Indications for combined high frequency ventilation in clinical use.

A retrospective study of 20 surgical intensive care unit patients is reported. They were ventilated with continuous positive pressure ventilation (CPPV) and then switched to combined high frequency ventilation (CHFV). To find why there were variable responses to CHFV, the data of 20 patients were retrospectively evaluated with respect to respiratory index (RI), compliance (C) and extravascular lung water (EVLW). The results suggest that the indication line for CHFV was a C value greater than 45 ml/cmH2O and an EVLW value greater than 15 ml/kg BW.