Monitoring of Biochemical Parameters in Preterm Infants on Special Regime Feeding

Monitoring of Biochemical Parameters in Preterm Infants on Special Regime Feeding Enriched human milk may stimulate gain weight in preterm infants during the neonatal period. Aim is the biochemical assessment of preterm infants, fed by mother's milk fortificated with the special domestic formula preImpamil during the first month of life. 80 preterm infants (45 male and 35 female), up to 36 weeks of gestation, BW less than 2500 g, started enteral intake in the first three days of life. Total volume intake was in range from 70 mL/kg first day, to 170-200 mL/kg after a 10th day of life. Mother's milk fortification was prepared as a 5% mixture solution of preImpamil. The dynamics of biochemical analyses started on the first day of study and was repeated once a week. We analysed levels of: total protein, albumin, prealbumin, transferin, urea, Ca ionised, P and alkaline phosphatase using standard biochemical methods. Statistical analyses were completed by ANOVA test, one-factorial analyses of variance. During monitoring the total protein level increased in the second week of life (p<0.01), as well as albumin (p<0.01). Prealbumin level increased, as well as transferin (p-NS). Initial level of ionised fraction of Ca was significantly lower (p<0.01) at the beginning of the study, compared to the rest. Serum level of P increased, as well as the level of alkaline phosphatase at the end of first and second week (p<0.01). Conclusion is that biochemical parameters, such as levels of protein and albumin, are important in the growth assessment of preterm infants on special feeding regimes. Praćenje Biohemijskih Parametara Kod Prevremeno Rođene Dece Na Specijalnom Režimu Ishrane Obogaćeno humano mleko može da stimuliš e napredovanje u telesnoj masi prevremeno rođene dece za vreme neonatalnog perioda. U radu su praćeni i procenjivani biohemijski parametri iz seruma ovih beba hranjenih majčinim mlekom obogaćenim specijalnom domaćom formulom preImpamil, za vreme prvog meseca života. Kod 80 prevremeno rođenih beba (45 muškog i 35 ženskog pola) ispod 36 gestacionih nedelja, TM ispod 2500 g, počet je enteralni unos u prva tri dana života. Ukupni volumni unos je bio u rasponu od 70 mL/kg prvog dana, do 170-200 mL/kg posle 10. dana života. Majčino mleko pripremano je kao mešavina sa 5% preImpamila. Biohemijski parametri su određivani 1. dana studije i ponavljani jednom nedeljno. Određivani su: totalni proteini, albumini, prealbumin, transferin, ureja, jonizovani kalcijum, fosfor i alkalna fosfataza, korišćenjem standardnih biohemijskih metoda. Od statističkih metoda primenili smo ANOVA test jednofaktorske analize varijanse. U praćenom periodu do 4. nedelje, nivo proteina i albumina pokazuje najveći skok u 2. nedelji života (p<0,01). Nivoi prealbumina i transferina su viši (p-NS). Inicijalni nivo jonizovanog kalcijuma je signifikantno niži (p<0,01) u odnosu na kasniji period. Nivoi serumskog fosfora kao i alkalne fosfataze značajno su viši na kraju prve i druge nedelje (p<0,01). Dobijeni rezultati ukazuju na to da su praćeni biohemijski parametri, a naročito proteini i albumini, važni u procesu napredovanja prevremeno rođene dece na specijalnim režimima ishrane, što dokazuje i paralelno praćenje antropometrijskih parametara.


Introduction
In the newborns it is essential to assess the obtained intrauterine fetal growth according to gestational age. Comparing to full-term infants, nutrition of the premature infants is very complex, and it de-Summary: Enriched human milk may stimulate gain weight in preterm infants during the neonatal period. Aim is the biochemical assessment of preterm infants, fed by mother's milk fortificated with the special domestic formula pre Impamil during the first month of life. 80 preterm infants (45 male and 35 female), up to 36 weeks of gestation, BW less than 2500 g, started enteral intake in the first three days of life. Total volume intake was in range from 70 mL/kg first day, to 170-200 mL/kg after a 10 th day of life. Mother's milk fortification was prepared as a 5% mixture solution of pre Impamil. The dynamics of biochemical analyses started on the first day of study and was repeated once a week. We analysed levels of: total protein, albumin, prealbumin, transferin, urea, Ca ionised, P and alkaline phosphatase using standard biochemical methods. Statistical analyses were completed by ANOVA test, one-factorial analyses of variance. During monitoring the total protein level increased in the second week of life (p<0.01), as well as albumin (p<0.01). Prealbumin level increased, as well as transferin (p-NS). Initial level of ionised fraction of Ca was significantly lower (p<0.01) at the beginning of the study, compared to the rest. Serum level of P increased, as well as the level of alkaline phosphatase at the end of first and second week (p<0.01). Conclusion is that biochemical parameters, such as levels of protein and albumin, are important in the growth assessment of preterm infants on special feeding regimes. Keywords: feeding of preterm infants, fortificated mother's milk, biochemical parameters, anthropometric parameters.

