| [ Summary ] |
In order to elucidate the mechanisms affecting changes in blood pressure during hemodialysis, it is necessary to monitor cardiac output as well as other hemodynamic variables in patients with renal failure. The NICOVIEW PA 1100 (NEC Medical Systems Ltd.) is a newly developed desktop-type display and filling device, which can continuously monitor cardiac and is output noninvasive, This uses the admittance plethysmography technique, which bears an inverse relation to that of impedance. We noninvasively monitored various neuronal and hemodynamic variables of the cardiovascular system during hemodialysis of five chronic renal failure patients. Their cardiac output was monitored continuously through the use of the NICOVIEW PA 1100. The heart rate and the index of sympathetic nerve activity, obtained from a power spectral analysis of heart-rate variability, increased during the first 200 minutes of hemodialysis by 19% and 89%, respectively, although blood pressure did not change. The stroke volume and cardiac output were decreased by 45% and 36%, respectively, the circulatory blood volume by 13%. These results suggest that blood pressure is maintained during hemodialysis by sympathetic nerve activation and reflex tachycardia in chronic hemodialysis patients, in spite of considerable reductions in circulatory blood volume, stroke volume and cardiac output. The NICOVIEW PA 1100 is a useful tool to monitor changes in hemodynamics during hemodialysis. |