A Study to Compare Adaptive Support Ventilation vs. Volume Controlled Ventilation for Management of Respiratory Failure in Patients With Neuroparalytic Snake Envenomation
Condition: Snake Envenomation; Invasive Mechanical Ventilation; Adaptive Support Ventilation
MeSH terms: Respiratory Insufficiency; Poisoning; Snake Bites
Study type: Interventional

Summary: 
      Neuroparalytic snake envenomation results in severe muscle weakness and respiratory failure.
      Treatment requires administration of anti-snake venom and supportive care in the form of
      invasive mechanical ventilation. Whether using adaptive support ventilation (a closed loop
      mode of ventilation) in comparison to volume controlled ventilation will shorten the duration
      of ventilation remains undetermined. The current study is planned to compare adaptive support
      ventilation (ASV) mode of ventilation versus volume controlled ventilation (VCV) during
      invasive mechanical ventilation for the management of respiratory failure secondary to
      neuroparalytic snake envenomation.
    

Detailed description: 
      Snake envenoming is a common medical emergency encountered in the tropical countries, and an
      estimated 35,000 -50,000 people die of snakebite every year in India. The bites of elapid
      snakes cause predominantly neurotoxicity, which manifests as ocular and bulbar paralysis, and
      paralysis of the muscles of respiration, with resultant respiratory failure. The management
      of these patients includes ventilatory support and administration of snake anti-venom.
      Respiratory failure requiring mechanical ventilatory support is a frequent cause of admission
      to the intensive care unit (ICU). Mechanical ventilation is a life-saving intervention, and
      once there is improvement of the underlying indication, it can be withdrawn abruptly in the
      majority. However, approximately 20-30% of patients still require gradual discontinuation
      (ie, weaning). This process is not only difficult in patients with chronic respiratory
      diseases and acute neuromuscular disorders, such as neurotoxic snake bite, but is also
      associated with important complications, such as nosocomial pneumonia, prolonged ICU stay,
      and even mortality, especially in those with persistent weaning failure.

      Adaptive support ventilation (ASV) is a closed-loop ventilation mode designed to provide a
      user-set minimum minute ventilation in intubated patients, either actively breathing or
      passively ventilated. ASV automatically selects a target ventilatory pattern based on user
      inputs [patient's predicted body weight (PBW), minimum minute volume, and pressure limit] and
      respiratory mechanics data from the ventilator monitoring system (respiratory system
      expiratory time constant and dynamic compliance). The algorithm selects ventilatory
      parameters so as to minimize total work of inspiration, and the ventilator continuously
      adapts to match changes in respiratory mechanics by using automatic controls for level of
      inspiratory pressure above positive end-expiratory pressure (PEEP), frequency, and
      inspiratory time of ventilator-initiated breaths.

      In most studies, ASV has been used only in the weaning phase, and patients were ventilated
      with conventional modes until weaning. However recent studies suggest its role in primary
      ventilation in the initial phase of respiratory failure. Previous use of ASV in patients with
      acute respiratory distress syndrome has been described from our center and the use of ASV was
      equally efficacious to conventional mode of ventilation (volume control). In another study
      the use of ASV in comparison to pressure control ventilation in patients with acute
      respiratory failure reduced the weaning duration and total duration of mechanical
      ventilation. Because ASV can be used from intubation to extubation, it may also offer some
      advantages before the weaning phase in patients with respiratory failure. Therefore, we
      hypothesize that ASV may shorten the total mechanical ventilation (MV) duration, weaning
      duration, and increase the weaning success rates when compared with conventional ventilation
      in the management of patients with neuroparalytic snake envenomation.
    

Intervention name(s): Adaptive support ventilation; Volume controlled ventilation
Intervention type(s): Other; Other
Intervention description(s): Adaptive support ventilation during invasive mechanical ventilation; Volume controlled ventilation during invasive mechanical ventilation
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment