Clinical Usefulness of Fluctuating PEEP (F-PEEP)

F-PEEP is a newly developed PEEP in which end-expiratory pressure(EEP) is periodically changed within a certain range. We carried out a comparative clinical trial of F-PEEP and conventional PEEP (C-PEEP). In two cases of relatively localized lung injury of aspiration pneumonia, PaO2 was rapidly and more increased creased by FPEEP than by C-PEEP. However, in a case of diffuse lung injury of bacterial pneumonia, F-PEEP failed to achieve better pulmonary oxygenation. The periodical changes in EEP, which is the major difference of F-PEEP against C-PEEP, may prevent a sustained overinflation of some alveoli with high compliance, and an desirable shift of blood flow to poorly ventilated alveoli. Although the entire mechanism for this enhanced improvement remains to be clarified, we believe that F-PEEP is a simply applicable and useful therapeutic maneuver in the management of acute hypoxic respiratory failure with an uneven distribution of lung injury. These phenomenon have been supported in our some canine models of asymmetrical lung injury already reported.