Recent advances in chemistry in relation to medical practice / by W. McKim Marriot.

  • Williams McKim Marriott
Date:
1928
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Licence: In copyright

Credit: Recent advances in chemistry in relation to medical practice / by W. McKim Marriot. Source: Wellcome Collection.

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    complete obstruction of a bronchus occurs, oxygen in- halation cannot be expected to be effective. When the respiratory center is injured by disease, so that it fails to respond to a normal stimulus, the respira- tions may be slow and infrequent. In such instances, the oxygen tension in the pulmonary alveoli falls because of insufficient aeration, and anoxemia results. Stimu- lation of the respiratory center by inhalation of carbon dioxide and oxygen mixtures is the treatment indicated. In alkalosis the normal stimulus to the respiratory cen- ter is lacking, and therapy consists in the administration of acid or the inhalation of carbon dioxide. Exposure to cold, by bringing about capillary stasis and increased desaturation of hemoglobin, leads, at times, to cyanosis. At high altitudes, on account of the diminished at- mospheric pressure, the tension of oxygen falls cor- respondingly and may become so low that the tension in the pulmonary alveoli is considerably below the level necessary for oxygen saturation of the blood. In such instances all the symptoms of anoxemia, including cy- anosis, occur. The symptoms may be relieved by the in- halation of oxygen. In certain types of cardiac disease, especially those associated with mitral lesions, cyanosis may be observed. The cyanosis in these cases seems to be the result, chiefly, of decreased oxygenation of the blood passing through the pulmonary circulation, this in turn being due to the back pressure induced in the pulmonary system. In- halation of oxygen benefits the majority of these pa- tients. Cyanosis in uncomplicated aortic disease rarely occurs. In congenital heart disease there occurs usually a shunting, or short circuiting, of a portion of the blood between the right and left sides of the heart. A passage of blood from left to right does not lead to cyanosis,
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