PEEP stands for Positive End-Expiratory Pressure, which is a value that can be set up in patients receiving invasive or non-invasive mechanical ventilation. PEEP is a mode of therapy used in conjunction with mechanical ventilation, which maintains the patients airway pressure above the atmospheric pressure at the end of mechanical or spontaneous exhalation. PEEP is used to keep the airways and alveoli open to allow for proper oxygen exchange.
PEEP is the positive pressure that will remain in the airways at the end of the respiratory cycle (end of exhalation) that is greater than the atmospheric pressure in mechanically ventilated patients. Applying PEEP increases alveolar pressure and alveolar volume, which increases the surface area by reopening and stabilizing collapsed or unstable alveoli. This splinting, or propping open, of the alveoli with positive pressure improves the ventilation-perfusion match, reducing the shunt effect. PEEP can also increase the compliance of the lung, which is the relationship between the change in volume and the change in pressure in the lung. With PEEP, less pressure is needed to get the same volume of air into the lung as the alveoli are already partially inflated and therefore do not need that high initial pressure to open them.
PEEP can cause some problems for those patients who have some airway obstruction, such as asthmatics and those with COPD. All healthcare professionals who look after ventilated patients should know the indications and potential adverse effects of PEEP. The ventilator settings should only be changed by one dedicated person, namely the respiratory therapist. Anytime a change is made, it should be charted. Nurses who look after ventilated patients should be aware that high PEEP can cause some problems.
