Analyze The Tolerance Of Fat Emulsion In Preterm Infants During The First Three Days Of Life

1.Background and Objection1.1 BackgroundNutrition and growth management of premature infants remains a major challenge for NICU(neonatal intensive care unit),both in developing and developed countries.Fat emulsion provides 25-40%of total non-protein calories of TPN(total parental nutrition)in premature infants.For preterm infants,routine monitoring of serum triglycerides and cholesterol concentration fluctuations found that preterm infants could tolerant the continuous intravenous infusion of 3g/kg/day of fat emulsion.But from the tolerance of fat emulsion was rarely studied form the perspective of metabolomics.It has been documented that early application of fat emulsion in preterm infants was safe and prevented the lack of essential fatty acids.Although the recommended starting dose of fat emulsion is I g/kg/day,and the rate of increase is 0.5-1.0 g/kg/day until 3.0 g/kg/day,the strength of recommendation evidence still needs to be further improved.Further studies are still needed to determine which type of fat milk(soybean oil,olive oil,etc.)is preferred,and what is the optimal dose of fat emulsion.In addition,the current preterm infants of different gestational ages of the initial recommended dose and the rate of increase are generalized,no refinement.But in fact,for the reason that the basal metabolic capacity and maturity of liver and kidney function of preterm infants are closely related to gestational age,so the metabolic capacity of fat emulsion of preterm may also be differentiated.1.2 ObjectionTo evaluate the tolerance of fat emulsion in premature infants of different gestational age during the first three days of life,by compare the differences of acylcarnitine concentrations in short,medium and long chain fat acids in preterm infants and the metabolic status of different doses of fat emulsion in premature infants of the same gestational age,so as to provide experimental basis for clinicians to better apply fat emulsion in the early postnatal period.2.MethodsAccording to the level of fat emulsion,98 low birth weight infants were divided into two groups:low fat milk group and high fat milk group.And then divided into three groups according to their gestational age(GA):extremely preterm(GA<28 weeks),very preterm(28 weeks ? GA<32 weeks),and moderate or late preterm(32 weeks ? GA<37 weeks),and each group was subdivided into two subgroups:low-fat milk group and high-fat milk group.Blood samples were collected from the cord blood and the first three days after birth.The contents of acylcarnitines were detected by tandem mass spectrometry.The organic acids in urine samples were detected by gas chromatography-mass spectrometry.The levels of acylcarnitine and organic acids in premature infants were analyzed and compared.3.Results3.1 The contents of acylcarnitine and organic acids in premature infants of high and low-dose fat emulsion groups were compared and analyzed.The results are that:? In the two groups,only octanoyl carnitine were statistically different(P<0.05).On the first day and the second day,some long-chain acylcamitines were statistically different(p<0.05).On the third day after birth,some medium and long chain acyl carnitines were statistically different(p<0.05).?There was no significant difference in the contents of organic acids between the two groups.?There was no significant difference in serum triglycerides between the two groups after birth.? There was no significant difference in the incidence of major complications between the two groups.3.2 The results of comparative analysis of acylcamitine contents in three preterm infants and their subgroups were analyzed.The umbilical cord blood of premature infants and the short and medium-chain acylcarnitine concentrations in the first three days of gestational age were not statistically different.However,the long-chain acylcarnitine concentrations in the super-premature and early preterm infants were lower(P<0.05),and the change of long-chain acylcarnitine concentration was positively correlated with gestational age.For extremely preterm,the concentrations of short,medium and long-chain acylcarnitines in low dose of fat emulsion group were significantly higher than those in the high dose of fat emulsion group(p<0.05).There was no significant difference in the short,medium and long-chain acylcarnitine concentrations between very preterm and moderate or late preterm.4.ConclusionsFrom the metabolomics point of view,high-dose fat emulsion may cause part of the long-chain acylcarnitine in preterm infants' body accumulation.The metabolic capacity of long-chain fatty acids in extremely preterm infants and early preterm infants was lower than that in moderately-late preterm infants.Early preterm infants and moderately-late preterm infants could tolerate the high-dose fat emulsion in their early life.But extremely preterm infants could not tolerate the high-dose fat emulsion in their early life in this study.