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Table 3 Flow-chart: enrollment, interventions and evaluations

From: Low tidal volume mechanical ventilation against no ventilation during cardiopulmonary bypass heart surgery (MECANO): study protocol for a randomized controlled trial

   Study period
Time pointsa   
Enrollment Allocation/intervention Post intervention Follow up Close out
Preoprative visit Before anesthesia During surgery Day 1 Day 2 Day 3 Day X Hospital discharge
(D-1 or D-2 before surgery)
 Eligibility screen X        
 Informed consent X        
 Physical examinationb X        
 History of previous diseasec X        
 FEV (1) and FVC X        
 Euroscore 2 X        
 Creatininemia (μmol/L) X        
 Randomization   x       
 Type of procedure    x      
 CPB (in minutes)    x      
 Number of red blood cell transfusions    x      
 Number of and reasons for manual insufflation    x      
 Temperature     x x x   
 PaO2     x x x   
 FiO2     x x x   
 Ventilation mode     x x x   
 Hemoglobinemia     x x x   
 Leucocytemia     x x x   
 Quantity of bleeding     x x x   
 Collection of data on the occurrence of primaryd and secondarye endpoints     x x x x x
 Serious adverse events     x x x x x
  1. Abbreviations: CPB cardiopulmonary bypass; D day; FiO2 fraction of inspired oxygen; PaO2 arterial oxygen tension; FEV (1) forced expiratory volume 1; FVC forced vital capacity
  2. aTime points: enrollment, interventions and assessments
  3. bPhysical examination: weight, height
  4. cHistory of previous disease: diabetes mellitus, peripheral arterial disease, pulmonary comorbidity, pulmonary infection in the past 30 days
  5. dPrimary endpoints: overall death, early respiratory failure defined as PaO2/FiO2 ratio <200 at 1 hour after arrival in the ICU, heavy oxygenation support (defined as a patient requiring either non-invasive ventilation, mechanical ventilation or high-flow oxygen) at 2 days after arrival in the ICU or ventilator-acquired pneumonia as defined by the Center of Disease Control
  6. eSecondary endpoints: pneumothorax, CPB duration, volume of postoperative bleeding, red blood cell transfusions, requirements for revision surgery, length of stay in the ICU and in the hospital and total hospitalization costs