Fluid Responsiveness Prediction During Prone Position

Not Applicable

Recruiting

• Conditions: Acute Respiratory Distress Syndrome
• Interventions: Diagnostic Test: Trendelenburg maneuver; Diagnostic Test: End-expiratory occlusion test (EE OCC); Diagnostic Test: End-expiratory and end-inspiratory occlusion test (EI OCC); Diagnostic Test: Tidal volume challenge; Diagnostic Test: Fluid bolus (reference diagnostic method)

• Registration Number: NCT05898269
• Lead Sponsor: Hospices Civils de Lyon

Brief Summary

Predicting fluid responsiveness is primordial when caring for patients with circulatory shock as it allows correction of preload-dependent low cardiac output states, while preserving patients of the deleterious effects of excessive fluid resuscitation.

Patients with severe acute respiratory distress syndrome (ARDS) treated with prone positioning (PP) are a specific subset of patients, as 1) they frequently present with shock; 2) excessive fluid administration may lead to respiratory worsening due to increased hydrostatic oedema with potential subsequent worse clinical outcome; and 3) all available dynamic tests evaluating fluid responsiveness can only be performed in patients in the supine condition (which in the case of severe ARDS patients in PP occurs only for 8h over 24h). These elements warrant the development of specific tests allowing the clinician to predict fluid responsiveness with enough exactitude when caring for these patients.

We hypothesize that there exists diagnostic heterogeneity in the predictive performance of 4 clinical tests to identify fluid responsiveness in ARDS patients in PP. For the matter of this study, these 4 tests are the Trendelenburg maneuver, the end-expiratory occlusion test, the end-expiratory occlusion test associated with the end-inspiratory occlusion test, and the tidal volume challenge. The diagnostic reference of the study will be the relative change in cardiac index measured by transpulmonary thermodilution before and after a 500 ml fluid bolus, and will allow the adjudication of patients as being fluid responsive or not.

The primary objective of the study is to determine the area under the ROC curve of each of the 4 tests, with their respective 95% confidence interval.

All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. Patients will only participate once. The expected duration of study participation is 30 minutes maximum.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2023-06-01
• Study First Submitted QC: 2023-06-01
• Study First Posted: 2023-06-12
• Study Start: 2023-10-06
• Status Verified: 2024-01
• Last Update Submitted: 2024-01-17
• Last Update Posted: 2024-01-18
• Primary Completion: 2026-10
• Study Completion: 2026-10

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 96

Inclusion Criteria

• adult patient (including patient under protective measures/wardship)
• with ARDS as defined by the Berlin criteria
• in the prone position as per international guidelines
• with a calibrated continuous cardiac output monitoring device
• with a clinical indication for a fluid bolus as prescribed by the clinician in charge, and fulfilling at least 2 clinical criteria: mottles, tachycardia, hypotension, drop in cardiac output, oliguria, high arterial lactate concentration, or any other detailed criterion
• with no respiratory efforts

Exclusion Criteria

• acute cor pulmonale
• patient treated with veno-venous extra-corporeal membrane oxygenation
• hemorrhagic shock
• Child-Pugh C cirrhosis
• death expected to occur in less than 24h
• decision to withhold or suspend active treatments
• intracranial hypertension
• lower limb amputation
• obstruction of the inferior vena cava
• acute abdominal syndrome
• absence of consent to participate
• pregnancy
• patient previously enrolled in the same study
• lack of affiliation to a social security regimen, as per French legislation
• patient deprived of its liberty

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Trendelenburg maneuver-EE OCC-EI OCC-Tidal volume challenge	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-EI OCC-Tidal volume challenge	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-Tidal volume challenge-EI OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EI OCC-EE OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-Tidal volume challenge-EE OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-EI OCC-Tidal volume challenge	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EI OCC-EE OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-EE OCC-Tidal volume challenge	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-Tidal volume challenge-EI OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EE OCC-EI OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EE OCC-EI OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-Tidal volume challenge-EE OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-EE OCC-Tidal volume challenge	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-EI OCC-Tidal volume challenge	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-Tidal volume challenge-EI OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-Tidal volume challenge-EI OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-Tidal volume challenge-EE OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-Trendelenburg maneuver-EI OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-EI OCC-Tidal volume challenge	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EE OCC-Tidal volume challenge-EI OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EI OCC-EE OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EE OCC-EI OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-Tidal volume challenge-EE OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EI OCC-EE OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EI OCC-EE OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EE OCC-EI OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-Tidal volume challenge-EE OCC-EI OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Tidal volume challenge-Trendelenburg maneuver	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Trendelenburg maneuver-Tidal volume challenge	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Trendelenburg maneuver-Tidal volume challenge	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-Tidal volume challenge-EE OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-EE OCC-Tidal volume challenge	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-EE OCC-Tidal volume challenge	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Tidal volume challenge-Trendelenburg maneuver	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Tidal volume challenge-Trendelenburg maneuver	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Tidal volume challenge-Trendelenburg maneuver	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Trendelenburg maneuver-Tidal volume challenge	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-Trendelenburg maneuver-EI OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Trendelenburg maneuver-EI OCC-EE OCC-Tidal volume challenge	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Tidal volume challenge-Trendelenburg maneuver	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-EI OCC-Trendelenburg maneuver	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-Tidal volume challenge-EI OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-Tidal volume challenge-EI OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-EI OCC-Tidal volume challenge	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Trendelenburg maneuver-Tidal volume challenge	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-EI OCC-Trendelenburg maneuver-Tidal volume challenge	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-EI OCC-Trendelenburg maneuver	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-EI OCC-Trendelenburg maneuver	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-Tidal volume challenge-EI OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-Tidal volume challenge-EI OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-Trendelenburg maneuver-EI OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-Trendelenburg maneuver-EI OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-Trendelenburg maneuver-EI OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-EI OCC-Trendelenburg maneuver	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-EI OCC-Tidal volume challenge	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-EI OCC-Tidal volume challenge	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-Trendelenburg maneuver-EE OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Tidal volume challenge-EI OCC-Trendelenburg maneuver	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-EE OCC-Trendelenburg maneuver	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-EE OCC-Tidal volume challenge	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-Tidal volume challenge-EE OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-Tidal volume challenge-EI OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-EI OCC-Tidal volume challenge	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-EE OCC-Trendelenburg maneuver	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-EE OCC-Trendelenburg maneuver	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-EE OCC-Trendelenburg maneuver	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-Trendelenburg maneuver-EE OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-Trendelenburg maneuver-EE OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EE OCC-Trendelenburg maneuver-EI OCC-Tidal volume challenge	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-EE OCC-Trendelenburg maneuver	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-Trendelenburg maneuver-EE OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-EE OCC-Tidal volume challenge	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-Tidal volume challenge-EE OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Trendelenburg maneuver-Tidal volume challenge	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Tidal volume challenge-Trendelenburg maneuver-EE OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-Tidal volume challenge-EE OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-Tidal volume challenge-EE OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Trendelenburg maneuver-Tidal volume challenge	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Tidal volume challenge-Trendelenburg maneuver	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-EE OCC-Tidal volume challenge	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Trendelenburg maneuver-Tidal volume challenge	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-EE OCC-Trendelenburg maneuver	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-EE OCC-Trendelenburg maneuver	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-EE OCC-Trendelenburg maneuver	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-EE OCC-Tidal volume challenge	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-EE OCC-Tidal volume challenge	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-Trendelenburg maneuver-Tidal volume challenge-EE OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Trendelenburg maneuver-Tidal volume challenge	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Tidal volume challenge-Trendelenburg maneuver	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Tidal volume challenge-Trendelenburg maneuver	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Tidal volume challenge-Trendelenburg maneuver	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Trendelenburg maneuver-Tidal volume challenge	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
EI OCC-EE OCC-Tidal volume challenge-Trendelenburg maneuver	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-Trendelenburg maneuver-EE OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-Trendelenburg maneuver-EE OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-EE OCC-Trendelenburg maneuver	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver- EI OCC-EE OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC-Trendelenburg maneuver- EI OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC-Trendelenburg maneuver- EI OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-EE OCC-Trendelenburg maneuver	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver-EE OCC- EI OCC	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver- EI OCC-EE OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC- EI OCC-Trendelenburg maneuver	Trendelenburg maneuver	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC- EI OCC-Trendelenburg maneuver	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-Trendelenburg maneuver-EE OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-Trendelenburg maneuver-EE OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver-EE OCC- EI OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver- EI OCC-EE OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EI OCC-Trendelenburg maneuver-EE OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver-EE OCC- EI OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver- EI OCC-EE OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC-Trendelenburg maneuver- EI OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver-EE OCC- EI OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver-EE OCC- EI OCC	Tidal volume challenge	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-Trendelenburg maneuver- EI OCC-EE OCC	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC-Trendelenburg maneuver- EI OCC	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC-Trendelenburg maneuver- EI OCC	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC- EI OCC-Trendelenburg maneuver	End-expiratory occlusion test (EE OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC- EI OCC-Trendelenburg maneuver	Fluid bolus (reference diagnostic method)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence
Tidal volume challenge-EE OCC- EI OCC-Trendelenburg maneuver	End-expiratory and end-inspiratory occlusion test (EI OCC)	All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. There are 24 different possibilities of sequence

Primary Outcome Measures

Name	Time	Method
Area under the ROC curve (AUROC) of the evaluated tests.	30 minutes	The AUROC will be determined for each of the 4 clinical tests evaluated in this study. The reference method to define the AUROC to design the curve will be the fluid responsive status (responder vs. non-responder) as determined by the fluid bolus. For each test, the AUROC will be accompanied with its 95% confidence interval.

Secondary Outcome Measures

Name	Time	Method
Diagnostic performance metrics of each test	30 minutes	Sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratios of the evaluated tests, computed for the optimal diagnostic threshold determined using the Youden J index of the ROC curve. The optimal threshold will only be computed for AUROCs significantly different from 0.5.
Weighted diagnostic performance of each test	30 minutes	Sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratios of the evaluated tests, computed for the optimal diagnostic threshold determined using the Youden J index of the ROC curve, and adjusted using weighting based on the clinical tradeoff of the subsequent fluid bolus on hemodynamic benefit vs. the respiratory risk. The optimal threshold will only be computed for AUROCs significantly different from 0.5.
Comparison of diagnostic performance of the evaluated tests.	30 minutes	For this outcome measure, the AUROCs will be determined as for the primary outcome measure. The AUROCs will be compared using the Delong's method, with adjustments for the repetition of measurements in a single patient.
Grey zone area of the optimal diagnostic threshold of each test	30 minutes	Determination of the boundaries of a grey zone around the value of the optimal threshold of each test, in which the diagnostic performance is deemed clinically insufficient (excessive misclassification risk due to lack of discrimination). The grey zone around the optimal threshold will only be computed for AUROCs significantly different from 0.5.

Trial Locations

Locations (4)

CHU de Nice - l'Archet 1; 🇫🇷 Nice, France

CHU Gabriel Montpied; 🇫🇷 Clermont-Ferrand, France

CHU Nice - Pasteur 2; 🇫🇷 Nice, France

Hôpital de la Croix Rousse, Hospices Civils de Lyon; 🇫🇷 Lyon, France