低酸素症の臨床的ならびに実験的研究 : 臨床編
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概要
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A) Clinical Observation The common concept that definite respiratory stimulation occurs with anoxia, has arisen chiefly from a consideration of experiments in which animals are exposed to very low (0-5%) concentration of O_2. It is true that animals and human beings usually respond to such marked anoxia with a vigorous hyperpnea. On the other hand, when one measures the respiratory response to moderate degrees of anoxemia, one finds that marked hyperventilation is the exception rather than the rule. In due consideration of the roles of both central and peripheral chemoreceptors, the cardio-vascular and respiratory responses in 16 cases of cardiac patients and 10 cases of hypertensive diseases to the low % 02 inhalation were examined with the use of Fick-Cournand's and newly improved Wezler's methods, and following results were obtained: 1. The cardiovascular and respiratory states of the patients under observation: There are found five slight or moderate arterial anoxemic cases in nine decompensated cardiac patients. Arterial O_2 saturation in decompensated group shows, of course, lower value than those in compensated group on average, but arterial O_2 saturation does not necessarily indicate the clinical severity even in each group of the same disease, because the determination of arterial oxygen saturation does not aid the diagnosis of some types of hypo-, anoxia. Arterial O_2 saturation in hypertensive cases mostly fluctuates within normal range except for one patient suffering from hypertensive cardiac disease complicated with cardiogenic bronchospasm. The anoxemia and cardio-respiratory date are discussed in detail, with special reference to compensatory factors for chronic anoxemia. 2. During 10 % O_2 inhalation, there can be still found two reaction modes, i.e. immediate and retard responses in bed side as well as in animal experiments which were observed in acute extreme anoxic inhalation by Kuroda and Kosaka, our collaborators. But the characteristic responses are so variant and so vague that, without exact observation the identification of two sorts of reaction modes can hardly be observed. Among the clinical manifestations during acute and severe anoxic test, the symptoms of the neuro-cellular derangement are predominant which was already emphasized in aviation medicine by Prof. S. Saitoh repeatedly. The respiratory response to moderate degrees of anoxemia shows little significant increase (within 20% of total observation) in pulmonary ventilation until 10 % O_2 is breathed in health. But the higher significance of 10% O_2 inhalation can be appreciated in such condition as congestive, hyper tensive or coronary heart failure observed by me, although the arterial oxygen saturation in such diseases is usually 80% or more. 3. During 10% O_2 inhalation there are analysed the circulatory dynamics which are detoriated in O_2 deficiency and improved by 100% inhalation. Practically it is very important that there is the existence of marked individual variation in response to anoxemia both in health and disease, but 100% O_2 inhalation shows generally more integrative response in cardiovascular and respiratory actions. 4. The action mode of morphine used in cardiac dyspnea is examined by our methods and we concluded that morphine proves entirely so called "clinical pharmacological" relief. The indication of 100% O_2 inhalation is not dyspnea or hyperpnea, but anoxia, for hyperpnea and dyspnea can appear without anoxia and anoxemia can occur without dyspnea and hyperpnea. So it may be safe to say that anoxemia can be defined a diminution of O_2 in blood indifferently from whether there is a reduction in tension, content or both tension and content of O_2. Only when the tension of O_2 in the arterial blood is reduced below normal, anoxemia increases pulmonary respiration. This in turn presupposes the integrity of the chemoreceptors of the carotid and aortic bodies.
- 千葉大学の論文
- 1957-03-28