Material and Methods
In the Institute of Neonatology a prospective study was conducted which included monitoring of the biochemical and anthropometric parameters in two groups of premature infants. One group of infants was fed with human milk, and the other with the specialized formula pre Impamil. In the study that lasted four months, we successively included infants (gestational age less than 36 weeks and body mass less than 2500 g) to whom it was possible to apply complete parenteral intake in the first 3 days of life.
In the study period of 4 weeks, we evaluated the tolerance of the formula and infant growth according to body length, as well as the head and thorax circumference.
At the same time, biochemical, hematological and blood gas analyses were followed-up in infants during the investigated period.
The study included 80 infants (45 male and 35 female), gestational age 32-36 weeks, having organized enteral feeding in the first 3 days of life. 48 infants were eutrophic and 32 were with intrauterine growth retardation. Apgar score and gestational age were the basic prognostic factors in making the decision about the right time for starting enteral feeding.
Control group consisted of 24 infants being fed only with mother's milk, and, depending on the maturation of the infants, they were fed by gastric tube or with bottles ( Table I).
We made a comparison of the human milk components from mothers having premature birth with the components of specialized formula pre Impamil, which we used to fortify mother's milk.
We also investigated the osmolality of each meal prepared from required amounts of pre Impamil added to mother's milk to obtain 5 -12% mixture, reaching in that way the recommended values for caloric and nutritive intake in infants. In this way, infants received high energetic and nutritive intake in smaller volume with permitted optimal osmolality 244-315 mOsmol/L. (Osmolality was measured by the cryoscopy method) ( Table II).
Feeding was organized as full volume intake in mL/kg/day, from 70 mL/kg/day at the beginning of the feeding, up to 150 mL/kg/day at the 5 th day of feeding, and 170-200 mL/kg/day at the 10 th day. At the beginning of the study (P 0 ) and once per week (P 1 -P 4 ) we performed: • Blood gas analyses from »arterialized« capillary blood on ABL 625 Blood Gas System-Radiometer.
• Hematological status through values of hemoglobin, hematocrit, erythrocite and platelet count on COBAS MICROS OT-ROCHE-ABX.
At the beginning and at the end of the study, for the evaluation of nutrition effects, we measured the values of prealbumine and transferine by the nephelometric »end-point« immunoprecipitation method (test »Orion-Diagnostica«).
For all analyses mentioned above, we used 300 mL of serum, and 150 mL of blood.
All data have been statistically analyzed using descriptive and parametrical testing and ANOVA testing one-factorial analyses of variance.

Results
Investigated infants improved in body mass 10-75 g/day, and during the whole study 600-800 g. Initial decrease in body weight in 7-9% of birth weight was physiological, and time for gaining weight at birth was statisticaly less significant in pre Impamil group (p<0.01) comparing to the control one ( Table  III).
The results of pH and BE during the investigated period show no statistically significant differences proving the stable acidobase status, which is a good point for the tolerance of pre Impamil. This study has not shown appearance of the postacidotic syndrome (Table IV).
During the growth, there was a statistically significant decrease in hemoglobin concentration (Hb), erythrocite (Er) and hematocrit (Hct), p<0.001, and a statistically significant increase in platelet count (PLT), p<0.001. These changes in hematological values are physiological for premature infants, so there is a recommendation for addition of Fe in formulas, with continuous follow-up of parameters for anemia assessment in the first six months of infant's life (3) ( Table V).
Biochemical parameters estimated once a week show no significant differences in glucose level, while the fraction of ionized calcium was significantly lower, so calcium was added parenteraly. Values of phosphorus and alkaline phosphatase were significantly higher (p<0.01) at the end of the first and second week (4) ( Table VI).
Level of protein fraction has been analyzed by measuring values of proteins, albumin, prealbumine, transferine and urea ( Table VII).
Values of total proteins and albumin fraction were statistically significantly higher (p<0.01) in the second study week, when the beginning of growth     (5). Concentrations of prealbumin and transferin increase with growth, but with no statistically significant differences. There was a decrease of urea value during the investigated four weeks within the reference ranges, showing good protein intake.

Discussion
Human milk fortified with the special domestic formula pre Impamil stimulates growth in premature infants during the neonatal period.
Time necessary for gaining birth weight is statistically significantly shorter in infants fed with pre Impamil.
Gaining in body weight (g/day) and length (cm) is statistically significantly increased in infants fed with pre Impamil.
Human milk fortified with pre Impamil is characterized with good peroral tolerance and absence of digestive disturbances, which is proved by the stable acidobase status.
Biochemical monitoring, especially of proteins and albumin, is of great importance in the process of evaluating the growth of premature infants on special feeding program, proved by paralel monitoring of anthropometric parameters.