Driving Pressures in a Closed-loop and a Conventional Mechanical Ventilation Mode
Condition: Acute Lung Injury
MeSH terms: Lung Injury; Acute Lung Injury
Study type: Interventional

Summary: 
      In mechanically ventilated patients, driving pressure (ΔP) assess the strain applied to the
      respiratory system and is related to ICU mortality. The aim of this randomized cross-over
      trial was to compare ΔP selected by a closed-loop system and by physician tailored mechanical
      ventilation mode. Pediatric patients admitted to PICU will be enrolled if they were
      invasively ventilated without any detectable respiratory effort, hemodynamic instability, or
      significant leakages. Two 60 minute periods of ventilation determined by randomization in
      APV-CMV and ASV 1.1 will be compared. Settings were adjusted to reach the same minute
      ventilation in both modes. ΔP will be calculated as the difference between plateau pressure
      and total PEEP measured using end-inspiratory and end-expiratory occlusion maneuvers,
      respectively.
    

Detailed description: 
      In 2015, Pediatric Acute Lung Injury Consensus Conference (PALICC) determined the pediatric
      acute respiratory distress syndrome (PARDS) definition. PALICC recommends using
      patient-specific tidal volume (VT) according to disease severity. Moreover, in the absence of
      transpulmonary pressure measurements (PL), an inspiratory plateau pressure limit of 28 cm H2O
      is recommended, allowing for slightly higher plateau pressures (29-32 cm H2O) for patients
      with reduced chest wall compliance. In adult ARDS, Amato et al. normalized VT to the
      compliance(C) by using driving pressure (ΔP) and reported that ΔP was the ventilation
      variable that best-stratified risk. Changes in ventilator settings resulting in a decrease in
      ΔP were associated with increased survival. One of the most common modes used in pediatric
      ventilation nowadays is synchronized controlled mandatory ventilation with adaptive pressure
      ventilation (APV-CMV). As compared to pressure control mode (P-CMV), APV-CMV prevents low or
      high VT when the compliance changes by adjusting the applied pressure. Adaptive support
      ventilation (ASV) is closed-loop ventilation mode, which for a given minute volume set by the
      clinician, adapts tidal volume (VT) and respiratory rate (RR) according to the patient's
      respiratory mechanics.

      This prospective randomized cross over study aimed to compare ΔP between physician tailored
      APV-CMV mode and ASV 1.1 in pediatric mechanically ventilated patients with acute respiratory
      failure. After the enrollment, the patients' ventilation periods will be determined by
      randomization using sealed opaque envelopes. The minute ventilation, fraction of inspired O2
      (FiO2) and positive end-expiratory pressure (PEEP) set by the clinician before study
      inclusion will be kept unchanged during all study periods. Patients will be ventilated in
      each mode for 60 minutes. Three consecutive -inspiratory and end-expiratory occlusion will be
      performed at 30 and 60 min and ΔP will be calculated for each period. Arterial blood gas will
      be measured at the end of each period. A wash-out period of 30 min using the ventilation mode
      and setting before inclusion will be performed in between the two study ventilation periods.
      ΔP will be calculated as the difference between plateau pressure (Pplat) and total PEEP and
      will be averaged for each ventilation period by using the mean of the six measurements
      mentioned above. VT will be calculated by integration of flow measurement. Resistance will be
      calculated by the least-squares fitting method. The expiratory time constant (RCexp) will be
      derived from the volume-flow curve at 75% of the VT and corresponding flow value. Static
      compliance (Cstat) will be calculated as VT divided by ΔP.

      The primary outcome will be ΔP. The secondary outcome will be VT, RR, Pplat, Ti, Te, Cstat,
      Resistance, RCexp, pH, PaO2, PaCO2 A pilot study was performed to calculate the sample size.
      The mean ΔP was 12.4 (±3.31) cm H2O in ASV 1.1 and 13.5 (±4.2) cm H2O in APV-CMV. By using
      these pilot data, and assuming the power of 0.95 and α-error of 0.05, investigators have
      calculated the study size as 26 patients.
    

Intervention name(s): closed loop; conventional
Intervention type(s): Device; Device
Intervention description(s): RR and VT will be selected according to the respiratory mechanics by closed loop algorithm; RR, VT, Ti will be selected by the clinician according to the respiratory mechanics
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Driving pressure,; Pediatric acute respiratory distress syndrome (PARDS),; Acute lung injury (ALI),; Closed loop ventilation; Pediatric intnsive care unit (PICU)