Sung Shin Kim

Erythropoietin Attenuates Brain Injury, Subventricular Zone Expansion, and Sensorimotor Deficits in Hypoxic-Ischemic Neonatal Rats

The aim of this study was to investigate the effect of erythropoietin (EPO) on histological brain injury, subventricular zone (SVZ) expansion, and sensorimotor function deficits induced by hypoxia-ischemia (HI) in newborn rat pups. Seven-day-old male rat pups were divided into six groups: normoxia control, normoxia EPO, hypoxia control, hypoxia EPO, HI control, and HI EPO group. Sham surgery or HI was performed in all animals. HI was induced by ligation of the right common carotid artery followed by 90 min of hypoxia with 8% oxygen. Recombinant human EPO 3 U/g or saline was administered intraperitoneally, immediately, at 24- and 48-hr after insult. At two weeks after insult, animals were challenged with cylinder-rearing test for evaluating forelimb asymmetry to determine sensorimotor function. All animals were then sacrificed for volumetric analysis of the cerebral hemispheres and the SVZ. The saline-treated HI rats showed marked asymmetry by preferential use of the non-impaired, ipsilateral paw in the cylinder-rearing test. Volumetric analysis of brains revealed significantly decreased preserved ipsilateral hemispheric volume and increased ipsilateral SVZ volume compared with the sham-operated animals. Treatment of EPO significantly improved forelimb asymmetry and preserved ipsilateral hemispheric volume along with decreased expansion of ipsilateral SVZ following HI compared to the saline-treated HI rats. These results support the use of EPO as a candidate drug for treatment of neonatal hypoxic-ischemic brain damage.

Comparison of Clinical Efficacy of Newfactan® versus Surfacten® for the Treatment of Respiratory Distress Syndrome in the Newborn Infants

Newfactan® is a domestically developed, bovine lung-derived, semi-synthetic surfactant. The aim of this study was to compare the clinical efficacy of Newfactan® with that of Surfacten® in the treatment of respiratory distress syndrome (RDS). Newfactan® or Surfacten® was randomly allocated to 492 newborn infants who were diagnosed as RDS and required surfactant instillation in four participating hospitals. The comparisons were made individually in two subsets of infants by birth weight (<1,500 g group [n=253] and ≥1,500 g group [n=239]). Short-term responses to surfactant and acute complications, such as the total doses of surfactant instilled, response type, extubation rate, ventilator settings, changes in respiratory parameters, air leak, patent ductus arteriosus, pulmonary hemorrhage, and intraventricular hemorrhage, and mortality during the 96 hr after surfactant instillation were measured. Long-term outcome and complications, such as total duration of intubation, bronchopulmonary dysplasia and periventricular leukomalacia, and ultimate mortality were measured. There were no significant differences in demographic and perinatal variables, short-term responses to surfactant and acute complications, and long-term outcome and complications between Newfactan® and Surfacten® in both birth weight groups. We concluded that Newfactan® was comparable to Surfacten® in the clinical efficacy in the treatment of RDS in both birth weight groups.

Decreasing Incidence of Chronic Lung Disease Despite the Gradual Reduction of Postnatal Dexamethasone Use in Very Low Birth Weight Infants

Dexamethasone has been widely used in very low birth weight infants (VLBWI) weighing less than 1,500 g at birth for the prevention or treatment of chronic lung disease (CLD). Recently, however the use of dexamethasone is being reduced, as its association with abnormal neurodevelopmental outcome is known. On the other hand, there have been persistent concerns about the increased risk of CLD according to the reduction of postnatal dexamethasone use. Hence, we did a retrospective cohort study to delineate the change in the incidence of CLD according to the reduction of dexamethasone use in VLBWI. The medical records of 559 VLBWI admitted to neonatal intensive care unit at Samsung Medical Center between November 1994 and December 2002 were reviewed with a focus on the use of postnatal dexamethasone and the incidence of CLD. The use of postnatal dexamethasone has significantly decreased over the study period. Especially, the use of high-dose regimen has markedly decreased. The day when postnatal dexamethasone therapy was begun has also been significantly delayed. The incidence of CLD has significantly decreased over the same period. In conclusion, the incidence of CLD has not increased despite the decreased use of postnatal dexamethasone.

