Spontaneous breathing during the transition from controlled to assisted ventilation in ARDS may be harmful, as high respiratory drive can generate large transpulmonary pressure swings and worsen lung injury. Higher PEEP may mitigate this by reducing inspiratory effort and lung stress, but patient response is variable and difficult to predict. While improved lung compliance appears to mediate the protective effects of PEEP, its bedside assessment is complex. Preclinical data suggest that changes in compliance are inversely reflected by changes in respiratory rate, but this relationship and its clinical utility in ARDS patients remain unclear.
Need of invasive mechanical ventilation
Patients who had fulfill ARDS criteria based on Berlin definition during any time of invasive mechanical ventilation.
Patient ventilated in pressure support ventilation.
Time of invasive ventilation expected to be longer than 24 hs after the day of enrollment.
Neuromuscular diseases (e.g., amyotrophic lateral sclerosis, Duchenne Erb)
previous diagnosis of chronic obstructed pulmonary disease
not resolved pneumothorax
bronchopleural fistula
Patients with acute respiratory distress syndrome ventilated using an endotracheal tube admitted to Anchorena San Martin intensive care unit who are ventilated in pressure support ventilation.
Cohort
Prospective
Positive end expiratory pressure
Other interventionInitially, the patients will be ventilated using pressure support ventilation with an inspiratory pressure adjusted to achieve 6 - 8 ml/kg of PBW with a minimal esophageal pressure swing of 5 cmH2O and a PEEP of 5 cmH2O. After 5 minutes, we will collect basic and advanced respiratory monitoring, including esophageal pressure and transpulmonary pressure swings. The same procedure will be carried out with 10 and 15 cmH2O of PEEP. Inspiratory pressure will be kept constant throughout the protocol.
Lung compliance response
changes in lung compliance from one PEEP level to the subsequent higher level, expressed in percentage of change
Esophageal pressure swing
Esophageal pressure swing will be calculated as the difference between end expiration and end inspiration esophageal pressure during the las 30-60 seconds of each PEEP condition evaluated
Dynamic transpulmonary pressure swing
Dynamic transpulmonary pressure swing will be calculated as the difference between end expiration and end inspiration dynamic transpulmonary pressure during the las 30-60 seconds of each PEEP condition evaluated
Respiratory rate response
changes in respiratory rate from one PEEP level to the subsequent higher level, expressed in percentage of change
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