Comparison of Effectiveness between Gas Flow 1 And 2 L.Min-1 for General Anesthesia in Infants and Children
Suwannee Suraseranivongse MD*, Sumitra Chowvanayotin MD*, Sangsom Pirayavaraporn MD*, Songyos Valairucha MD*, Naiyana Arunpruksakul MD*, Somsak Areewatana MD*
Affiliation : * Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University
Objectives : To determine 1) Success rate of using fresh gas flow (FGF) 1 l.min-1 compared to 2 l.min-1 in
pediatric patients 2) Necessity of using anesthetic agent analyzer 3) predicting volatile anesthetic concen-
tration 4) cost difference
Method : Seventy-seven patients (age 10 days to 8 years) who underwent general anesthesia were randomly
allocated into 2 groups: the control group (FGF 2 l.min-1) and the study group (FGF 1 l.min-1). Outcome
measures included system leakage, SaO2, PECO2, FiO2, Fi and FeN2O, isoflurane dial setting, Fi and Fe
isoflurane, isoflurane mass consumed and sodalime used.
Results : There was no difference between the groups regarding demographic data, duration of surgery and
anesthesia. Success rate in using FGF 2 l.min-1 was 100% and FGF 1 l.min-1 was 92%. All failure cases (8%)
were due to system leakage. The necessity of using a capnometer was similar at 5.3-7.7% in both groups. FiO2
was > 0.3 at any time. FiN2O and FeN2O were not different. Fi isoflurane was 13-15% lower than dial setting.
Overall savings from using FGF 1 l/min was 37.8%.
Conclusion : FGF 1 l.min-1 could be safely used in most pediatric patients with lower cost. Capnometer was
recommended, whereas FiO2 and Fi isoflurane could be clinically adjusted.
Keywords : Low flow anesthesia, Infant, Children
