Describe the Positive End Expiratory Pressure (PEEP)?

A positive pressure may be applied at the end of the expiratory phase during mechanical ventilation, instead of allowing the pressure to drop down to zero or atmospheric pressure- this is called Positive End Expiratory Pressure or PEEP. By applying PEEP, closure of terminal airways during mechanical ventilation may be prevented. By maintaining a positive pressure at all times during the respiratory cycle, transcapillary leak of fluid into the lung may also be prevented. PEEP may thus be of benefit in acute cardiogenic pulmonary edema. When PEEP is applied to a spontaneous mode of ventilation (like pressure support), it is called Continuous Positive Airway Pressure or CPAP.