Comparative evaluation of the haemodynamic effects of continuous negative external pressure (CNEP) and positive end-expiratory pressure (PEEP) in mechanically ventilated trauma patients.

Abstract

To compare the haemodynamic effects of identical values of continuous negative external pressure (CNEP) and positive end-expiratory pressure (PEEP) in a group of mechanically ventilated patients. General ICU, Vicenza Hospital, Italy. 15 consecutive patients, admitted after road accident trauma. We compared the haemodynamic effects of ZEEP, 10 cmH2O of PEEP, and 10 cmH2O CNEP, applied in random order, in 15 head trauma patients under going controlled mechanical ventilation; 9 had associated thoracic trauma, while 6 did not have lung involvement. CNEP was obtained with a "poncho". We observed a significant increase in CI during CNEP, compared with both ZEEP and PEEP 10 cmH2O. Accordingly the oxygen delivery index significantly increased during CNEP, compared with PEEP 10 cmH2O. Conversely, Qs/Qt decreased with CNEP, if compared with PEEP, both in patients with and without lung damage. CNEP can significantly increase CI in mechanically ventilated patients in patients with and without associated lung damage.