Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands.
Department of Geriatric Medicine, Radboud University Medical Center, Nijmegen, the Netherlands.
Geroscience. 2023 Aug;45(4):2643-2657. doi: 10.1007/s11357-023-00791-9. Epub 2023 Apr 12.
Orthostatic hypotension (OH) is highly prevalent in older adults and associated with dizziness, falls, lower physical and cognitive function, cardiovascular disease, and mortality. OH is currently diagnosed in a clinical setting with single-time point cuff measurements. Continuous blood pressure (BP) devices can measure OH dynamics but cannot be used for daily life monitoring. Near-infrared spectroscopy (NIRS) has potential diagnostic value in measuring cerebral oxygenation continuously over a longer time period, but this needs further validation. This study aimed to compare NIRS-measured (cerebral) oxygenation with continuous BP and transcranial Doppler-measured cerebral blood velocity (CBv) during postural changes. This cross-sectional study included 41 participants between 20 and 88 years old. BP, CBv, and cerebral (long channels) and superficial (short channels) oxygenated hemoglobin (OHb) were measured continuously during various postural changes. Pearson correlations between BP, CBv, and OHb were calculated over curves and specific characteristics (maximum drop amplitude and recovery). BP and OHb only showed good curve-based correlations (0.58-0.75) in the initial 30 s after standing up. Early (30-40 s) and 1-min BP recovery associated significantly with OHb, but no consistent associations were found for maximum drop amplitude and late (60-175 s) recovery values. Associations between CBv and OHb were poor, but stronger for long-channel than short-channel measurements. BP associated well with NIRS-measured OHb in the first 30 s after postural change. Stronger associations for CBv with long-channel OHb suggest that long-channel NIRS specifically reflects cerebral blood flow during postural transitions, necessary to better understand the consequences of OH such as intolerance symptoms.
体位性低血压（OH）在老年人中非常普遍，与头晕、跌倒、较低的身体和认知功能、心血管疾病和死亡率有关。OH 目前是在临床环境中通过单点袖口测量来诊断的。连续血压（BP）设备可以测量 OH 动态，但不能用于日常生活监测。近红外光谱（NIRS）在连续测量大脑氧合方面具有潜在的诊断价值，可以在较长时间内进行，但需要进一步验证。本研究旨在比较 NIRS 测量的（大脑）氧合与连续 BP 和经颅多普勒测量的脑血流速度（CBv）在体位变化期间的变化。这项横断面研究包括 41 名年龄在 20 岁至 88 岁之间的参与者。在各种体位变化期间连续测量 BP、CBv 和大脑（长通道）和浅层（短通道）氧合血红蛋白（OHb）。计算了 BP、CBv 和 OHb 之间在曲线和特定特征（最大下降幅度和恢复）上的 Pearson 相关性。BP 和 OHb 仅在站立后 30 秒内显示出良好的基于曲线的相关性（0.58-0.75）。早期（30-40 秒）和 1 分钟 BP 恢复与 OHb 显著相关，但最大下降幅度和晚期（60-175 秒）恢复值没有一致的相关性。CBv 和 OHb 之间的相关性较差，但长通道测量的相关性更强。BP 在体位变化后 30 秒内与 NIRS 测量的 OHb 相关性良好。CBv 与长通道 OHb 的相关性更强，表明长通道 NIRS 特异性反映了体位转换期间的脑血流，这对于更好地理解 OH 的后果（如不耐受症状）是必要的。
