Personalized Tidal Volume in ARDS (VT4HEMOD)

Hospices Civils de Lyon10 enrolled

Overview

Treatment of acute respiratory distress syndrome (ARDS) relies on invasive mechanical ventilation with supposedly protective settings (low tidal volume ventilation). Mortality of ARDS remains high in observational studies (40 to 50%). Approximately 30% of ARDS patients exhibit tidal hyperinflation despite low tidal volume ventilation, suggesting that personalization of tidal volume is required to improve ARDS prognostic. To date, reliable bedside tools to adjust tidal volume are lacking. Excessive tidal volume can be detected using computed tomography by quantification of tidal hyperinflation, but this technique is reserved to research studies and requires patient transport to imaging facility. Mechanical ventilation generates cardio-pulmonary interaction, whose magnitude is influenced by tidal volume and respiratory system characteristics. Pulse pressure variation is a bedside tool with potential to quantify cardio-pulmonary interactions. Increasing tidal volume will decrease right ventricular preload and increase right ventricular afterload, hence maximizing cardio-pulmonary interactions. The investigators hypothesize that pulse pressure variation might help to detect excessive tidal volume during a tidal volume challenge (i.e. stepwise increase in tidal volume)

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Acute Respiratory Distress Syndrome

Interventions

Standardized ventilationPROCEDURE

Patient will be ventilated with tidal volume 6 mL/kg predicted body weight (PBW) and positive end-expiratory pressure (PEEP) according to the PEEP-FiO2 table of the ARMA trial. A CT scan will be performed with this ventilatory setting and the patients will be switched to the other group

Personalized ventilationPROCEDURE

Patient will be ventilated with PEEP according to the PEEP-FiO2 table of the ARMA trial. Tidal volume will be selected as the tidal volume minimizing cardiopulmonary interactions as assessed on arterial pressure tracing, during a VT trial. A CT scan will be performed with this ventilatory setting and the patients will be switched to the other group.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Age greater then 18 years old 2. ARDS according to the BERLIN definition with PaO2/FiO2 ratio ≤ 150 mm Hg 3. invasive mechanical ventilation in volume controlled mode with tidal volume set to 6 ml/kg predicted body weight 4. use of sedation and neuromuscular-blocking agents 5. arterial catheter allowing computation of pulse contour cardiac output calibrated with thermodilution 6. central venous catheter implanted in the superior vena cava territory 7. esophageal balloon 8. Computed tomography planned by attending physician Exclusion Criteria: 1. Previous inclusion in current study 2. Acute cor pulmonale 3. ECMO 4. Arterial pH \< 7.21 despite respiratory rate set to a maximum of 35/min 5. Pneumothorax or bronchopleural fistula 6. Decision to withdraw or withhold life sustaining treatment with 24 hours from inclusion 7. Contra-indication of transport to imaging facility 8. Intracranial hypertension 9. Tricuspid or pulmonary mechanical valve 10. Tricuspid or pulmonary infective endocarditis 11. Pace maker with intracardiac leads 12. Right ventricle tumor 13. Complete left bundle block 14. Intrathoracic metallic device 15. COPD 16. Cardiac arrythmia 17. Vesical pressure \> 15 mm Hg 18. Lower limb amputation 19. Inferior vena cava thrombosis 20. Patient under an exclusion period relative to participation to another clinical trial 21. Patient under a legal protective measure 22. Patient not affiliated to social security 23. lac of patient/representative consent 24. Pregnancy 25. Breast feeding

Outcomes

Primary Outcomes

Tidal hyperinflation

Difference between hyperinflated volume in computed tomography images acquired at end-inspiration (defined by the volume of voxels with CT-number \< -900) and hyperinflated volume in computed tomography images acquired at end-expiration (defined by the volume of voxels with CT-number \< -900). This difference will be standardized to predicted body weight using the formula of the ARMA trial.

Time frame: 5 minutes - This endpoint will be assessed 5 minutes after ventilatory adjustment

Secondary Outcomes

Tidal volume

Standardized versus personalized tidal volume

Time frame: 5 hours - This endpoint will be assessed through study completion (approximately 4-5 hours after study inclusion)