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METHOD FOR DETERMINATION OF PULMONARY GAS EXCHANGE IN CONNECTION WITH BIRTH
Author(s) -
TUNELL RAGNAR
Publication year - 1975
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1975.tb04379.x
Subject(s) - carbon dioxide , nitrous oxide , medicine , oxygen , exhaled air , fraction of inspired oxygen , reproducibility , calibration , anesthesia , degree (music) , mixing (physics) , expired air , zoology , room air distribution , fraction (chemistry) , chromatography , chemistry , mechanical ventilation , toxicology , thermodynamics , organic chemistry , statistics , physics , mathematics , quantum mechanics , acoustics , biology
Abstract. Tunell, R. (Department of Paediatrics, Karolinska Sjukhuset, Stockholm, Sweden). Method for determination of pulmonary gas exchange in connection to birth. Acta Paediatr Scand, 64:49, 1975.–An apparatus built on the “open” system for determination of pulmonary gas exchange in the newborn infant after birth is described. At four‐minute intervals diluted expired air (5–7 1/min) was collected in bags. The oxygen and carbon dioxide fraction in the bags were analysed with a Nyons Diaferometer (working on the principle of thermoconductivity). In calibration experiments using a gas‐mixing technique a high degree of linearity was found, both in the determination of the fraction of oxygen and carbon dioxide (r=0.9996). Reproducibility from duplicate readings was also good (for oxygen determination 0.9% and for carbon dioxide determination 0.8%). Duplicate determinations performed on infants with the same degree of motor activity resulted in an estimated error of the method of 5.8 % for V 02 and 7.8 % for V co2 respectively. A metabolic chamber was used to control environmental temperature. The air temperature and wall temperature in the chamber were regulated by water from a thermostatically controlled waterbath and were kept equal within 0.5 o C. As the method for determination of the fraction of oxygen and carbon dioxide is not specific, other gaseous materials exhaled by the infants influence the measurements and nitrous oxide was found to interfere with the determinations, and made V o2 and V Co2 determinations in these patients impossible. Experience from more than 50 investigations on newborn infants has shown that the method is well suited to this particular type of study.