Pression expiratoire positive et pression expiratoire positive intrinsèque dans les modes ventilatoires assistés

Auto-positive end-expiratory pressure (auto-PEEP) is defined as pressure in the alveoli at the end of exhalation that is greater than the atmospheric pressure. Auto-PEEP is a common problem in patients receiving full or partial ventilatory support, as well as in those ready to be weaned from the ventilator. Unexpected auto-PEEP occurs in up to 35% of patients during weaning and/or receiving assist ventilation even when there is no significant history of COPD. Physicians should be alert for auto-PEEP and take measures to reduce it because auto-PEP can have serious hemodynamic and respiratory consequences. The main consequences of dynamic hyperinflation during spontaneous and assisted ventilation are the patient's increased effort to breathe and patient ventilator asynchrony. In some patients with auto-PEEP due to airflow obstruction and dynamic hyperinflation, external PEEP (around 80% of the auto-PEEP value) may be used to decrease the work of breathing and relieve dyspnea. Auto-PEEP is more common than previously thought in critically ill mechanically ventilated patients. The clinician needs to fully understand the physiology of auto-PEEP to choose appropriate ventilator settings.