Neurocritical Care Unit, University College Hospitals, WC1N 3BG, London, UK.
Medical Physics & Bioengineering, University College London, WC1E 6BT, London, UK.
Adv Exp Med Biol. 2013;789:21-27. doi: 10.1007/978-1-4614-7411-1_4.
Near-infrared spectroscopy (NIRS)-derived measurement of oxidized cytochrome c oxidase concentration ([oxCCO]) has been used as an assessment of the adequacy of cerebral oxygen delivery. We report a case in which a reduction in conscious level was associated with a reduction in [oxCCO]. Hypoxaemia was induced in a 31-year-old, healthy male subject as part of an ongoing clinical study. Midway through the hypoxaemic challenge, the subject experienced an unexpected vasovagal event with bradycardia, hypotension and reduced cerebral blood flow (middle cerebral artery blood flow velocity decrease from 70 to 30 cm s(-1)) that induced a brief reduction in conscious level. An associated decrease in [oxCCO] was observed at 35 mm (-1.6 μM) but only minimal change (-0.1 μM) at 20-mm source-detector separation. A change in optical scattering was observed, but path length remained unchanged. This unexpected physiological event provides an unusual example of a severe reduction in cerebral oxygen delivery and is the first report correlating change in clinical status with changes in [oxCCO].
近红外光谱（NIRS）衍生的氧化细胞色素 c 氧化酶浓度（[oxCCO]）测量已被用作评估脑氧输送充足性的指标。我们报告了一个病例，该病例中意识水平降低与[oxCCO]降低有关。在一项正在进行的临床研究中，将一名 31 岁健康男性的低氧血症作为一部分进行诱导。在低氧血症挑战进行到一半时，该患者经历了一次意外的血管迷走神经性事件，伴有心动过缓、低血压和脑血流减少（大脑中动脉血流速度从 70cm/s 降至 30cm/s），导致意识水平短暂降低。观察到[oxCCO]下降了 35mm（-1.6μM），但在 20mm 源-探测器分离时仅发生了微小变化（-0.1μM）。观察到光散射的变化，但光程没有变化。这种意外的生理事件提供了一个严重脑氧输送减少的不寻常例子，并且是首次将临床状态变化与[oxCCO]变化相关联的报告。
