[The effect of positive end-expiratory pressure (PEEP) on extravascular lung water in intensive care patients].

The use of positive end-expiratory pressure (PEEP) has been highly recommended because of its favourable effects on pulmonary gas exchange and circulation. It was the aim of this study to investigate the influence of PEEP on extravascular lung water (EVLW), which was estimated by the thermal-dye technique. In 12 intensive care patients PEEP was changed every 30 minutes from 0 to 5, 10, 15 and 0 cm H2O, thereby causing a non-significant increase in EVLW of 2, 10, 7 and 1%. Analysis of individual EVLW-dynamics revealed a more than 20% increase in 6 of 7 patients with normal EVLW (5.8 +/- 0.9 ml/kg), whereas this occurred in only one of the five patients with elevated EVLW (10.9 +/- 1.1 ml/kg). Intraindividual regression analysis between EVLW and PaO2/FiO2, AaDO2/FiO2, Qs/Qt, and CO revealed no correlation between these parameters. Therefore, shorttime application of PEEP did not affect EVLW. Patients with normal EVLW were more prone to show increased EVLW during PEEP than patients with elevated EVLW. PEEP-induced improvement of gas exchange and pulmonary shunt were not accompanied by changes in EVLW.