• Clinical and Experimental Pediatrics
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• v.48 no.10
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• pp.1096-1101
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• 2005

Purpose : Recently, early surfactant replacement and tidal volume based gentle ventilation has been a fundamental treatment of respiratory distress syndrome(RDS). The aims of this study were to survey the changes in ventilator care duration and rate of complication in RDS groups. Methods : We performed a retrospective study of 255 newborn infants less than 1,500 g admitted to the neonatal intensive care unit(NICU) and discharged from January 1999 to December 2003. 141 of 255 newborn infants were RDS groups that required invasive management, such as endotracheal intubation, surfactant replacement and assisted ventilation. We analyzed epidemiologic data to study the changes in ventilator care duration and outcome of RDS groups. Results : Of 141 RDS groups, 135 were mild to moderate RDS groups and only 6 were severe RDS groups. 24(17.8%) of 135 mild to moderate RDS groups and 3(50%) of 6 severe RDS groups were antenatal no use of maternal dexamethasone. 127(90.1%) of 141 RDS groups underwent replacement of surfactant during 3 hours after birth. 121(85.9%) weaned within 48 hours. Conclusion : Our study shows a decreased frequency of severe RDS by a antenatal use of maternal dexamethasone and decreased duration of ventilator care by early surfactant replacement and gentle ventilation.

• Clinical and Experimental Pediatrics
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• v.49 no.5
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• pp.500-506
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• 2006

Purpose : We evaluated an outbreak of Serratia marcescens infections in 24 neonates in a neonatal intensive care unit(NICU). Methods : From January to August, 2004 a nosocomial outbreak of S. marcescens occurred in our NICU. We describe the clinical characteristics of the outbreak and analyse the risk factors for infections with S. marcescens. After the outbreak stopped, 7 isolates from blood were typed using rapid amplified polymorphic DNA analysis(RAPD). Results : S. marcescens was isolated from 24 neonates, 19 infected and 5 colonized. Seven out of nineteen neonates had bacteremia, 4 had ventilator associated pneumonia, 4 had purulent conjunctivitis, 2 had UTI, 1 had meningitis and 1 had a wound infection. Three neonates died due to S. marcescens infection, 2 of 3 had ventilator associated pneumonia, 1 had meningitis complicated with abscess. The mortality rate of S. marcescens infection was 15.8%. Factors associated with S. marcescens infections were previous antibiotic therapy, indwelling catheter and use of ventilators. The isolated strains were resistant to most antibiotics, but frequently sensitive to imipenem, bactrim and amikacin. RAPD typing results show that at least 3 epidemic strains were related with this outbreak. But one genotype was predominant type in this outbreak. The control measures were instituted and the outbreak stopped within 2 months. Conclusion : S. marcescens can cause rapidly spreading outbreaks associated with fatal infections in neonates. If S. marcescens is isolated from clinical specimens, meticulous infection control measures and epidemiologic investigations should be done at an early stage of the outbreak.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1194-1199
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• 2003

Purpose : To determine the change in the limit of viability in fetal infants and the incidence of major complications in neonatal intensive care unit(NICU) at Samsung Medical Center(SMC). Methods : Sevety-three infants weighing less than 800 g at birth and 117 infants born earlier than 27 weeks gestational age, who were admitted to NICU at SMC between November 1994 and December 2002, were enrolled. Their medical records were reviewed with a focus on the survival and major complications, including chronic lung disease, retinopathy of prematurity, intraventricular hemorrhage, and periventricular leukomalacia. The limit of viability in fetal infants was defined as the birth weight or gestational age at which a 50% survival rate is reached and the incidence of major complications were compared by period(period I : Nov. 1994-Dec. 1998, period II : Jan. 1999-Dec. 2002). Results : The limit of viability in fetal infants was markedly lowered from birth weight range of 800-900 g or gestational age range of $26^{+0}-26^{+6}$ weeks in period I to birth weight range of 600-700 g or gestational age range of $24^{+0}-24^{+6}$ weeks in period II. The incidence rates of major complications at the limit of viability were all less than 50% in period II. There was no definite trend toward increased incidence of major complications as birth weight get smaller and gestational age get younger. Conclusion : Our results indicate that at present, fetal infants whose body weight is over 600 g, or whose gestational age is over 24 weeks should be resuscitated vigorously. The risk of major complications at this birth weight or gestational age seems to be not greater than that at a bigger birth weight or an older gestational age.

