In an adult with sepsis‑associated hypotension, how should the Rapid Ultrasound for Shock (RUSH) exam be used to guide initial fluid resuscitation and vasopressor therapy?

RUSH Exam for Fluid Resuscitation in Septic Shock

Use bedside cardiac ultrasound (BCU) to assess left and right ventricular function in septic patients to guide fluid resuscitation decisions, as excessive fluid administration in the presence of ventricular dysfunction will worsen outcomes. 1

Role of RUSH in Initial Assessment

The RUSH (Rapid Ultrasound in SHock) examination provides a systematic approach to evaluate the "pump, tank, and pipes" in undifferentiated hypotension, helping differentiate between hypovolemic, cardiogenic, obstructive, and distributive shock. 2, 3

For septic patients specifically, the cardiac component of RUSH is most critical for guiding fluid and vasopressor decisions:

• Assess left ventricular (LV) function first - LV dysfunction occurs commonly in sepsis and will resolve spontaneously as the patient improves, but early recognition prevents harmful fluid overload. 1

• Evaluate right ventricular (RV) function - RV dysfunction occurs in up to 30% of septic patients and requires different management of fluids, inotropes, and vasopressors to minimize dysfunction. 1

Integration with Surviving Sepsis Campaign Protocol

Begin with the standard 30 mL/kg crystalloid bolus within 3 hours as recommended by Surviving Sepsis Campaign guidelines, but use RUSH findings to guide subsequent fluid administration. 1, 4

After Initial Fluid Bolus:

• If BCU shows normal LV and RV function with a collapsible IVC → Continue aggressive fluid resuscitation guided by dynamic measures of fluid responsiveness. 4

• If BCU shows LV systolic or diastolic dysfunction → Limit further fluids and add inotropic support (dobutamine) to augment cardiac output rather than volume loading. 1

• If BCU shows isolated RV dysfunction → Cautiously titrate fluids while optimizing RV afterload with vasopressors (norepinephrine) and consider inotropes. 1

Hemodynamic Targets Remain Unchanged

Regardless of RUSH findings, maintain these endpoints:

• Mean arterial pressure ≥ 65 mmHg 1, 4
• Urine output ≥ 0.5 mL/kg/hr 4
• Lactate normalization 1, 4

Critical Pitfall to Avoid

The most dangerous error is continuing aggressive fluid resuscitation when BCU demonstrates ventricular dysfunction. Excessive fluid administration in the presence of LV or RV dysfunction leads to pulmonary edema, tissue edema, and worsened outcomes. 1 The RUSH exam specifically prevents this by identifying patients who need inotropes or vasopressors rather than additional volume. 5, 6

Practical Implementation

• Perform RUSH immediately upon recognizing septic shock, ideally during or immediately after the initial fluid bolus. 2, 3

• The cardiac assessment has high accuracy - studies show Kappa index of 0.7-0.71 for shock type diagnosis, with particularly high reliability for identifying cardiogenic shock (>90% for all indices). 5, 6

• Reassess frequently - BCU should be repeated as hemodynamic status changes, as septic cardiomyopathy can develop or resolve during the course of illness. 1

Vasopressor Initiation

Start norepinephrine as the first-line vasopressor after appropriate fluid resuscitation in distributive shock. 1 If RUSH shows myocardial depression with persistent hypotension despite adequate MAP, add dobutamine to norepinephrine or switch to epinephrine as a single agent. 1