Titrating Optimal PEEP at the Bedside

Abstract

Determining what is the optimal positive end-expiratory pressure (PEEP) to use in a given patent with acute respiratory distress syndrome (ARDS) has been a controversial topic for several decades now. This controversy, no doubt, exists for two main reasons. One is that there has never been a good ‘gold-standard’ by which to judge success. The other, and more important reason, is that in all likelihood, finding optimal PEEP is an impossible task. All levels of PEEP carry both benefits and detriments. High levels of PEEP have been shown to prevent end-expiratory collapse of lung units and open previously closed units, but come at the expense of potential hemodynamic compromise and overdistention of the lungs. Lower levels of PEEP can avoid these problems but may not be sufficient to recruit or maintain open lung. Added to these difficulties is the fact that the physiology of a patient’s lung with ARDS is constantly changing with fluid shifts, inflammatory responses, body position, and even the effect of the ventilator itself.