Gaseous homeostasis during low-flow anaesthesia.
The object of this clinical study was to investigate the circle system gas homeostasis during low-flow anaesthesia using a technique designed to keep a constant inspired oxygen fraction of 0.30. Denitrogenation was adequately accomplished with mask preoxygenation, 10 l/min, for 1 min and an initial fresh gas flow of 5 l/min for 6 min after intubation. There was no need to wash out accumulated nitrogen at intervals, since the already low nitrogen concentration in the system tended to decrease after 1 h. The fresh gas flow of nitrous oxide to oxygen ratio and the inspiratory to end-expiratory oxygen concentration difference both reflected the uptake of nitrous oxide. The calculated rates of uptake of nitrous oxide, a subject of controversy, were in accordance with those found by Severinghaus and Barton & Nunn.
Bengtson
J P
JP
Department of Anaesthesia and Intensive Care, Sahlgren's Hospital, University of Göteborg, Sweden.
Sonander
H
H
Stenqvist
O
O
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000769:Anesthesia, Inhalation; D005260:Female; D006706:Homeostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009609:Nitrous Oxide; D010100:Oxygen
D009609:Nitrous Oxide; D010100:Oxygen