Effects of Inversed Ratio Ventilation and Positive End-expiratory Pressure Ventilation on Cardiorespiratory Functions in Acute Repiratory Failure

The effects of inversed ratio ventilation (IRV) or those of positiv endexpiratory presure (PEEP) on hemodynamics, pulmonary oxygenation and oxygen delivery were examined in 12 patients each who needed prolonged mechanical ventilation because of acute repiratory failure. Patients were divided into two groups : IRV group and PEEP group. No significant shange in hemodynamics and oxygen delivery was observed during the study in either IRV or PEEP group. Inversed ratio ventilation and PEEP increased significantly in PaO2/FIO2, which was taken for 6 hours by IRV (I:E=2:1) and for 2 hours by PEEP (5cm H2O), repectivery. Further improvement of oxygenation was not observed in IRV even if inspiratory time was prolonged above 2:1. Inversed ratio ventilation showed a liner correlation between PaO2/FIO2 (y) and mean airway pressure (MAWP

Respiration

IRV

I : E ratio

PEEP

Circulation

oxygen delivery