Postnatal weight gain in the first two weeks as a predicting factor of severe retinopathy of prematurity requiring treatment

Purpose This study aimed to investigate the relative weight gain at 2-week intervals up to 6 weeks after birth to predict retinopathy of prematurity (ROP) requiring treatment among very low birth weight infants. Methods A total of 211 preterm infants with birth weights <1,500 g and gestational age <32 weeks were retrospectively reviewed. The main outcome was the development of ROP requiring treatment. Body weight measurements were recorded daily. Relative weight gains (g/kg/day) were calculated at the second, fourth, and sixth week after birth. Results Of the 211 infants, 89 developed ROP, of which 41 spontaneously regressed and 48 with early treatment of ROP type I required laser treatment. The relative weight gain at 2, 4, and 6 weeks postnatal age was significantly lower in infants with ROP requiring treatment than in infants without ROP or those with spontaneous regression (P<0.001, P=0.005, and P=0.004, respectively). On logistic regression, poor relative weight gain in the first 2 weeks was found to be related to ROP requiring treatment (adjusted odds ratio, 0.809; 95% confidence interval, 0.695-0.941; P=0.006). Relative weight gain at 2 weeks postnatal age was significantly lower in infants with ROP requiring treatment compared to that in ROP requiring no treatment (P=0.012). Conclusion Poor postnatal weight gain in the first 2 weeks of life is an important and independent risk factor for ROP requiring treatment. Postnatal weight gain can predict the development of severe ROP requiring treatment.

Short-term outcomes comparison between preterm infants with and without acute hypoxic respiratory failure attributable to presumed pulmonary hypoplasia after prolonged preterm premature rupture of membranes before 25 gestational weeks

Abstract Objective: To determine the updated outcomes of preterm infants with acute hypoxic respiratory failure attributable to presumed pulmonary hypoplasia (PH) following maternal midtrimester prolonged preterm premature rupture of membranes (PPROM). Study design: Among preterm infants with birthweight <1500 g and 23–34 weeks gestational age in a single center, infants exposed to maternal prolonged (≥7 days) PPROM before 25 gestational weeks (PPPROM25, n = 76) were retrospectively reviewed. They were 1:1 matched with infants of matched control group (n = 76) who were unexposed to or exposed to maternal PPROM within 24 hours of delivery by year, gestational age, and weight at birth, sex, and antenatal steroid exposure. The PPPROM25 group was subdivided into infants with and without acute hypoxic respiratory failure attributable to PH (with PH, n = 20, without PH, n = 56, respectively). Clinical characteristics and major outcomes were compared. Risk factors for mortality and morbidity were analyzed using a multivariate logistic regression in the PPPROM25 group. Results: The PH incidence rates were 1.3 and 26.3% and in the matched control and PPPROM25 group, respectively (p < .05). The survival rates were 92.1 and 81.6% in the matched control and PPPROM25 group (p > .05); 87.5 in the PPPROM25 group without PH and 65.0% in group with PH, respectively (p < .05). While there were no significant differences between matched control and PPROM25 group, the PPROM25 with PH group had a significantly higher rate of periventricular leukomalacia (PVL) and composite morbidity, including mortality, bronchopulmonary dysplasia, high-grade intraventricular hemorrhage, and PVL than PPPROM25 without PH group. PH was a significant risk factor for mortality and composite morbidity in the PPPROM25 group. Conclusions: Despite the improved outcomes in the infants with maternal prolonged PPROM before 25 gestational weeks, presumed PH is still a significant risk factor for their mortality and morbidity.