Work of Breathing Assessment During Weaning From Mechanical Ventilation
Condition: Mechanical Ventilation
MeSH terms: Respiratory Aspiration
Study type: Interventional

Summary: 
      Introduction In patients assisted by mechanical ventilation, the Work Of Breathing (WOB) is
      shared between the patient and the ventilator. During weaning from mechanical ventilation,
      the WOB performed by the patient must be adequate and efficient to sustain spontaneous
      ventilation after extubation. The monitoring of WOB during weaning might allow a better
      management of the weaning process. Esophageal pressure (PES) is the reference technique to
      measure WOB but alternate tools have been proposed. The main hypothesis is that Indirect
      Calorimetry (IC) is valid to track the changes in energy expenditure due to the changes in
      WOB in mechanically ventilated children during weaning from mechanical ventilation. The
      primary objective of this study is to assess the validity of IC method for the WOB assessment
      when compared to PES measurement and Electrical Activity of the diaphragm (EAdi) during a
      spontaneous breathing trial (SBT) in continuous positive airway pressure, which is a routine
      extubation readiness test which generally induces an increase in WOB.

      Methods This is a prospective single center study. All intubated and mechanically ventilated
      children >1 months and <18 years old, hospitalized in the pediatric intensive care unit will
      be eligible.

      Simultaneous recordings of Energy Expenditure, PES and EAdi will be performed during 3 steps:
      before, during and after the SBT. Then outcome of patients will be collected.

      The investigators plan to study a sample of 15 patients to be representative.

      Relevance to the importance of child health in Canada The investigators expect that the
      IC-based less invasive method will provide an accurate estimation of WOB assessment. Once
      this tool is validated, the interest of IC to (i) early detect an increase in WOB during
      mechanical ventilation in children, (ii) to assess the ability to extubate them and (iii) to
      optimize nutritional support will be assessed in future studies.
    


Intervention name(s): Measurement of work of breathing using indirect calorimeter
Intervention type(s): Device
Intervention description(s): Preparation:
Patient baseline characteristics will be collected.
Connection of the Indirect Calorimeter to the respiratory circuit.
Nasogastric tube installation: a specific modified Neurally Adjusted Ventilatory Assist (NAVA) catheter equipped with both microelectrodes for Electrical Activity of the diaphragme (EAdi) monitoring and an esophageal balloon (for esophageal pressure (PES) monitoring) will be installed.
Simultaneous recordings of: Oxygen Consumption (VO2) and Energy Expenditure (EE); Esophageal Pressure (PES), Airway Pressure (PAW), respiratory volume and flow; EAdi during (i) Conventional mechanical ventilation (ii) Spontaneous Breathing Trial in Continuous Positive Airway Pressure and (iii) Second period of Conventional mechanical ventilation with the same ventilator parameters set in STEP 1.
End of the physiological recordings. Collection of Pediatric Intensive Care Unit (PICU) outcome of patients.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Mechanical ventilation; Children; Work of breathing