Arterial Blood Carbon Dioxide Tension Research Articles

じん肺症の肺機能障害に関する研究

According to the regulation of the Pneumoconiosis Act (1960), roentgenological classification of the type of pneumoconiosis, Maximum Breathing Capacity, and Exercise Index were studied in 824 workers exposed to dust and 222 healthy adults. There were not so significant correlations between X-ray findings and pulmonary function disterbances. Most of PR1 and PR2 showed normal or slight disorder in functional tests. As to % MBC, PR1 and PR2 showed normal while PR3 was mostly under 90%. As to Exercise Index, PR2 was above 25%. Comparison of alveolar gas exchange during the step-up exercise tests were made among three groups (69 cases in total), i.e. silicosis (48 cases), tuberculosis (11 cases) and healthy adults (11 men). In these cases, exercise ventilation (ventilation during the third minute of exercise), oxygen uptake, oxygen removal, presence of oxygen debt at the fifth minute after exercise, rate of arterial blood oxygen saturation, carbondioxide tension of arterial blood, and intrapulmonary distribution of inspired gas were measured. 48 cases of silicosis were classified in four groups and the progress of the disease was discussed. First Group … Emphysematous changes advanced, alveolar hypoventilation and uneveness of intrapulmonary distribution of gas appeared. Exercise Index showed normal value while % MBC decreased. This group was often under estimated in the screening test practice as prescribed by the Pneumoconiosis Act. Second Group … Fibrotic changes advanced, disturbance of oxygen uptake was greater than ventilatory disturbance. Rate of oxygen saturation in arterial blood decreased. In this group, % MBC decreased and Exercise Index increased. Third Group … Insufficiency of gas exchanges were compensated by hyperventilaton. This group was divided in two subgroups, adequately compensated (sub-A) and inadequately compensated (sub-B). Both sub-groups showed normal level of oxygen saturation during exercise but oxygen debt exsisted in sub-A and not in sub-B. In sub-B group, Exercise Index showed relatively high value while % MBC was normal. This group was often overestimated in the practice of the screening tests. Fourth Group … Normal gas exchange level was maintained.

Electrical activity of the human respiratory muscles during the action of various humoral influences on the respiratory center

The electrical activity of human inspiratory and expiratory muscles was studied in hypoxia, hyperoxia, and hypercapnia during added resistance to respiration. The results obtained confirmed that in man the inspiratory and expiratory zones are reciprocally related. This condition was distinctly demonstrated during changes of the arterial blood oxygen and carbon dioxide tensions. In hypoxic hypoxia and hypercapnia electrical activity of the inspiratory muscles was enhanced, and that of the expiratory muscles reduced. The reverse effect was obtained during the inhalation of pure oxygen.

THE INITIATION OF RESPIRATION AFTER ANAESTHESIA ACCOMPANIED BY PASSIVE PULMONARY HYPERVENTILATION

SUMMARY Twelve patients anaesthetized with a mixture of nitrous oxide and oxygen were passively hyperventilated, muscular relaxation being provided by d-tubocurarine. Spontaneous res-piration commenced when the patients still had a marked respiratory alkalosis; in three patients active pulmonary hyperventilation occurred in the immediate postanaesthetic period. Five patients with a pre-existing respiratory acidosis also started to breathe with a blood carbon dioxide tension below the pre-operative level. It is concluded that, in conditions in which the respiratory centre is not depressed, stimuli arising in the periphery may initiate respiration despite a low arterial blood carbon dioxide tension. The clinical importance of this is discussed.

Some effects of apneic underwater diving on blood gases, lactate, and pressure in man.

Five men of outstanding diving ability performed apneic underwater dives in a specially fitted tank. The divers hyperventilated to extreme degrees of hypocapnia before submerging, and their arterial blood carbon dioxide tensions rarely rose above normal levels during a dive. Arterial blood oxygen content was 15.5 vol % or above at the end of two 3-min resting dives and of three 1.5-min exercise dives. Blood lactate concentrations increased during the latter half of exercise dives and reached peak values after surfacing. A rise in arterial blood pressure began by 10 sec in each dive and persisted, coincident with a falling heart rate, to the end of the dive. The rate of blood pressure rise was greater during a dive in water of 26 C than with breath holding by the same subject out of water. Some differences between the adaptations of diving men and of other diving mammals are briefly discussed. Submitted on April 2, 196

Simple method for the measurement of alveolar carbon dioxide.

Measurement of alveolar carbon dioxide tension is important in the diagnosis and care of patients with pulmonary disease, during anesthesia, in coma, and in other conditions with increased or depressed alveolar ventilation. A previous communication 1 described a simple, accurate, inexpensive apparatus for the bedside measurement of alveolar carbon dioxide tension. The present report deals with the clinical application of this method to eucapnic, hypercapnic, and hypocapnic subjects. The results are compared with simultaneous measurement of arterial blood carbon dioxide tension, and a method is outlined for use of the apparatus in patients in coma or unable to produce an adequate alveolar sample on a single breath. Materials and Methods Nineteen patients referred for pulmonary function studies and presenting a variety of cardiopulmonary diseases were studied. Simultaneous measurements were made of the carbon dioxide tension of their arterial blood and end-expired or rebreathing gas samples, or both. The principle of

Influence of alterations in arterial blood pH and carbon dioxide tension on plasma potassium levels in humans anesthetized with nitrous oxide, thiopental and succinyldicholine.

Plasma K+ levels were followed during states of normocapnea, hypercapnea, hypocapnea and the ‘blow-off’ period immediately following hypercapnea. Plasma potassium remained unaltered during normocapnea and hypercapnea. A statistically significant decrease in plasma potassium was noted in hypocapnea. A tendency for plasma potassium to rise during the posthypercapneic period was observed. No significant electrocardiographic changes were noted. Possible explanations of these findings are discussed. Submitted on February 6, 1957

Normal variations in end-tidal air and arterial blood carbon dioxide and oxygen tensions during moderate exercise.

Normal variations in end-tidal air and arterial blood carbon dioxide and oxygen tensions during moderate exercise.