Division of Neonatology, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria.
Research Unit for Neonatal Micro- and Macrocirculation, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria.
Neonatology. 2022;119(1):10-17. doi: 10.1159/000519636. Epub 2021 Oct 28.
Carbon dioxide (pCO2) induces changes in the tone of cerebral vessels. The aim of the present study was to evaluate the impact of pCO2 on cerebral regional tissue oxygen saturation (crSO2), cerebral fractional tissue oxygen extraction (cFTOE), and cerebral tissue oxygen extraction (cTOE), measured with near-infrared spectroscopy (NIRS), in preterm and term infants 15 min after birth.
Post hoc analyses of secondary outcome parameters of prospective observational studies were performed. Stable preterm and term infants with cerebral NIRS monitoring (INVOS 5100C) until minute 15 after birth and a blood gas analysis, performed between minutes 14-18 after birth, were included. Heart rate (HR) and arterial oxygen saturation (SpO2) were recorded. pCO2 was correlated with crSO2, cFTOE, cTOE, SpO2, HR, and partial pressure of oxygen (pO2).
Eleven preterm infants with a median (IQR) gestational age of 34.8 (32.7-36.1) weeks were analyzed. Mean ± SD pCO2 was 53.5 ± 4.2 mm Hg. At minute 15 after birth, crSO2 was 82.6 (74.3-91.3)%, cFTOE 0.15 ± 0.09, cTOE 14.6 ± 8.4%, SpO2 97.4 ± 2.1%, and HR 152 (136-167) bpm. pCO2 correlated negatively with crSO2 (p = 0.012) and positively with cFTOE (p = 0.035) and cTOE (p = 0.037). Eighty-four term infants with a gestational age of 39.0 (38.5-38.9) weeks were analyzed. pCO2 was 53.5 ± 6.3 mm Hg. At minute 15 after birth, crSO2 was 84.4 (80.8-85.1)%, cFTOE 0.14 ± 0.08, cTOE 13.6 ± 7.9%, SpO2 96.5 ± 2.6%, and HR 155 (153-163) bpm. pCO2 did only negatively correlate with pO2 (p = 0.034) in term infants.
In preterm infants, higher pCO2 was associated with lower crSO2 and higher cFTOE/cTOE. In term infants, no associations were observed. The present findings suggest that the vasodilatative effect of pCO2 is less pronounced in preterm infants during immediate postnatal transition.
二氧化碳（pCO2）会引起脑血管张力变化。本研究旨在评估 pCO2 对早产儿和足月儿出生后 15 分钟时脑局部组织氧饱和度（crSO2）、脑分比组织氧摄取量（cFTOE）和脑组织氧摄取量（cTOE）的影响，采用近红外光谱（NIRS）进行测量。
对前瞻性观察研究的次要结局参数进行了事后分析。纳入了在出生后 15 分钟内进行脑 NIRS 监测（INVOS 5100C）并在出生后 14-18 分钟内进行血气分析的稳定早产儿和足月儿。记录心率（HR）和动脉血氧饱和度（SpO2）。pCO2 与 crSO2、cFTOE、cTOE、SpO2、HR 和氧分压（pO2）相关。
分析了 11 名中位（IQR）胎龄为 34.8（32.7-36.1）周的早产儿。平均±SD pCO2 为 53.5±4.2mmHg。出生后 15 分钟时，crSO2 为 82.6（74.3-91.3）%、cFTOE 为 0.15±0.09、cTOE 为 14.6±8.4%、SpO2 为 97.4±2.1%、HR 为 152（136-167）bpm。pCO2 与 crSO2 呈负相关（p=0.012），与 cFTOE 和 cTOE 呈正相关（p=0.035、p=0.037）。分析了 84 名胎龄为 39.0（38.5-38.9）周的足月儿。pCO2 为 53.5±6.3mmHg。出生后 15 分钟时，crSO2 为 84.4（80.8-85.1）%、cFTOE 为 0.14±0.08、cTOE 为 13.6±7.9%、SpO2 为 96.5±2.6%、HR 为 155（153-163）bpm。足月儿中仅 pCO2 与 pO2 呈负相关（p=0.034）。
在早产儿中，较高的 pCO2 与较低的 crSO2 和较高的 cFTOE/cTOE 相关。在足月儿中，未观察到相关性。本研究结果表明，pCO2 的血管扩张作用在早产儿出生后的即刻过渡期中不那么明显。
