A Clinical Study on the Determination of Expected F1o2 / 대한마취과학회지

ABSTRACT

On the 25 open heart patients with mechanical ventilatory support, we compared the stabilities of oxygen derived variable for predicting Pao2 after F1o2 modification. With arterial blood gas values in F1o2 1.0, F1o2 was reset succeesively by using AaDO2, a/A Po2 and Pao2/F1o2 to obtain the desired Pao2(100 torr). A total of 100 data were used to compare the Qs/Qt and varying F1o2 with AaDO2, a/A Po2 and PaO2/FlO2 respectively. 1) PaO2 obtained by a/A PO2 or PaO2/F1O2 was much closer to the expected PaO2(100 torr) than that by AaDO2. 2) The calculated values of F1o2 were decreased successively in order of equations used by AaDO2, a/A Po2 and PaO2/F1O2. 3) a/A Po2 anfl Pao2/Flo2 were constant mathematically with varying Flo2. 4) Qs/Qt was higher in F1o2 1.0 than in Flo2 below 1.0. In varying F1o2, it was difficult to find statistical correlations between a/A Po2, Pao2/F1o2 and Qs/Qr, but AaDO2 was relative Qs/Qt due to the used equation. 5) We found high Statistical Correlations (R>0.99) among AaDO2, a/A Po2 and Pao2/F1o2 in Flo2 1.0 which were decreased after F1o2 changes. AaDO2 ranged from 213 torr to 452 torr in Flo2 1.0 and it was decreased Progressivelr in Flo2 below 0.8. The Flo2 modified by AaDO2 in Flo2 1.0 must be changed to the lower level to keep the Pao2 100 torr. a/A Po2 could not be discarded due to its stability in spite of its complexity to calculate. But Pao2/F1o2 was also stable and had the advantage of a/A Po2 in point of simplicity to calculate.