[Effects of continuous negative extrathoracic pressure ventilation (CNETPV) on gas exchange and hemodynamics in dogs with oleic-acid-induced pulmonary edema].

To investigate usefulness of continuous negative extrathoracic pressure ventilation (CNETPV) as a method of respiratory care for pulmonary edema, we compared effects of CNETPV on gas exchange and hemodynamics with those of CPPV in dogs with oleic-acid-induced pulmonary edema. End-expiratory negative extrathoracic pressure was adjusted to obtain the same increase in functional residual capacity as that obtained with PEEP of 10 cmH2O. Transmural pressure was calculated by subtracting intrapleural pressure from intravascular pressure. Both CNETPV and CPPV improved gas exchange, and changes in PaO2 and venous admixture were similar with two ventilatory modes. During CNETPV, PvO2 and oxygen delivery were significantly greater than those in CPPV. CPPV did not alter transmural filling pressures but decreased cardiac output, whereas CNETPV increased transmural filling pressure and preserved cardiac output. These results indicate that CNETPV can offer comparable improvement in gas exchange with CPPV, when two ventilatory modes are matched for lung volume. In addition, these results suggest that CNETPV may be superior to CPPV because of less depression of cardiac output and greater oxygen delivery to organs.