Measurement of air trapping, intrinsic positive end-expiratory pressure, and dynamic hyperinflation in mechanically ventilated patients.
Severe airflow obstruction is a common cause of acute respiratory failure. Dynamic hyperinflation affects tidal ventilation, increases airways resistance, and causes intrinsic positive end-expiratory pressure (auto-PEEP). Most patients with asthma and chronic obstructive pulmonary disease have dynamic hyperinflation and auto-PEEP during mechanical ventilation, which can cause hemodynamic compromise and barotrauma. Auto-PEEP can be identified in passively breathing patients by observation of real-time ventilator flow and pressure graphics. In spontaneously breathing patients, auto-PEEP is measured by simultaneous recordings of esophageal and flow waveforms. The ventilatory pattern should be directed toward minimizing dynamic hyperinflation and auto-PEEP by using small tidal volume and preserving expiratory time. With a spontaneously breathing patient, to reduce the work of breathing and improve patient-ventilator interaction, it is crucial to set an adequate inspiratory flow, inspiratory time, trigger sensitivity, and ventilator-applied PEEP. Ventilator graphics are invaluable for monitoring and treatment decisions at the bedside.
Blanch
Lluís
L
Critical Care Center, Hospital de Sadabell, Institut Universitari Fundaciò Parc Taulì, Corporaciò Parc Taulì, Universitad Autònoma de Barcelona, Sadabell, Spain. lblanch@cspt.es
Bernabé
Francesca
F
Lucangelo
Umberto
U
D000402:Airway Obstruction / Q000628:therapy*; D001249:Asthma / Q000503:physiopathology; D006801:Humans; D011175:Positive-Pressure Respiration / Q000009:adverse effects*; D018467:Positive-Pressure Respiration, Intrinsic / Q000503:physiopathology* / Q000628:therapy; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology; D012121:Respiration, Artificial / Q000379:methods; D012128:Respiratory Distress Syndrome / Q000628:therapy; D014939:Work of Breathing