Predictors of Weaning Outcomes for Brain Injured Patients
Condition: Brain Injuries
MeSH terms: Brain Injuries
Study type: Observational

Summary: 
      Brian injured patients are predisposed to various complications related to mechanical
      ventilation. Appropriate decision making of the weaning is crucial and validated predictive
      parameters are desirable. In present study, the investigators aim to a) validate the
      electrical activity of diaphragm (EAdi) derived parameters, and b) evaluate the traditional
      predictive parameters in weaning prediction in brain injured patients.
    

Detailed description: 
      In general intensive care unit (ICU), about 20% patients are ventilated because of
      neurological illness. This proportion might be much higher in brain injured patients. As with
      general intensive care patients, brain injured patients are predisposed to a number of
      complications associated with mechanical ventilation. Both unnecessarily delaying and
      premature attempts of withdrawal of mechanical ventilation will increase the rate of
      complications, prolonged mechanical ventilation, the length of stay, motility, and the cost.

      Numerous studies had examined factors that predict combined liberation/extubation outcomes,
      including vital capacity (VC), minute ventilation(VE), and maximum inspiratory pressure
      (MIP), airway pressure developed 100 ms after the beginning of inspiration against an
      occluded airway (P0.1), breathing pattern variability (BPV), and the "rapid shallow breathing
      index" (RSBI, Breathing frequency-tidal volume ratio, f/Vt). The introduction of Neurally
      Adjusted Ventilatory Assist (NAVA) has made available a standardized and validated method to
      monitor and measure diaphragm electrical activity (EAdi) both during conventional modes of
      ventilation and spontaneous breathing trail (SBT). Neuroventilatory efficiency index (NVE,
      Tidal volume - EAdi ratio, Vt/EAdi) and neuromechanical efficiency index (NME, tidal volume -
      EAdi ratio, Paw/EAdi) had also been proposed and showed a promising prospect.

      However, all those physiological and mechanical parameters are either have limitations on
      using in brain injured patients, or have not yet been proved to be validity or even had a
      poor predictive ability. In part this is because respiratory failure of brain injured patient
      results from two principle etiologic entities: primary pulmonary dysfunction and neurogenic
      pulmonary dysfunction. The latter brings us quite different characters of brain injury
      patients, which required specially consideration. Another reason is that, patients with brain
      injured but no other indication for mechanical ventilation constitute a group in whom the
      needs for ventilatory support and for an artificial airway might be separate. Previous study
      that, in neurosurgical patients passed SBT, a median of 2 days elapsed before the attempted
      extubation, and 45% patients suffered reintubation or tracheostomies. Nonetheless, in most
      studies, disconnection of ventilatory support and extubation are often lumped together.
      Although some studies investigated the factors that are predictive of successful extubation,
      few study considered about the solely liberation of mechanical ventilation.

      Therefore, in present study, the investigators separate the liberation of ventilatory support
      as a standalone part from the traditional weaning/extubation process. Patients are divided
      into two groups: weaning success and weaning failure, without consideration of the artificial
      airway status. The primary aims of the study are: a) validate the EAdi derived values, and b)
      evaluate the traditional predictive parameters in weaning prediction in brain injured
      patients.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Brain injured patients receiving mechanical ventilation
      
Keywords: brain injury; mechanical ventilation; weaning