Fluid Responsiveness Prediction During Prone Position

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.

Conditions

• Acute Respiratory Distress Syndrome

Interventions

DIAGNOSTIC_TEST

Trendelenburg maneuver

Bed tilting from the +13° position to the -13° position for 60 seconds. Evaluator: relative change in continuous cardiac index between baseline, and the highest value observed during the maneuver

DIAGNOSTIC_TEST

End-expiratory occlusion test (EE OCC)

End-expiratory pause performed on the ventilator, and maintained for 15 seconds. Evaluator: relative change in continuous cardiac index between baseline, and the value observed in the last 5 seconds of the respiratory pause

DIAGNOSTIC_TEST

End-expiratory and end-inspiratory occlusion test (EI OCC)

End-inspiratory pause performed on the ventilator, and maintained for 15 seconds. Evaluator: relative change in continuous cardiac index between baseline, and the value observed in the last 5 seconds of the respiratory pause. The evaluator is calculated as the sum of the relative change in cardiac index observed during the end-expiratory pause and that of the end-inspiratory pause. Hence, for this test, the evaluator will be coupled with that of intervention 2 (end-expiratory occlusion test).

DIAGNOSTIC_TEST

Tidal volume challenge

Increase in tidal volume set on the ventilator from 6 ml.kg-1 of predicted body weight, to 8 ml.kg-1 for 60 seconds. Evaluator: difference in the pulse pressure variation measured at 6 ml.kg-1 and at 8 ml.kg-1.

DIAGNOSTIC_TEST

Fluid bolus (reference diagnostic method)

After the 4 tests, the patient will receive a 500-ml fluid bolus of crystalloids in less than 15 minutes. Evaluator (reference method): cardiac index measured by transpulmonary thermodilution before and immediately after the fluid bolus. Patients with a relative change in cardiac index \> 15% will be identified as being fluid responders, and the others as non-responders.

Sponsors & Collaborators

• Hospices Civils de Lyon

  lead OTHER

Principal Investigators

• Hodane YONIS, Dr · Hospices Civils de Lyon

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-10-06

Primary Completion

2026-10-31

Completion

2026-10-31

Countries

• France

Study Locations