringer's Lactate versus normal saline (HR 1.78, P=0.035). 3
Synthetic colloids are not recommended—they worsen neurological prognosis at 6 months in subarachnoid hemorrhage patients. 3
Albumin is contraindicated in traumatic brain injury—the SAFE study showed increased mortality (RR 1.63, P=0.003). 3
Sepsis and Critical Illness
Administer at least 30 mL/kg of balanced crystalloid within the first 3 hours for sepsis-induced hypoperfusion. 1
Target mean arterial pressure of 65 mmHg in patients requiring vasopressors. 1
Use dynamic variables (pulse pressure variation, stroke volume variation) rather than static variables (central venous pressure) to predict fluid responsiveness. 1
Normalize lactate levels as a resuscitation goal when elevated. 1
Perioperative Fluid Management
Use balanced crystalloids as the primary intraoperative fluid, particularly in patients with end-stage renal disease or those undergoing major surgery. 2, 6
The potassium content in balanced solutions (5 mmol/L) does not cause significant hyperkalemia even in at-risk patients. 6
Target mildly positive fluid balance (+1-2 L) by end of surgery in ESRD patients to protect remaining kidney function. 6
Special Populations
Pediatric Patients
Pediatric patients (28 days to 18 years) requiring maintenance IV fluids should receive isotonic balanced solutions with appropriate potassium chloride AND dextrose (2.5%-5%) to prevent hypoglycemia. 2
Infants at risk for hypoglycemia should receive D10 normal saline to meet glucose requirements of 4-6 mg/kg/min. 2
In diabetic ketoacidosis, switch to D5 with 0.45-0.75% saline when glucose reaches 250 mg/dL. 2
Monitor serum glucose hourly during acute resuscitation, then every 2-4 hours once stable. 2
Peripartum Period
No specific recommendation can be made for peripartum shock due to absence of data—default to the fluid choice recommended for the clinical context (e.g., hemorrhagic shock guidelines). 3
What NOT to Use
Synthetic Colloids (Hetastarch)
Do not use synthetic colloids for routine resuscitation—they offer no mortality benefit and increase risks of renal impairment and coagulopathy. 2, 7
Maximum dose is 1500 mL per day for typical 70 kg patient (20 mL/kg). 7
Contains calcium and cannot be administered simultaneously with blood through same line due to coagulation risk. 7
Albumin
Albumin is not recommended for routine fluid resuscitation due to higher cost without demonstrated benefit over crystalloids. 1, 8
Specific contraindication: Traumatic brain injury (increased mortality). 3
Possible indication: Severe hypoproteinemia with edema, though this is symptomatic treatment only. 8
Usual adult dose when indicated: 50-75 g daily; pediatric dose: 25 g daily. 8
Rate should not exceed 2 mL/min in hypoproteinemic patients to avoid circulatory embarrassment and pulmonary edema. 8
Critical Monitoring and Pitfalls
Avoid Fluid Overload
Both inadequate and excessive IV fluid administration lead to poor outcomes including increased infection risk and organ dysfunction. 1, 9
Reassess frequently using heart rate, blood pressure, oxygen saturation, respiratory rate, temperature, and urine output. 1
Use goal-directed therapy with frequent hemodynamic reassessment. 1
When to Avoid Normal Saline
Normal saline should only be used when balanced crystalloids are unavailable. 2