Brun N C, Greisen G
Department of Neonatology, Rigshospitalet, Copenhagen, Denmark.
Pediatr Res. 1994 Jul;36(1 Pt 1):20-4. doi: 10.1203/00006450-199407001-00004.
Near-infrared spectrophotometry can be used to measure cerebral concentrations of oxyhemoglobin and deoxyhemoglobin. This has been applied to developing methods for quantifying cerebral blood volume (CBV), which is relevant for the investigation of the pathogenesis of brain injury in newborn infants as well as older infants. This study investigates the internal consistency between measurements of CBV using two methods: the oxygen method, which is able to determine absolute values of CBV, and the total Hb method, which can detect changes in CBV only. Cerebral blood flow (CBF) was also measured. Fifteen premature infants were examined. Due to practical problems, in only eight of these was a minimum of two CBF and two CBV values obtained both before and after a change in arterial PCO2 of at least 0.5 kPa. A significant difference between the CBV-CO2 reactivity found by the two methods was demonstrated: 0.89 mL/100 g/kPa (95% confidence interval = 0.63-1.26) for the oxygen method and 0.22 mL/100 g/kPa (95% confidence interval = 0.08-0.36) for the total Hb method. This finding is substantiated by the absolute values of CBV [mean value = 3.7 mL/100 g (SD = 1.1)], CBF [mean value = 11.3 mL/100 g/min (SD = 5.9)], and CBF reactivity [59 +/- 9% (SEM)]. All the values correspond well with previous findings, although the CBV reactivity determined by the oxygen method has not been reported previously. The reason for the discrepancy between the two methods is unclear, but induced changes in the scattering properties of the brain would give rise to errors influencing the total Hb method rather than the oxygen method.
近红外分光光度法可用于测量脑内氧合血红蛋白和脱氧血红蛋白的浓度。这已被应用于开发定量脑血容量（CBV）的方法，这对于研究新生儿以及较大婴儿脑损伤的发病机制具有重要意义。本研究调查了使用两种方法测量CBV的内部一致性：氧方法，能够确定CBV的绝对值；总血红蛋白方法，只能检测CBV的变化。还测量了脑血流量（CBF）。对15名早产儿进行了检查。由于实际问题，其中只有8名婴儿在动脉PCO2至少改变0.5 kPa之前和之后获得了至少两个CBF和两个CBV值。结果表明，两种方法所发现的CBV-CO2反应性存在显著差异：氧方法为0.89 mL/100 g/kPa（95%置信区间=0.63-1.26），总血红蛋白方法为0.22 mL/100 g/kPa（95%置信区间=0.08-0.36）。CBV [平均值=3.7 mL/100 g（标准差=1.1）]、CBF [平均值=11.3 mL/100 g/分钟（标准差=5.9）]和CBF反应性[59±9%（标准误）]的绝对值证实了这一发现。所有这些值与先前的研究结果吻合良好，尽管此前尚未报道过用氧方法测定的CBV反应性。两种方法之间存在差异的原因尚不清楚，但脑散射特性的诱导变化会导致影响总血红蛋白方法而非氧方法的误差。
