Ho Seon Eun

Serological investigation of Ureaplasma urealyticum in Korean preterm infants

Purpose Ureaplasma colonization is related with perinatal complications in preterm infants. Little is known about the difference in virulence among various Ureaplasma urealyticum serovars. The aim of this study was to determine U. urealyticum serovars of preterm infants in order to assess whether any of the serovars were associated with bronchopulmonary dysplasia (BPD). Methods Three hundred forty-four preterm infants with a gestational age less than 34 weeks admitted to Gangnam Severance Hospital neonatal intensive care unit from July 2011 to December 2012 were included in this study. Tracheal and gastric aspirations were conducted on infants to confirm Ureaplasma colonization. Ureaplasma colonization was confirmed in 9% of infants, of these, serovars were determined by real-time polymerase chain reaction. Results A total of 31 infants (gestational age, 29.3±3.1 weeks; birth weight, 1,170±790 g) were U. urealyticum positive. The Ureaplasma positive group treated for more days with oxygen and ventilation than the negative group (P<0.05). Histologic chorioamnionitis and moderate to severe BPD were more frequent in the Ureaplasma positive group than in the negative group (P<0.05). U. urealyticum isolates were either found to be a mixture of multiple serovars (32%), serovar 9 alone or combined with other serovars (39%), serovar 11 (26%), 2 (13%), 8 (10%), 10 (13%), and 13 (25%). No individual serovars were significantly associated with moderate to severe BPD and chorioamnionitis. Conclusion This is the first study to describe the distribution of U. urealyticum serovars from Korean preterm infants. Ureaplasma-colonized infants showed higher incidence of BPD and chorioamnionitis.

Experience and pharmacokinetics of levetiracetam in Korean neonates with neonatal seizures

Purpose The aims of this study were to evaluate the safety and pharmacokinetics of levetiracetam (LEV) in neonates with seizures and to establish a population pharmacokinetics (PPK) model by using the software NONMEM. Methods A retrospective analysis of 18 neonatal patients with seizures, who were treated with LEV, including 151 serum samples, was performed. The mean loading dose was 20 mg/kg, followed by a mean maintenance dose of 29 mg/kg/day. Results Seventeen neonates (94%) had seizure cessation within 1 week and 16 (84%) remained seizure-free at 30 days under the LEV therapy. The mean serum concentration of LEV was 8.7 µg/mL. Eight samples (5%) were found above the therapeutic range. No serious adverse effects were detected. In the PPK analysis for Korean neonates, the half-life was 9.6 hours; clearance, 0.357 L/hr; and volume of distribution, 4.947 L, showing differences from those in adults. Conclusion LEV is a safe and effective option for the treatment of neonatal seizures with careful therapeutic drug monitoring.

Postdischarge growth assessment in very low birth weight infants

Purpose The goal of nutritional support for very-low-birth-weight (VLBW) infants from birth to term is to match the in utero growth rates; however, this is rarely achieved. Methods We evaluated postdischarge growth patterns and growth failure in 81 Korean VLBW infants through a retrospective study. Weight and height were measured and calculated based on age percentile distribution every 3 months until age 24 months. Growth failure was defined as weight and height below the 10th percentile at 24 months. For the subgroup analysis, small-for-gestational age (SGA) and extremely low birth weight (ELBW) infants were evaluated. The growth patterns based on the Korean, World Health Organization (WHO), or Centers for Disease Control and Prevention (CDC) standard were serially compared over time. Results At postconception age (PCA) 40 weeks, 47 (58%) and 45 infants (55%) showed growth failure in terms of weight and height, respectively. At PCA 24 months, 20 infants (24%) showed growth failure for weight and 14 (18%) for height. Growth failure rates were higher for the SGA infants than for the appropriate-weight-for-gestational age infants at PCA 24 months (P=0.045 for weight and P=0.038 for height). Growth failure rates were higher for the ELBW infants than for the non-ELBW infants at PCA 24 months (P<0.001 for weight and P=0.003 for height). Significant differences were found among the WHO, CDC, and Korean standards (P<0.001). Conclusion Advancements in neonatal care have improved the catch-up growth of VLBW infants, but this is insufficient. Careful observation and aggressive interventions, especially in SGA and ELBW infants, are needed.

Abnormal neurodevelopmental outcomes are very likely in cases of bilateral neonatal arterial ischaemic stroke

Neonatal arterial ischaemic stroke (AIS) is an important cause of severe neurological disability. This study aimed to analyse the clinical manifestations and outcomes of AIS patients.

Usefulness of serum cystatin C to determine the dose of vancomycin in neonate.

Purpose The vancomycin dosage regimen is regularly modified according to the patients glomerular filtration rate (GFR). In the present study, we aimed to assess the usefulness of serum cystatin C (Cys-C) concentration, compared with serum creatinine (SCr) concentration, for predicting vancomycin clearance (CLvcm) in neonates. Methods We retrospectively analyzed the laboratory data of 50 term neonates who were admitted to the neonatal intensive care unit and received intravenous vancomycin, and assessed the pharmacokinetic profiles. Creatinine clearance (CLcr) and GFR based on Cys-C (GFRcys-c) were estimated using the Schwartz and Larsson formulas, respectively. Results The mean CLvcm (±standard deviation) was 74.52±31.17 L/hr, the volume of distribution of vancomycin was 0.67±0.14 L, and vancomycin half-life was 9.16±17.42 hours. The SCr was 0.46±0.25 mg/dL and serum Cys-C was 1.43±0.34 mg/L. The peak and trough concentrations of vancomycin were 24.65±14.84 and 8.10±5.35 mcg/mL, respectively. The calculated GFR based on serum creatinine concentration (GFR-Cr) and GFRcys-c were 70.2±9.45 and 63.6±30.18 mL/min, respectively. The correlation constant for CLvcm and the reciprocal of Cys-C (0.479, P=0.001) was significantly higher than that for CLvcm and the reciprocal of SCr (0.286, P=0.044). GFRcys-c was strongly correlated with CLvcm (P=0.001), and the correlation constant was significantly higher than that for CLvcm and CLcr (0.496, P=0.001). Linear regression analysis showed that only GFRcys-c was independently and positively correlated with CLvcm (F=41.9, P<0.001). Conclusion The use of serum Cys-C as a marker of CLvcm could be beneficial for more reliable predictions of serum vancomycin concentrations, particularly in neonates.