Conventional mechanical ventilation compared with classic and superimposed high frequency oscillation

摘要

The gas exchange efficacy of high frequency oscillation superimposed on conventional mechanical ventilation (CMV-HFO) was compared to high frequency oscillation (HFO) and conventional mechanical ventilation (CMV) in the experimental RDS of the rat. Experimental RDS was induced in 36 adult rats by repeated alveolar lavage with saline. Arterial blood gases, tidal volume and compliance were measured before and after 6o minutes of ventilation with pure oxygen. CMV was delivered using a time-cycled ventilator with following settings: Pinsp: 25 mbar, PEEP: 5 mbar, frequency 3o/min. The HFO-frequency was 2o Hz, TVoscill.: 3,75 ml.kg. With CMV-HFO the ventilator delivered a Pinsp: 15 mbar, no PEEP. The superimposed oscillations had a TVoscill. 3,75 ml/kg at 2o Hz. The following results were obtained:Tidal volume increased slightly and equally in the three groups.Our data do not suggest a beneficial effect of HFO or CMV-HFO in the early treatment of experimental RDS.