Which isotonic balanced crystalloid fluids should be used for maintenance and resuscitation in the preoperative and postoperative periods for routine adult surgeries?

Perioperative Fluid Management for Routine Surgeries

Use buffered/balanced isotonic crystalloid solutions (Ringer's Lactate or Plasma-Lyte) for both maintenance and resuscitation in all routine adult surgeries, targeting a mildly positive fluid balance of 1-2 liters by the end of the case, then transition immediately to oral intake postoperatively while minimizing IV fluids. 1, 2

Fluid Type Selection

Primary Recommendation: Balanced Crystalloids

• Balanced crystalloids (Ringer's Lactate, Plasma-Lyte) are strongly recommended over 0.9% saline for perioperative fluid therapy based on high-quality evidence showing reduced acute kidney injury rates and improved acid-base balance 1, 2

• These solutions contain physiological chloride concentrations and buffers (lactate, acetate, or gluconate) that prevent hyperchloremic metabolic acidosis, which occurs with large volumes of normal saline 2, 3

• The 2024 British Journal of Anaesthesia guidelines provide a strong recommendation with high-quality evidence for buffered crystalloids in surgical patients 1

Avoid These Fluids

• Do NOT use synthetic colloids (hydroxyethyl starch, gelatins) routinely - strong recommendation with high-quality evidence showing increased renal failure risk without mortality benefit 1, 2

• Do NOT use albumin routinely - strong recommendation showing no mortality advantage over crystalloids with substantially higher cost 1, 4

• Limit 0.9% saline to maximum 1-1.5 liters if it must be used, as larger volumes cause hyperchloremic acidosis, renal vasoconstriction, and increased mortality 1, 2, 4

Intraoperative Fluid Strategy

Volume Targets

• Administer fluids targeting a mildly positive balance of +1 to +2 liters by end of surgery to protect kidney function while avoiding fluid overload 1, 4

• A large multicenter RCT of 3,000 patients demonstrated that stringently restrictive "zero-balance" regimens resulted in significantly higher acute kidney injury rates compared to modestly liberal regimens (1.6 kg weight gain vs 0.3 kg) 1

• Infusion rates of 1-2 ml/kg/hour during surgery minimize postoperative complications including nausea/vomiting and lung injury 1, 4

Goal-Directed Therapy Considerations

• For open major surgery, high-risk patients, blood loss >7 ml/kg, or prolonged procedures, consider using flow measurements (esophageal Doppler, arterial waveform analysis) to optimize cardiac output 1

• Goal-directed fluid therapy demonstrates faster return of bowel function, reduced infection rates, less nausea/vomiting, and lower acute kidney injury incidence 1, 4

Postoperative Fluid Management

Transition Strategy

• Discontinue IV fluids as soon as practicable - preferably no later than the morning after surgery 1, 4

• Transition immediately to oral/enteral intake as the preferred route for maintaining hydration 1, 4

• Postoperative IV fluids should be minimized to maintain normovolemia and avoid fluid excess 1

Managing Epidural-Induced Hypotension

• For hypotensive normovolemic patients with epidural anesthesia, treat with vasopressors rather than excess fluid 1

• This prevents fluid overload while effectively managing blood pressure 1

Critical Pitfalls to Avoid

Fluid Overload Complications

• Fluid overload (>2.5 kg perioperative weight gain) significantly increases complications including anastomotic leak risk, pulmonary complications, ventilator dependence, gut edema, ileus, and poor wound healing 1, 4

• Both intravascular hypovolemia and fluid overload are harmful and associated with organ dysfunction 1

Hyperchloremic Acidosis from Saline

• Large volumes of 0.9% saline cause hyperchloremic metabolic acidosis due to supraphysiologic chloride concentration (154 mmol/L vs physiologic 100 mmol/L) 2, 4, 3

• This leads to renal vasoconstriction, acute kidney injury, and increased 30-day mortality when hyperchloremia develops 2, 4

High-Risk Patient Populations

• Patients with congestive heart failure, chronic kidney disease, and lung disease have lower fluid tolerance and higher risk of fluid accumulation, requiring more conservative administration 1, 4

• These patients need careful volume monitoring with point-of-care ultrasonography or dynamic hemodynamic variables 2, 4

Special Surgical Considerations

Minor Noncardiac Surgery

• A mildly positive fluid balance reduces postoperative nausea and vomiting (PONV) incidence, with infusion rates of 2 ml/kg/hour being adequate 1, 4

• This represents both a quality-of-life benefit and indirect pain management advantage 4

Lung Resection

• Avoid positive fluid balance in the first 24 hours following lung resection to prevent pulmonary complications 4

Neurosurgery Exception

• For traumatic brain injury or neurosurgical patients, use 0.9% saline rather than balanced crystalloids to avoid hypotonic solutions that could worsen cerebral edema 1, 4

• Hypotonic solutions are absolutely contraindicated in patients with impending cerebral edema 1, 5

Preoperative Considerations

• Allow patients scheduled for elective surgery to drink clear fluids (water, pulp-free juice, tea/coffee without milk) up to 2 hours before surgery 1

• This reduces preoperative dehydration without increasing aspiration risk 1

Summary Algorithm

1. Preoperatively: Clear fluids until 2 hours before surgery 1
2. Intraoperatively: Balanced crystalloids (Ringer's Lactate or Plasma-Lyte) at 1-2 ml/kg/hour, targeting +1 to +2 L positive balance by end of case 1, 4
3. Postoperatively: Transition immediately to oral intake, discontinue IV fluids by morning after surgery 1, 4
4. Exception: Use 0.9% saline (not balanced solutions) for neurosurgical/TBI patients 1, 4
5. Never use: Synthetic colloids or routine albumin 1, 2