Center for Biomedical Engineering, Wenner-Gren Research Laboratory, University of Kentucky, Lexington, KY 40506-0070, USA.
Am J Physiol Regul Integr Comp Physiol. 2012 Mar 1;302(5):R541-50. doi: 10.1152/ajpregu.00174.2011. Epub 2011 Nov 2.
Cardiac and vascular dysfunctions resulting from autonomic neuropathy (AN) are complications of diabetes, often undiagnosed. Our objectives were to: 1) determine sympathetic and parasympathetic components of compromised blood pressure (BP) regulation in patients with peripheral neuropathy and 2) rank noninvasive indexes for their sensitivity in diagnosing AN. We continuously measured electrocardiogram, arterial BP, and respiration during supine rest and 70° head-up tilt in 12 able-bodied subjects, 7 diabetics without, 7 diabetics with possible, and 8 diabetics with definite, sensory, and/or motor neuropathy (D2). During the first 3 min of tilt, systolic BP (SBP) of D2 decreased [-10.9 ± 4.5 (SE) mmHg] but increased in able-bodied (+4.8 ± 5.4 mmHg). Compared with able-bodied, D2 had smaller low-frequency (0.04-0.15 Hz) spectral power of diastolic BP, lower baroreflex effectiveness index (BEI), and more SBP ramps. Except for low-frequency power of SBP, D2 had greater SBP and smaller RR interval harmonic and nonharmonic components at rest across the 0.003- to 0.45-Hz region. In addition, our results support previous findings of smaller HF RR interval power, smaller numbers of baroreflex sequences, and lower baroreflex sensitivity in D2. We conclude that diabetic peripheral neuropathy is accompanied by diminished parasympathetic and sympathetic control of heart rate and peripheral vasomotion and diminished baroreflex regulation. A novel finding of this study lies in the sensitivity of BEI to detect AN, presumably because of its combination of parameters that measure reductions in both sympathetic control of vasomotion and parasympathetic control of heart rate.
自主神经病变引起的心脏和血管功能障碍是糖尿病的并发症，通常未被诊断。我们的目的是：1）确定周围神经病变患者血压（BP）调节受损的交感和副交感成分，2）评估非侵入性指标对自主神经病变的诊断敏感性。我们连续测量了 12 名健康受试者、7 名无糖尿病、7 名可能有糖尿病和 8 名有明确的感觉和/或运动神经病变（D2）的糖尿病患者在仰卧休息和 70°头高位倾斜期间的心电图、动脉血压和呼吸。在倾斜的前 3 分钟，D2 的收缩压（SBP）下降[-10.9 ± 4.5（SE）mmHg]，而健康受试者则增加[+4.8 ± 5.4 mmHg]。与健康受试者相比，D2 的舒张压低频（0.04-0.15 Hz）谱功率较小，压力反射有效性指数（BEI）较低，SBP 斜率较大。除了 SBP 的低频功率外，D2 在 0.003-0.45 Hz 频率范围内，休息时的 SBP 和 RR 间隔谐波和非谐波成分都较大，而 RR 间隔较小。此外，我们的结果支持先前的研究结果，即 D2 中的 HF RR 间隔功率较小、压力反射序列较少以及压力反射敏感性较低。我们得出结论，糖尿病周围神经病变伴有心率和外周血管运动的副交感和交感控制减弱以及压力反射调节减弱。本研究的一个新发现是 BEI 对自主神经病变的检测具有敏感性，这可能是因为它结合了参数，这些参数可测量血管运动的交感控制和心率的副交感控制的降低。
