Airway pressure release ventilation (APRV) is a time-cycled, pressure controlled, intermittent mandatory ventilation mode with extreme inverse I:E ratios. Currently it is considered as a non-conventional ventilatory mode. The investigators aim to compare APRV with conventional mechanical ventilation (MV) in patients with acute respiratory distress syndrome (ARDS).
Despite the advances in technology and ventilatory modes, mortality of ARDS is still around 40%. Besides prone positioning, the best approach of management is low tidal volume ventilation (LTV). This 'protective ventilation' strategy is not aways effective to improve oxygenation and is associated with an increased requirement of sedation and neuromuscular blocking agents, which increase length of stay and morbidity. APRV is a ventilatory mode based on relatively high and sustained continuous positive pressure, combined with a short phase of release to allow carbon dioxide removal. It also allows unrestricted spontaneous breathing throughout respiration, independent of the ventilator cycle. Providing sustained inflation while limiting duration and frequency of release phase permits limiting volume loss, resulting in progressive and improved alveolar recruitment, an increased alveolar surface area available for gas exchange and improved ventilation-perfusion matching. In this multi-center, prospective, randomized, controlled, open trial, the investigators aim to compare the effects and safety of the early application of time-controlled adaptive method of APRV and conventional ventilation with LTV strategy in patients with severe to moderate ARDS.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
150
APRV consist of an extended time at plateau pressure (a continuous positive airway pressure phase) comprising about 90% of the respiratory cycle, while providing very brief releases to enhance carbon dioxide removal. Time-controlled adaptive method requires interpretation of the expiratory flow curve to assess changes in lung elastance and, therefore, set the Time low to optimize carbon dioxide removal, but not at the expense of alveolar derecruitment and instability.
Lung protective ventilation consist of delivery of low tidal volumes (4-6 ml/kg PBW), high PEEP enough to avoid de-recruitment, titrated according to ARDSNet PEEP/fraction of inspired oxygen (FiO2) table, while avoiding excessive transpulmonary pressure.
Hospital Civil Fray Antonio Alcalde
Guadalajara, Jalisco, Mexico
RECRUITINGMechanical ventilation free days
Time frame: 28 days
All causes mortality
Time frame: 28 days
ICU length of stay
Time frame: 28 days
Hospital length of stay
Time frame: 60 days
Mean airway pressure, peak airway pressure, maximum P high
Measured in cmH20
Time frame: 7 days
Average expiratory time
Measured in seconds
Time frame: 7 days
Minute ventilation
Time frame: 7 days
oxygen partial pressure (pO2)
Time frame: 7 days
pCO2 (carbon dioxide partial pressure)
Time frame: 7 days
Mean arterial pressure
Time frame: 7 days
Maximum dosage of vasopressors requirement
Time frame: 7 days
Richmond Sedation-Agitation Scale
Range from -5 (unarousable) to +4 (combative)
Time frame: 7 days
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Average dose of propofol use
Time frame: 7 days
Rate of neuromuscular blocking agents utilization
Time frame: 7 days
Prone position rate
Time frame: 7 days
Average of prone position sessions
Time frame: 7 days
Rate of recruitment maneuvers
Time frame: 7 days
Tracheostomy rate
Time frame: 28 days