Objective Cerebral oximetry using near-infrared spectroscopy (NIRS) is a noninvasive optical technology widely used in neonatology. The present study aimed to define reference ranges for cerebral tissue oxygen saturation (crSO₂) with a new four-wavelength NIRS device, Masimo O3^® oximeter, during immediate transition after birth and compare values with those obtained previously with NIRO 200NX^®.

Study Design This was a prospective observational study using Masimo O3 device to measure crSO₂ and regional cerebral fractional tissue oxygen extraction (cFTOE) in healthy term newborns delivered by primary cesarean section, during the 15 minutes after cord clamping. The neonates who required any medical support were excluded. The NIRS sensor was placed on the right forehead. Peripheral oxygen saturation and heart rate were continuously measured by pulse oximetry. Previous studies which established centiles for crSO₂ with NIRO 200NX were used for comparison.

Results A total of 44 newborns were included. The median crSO₂ and cFTOE (interquartile range) at 2, 5, and 7 minutes was 54% (49–54), 71% (64–86), and 79% (73–84) and 0,25 (0,18–0,33), 0,19 (0,15–0,23), and 0,16 (0,12–0,21), respectively, with no further changes afterwards. The crSO₂ measurements were significantly higher with Masimo O3 compared with NIRO-200NX.

Conclusion The present observational study presented reference ranges for crSO₂ and cFTOE measured with Masimo O3 oximeter during the immediate neonatal transition. Values obtained with O3 were higher than those obtained with other oximeters. For this reason, crSO₂ is device-specific so there must be known reference values for each oximeter to define therapeutic interventions based on crSO₂ and assess cerebral oxygenation in clinical studies.

Key Points

目的 使用近红外光谱 (NIRS) 的脑血氧测定是一种广泛应用于新生儿学的无创光学技术。本研究旨在使用新型四波长 NIRS 设备 Masimo O3 ^®血氧计定义出生后立即过渡期间脑组织氧饱和度 (crSO _{2 ) 的参考范围，并将值与之前使用 NIRO 200NX} ^®获得的值进行比较。

研究设计 这是一项前瞻性观察性研究，使用 Masimo O3 装置测量初次剖宫产的健康足月新生儿在脐带夹闭后 15 分钟内的crSO _{2和局部脑组织氧提取分数 (cFTOE)。}需要任何医疗支持的新生儿被排除在外。NIRS 传感器放置在右额头上。通过脉搏血氧仪连续测量外周血氧饱和度和心率。之前的研究使用 NIRO 200NX 建立了 crSO ₂的百分位数来进行比较。

结果 共纳入44名新生儿。2、5 和 7 分钟的中位 crSO ₂和 cFTOE（四分位距）分别为 54% (49–54)、71% (64–86) 和 79% (73–84) 和 0,25 (0,分别为 18–0,33)、0,19 (0,15–0,23) 和 0,16 (0,12–0,21)，之后没有进一步的变化。与 NIRO-200NX 相比，Masimo O3 的crSO _{2测量值显着更高。}

结论 本观察性研究提出了在新生儿过渡期间使用 Masimo O3 血氧计测量的crSO _{2和 cFTOE 的参考范围。}使用 O3 获得的值高于使用其他血氧计获得的值。因此，crSO ₂是特定于设备的，因此每个血氧计必须有已知的参考值，以定义基于 crSO ₂的治疗干预措施并评估临床研究中的脑氧合。

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