A comparison of methods of obtaining alveolar air / Walter M. Boothby, M.D., and Francis W. Peabody, M.D. Boston.

  • Boothby, Walter M.
Date:
1914
Catalogue details

Licence: In copyright

Credit: A comparison of methods of obtaining alveolar air / Walter M. Boothby, M.D., and Francis W. Peabody, M.D. Boston. Source: Wellcome Collection.

    7/16 (page 5)
    duced into the month, and the end passed as far back as is possible without bothering the patient. At a point about 3 cm. from the mouth a small feather is attached to the tube to serve as an index of the phases of respiration. The other end of the lead tube is attached to one of the sampling-pipets used by Krogh, with an easy working tap at the top, but none at the bottom. The opening at the bottom of the tube must be wide so that the mercury falls rapidly and the sample is taken quickly. The subject breathes naturally and at a word given at the end of an inspiration gives a deep forcible expiration of at least 600 or 800 c.c. At almost the end of the expiration the tap on the sampling-tube is turned quickly and from 3 to 5 c.c. of air taken into the tube from the back of the mouth. Deep expirations are given at intervals until a large enough sample is obtained for analysis. The following examples illustrate the probable accuracy of the method: April 13; Miss B.: C02 in successive samples A. (1) 38.8 mm.; (2) 40.9 mm.; (3) 39.1 mm.; (4) 38.8 mm. B. (1) 40.8 mm.; (2) 42.0 mm.; (3) 43.1 mm.; Controls by Haldane method: Inspiration, C02 = 41.8 mm. Expiration, C02 = 41.9 mm. These figures present some interesting points for study. It is prob¬ able that the tension of carbon dioxid in the alveolar air of this patient was practically 42 mm. Series A was taken by one of us and Series B by the other. We have frequently seen a slightly lower average by one observer than by the other. We attribute this to the difficulty of exactly timing the opening of the tap, and do not consider that it represents an actual change in the alveolar air. The following experiments were done by the same method: April 14; F.: C02 in successive samples = (1) 40.4 mm. (2) 41.3 mm.; (3) 41.3 mm.; (4) 40.5 mm. Average = 40.8 mm. Controls by Haldane method: Inspiration, C02 = 39.1 mm. Expiration, C02 = 41.3 mm. Average =40.2 mm. April 15; B.: C02 in successive samples = (1) 38.2 mm.; (2) 40.0 mm.; (3) 39.2 mm.; (4) 38.2 mm. Average = 38.9 mm. Controls by Haldane method: Inspiration, C02 = 37.2 mm. Expiration, C02 = 41.5 mm. Average =39.3 mm. April 16; B.; C02 in successive samples = (1) 38.6 mm.; (2) 39.8 mm.; (3) 40.0 mm.; (4) 40.1 mm. Average = 39.6 mm. Controls by Haldane method: Inspiration, C02 = 38.9 mm. Expiration, CO2 = 41.0 mm. Average = 39.9 mm. April 16; F.: C02 in successive samples = (1) 41.3 mm.; (2) 42.6 mm.; (3) 42.6 mm.; (4) 42.8 mm. Average = 42.1 mm. Controls by Haldane method: Inspiration, C02 = 40.0 mm. Expiration, C02 = 42.9 mm. Average = 41.7 mm. May 27; W. (patient): C02 in successive samples = (1) 42.4 mm.; (2) 43.0 mm. Average = 42.7 mm. Controls by Haldane method: Inspiration, C02 = 43.0 mm. Expiration, C02 = 41.4 mm. Average = 42.2 mm. June 2; S. (patient): C02 in successive samples=(l) 33.6 mm.; (2) 36.6 mm.; (3) 35.5 mm.; (4) 36.6 mm. Average = 35.6 mm. Controls by Haldane method: Inspiration, C02 = 35.3 mm. Expiration, C02 = 34.9 mm. Average = 35.2 mm.