To assure eligibility of the electrical impedance plethysmography as a useful, nontraumatic monitor of intrathoracic ventilatory and circulatory events, a series of experimental studies were carried out since 1967.
In this first part of the report, intrapulmonary flux of the electrical current (52kHz, 1.8mA) which was applied directly on the thoracic surface through 2-P or 4-P electrode arrangement, and correlative changes of the relatively non-variable component of the thoracic impedance (Z₀ component) and of the pulsatile impedance variation (pulsatile dz component) superimposed on the Z₀ component to intrathoracic respiratory and circulatory events were analysed during various manipulations of pulmonary blood flow and intrapulmonary gas within the FRC level.
From these experiments, following results were obtained. The current penetrates through the thoracic wall and distributes preferentially within the lung. Volume of the intravascular and extravascular water within the lung and of the air under FRC level affect Z₀ component of the thoracic impedance. The physiological event as the cause of dz component is pulsatile blood volume change within the pulmonary vasculature, not the mechanical movement during these vascular motion as proposed by D. W. Hill.
From these results, it was suggested that the method is capable to detect congestion and edema of the lung in their early stages, uneven distribution of pulmonary perfusion and changes of pulmonary blood flow as though it is qualitative at present. Further investigation will clarify its value as a clinical monitor of these pysiological events.

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Red cell 2, 3-diphosphoglycerate (DPG) level was mesured in patients with respiratory insufficiency and factors affecting to the DPG level were studied.
Normal value of red cell DPG was 4.89±46μmoles/ml of cells.
The closest correlation was observed between arterial blood pH and red cell DPG level. The red cell DPG levels in the cases of arterial blood pH less than 7.35 were lowered and in the cases of more than 7.45 the level was elevated than normal.
The red cell DPG level was high in patients with severe anemia (hematocrit, lower than 34%).
In patients with normal arterial blood pH (7.35-7.45), PaO₂ and red cell DPG level was reversely correlated. The red cell DPG levels in the cases of PaO₂ below 50mmHg were higher than that of PaO₂ over 90mmHg in normal pH range.
The red cell DPG level was high in patients with liver disease.
Control factors of red cell DPG level were discussed.
A number of different factors may affect the concentration of DPG in arterial blood.
Metabolism of DPG in arterial blood may be important for evaluation of respiratory insufficiency.

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[in Japanese]

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[in Japanese]

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