Prediction of inspired oxygen concentration within a circle anaesthetic system. 1976

J A Raymond

Fresh gas flows of nitrous oxide, oxygen and halothane at 6, 3, 2 and 1 litre/min were introduced into a circle absorber system. Spontaneous respiration and IPPV were studied and a regression of inspired on delivered oxygen concentration % was calculated. The difference between delivered and inspired oxygen concentration % was increased by decreasing the fresh gas flow and by decreasiing the proportion of oxygen in that flow, especially during IPPV. Circuits designed to allow a maximum overflow of alveolar gas provided a greater inspired oxygen concentration. The patients' height and weight were related to the scatter of inspired values observed at 1 litre/min of fresh gas flow with IPPV.

UI MeSH Term Description Entries
D008297 Male Males
D009609 Nitrous Oxide Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream. Laughing Gas,Nitrogen Protoxide,Gas, Laughing,Oxide, Nitrous
D010100 Oxygen An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration. Dioxygen,Oxygen-16,Oxygen 16
D011175 Positive-Pressure Respiration A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange. Positive End-Expiratory Pressure,Positive-Pressure Ventilation,End-Expiratory Pressure, Positive,End-Expiratory Pressures, Positive,Positive End Expiratory Pressure,Positive End-Expiratory Pressures,Positive Pressure Respiration,Positive Pressure Ventilation,Positive-Pressure Respirations,Positive-Pressure Ventilations,Pressure, Positive End-Expiratory,Pressures, Positive End-Expiratory,Respiration, Positive-Pressure,Respirations, Positive-Pressure,Ventilation, Positive-Pressure,Ventilations, Positive-Pressure
D012119 Respiration The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration ( Breathing
D005260 Female Females
D006221 Halothane A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178) 1,1,1-Trifluoro-2-Chloro-2-Bromoethane,Fluothane,Ftorotan,Narcotan
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328 Adult A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available. Adults
D000769 Anesthesia, Inhalation Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract. Insufflation Anesthesia,Anesthesia, Insufflation,Inhalation Anesthesia
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