Physiological and clinical consequences of positive end-expiratory pressure

The aims of positive end-expiratory pressure (PEEP) are: 1) in acute lung failure, to increase lung volume and to improve oxygenation; 2) in acute exacerbation of chronic obstructive pulmonary disease (COPD), to unload inspiratory muscles. Excessive levels of PEEP may increase the risk of barotrauma. Application of low levels of PEEP may replace intrinsic PEEP in acute exacerbation of COPD, without increasing lung volume; however, the haemodynamic consequences of PEEP must be taken into account.