Pelosi G, Emdin M, Carpeggiani C, Morales M A, Piacenti M, Dattolo P, Cerrai T, Macerata A, L'abbate A, Maggiore Q
C.N.R. Institute of Clinical Physiology, Pisa, Italy.
Clin Sci (Lond). 1999 Jan;96(1):23-31.
The purpose of this study was to evaluate the autonomic response to standard haemodialysis and the changes associated with the onset of intradialytic hypotension in 12 normotensive patients with uraemia. Power spectra of R-R interval and of blood pressure fluctuations were obtained during a standard dialysis session and estimated in the low-frequency (LF, 30-150 mHz) and high-frequency (HF, 150-400 mHz) range. The absolute power of the LF component of blood pressure variations and the LF/HF ratio of R-R interval were assumed as indexes of sympathetic activity. Standard haemodialysis induced hypotension in six patients (unstable) while a minor pressure decline was present in the other six (stable). Normalized blood volume before dialysis and percentage volume reduction were similar in the two groups. Tachycardia in response to pressure and volume decrease was more pronounced in stable than in unstable patients, as evidenced by a higher slope of the relation between R-R interval and systolic blood pressure (7.9 versus 0.9 ms/mmHg, P<0.01). Sympathetic tone was enhanced during early dialysis in all patients (+2+/-1 for R-R LF/HF ratio, +2.4+/-0.6 mmHg2 and +7.2+/-2 mmHg2 for absolute LF power of diastolic and of systolic blood pressure respectively, P<0.05), compared with baseline predialysis values. During late dialysis, unstable patients showed an impairment of sympathetic activation which preceded hypotension and was maximal during the crisis (-2.9+/-1.4 for R-R LF/HF ratio, -2.7+/-1.4 mmHg2 and -8.6+/-4.0 mmHg2 for absolute LF power of diastolic and of systolic blood pressure respectively, P<0.05). On the contrary, stable patients showed constantly elevated indexes (+3.7+/-1.4 for R-R LF/HF ratio, +5.9+/-2.7 mmHg2 and +13.3+/-6.2 mmHg2 for LF of diastolic and of systolic blood pressure, P<0.05). Values returned to predialysis levels after the end of the dialysis session in all patients. We conclude that standard haemodialysis activates a marked and reversible sympathetic response in both stable and unstable uraemic patients. However, in unstable patients, such activation is impaired in late dialysis, therefore contributing to the onset of the hypotensive crisis.
本研究旨在评估12例血压正常的尿毒症患者对标准血液透析的自主神经反应以及与透析中低血压发作相关的变化。在标准透析过程中获取R-R间期和血压波动的功率谱，并在低频（LF，30 - 150 mHz）和高频（HF，150 - 400 mHz）范围内进行估计。将血压变化的LF成分的绝对功率和R-R间期的LF/HF比值作为交感神经活动的指标。标准血液透析使6例患者（不稳定组）出现低血压，而另外6例（稳定组）血压仅有轻微下降。两组患者透析前的归一化血容量和血容量减少百分比相似。稳定组患者对压力和容量降低的心动过速反应比不稳定组更明显，R-R间期与收缩压之间关系的斜率更高（分别为7.9对0.9 ms/mmHg，P<0.01）。与透析前基线值相比，所有患者在透析早期交感神经张力均增强（R-R LF/HF比值增加2±1，舒张压和收缩压的绝对LF功率分别增加2.4±0.6 mmHg²和7.2±2 mmHg²，P<0.05）。在透析后期，不稳定组患者在低血压发作前交感神经激活受损，在低血压发作时最为明显（R-R LF/HF比值为 - 2.9±1.4，舒张压和收缩压的绝对LF功率分别为 - 2.7±1.4 mmHg²和 - 8.6±4.0 mmHg²，P<0.05）。相反，稳定组患者的指标持续升高（R-R LF/HF比值为3.7±1.4，舒张压和收缩压的LF分别为5.9±2.7 mmHg²和13.3±6. mmHg²，P<0.05）。所有患者在透析结束后数值均恢复到透析前水平。我们得出结论，标准血液透析在稳定和不稳定的尿毒症患者中均激活明显且可逆的交感神经反应。然而，在不稳定患者中，这种激活在透析后期受损，从而导致低血压发作。
