Intravenous Fluid Management Guidelines for Adults

Fluid Rate Selection

• General maintenance (non‑aggressive) hydration: administer isotonic crystalloid at ≈ 1.5 mL kg⁻¹ h⁻¹ (≈ 105 mL h⁻¹ for a 70‑kg adult), which is defined as a rate < 10 mL kg⁻¹ h⁻¹. [1][2]3
• Alternative regimen for maintenance: give a 10 mL kg⁻¹ bolus over 2 h, then continue at 1.5 mL kg⁻¹ h⁻¹ for the first 24 h, resulting in < 500 mL h⁻¹ or < 4 L total in 24 h. [1][2]3
• Peri‑operative goal: achieve a net positive fluid balance of 1–2 L by the end of the surgical case to compensate for insensible losses and third‑space shifts. 4
• Sepsis/ septic shock initial resuscitation: deliver at least 30 mL kg⁻¹ (≈ 2,100 mL for a 70‑kg patient) within the first 3 h; subsequent fluid administration should be titrated to frequent hemodynamic reassessment. [5][6]7

Fluid Type Selection

• First‑line solution: use buffered crystalloid (e.g., lactated Ringer’s) in patients without hypochloremia, as it reduces the risk of hyperchloremic metabolic acidosis and renal dysfunction compared with 0.9 % saline. 4
• Routine avoidance: do not use albumin or synthetic colloids for standard fluid replacement. 4

Monitoring Parameters

Vital‑Sign and Clinical Assessment

• Monitor heart rate, blood pressure, respiratory rate, temperature, and oxygen saturation at regular intervals during fluid therapy. [5][6]7

Urine Output

• Target urine output ≥ 0.5 mL kg⁻¹ h⁻¹ (≥ 35 mL h⁻¹ for a 70‑kg adult). [5][6]7

Signs of Fluid Overload

• Watch for rapid weight gain, pulmonary edema, peripheral edema, new ascites, jugular venous distension, and abdominal compartment syndrome as indicators of excessive fluid administration. [3][6][8][9]

Laboratory Monitoring

• Obtain serial serum electrolytes (Na⁺, K⁺, Cl⁻) and renal function tests (BUN, creatinine) to detect electrolyte disturbances and kidney injury. [1][2][3][8]9
• In acute pancreatitis, track hematocrit and BUN changes within 48 h as surrogate markers of adequate hydration. [8][9]
• Measure lactate levels and aim for normalization in patients with tissue hypoperfusion. [5][6]7

Hemodynamic Monitoring (when available)

• Maintain a mean arterial pressure ≥ 65 mmHg in septic shock patients receiving vasopressors. [5][6]7
• Prefer dynamic indices (pulse‑pressure variation, stroke‑volume variation) over static measures to predict fluid responsiveness. [5][6]7

Risks of Aggressive Hydration

• Acute pancreatitis: fluid rates > 10 mL kg⁻¹ h⁻¹ (or > 500 mL h⁻¹) are associated with a roughly three‑fold increase in mortality compared with non‑aggressive regimens. [1][2][3][8]10
• The WATERFALL trial demonstrated higher incidence of fluid overload and potential mortality rise in non‑severe acute pancreatitis patients receiving aggressive IV fluid resuscitation. 10

Frequency of Reassessment

• Perform clinical and hemodynamic reassessment every 1–4 hours during active resuscitation or acute illness. [5][6]7
• In hemodynamically unstable patients or those on aggressive fluid protocols, reassess at least hourly or use continuous monitoring. 7
• After initial stabilization, extend reassessment intervals to every 4–6 hours while continuing intake/output and clinical status checks. 6

Fluid Choice Recommendations for Emergency Abdominal Surgery

Crystalloid Selection

• For adult patients undergoing emergency abdominal surgery (e.g., strangulated umbilical hernia), balanced crystalloids such as Ringer’s lactate or Plasmalyte should be used as the first‑line resuscitation fluid instead of 0.9 % saline, because they lower the risk of hyperchloremic metabolic acidosis and acute kidney injury【11】.

Colloid Avoidance

• In the same clinical setting, colloid solutions—including albumin and hydroxyethyl starches—should be avoided, as they have not demonstrated a mortality benefit and are associated with an increased risk of intra‑operative bleeding【11】.

Risks of 0.9 % Saline

• Using 0.9 % saline as the sole resuscitation fluid is linked to hyperchloremic acidosis and poorer renal outcomes compared with balanced crystalloid solutions in patients undergoing emergency abdominal procedures【11】.