[A new indicator to determine the optimal PEEP (author's transl)].

To elucidate the optimal PEEP for respiratory treatment, respiratory and haemodynamic studies were performed on 12 normovolemic patients with ARDS for various levels of PEEP (PEEP = 0, 5, 10, 20 cm H2O). In this study, it became clear, that Suter's best PEEP (maximal O2 transport should be taken as a reference for optimal PEEP) cannot be used in practice because O2 transport is usually maximal in ZEEP (PEEP=0) and changes with the alteration of FIO2. We propose "intrapulmonary nonshunt flow ((Qt-Qs)" as a new indicator to determine the optimal PEEP. The level of PEEP to achieve the maximal intrapulmonary non-shunt flow must be such that the decrease in intrapulmonary shunt flow is attained with minimal decrease of cardiac output.