Objective: To examine blood concentrations of free carnitine (FC) in preterm infants with different gestational ages (GA) and birth weights (BW).
Methods: A total of 3 368 preterm infants were enrolled as subjects. According to GA, they were divided into extremely preterm birth (EPTB) group (GA <28 weeks; n=39), very preterm birth (VPTB) group (28 ≤GA <32 weeks; n=405), moderately preterm birth (MPTB) group (32 ≤GA <34 weeks; n=507), and late preterm birth (LPTB) group (34 ≤GA <37 weeks; n=2 417); according to BW, they were divided into extremely low birth weight (ELBW) group (BW <1 000 g; n=36), very low birth weight (VLBW) group (1 000 g ≤BW <1 500 g; n=387), low birth weight (LBW) group (1 500 g ≤BW <2 500 g; n=1 873), and normal birth weight (NBW) group (2 500 g ≤ BW <4 000 g; n=1 072). Blood concentrations of FC were measured between 72 hours and 7 days after birth.
Results: The EPTB and VPTB groups had significantly higher FC concentrations than the MPTB and LPTB groups (P<0.05), and the MPTB group had significantly higher FC concentrations than the LPTB group (P<0.05). The lower limit of the 95% medical reference range of FC increased with the reduction in GA. The ELBW and VLBW groups had significantly higher FC concentrations than the LBW and NBW groups (P<0.05). The LBW group had significantly higher FC concentrations than the NBW group (P<0.05). The lower limit of the 95% medical reference range of FC increased with the reduction in BW.
Conclusions: There is a significant increase in blood FC concentrations in very/extremely preterm infants and very/extremely low birth weight infants, and tend to decrease with the increases in GA and BW.
目的: 检测不同胎龄及出生体重早产儿血游离肉碱（FC）浓度，为制定早产儿FC补充治疗方案提供依据。
方法: 选取3 368例早产儿为研究对象。根据胎龄（GA）分为超早产（EPTB，GA < 28周）组（n=39）、极早产（VPTB，28≤GA < 32周）组（n=405）、中期早产（MPTB，32≤GA < 34周）组（n=507）、晚期早产（LPTB，34≤GA < 37周）组（n=2 417）；根据出生体重（BW）分为超低出生体重（ELBW，BW < 1 000 g）组（n=36）、极低出生体重（VLBW，1 000 g≤BW < 1 500 g）组（n=387）、低出生体重组（LBW，1 500 g≤BW < 2 500 g）组（n=1 873）、正常出生体重（NBW，2 500 g≤BW≤4 000 g）组（n=1 072）。于生后72 h~7 d内采血进行FC浓度测定并进行比较。
结果: EPTB、VPTB组FC浓度明显高于MPTB、LPTB组（P < 0.05），MPTB组FC浓度明显高于LPTB组（P < 0.05）；胎龄越小，FC的95%医学参考范围下限越高。ELBW、VLBW组FC浓度明显高于LBW、NBW组（P < 0.05），LBW组FC浓度明显高于NBW组（P < 0.05）；出生体重越低，FC的95%医学参考范围下限越高。
结论: 极/超早产儿、极/超低出生体重儿血FC浓度明显升高，并且随着胎龄及出生体重的增加呈明显下降的趋势。