[Equilibration period for PaO2 following alteration of FIO2 in mechanically ventilated patients].
To determine arterial oxygen tension (PaO2) in mechanically ventilated patients, we repeatedly measured arterial blood gas (ABG) to examine changes in PaO2 until equilibration following alteration of fractional concentrations of oxygen in inspired gas (FIO2). Forty anesthetized patients with normal arterial oxygenation were randomly assigned to one of four groups. Group 1 (n = 10): Arterial blood samples were drawn every one minute during a 15-min period of equilibration after change of FIO2 from 1.0 to 0.21. Then FIO2 was returned to 1.0 and the similar sampling was repeated. Group 2 (n = 10): The protocol was same as in Group 1 except for FIO2 targeted for 0.8 and 0.4. Group 3 (n = 10): Blood sampling was every two minutes during a 14-min period and repeated while FIO2 was altered as in Group 1. Group 4 (n = 10): The protocol was same as in Group 3 except for the target FIO2 similar to Group 2. PaO2 was stabilized in 4 min at earliest and in 6 min at latest after change of FIO2 in every settings of this study. In mechanically ventilated patients with normal arterial oxygenation, PaO2 could be stabilized after a 6-min period of equilibration following alteration of FIO2.
Utada
K
K
Department of Anesthesia, Yamaguchi Prefectural Central Hospital, Houfu.
Matayoshi
Y
Y
Fujita
F
F
Nakamura
K
K
Matsuda
N
N
Kondoh
K
K
Tamura
H
H
D001784:Blood Gas Analysis; D001944:Breath Tests; D006801:Humans; D010100:Oxygen / Q000032:analysis / Q000097:blood*; D010313:Partial Pressure; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012121:Respiration, Artificial; D013997:Time Factors
D010100:Oxygen