TY - JOUR
T1 - Air-oxygen mixtures in circle systems
AU - Hendrickx, Jan F.A.
AU - De Cooman, Sofie
AU - Vandeput, Dirk M.
AU - Van Alphen, Jan
AU - Coddens, José
AU - Deloof, Thierry
AU - De Wolf, Andre M.
PY - 2001
Y1 - 2001
N2 - Study Objective: To determine the effect of different air-O 2 mixtures and fresh gas flows (FGF) on the relationship between the delivered (F DelO 2) and inspired O 2 fraction (FIO 2) in a circle system. Study Design: Randomized clinical study. Setting: Large teaching hospital. Patients: 160 ASA physical status I, II, and III patients undergoing a variety of cardiovascular procedures with general endotracheal anesthesia. Interventions: 160 patients were randomly assigned to one of 20 groups (n = 8 each), depending on the combination of total FGF (0.5, 1, 2, 4, or 8 L/min) and air-O 2 mixture used (ratios of 4/1, 3/2, 2/3, or 1/4), corresponding to a F DelO 2 of 0.37, 0.53, 0.68, and 0.84. For each combination of FGF and air-O 2 mixture, FIO 2 after equilibration was compared with F DelO 2. Measurements and Main Results: With any air-O 2 mixture with a FGF ≤ 2 L/min, FIO 2 became lower than F DelO 2. Because FIO 2 decreased below 0.25 after 13 and 26 minutes in the first two patients of the 4/1 0.5 L/min air-O 2 group, this study limb was terminated. Conclusions: When using air-O 2 mixtures in a circle system, FIO 2 becomes lower than the F DelO 2 with FGF ≤ 2 L/min. The relative proportion of O 2 in the FGF has to be increased accordingly.
AB - Study Objective: To determine the effect of different air-O 2 mixtures and fresh gas flows (FGF) on the relationship between the delivered (F DelO 2) and inspired O 2 fraction (FIO 2) in a circle system. Study Design: Randomized clinical study. Setting: Large teaching hospital. Patients: 160 ASA physical status I, II, and III patients undergoing a variety of cardiovascular procedures with general endotracheal anesthesia. Interventions: 160 patients were randomly assigned to one of 20 groups (n = 8 each), depending on the combination of total FGF (0.5, 1, 2, 4, or 8 L/min) and air-O 2 mixture used (ratios of 4/1, 3/2, 2/3, or 1/4), corresponding to a F DelO 2 of 0.37, 0.53, 0.68, and 0.84. For each combination of FGF and air-O 2 mixture, FIO 2 after equilibration was compared with F DelO 2. Measurements and Main Results: With any air-O 2 mixture with a FGF ≤ 2 L/min, FIO 2 became lower than F DelO 2. Because FIO 2 decreased below 0.25 after 13 and 26 minutes in the first two patients of the 4/1 0.5 L/min air-O 2 group, this study limb was terminated. Conclusions: When using air-O 2 mixtures in a circle system, FIO 2 becomes lower than the F DelO 2 with FGF ≤ 2 L/min. The relative proportion of O 2 in the FGF has to be increased accordingly.
KW - Air, oxygen
KW - Anesthesia techniques
KW - Circle system
KW - Low-flow anesthesia
KW - Patient safety
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U2 - 10.1016/S0952-8180(01)00303-8
DO - 10.1016/S0952-8180(01)00303-8
M3 - Article
C2 - 11578893
AN - SCOPUS:0034803901
SN - 0952-8180
VL - 13
SP - 461
EP - 464
JO - Journal of Clinical Anesthesia
JF - Journal of Clinical Anesthesia
IS - 6
ER -