COMPARISON OF VENTILATORY SUPPORT WITH INTRATRACHEAL PERFLUOROCARBON ADMINISTRATION AND CONVENTIONAL MECHANICAL VENTILATION IN ANIMALS WITHACUTE RESPIRATORY-FAILURE

We investigated the efficacy of intratracheal perfluorocarbon (PFC) ad ministration combined with mechanical ventilation to support gas excha nge in adult animals with acute respiratory failure. These were compar ed with a similar group of animals treated with continuous positive-pr essure ventilation (CPPV) with respect to respiratory parameters and p ostmortem lung histology. After lung lavage with saline, 18 adult rabb its were divided into three groups (n = 6 per group). All groups recei ved conventional CPPV Additionally, one group received intratracheal P FC administration at a volume of 18 ml/kg (corresponding to functional residual capacity) (PFC group); another received 18 ml/kg of saline a dministration (saline group), and the last had no further treatment (C PPV group). All groups were ventilated for 3 h using 100% oxygen, with the same ventilator settings of tidal volume of 12 ml/kg, respiratory frequency of 30/min, and positive end-expiratory pressure of 6 cm H2O . In the PFC group, Pa(O2) increased from 67.2 +/- 11.4 to 424.2 +/- 1 4 mm Hg and remained stable for 3 h with well-preserved Pa(CO2) values . Only in the PFC group were significant decreases in airway pressures and increase in respiratory system compliance seen. In the CPPV group , Pa(O2) stayed around 60 mm Hg and Pa(CO2) gradually increased. PFC t reatment with conventional mechanical ventilation in acute respiratory failure proved to be a successful supportive technique to improve gas exchange at low inflation pressures.