What is the recommended fluid management for a patient in shock?

Maintenance Fluid Management in Shock

For patients in shock, crystalloids are the fluid of choice for initial resuscitation, with at least 30 mL/kg administered within the first 3 hours, followed by ongoing fluid challenges guided by dynamic hemodynamic monitoring—not maintenance fluids—until perfusion is restored and vasopressors are initiated if hypotension persists. 1

Initial Resuscitation Phase (First 3 Hours)

Crystalloid Administration

• Administer a minimum of 30 mL/kg of crystalloid solution within the first 3 hours of recognizing shock, regardless of shock etiology (septic, hypovolemic, or distributive). 1, 2
• Use balanced crystalloids (lactated Ringer's or Plasma-Lyte) over normal saline when available to reduce the risk of hyperchloremic metabolic acidosis and potential acute kidney injury. 2, 3
• Many patients will require significantly more than 30 mL/kg—this is a starting point, not a ceiling. 1

Albumin Supplementation

• Consider adding albumin to crystalloids when patients require substantial volumes of crystalloid (typically after several liters) to maintain adequate blood pressure. 1, 4
• Albumin is particularly useful in oncotic deficits, long-standing shock, or when large crystalloid volumes have been administered. 1, 4

Fluids to Avoid

• Never use hydroxyethyl starch solutions—they increase mortality and acute kidney injury risk in septic shock. 1, 2, 5
• Avoid gelatins when crystalloids are available. 1

Ongoing Fluid Management Beyond Initial Resuscitation

Dynamic Assessment Approach

• Continue fluid challenges as long as hemodynamic parameters improve, using either dynamic or static measures. 1, 2
• Dynamic measures (preferred): pulse pressure variation, stroke volume variation, passive leg raise with stroke volume measurement. 1
• Static measures (when dynamic unavailable): mean arterial pressure, heart rate, mental status, urine output, skin perfusion. 1, 2
• Stop fluid administration when: no improvement in tissue perfusion occurs, signs of fluid overload develop (pulmonary crackles, increased jugular venous pressure), or hemodynamic parameters plateau. 2, 6

Critical Pitfall: CVP Monitoring

• Do not use central venous pressure (CVP) alone to guide fluid therapy—CVP has poor predictive ability for fluid responsiveness when in the 8-12 mmHg range. 1, 2
• Static pressure measurements (CVP, pulmonary artery occlusion pressure) are unreliable predictors of fluid responsiveness. 1

Vasopressor Initiation

When to Start Vasopressors

• Initiate norepinephrine as the first-choice vasopressor if hypotension persists despite adequate fluid resuscitation, targeting a mean arterial pressure (MAP) ≥65 mmHg. 1, 2, 5, 6
• Place an arterial catheter as soon as practical for accurate blood pressure monitoring in all patients requiring vasopressors. 1, 5

Vasopressor Escalation

• Add vasopressin (0.03 units/minute) to norepinephrine when additional MAP support is needed or to reduce norepinephrine dose. 1, 5
• Add epinephrine if further pressor support is required despite norepinephrine ± vasopressin. 1, 5, 6
• Avoid dopamine except in highly selected patients (bradycardic, low tachyarrhythmia risk)—it causes more cardiac adverse events. 1, 5
• Never use low-dose dopamine for renal protection—it is completely ineffective. 1, 2, 5

Inotropic Support

• Administer dobutamine (up to 20 μg/kg/min) when myocardial dysfunction with low cardiac output persists despite adequate volume status and MAP, particularly in patients with reduced ejection fraction heart failure. 1, 5
• Look for signs of low cardiac output: elevated cardiac filling pressures, ongoing hypoperfusion despite adequate MAP and volume. 1, 5

Special Considerations

Obesity

• Use ideal body weight or adjusted body weight (not actual body weight) when calculating the 30 mL/kg bolus in severely obese patients to avoid massive fluid overload. 7

Dehydrated Patients

• If the patient is dehydrated interstitially, additional crystalloids must be given when using 25% albumin, or alternatively use 5% albumin instead. 4

Heart Failure Patients

• Apply the standard 30 mL/kg crystalloid bolus even in patients with chronic systolic heart failure (EF <40%)—withholding fluids is not supported by evidence. 5
• Monitor closely for signs of fluid overload and use dynamic measures to guide ongoing fluid administration. 5

Key Monitoring Parameters

• Continuously assess: heart rate, blood pressure, respiratory rate, oxygen saturation, mental status, urine output, peripheral perfusion, and lactate clearance. 1, 2, 6
• Reassess frequently—shock management requires ongoing reevaluation of response to treatment, not a fixed maintenance regimen. 1

Critical Pitfalls to Avoid

• Do not delay resuscitation due to concerns about fluid overload—delayed resuscitation increases mortality more than the risk of fluid overload in the initial phase. 2
• Do not continue fluids indefinitely without hemodynamic improvement—this leads to harmful fluid accumulation without benefit. 2, 8, 9
• Do not use a "maintenance fluid" mindset in shock—shock requires active resuscitation with repeated assessment, not passive maintenance. 1, 8