Colombo R, Marchi A, Borghi B, Fossali T, Tobaldini E, Guzzetti S, Raimondi F
Anesthesiology and Intensive Care Unit, Azienda Ospedaliera "L. Sacco", Milano, Italy.
Physiol Res. 2015;64(2):183-9. doi: 10.33549/physiolres.932798. Epub 2014 Oct 15.
Surgical Plethysmographic Index (SPI), calculated from pulse photo-plethysmographic amplitude oscillations, has been proposed as a tool to measure nociception anti-nociception balance during general anesthesia, but it is affected by several confounding factor that alter the autonomic nervous system (ANS) modulation. We hypothesized that SPI may be mainly affected by sympathetic stimulation independently from nociception. We studied the effects of two sympathetic stimuli on SPI, delivered through passive head-up tilt at 45 and 90 degrees angles, in nine awake healthy adults. The sympathetic modulation was assessed by means of heart rate variability (HRV) analysis. Mean (SD) SPI significantly increased from baseline to 45 degrees [from 38.6 (13.7) to 60.8 (7.6), p<0.001)] and to 90 degrees angle tilt [82.3 (5.4), p<0.001]. The electrocardiographic mean R-to-R interval significantly shortened during both passive tilts, whereas systolic arterial pressure did not change during the study protocol. HRV changed significantly during the study protocol towards a predominance of sympathetic modulation during passive tilt. Gravitational sympathetic stimulation at two increasing angles, in absence of any painful stimuli, affects SPI in awake healthy volunteers. SPI seems to reflect the sympathetic outflow directed to peripheral vessels.
手术体积描记指数（SPI）由脉搏光电容积描记幅度振荡计算得出，已被提议作为一种在全身麻醉期间测量伤害感受与抗伤害感受平衡的工具，但它受到多种改变自主神经系统（ANS）调节的混杂因素影响。我们假设SPI可能主要受交感神经刺激影响，与伤害感受无关。我们研究了两种交感神经刺激对SPI的影响，这两种刺激通过将头部被动抬高至45度和90度来施加，研究对象为9名清醒的健康成年人。通过心率变异性（HRV）分析评估交感神经调节。平均（标准差）SPI从基线到45度时显著增加[从38.6（13.7）增至60.8（7.6），p<0.001]，到90度倾斜时进一步增加[82.3（5.4），p<0.001]。在两次被动倾斜过程中，心电图平均R - R间期显著缩短，而在研究过程中收缩动脉压未发生变化。在研究过程中，HRV发生了显著变化，在被动倾斜期间交感神经调节占主导。在没有任何疼痛刺激的情况下，两个逐渐增加角度的重力交感神经刺激会影响清醒健康志愿者的SPI。SPI似乎反映了导向外周血管的交感神经输出。
