Flow Controlled Ventilation (FCV) With the Evone Ventilator and Tritube Versus Volume Controlled Ventilation (VCV)
Condition: Pulmonary Ventilation
Study type: Interventional
Phase: Phase 3

Summary: 
      The Evone® ventilator is a new device capable of lung ventilation through a narrow-bore
      cannula, the Tritube.Two ventilation modes are possible: high frequency jet ventilation
      (HFJV) and flow-controlled ventilation (FCV). In this prospective pilot study the efficacy of
      FCV using the Evone® ventilator and Tritube is investigated when compared with Volume
      Controlled Ventilation (VCV) via a normal tracheal tube.
    

Detailed description: 
      The Evone® (Ventinova Medical, Eindhoven, The Netherlands) is an automated mechanical
      ventilator providing pulmonary ventilation by generating a continuous flow into the patient's
      lungs during inspiration as well as a continuous flow during expiration (flow controlled
      ventilation, FVC). FCV is a relatively new concept in which ventilation via the Tritube
      (Ventinova), an ultrathin endotracheal tube, has been made possible due to active suctioning
      of gas from the lungs during expiration (expiratory ventilation assistance, (EVA)).
      Adjustable parameters that govern the FCV cycle are: Inspiration Flow, Inspiratory:Expiratory
      ratio (I:E ratio), maximum tracheal pressure (PMAX) and end expiratory pressure (EEP).
      Measured parameters are: end-tidal carbon dioxide partial pressure (PE'CO2 ) as measured by
      capnography, Minute Volume, Peak Tracheal Pressure, End Expiratory Pressure, Respiratory
      Frequency, I:E ratio and Tidal Volume ( VT). The ventilator screen continuously displays a
      capnograph with end-tidal CO2, intra-tracheal pressure and inspiratory tidal volume
      waveforms. In FCV mode, inspiration occurs with the pre-set, constant inspiratory flow until
      the intratracheal pressure reaches the pre-set value. Assisted expiration then occurs until
      the pre-set EEP is reached. Expiratory flow is controlled in such a way to achieve a mainly
      linear reduction in tracheal pressure, whilst ensuring the set I:E ratio. There are no
      inspiratory or expiratory pauses and EVA does not result in negative tracheal pressures.
      Thus, minute volume is determined by the set flow rate and the I:E ratio. The set inspiratory
      peak and end expiratory pressures determine the tidal volumes. Ventilatory frequency is a
      result of these parameter settings.

      The Tritube is a 40 centimeter long narrow diameter cuffed tracheal tube (internal diameter
      2.4 millimeter, outer diameter 4,4 millimeter) that can be used with either the manual
      Ventrain® or automated Evone® ventilator. It consists of three lumens: a ventilatory channel
      with Murphy eye, a channel for airway pressure measurement and a channel for inflating the
      high volume, low pressure polyurethane cuff. Preliminary data suggests that Evone® not only
      provides adequate ventilation via the Tritube, but in comparison with conventional modes of
      ventilation (volume-controlled, pressure-controlled modes) may result in improved alveolar
      gas distribution, ventilation/perfusion matching, respiratory mechanics and oxygenation. In
      this prospective pilot study the efficacy of FCV using the Evone® ventilator and Tritube is
      investigated when compared with VCV (Aisys Carestation, GE Healthcare, WI, USA) via a normal
      tracheal tube.

      All participants meeting inclusion criteria and having signed Informed Consent will undergo
      anesthesia and monitoring as per standard of care for the designated surgical procedure (5
      lead ECG, non-invasive blood pressure cuff, saturation monitor). Neuromuscular blockade will
      be monitored by use of the TOF Watch®SX (train-of- four). Depth of anesthesia will be
      monitored by use of NeuroSENSE ®NS 701 Monitor( NeuroWave Systems incorporated - Cleveland
      Heights,OH). Following placement of a peripheral intravenous infusion, induction of standard
      intravenous anesthesia (propofol/remifentanil) and deep neuromuscular relaxation (rocuronium)
      will be established. Following 3 minutes of preoxygenation (Fractional end-tidal oxygen
      concentration (FE'O2> 0.9), patients will be intubated with a conventional cuffed tracheal
      tube cut to 24 centimeter length via oral route and ventilated in standard VCV mode with
      Fractional Inspired Oxygen concentration (FIO2) at 0.3 percent, Positive End Expiratory
      Pressure (PEEP + 5cmH2O) and frequency (f) of 12 breaths per minute. Tidal volume will be
      adjusted to ensure normocapnia. A radial arterial catheter will be placed and attached to a
      FloTrac sensor and Vigileo monitor ( Edwards Lifesciences, Irvine CA, USA) for continuous
      measuring of arterial blood pressure and cardiac output. It will facilitate blood gas
      sampling. Bladder temperature is monitored by means of a urinary catheter and patient is kept
      warm by means of a warming mattress and air warming blanket. After this preparation phase and
      prior to start of surgery, each subject will undergo two randomly allocated study periods:
      one with VCV, the other with FCV. In both cases FIO2 will be 0.3%, EEP at +5 cmH2O and I:E
      1:1. Before starting the study protocol all subjects will be pre-oxygenated with 100% Oxygen
      for three minutes and undergo a recruitment manoeuvre. The recruitment manoevre will be
      conducted as follows: respiratory rate 12 breaths/minute, tidal volume 6mL/kg, initial PEEP
      5cm H2O, with PEEP increasing in 5cm H2O increments to 15cm H2O per 5 breaths and then in
      decremental steps of 5cm H2O per 5 breaths back to 5 cm H2O PEEP. Peak pressure will be
      limited to 35 cm H2O.The respiratory circuit will then be disconnected for one minute. This
      provides sufficient time for placement of the Tritube through the tracheal tube when the
      subject is randomised to FCV in the first study period. For subjects initially randomised to
      VCV, VCV will be continued after this sham manoevre. Data collection starts after 15 minutes
      to allow stabilisation of respiratory and hemodynamic variables. Following data collection, a
      second 3 minutes pre-oxygenation period with recruitment manoevre and 1 minute apnea will be
      used before switching to the second ventilation mode.
    

Intervention name(s): Aisys Carestation ventilator and normal endotracheal tube; Evone ventilator and Tritube
Intervention type(s): Device; Device
Intervention description(s): Fraction of Inspired Oxygen (FIO2) 0.3 End Expiratory Pressure (EEP) at +5 cm H2O Ratio of duration of inspiration to the duration of expiration (I:E ratio) 1:1 Tidal Volume: 6 mL/kg Zero inspiratory pause Respiratory frequency will be adapted to produce an End-Tidal CO2 35-40 mmHg; Fraction of Inspired Oxygen (FIO2) 0.3 Ratio of duration of inspiration to the duration of expiration (I:E ratio) 1:1 End Expiratory Pressure (EEP) at +5 cm H2O Flow: start with 10 L/min and adjusted along with the peak inspiratory pressure to produce a tidal volume of 6 mL/kg and End-Tidal CO2 35-40 mmHg
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Patients undergoing craniotomy will be ventilated during surgery using both conventional VCV and FVC modes. Standard baseline VCV is used for induction and stabilization of anesthesia. The order of ventilation mode is randomly assigned.
Masking: None (Open Label)
Primary purpose: Other