Extremely low birth weight infants remain at increased risk of intraventricular hemorrhage from the fragile vascular bed of the germinal matrix; the roles of hypotension (ischemia) and reperfusion (hyperemia) in the development of intraventricular hemorrhage are still debated. Cerebrovascular pressure autoregulation protects the brain by maintaining constant cerebral blood flow despite changes in blood pressure. The ontogeny of cerebrovascular pressure autoregulation has not been well established and uncertainty remains about the optimal arterial blood pressure required to support brain perfusion. Another important aspect of premature cerebral hemodynamics is the critical closing pressure--the arterial blood pressure at which cerebral blood flow ceases. Interestingly, in premature infants, the critical closing pressure approximates the mean arterial blood pressure. Often in this unique population, cerebral blood flow occurs only during systole when the diastolic arterial blood pressure is equal to the critical closing pressure. Moreover, the diastolic closing margin, a metric of cerebral perfusion that normalizes diastolic arterial blood pressure to the critical closing pressure, may be a better measure than arterial blood pressure for defining cerebral perfusion in premature infants. Elevated diastolic closing margin has been associated with intraventricular hemorrhage. This review summarizes the current state of understanding of cerebral hemodynamics in premature infants.

We need to understand the outcomes into adulthood for survivors born either extremely low birthweight (ELBW; <1,000 g) or extremely preterm (EP; <28 weeks' gestational age), particularly their blood pressure and cardiovascular metabolic status,respiratory function, growth, psychological and mental health performance, and functional outcomes. Blood pressure is higher in late adolescence and early adulthood in ELBW/EP survivors compared with controls. In some studies, expreterm survivors have higher insulin and blood lipid concentrations than controls, which may also increase their risk for later cardiovascular disease. ELBW/EP survivors have more expiratory airflow obstruction than do controls. Those who had bronchopulmonary dysplasia (BPD) in the newborn period have even worse lung function than those who did not have BPD. As a group, they are unlikely to achieve their full lung growth potential, which means that more of them are likely to develop chronic obstructive airway disease in later life. Although they are smaller than term born controls, their weight gradually rises and ultimately reaches a mean z-score close to zero in late adolescence, and they ultimately attain a height z-score close to their mid-parental height z-score. On average, ex-preterm survivors have intelligence quotient (IQ) scores and performance on tests of academic achievement approximately 2/3 SD lower than do controls, and they also perform less well on tests of attention and executive function. They have similar high rates of anxiety and depression symptoms in late adolescence as do controls. They are, however, over-represented in population registries for rarer disorders such as schizophrenia and Autism Spectrum Disorder. In cohort studies, ex-preterm survivors mostly report good quality of life and participation in daily activities, and they report good levels of self-esteem. In population studies, they require higher levels of economic assistance, such as disability pensions, they do not achieve education levels as high as controls, fewer are married, and their rates of reproduction are lower, at least in early adulthood. Survivors born ELBW/EP will present more and more to health carers in adulthood, as they survive in larger numbers.

Purpose: This study investigated predictive factors for severe neonatal thrombocytopenia, which greatly increases the need for intensive care and is associated with a high mortality rate in premature infants. Factors adopted for prompt identification of at-risk newborns include blood test results and birth history. This study analyzed the relationship between the presence of severe neonatal thrombocytopenia and the mortality rate. The causes of thrombocytopenia in premature infants were also examined. Methods: This retrospective study evaluated 625 premature infants admitted to the neonatal intensive care unit (NICU) at Chung-Ang University Medical Center. The neonates were classified into 3 groups according to the severity of thrombocytopenia: mild ($100{\times}10^9/L{\leq}platelet<150{\times}10^9/L$), moderate ($50{\times}10^9/L{\leq}platelet<100{\times}10^9/L$), or severe (platelet<$50{\times}10^9/L$). Analysis of blood samples obtained at the onset of thrombocytopenia included platelet count, white blood cell (WBC) count, hemoglobin level, hematocrit level, absolute neutrophil count, and high-sensitivity C-reactive protein level. Results: Of the 625 premature infants admitted to our NICU, 214 were detected with thrombocytopenia. The mortality rate in thrombocytopenic neonates was 18.2% (39/214), whereas a mortality rate of only 1.0% was observed in non-thrombocytopenic neonates. The major causes of thrombocytopenia were perinatal insufficiency and sepsis in premature infants. Severe thrombocytopenia was noted more frequently in premature infants with higher WBC counts and in those with a younger gestational age. Conclusion: Platelet count, WBC count, and gestational age are reliable predictors for severe neonatal thrombocytopenia. The major causes of thrombocytopenia were perinatal insufficiency and sepsis in premature infants.

Purpose: Abdominoperineal solid tumors presenting in neonates often require surgical intervention during the neonatal period. Although we report our single-center experience, this study would be meaningful to understand the clinical implications of these neoplasms. Methods: We retrospectively reviewed and analyzed the clinical data and characteristics of 22 patients (${\leq}28$ days old) diagnosed with histopathologically confirmed abdominoperineal solid neoplasms (benign or malignant) after surgical resection. Results: The mean gestational age and postnatal age at the time of operation were $38.3{\pm}1.8weeks$ and $13.5{\pm}8.3days$, respectively. Most patients (18/22, 81.8%) were diagnosed during antenatal care visits; however, 4 (18.2%) were identified after birth. The mean tumor size was $6.4{\times}5.3cm$ (3.5-17.0 cm), and tumors occurred most frequently within the sacrococcygeal region (8/22, 36.4%). Histopathologically, 14 patients (63.6%) demonstrated benign tumors and 8 (36.4%) demonstrated malignant tumors. Germ cell tumors and hepatoblastomas were the most commonly observed tumors. Fortunately, all patients showed a localized pattern of tumor involvement without distant metastasis. No recurrence or mortality was observed during the follow-up period (mean $66.4{\pm}44.2months$). Conclusion: Abdominoperineal solid tumors occurring in neonates show variable clinical patterns during the antenatal and postnatal monitoring/screening periods. We conclude that aggressive and multidisciplinary approaches could achieve good clinical results in these patients.

Purpose: The purpose of this study was to investigate the outcome after changes in the treatment strategies for very low birth weight infant (VLBWI) in a single neonatal intensive care unit (NICU) center. Methods: We performed a retrospective review of 300 VLBWI born from 1st January 2010 to 31th December 2016. We compared the outcomes including survival rate, birth weight (BW), gestational age (GA), and morbidities between period I (2010-2013, P-I) and period II (2014-2016, P-II). Results: The average survival rate was not different between P-I and P-II. However, the survival rate of ${\leq}24$ weeks' GA, 25 weeks' GA, 26 weeks' GA were 57%, 69%, 93% respectively in P-II and 31%, 59%, 87% in P-I respectively. The survival rate of infants with birth weight <500 g, 500-749 g, 750-999 g were 100%, 55%, 90% respectively in P- II and 50%, 24%, 80%, respectively in P-I. The incidence of bronchopulmonary dysplasia (BPD) was higher in P-II than in P-I (P=0.012) and moderate-to-severe BPD was also higher in P-II (P=0.004). Incidence of patent ductus arteriosus (PDA) with treatment, necrotizing enterocolitis (stage ${\geq}2$), and abnormal brain sonography were significantly lower in P-II (P=0.027, P=0.032, P=0.005). Incidences of retinopathy of prematurity (ROP) with laser treatment and early sepsis were not different. Conclusion: The survival rate and complications of VLBWI were improved in period II, especially in less than 750 g and below 26 weeks, except incidence of BPD. Changes of NICU strategies were effective to improve mortality and morbidity in VLBWI.

Purpose: Meconium-related ileus is common in preterm infants. Without proper management, it can cause necrotizing enterocolitis and perforation requiring emergent operation. This study was conducted to describe the efficacy and safety of ultrasound-guided Gastrografin enema at bedside for preterm infants with meconium-related ileus. Methods: Between March 2013 and December 2014, this study enrolled preterm infants with birth weight <1,500 g, who were diagnosed with meconium-related ileus requiring ultrasound-guided Gastrografin enema refractory to glycerin or warm saline enemas. Gastrografin was infused until it passed the ileocecal valve with ultrasound guidance at bedside. Results: A total of 13 preterm infants were enrolled. Gestational age and birth weight were 28.6 weeks (range, 23.9-34.3 weeks) and 893 g (range, 610-1,440 g), respectively. Gastrografin enema was performed around postnatal day 8 (range, day 3-11). The success rate was 84.6% (11 of 13 cases). Three of these 11 infants received a second procedure, which was successful. Among 2 unsuccessful cases, one failed to pass meconium while the other required surgery due to perforation. The time required to pass meconium was $2.8{\pm}1.5hours$ (range, 1-6 hours). The time until radiographic improvement was $2.8{\pm}3.4days$ (range, 1-14 days) after the procedure. Conclusion: Ultrasound-guided Gastrografin enema at bedside as a first-line treatment to relieve meconium-related ileus was effective and safe for very low birth weight infants. We could avoid unnecessary emergent operation in preterm infants who have high postoperative morbidity and mortality. This could also avoid transporting small preterm infants to fluoroscopy suite.

Platyspondylic lethal skeletal dysplasia, Torrance type (PLSD-T), is one of the pheno-types of type II collagenopathy and is characteristic of severe bone growth disorder. This phenotype may limit the growth and expansion of the lungs, which is known to cause death from respiratory failure during or shortly after birth, but in few less severe cases, patients have been reported to have survived to adulthood. We have experienced a case of PLSD-T in a preterm infant who was delivered via cesarean section at the gestational age of 29 weeks 3 days, with a birth weight of 1.15 kg. Physical examination of the infant revealed characteristic findings of short arms and legs, small thorax, distended abdomen, and cleft palate. On the basis of the subsequent genetic testing, the patient had a heterozygous mutation in the encoded c-propeptide region of collagen, type II, alpha 1 (COL2A1), c.4335G>A ($p.Trp1445^{\ast}$) in exon 52. This is the first case of PLSD-T diagnosed in Korea, and we hereby report the case.

Arterial tortuosity syndrome (ATS) is a very rare autosomal recessive connective tissue disease characterized by generalized elongation and tortuosity of the medium- to large-sized arteries, and other systemic connective tissue manifestations. To date, this disease entity has not been reported in Korea. We report a case of ATS diagnosed in a neonate who presented with severe elongation and tortuosity of the aorta and its major branches, as well as the intracranial arteries. Additionally, the patient presented with a tortuous dilatation of the inferior vena cava, an aneurysmal dilatation of the extra-hepatic bile ducts, and an inguinal and sliding hiatal hernia. The diagnosis was confirmed using DNA sequencing analysis, and the patient demonstrated a compound heterozygosity for two novel mutations (c.738delG [p.Gln247Serfs*33] and c.362T>C [p.Ile121Thr]) in exon 2 of the SLC2A10 gene. Genetic analysis also confirmed that both parents were heterozygous carriers of the responsible mutations. Owing to such clinical manifestations, ATS is often misdiagnosed as other connective tissue diseases including Loeys-Dietz syndrome, Marfan syndrome, and Ehlers-Danlos syndrome. In patients presenting with a high index of suspicion, thorough clinical evaluation and screening for ATS including computed tomography or magnetic resonance angiography and target gene analysis are necessary for early diagnosis and management.