혈장칼륨이온 농도와 심장박출량 및 혈액산도

Abstract

Cardiac output was determined in rabbit under various plasma potassium ion concentration by the intravenous infusion of potassium chloride solution. Cardiac output was calculated anaiyzing the saline dilution curve drawn on physiograph. theextraarterial conductivity. using Stewart-Hamilton formula. Under each level of plasma potassium ion concentration, arterial pH was measured and relation between them was analyzed. I. Normal cardiac output measured by saline conductivity method in rabbit (2.0-2.8 kg) was 76(±4. 3) ml/min. Stroke volume. heart rate. mean arterial blood pressure and total peripheral resistance were 0.20 (±O. 026)mI. 261(±6. 1) Imino 102 (±3.6) mm Hg and 1.34 (±0.158) mmHg/ml/min. respectively. 2. Increasing the plasma potassium ion concentra• tion from 2.9 to 3.8. 4.8 and 5.7 mEq/L. Cardiac output decreased from 76ml/min to 51(±4.9). 55 (±12.3) and 33 (±13.7) ml/min. respectively 3. Increasing the plasma potassium ion concentra• tioD, there was negligible changes in stroke volume , however heart rate decreased inversly to pota • ssium ion concentration. Therefore it appears that the decrease of cardiac output would be primarily due to the decrease of heart rate. Heart rate decreased from 261 to 245. 195 and 152 beats/min. respectively. 4. Bl ood pressure maintained fairly constant in hyperkalemia. however in severe hyperkalemia it tended to decrease. Total peripheral resistance increased proportionally to plasma potassium ion concentration from 1.34 mmHg/ml/min to 2.10. 1.97 and 2.60 mmHg/ml/min. respectively. Decreasing plasma potassium ion concentration from 2.9 to 2.3 mEq/L there was no detectable changes in hemodynamics. 5. The piasma hydrogen ion concentration in corre spand to increase of plasma potassium ion concentration was approximately proportional each other. Increasing potassium ion concentration from 2.9 to 5.7 mEq/L. hydrogen ion concentration increased from 38 to 79 nM/L.