Overview

Evaluating preload dependence is crucial for managing fluid administration in septic shock patients. To avoid unnecessary fluid administration, it's recommended to use dynamic tests like the passive leg raising (PLR) maneuver or a fluid challenge (FC) to see if a patient's cardiac output will increase after fluid resuscitation. Transthoracic echocardiography (TTE) is preferred for this because it can non-invasively, reliably, and reproducibly measure the increase in cardiac output. A patient is considered a "responder" if their stroke volume (SV) increases by more than 15% after an FC. Two-dimensional (2D) right atrial strain (RAS) is a promising tool for evaluating right atrial function. According to the Frank-Starling law, measuring changes in the RA reservoir strain phase (RASr) can identify acute changes in preload, like those induced by a PLR maneuver or an FC.

The aims of this study are to assess the ability of ∆RASr to identify responders after a fluid challenge (FC) and to evaluate the ability of ∆RASr variation induced by a PLR maneuver to distinguish responders from non-responders to volume expansion.

Eligibility

Inclusion Criteria:

• Adult patient (>18 years old)
• Patient hospitalized in the Intensive Care Unit at Amiens University Hospital with septic shock for less than 48 hours, defined by the presence of all the following criteria: presence of sepsis, hypotension requiring vasopressors to maintain a mean arterial pressure ≥ 65 mmHg despite adequate prior fluid resuscitation, and blood lactate levels > 2 mmol/l (18 mg/dl).
• Patient requiring fluid resuscitation with crystalloids/colloids
• Patient on invasive mechanical ventilation in assisted-controlled mode.
• Blood pressure monitored via a radial or femoral arterial catheter connected to a MostCareUp (Vygon, France).
• Patient or family informed and non-opposition documented.

Exclusion Criteria:

• Poor echocardiographic image quality preventing RASr assessment
• Patient with a contraindication to the PLR maneuver: severe head trauma or intracranial hypertension
• Patient with a history of pericardiectomy
• Patient with a clinical examination consistent with abdominal compartment syndrome
• Patient with aortic pathology, mitral regurgitation greater than grade 2, tricuspid regurgitation greater than grade 2, mitral stenosis, or intracardiac shunt
• Patient with internal or external atrial/ventricular pacing
• Pregnant woman
• Patient on extracorporeal membrane oxygenation and mechanical circulatory support
• Moribund patient
• Patient with supraventricular or ventricular arrhythmia during echocardiographic measurement series
• Patient on renal replacement therapy during echocardiographic examination