Personalized Tidal Volume in ARDS (VT4HEMOD)

Condition(s) studied

Investigational drug(s) / intervention(s)

Standardized ventilation: 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 ventilation: 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.

Study summary

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)

Eligibility

Primary outcome measure(s)

• Tidal hyperinflation — 5 minutes - This endpoint will be assessed 5 minutes after ventilatory adjustment
  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.

Trial sites (1)

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