• Clinical and Experimental Pediatrics
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• v.46 no.1
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• pp.24-32
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• 2003

Purpose : Nosocomial infection with Staphylococcus aureus, especially methicillin resistant S. aureus, has become a serious concern in the neonatal intensive care unit. The aim of this study is to investigate the virulence factors, and the relationship between the antibiotic resistance and the associated genes of Staphylococcus aureus isolated from nasal cavity of neonates. Methods : Fifty one isolates of S. aureus were obtained from nasal swab taken in 28 neonates in the NICU and nursery of Pusan National University Hospital between February and May, 2001. They were tested in regard to antibiotic susceptibility, coagulase test and typing, plasmid DNA profile, as well as reactivity to enterotoxin A-E(sea, seb, sec, sed, see) genes and toxic shock syndrome toxin-1(tst) gene by polymerase chain reaction(PCR). Associated genes such as mecA, mecR1, mecI, and femA were also determined by PCR. The origin of MRSA strains was assessed using DNA fingerprinting by arbitrarily-primed polymerase chain reaction(AP-PCR). Results : Twenty three(45.1%) and six(11.8%) isolates were resistant to oxacillin and vancomycin respectively. Multidrug resistance to three or more of the antibiotics tested was observed in 51.0% of the isolates. Forty two isolates were coagulase positive and twenty two isolates had mecA gene. Sixteen isolates had both mecA and femA genes and had type I-III plasmids. 64.7% of isolates carried sec gene, and 80.4% carried tst gene. DNA fingerprinting by AP-PCR for 12 MRSA strains showed 10 distinct patterns, suggesting different origins. Conclusion : We confirmed that the prevalence of nasal carriage of S. aureus and the incidence of antimicrobial-resistant S. aureus, especially vancomycin resistance, is very high in neonates who were admitted in NICU and nursery. It is possible that these pathogens are responsible for serious nosocomial infections in neonates. The need for improved surveillance and continuous control of pathogens is emphasized.

• Clinical and Experimental Pediatrics
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• v.50 no.7
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• pp.643-648
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• 2007

Purpose : Sepsis is a common complication in Neonatal Intensive Care Units (NICU), seen especially in low birth weight (LBW) infants. A recent study showed that fungal or gram-negative sepsis is associated with a greater degree of thrombocytopenia than is seen with gram-positive sepsis. So, this study was undertaken to examine the platelet counts and platelet indices in LBW infants during episodes of sepsis. Methods : We analyzed 36 cases with culture-proven sepsis on chart review in LBW infants admitted to the NICU at Wonkwang University Hospital from January 2001 to June 2006. Results : Patients were grouped by organism type: gram-positive bacteria ($1,521{\pm}309g$, $31.3{\pm}2.9wk$, 15/36), gram-negative bacteria ($1,467{\pm}290g,\;30.6{\pm}3.6wk$, 17/36), and fungi ($1,287{\pm}205g,\;30.0{\pm}3.9wk$, 4/36). The most common organism was Staphylococcus epidermis and the incidence of thrombocytopenia was 88.9%. When compared with infants with gram-positive sepsis, those with gram-negative sepsis had significantly higher incidences of thrombocytopenia, lower initial platelet count, lower platelet nadir, and greater mean percentage decrease in platelet count from before the onset of sepsis. Those with fungal infections were similar to gram-negative sepsis, but they were not significant because of the small number of patients. And mean platelet volume (MPV) in sepsis was increased more significantly in time of platelet nadir than before the onset of sepsis. Conclusion : We conclude that decrease in platelet count was significantly greater in gram-negative sepsis than gram-positive sepsis, and also greater than fungal sepsis-which was insignificant because of the small number of patients-in LBW infants. And elevation in MPV will be helpful in the diagnosis and treatment of sepsis in LBW infants.

• Neonatal Medicine
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• v.18 no.2
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• pp.211-220
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• 2011

Purpose: Late-onset hypotension in preterm infants is not a rare condition. Late circulatory collapse due to adrenal insufficiency (AI) is one of the major causes of late-onset hypotension. We assessed the incidence and causes of late-onset hypotension. We also compared the clinical findings according to the presence of AI. Methods: In total, 244 preterm infants with a gestational age ${\leq}$32 weeks and who were admitted to the neonatal intensive care unit (NICU) of Seoul National University Boramae Hospital and Seoul National University Hospital from January 2009 to April 2011 were included. Clinical findings were analyzed retrospectively. Results: Forty-four infants (18%) suffered from late-onset hypotension. Hydrocortisone was administered to 30 infants (68.2%) and AI occurred in 16 infants (36.4%). Cesarean section, sepsis before hypotension, and gastrointestinal surgery were independently associated with late-onset hypotension. Intrauterine growth retardation (IUGR) was less frequent in the hydrocortisonetreated group than in infants not treated with hydrocortisone. The AI group had fewer IUGR infants, and the duration of hospitalization was shorter in the AI group than in infants who were not administered hydrocortisone. Blood pressure tended to normalize more quickly in the AI group, however, the difference was not significant. Conclusion: AI was a major cause of late-onset hypotension, and the use of hydrocortisone shortened the length of hospitalization.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1224-1229
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• 2003

Purpose : Bacterial meningitis is a serious disease, especially in the neonatal period, and it carries a significant degree of mortality and morbidity. Group B streptococcus(GBS) is a common cause of neonatal bacterial meningitis. The purpose of this study was to evaluate the clinical manifestations, treatment results and complications of GBS meningitis. Methods : We analyzed 29 cases retrospectively who had been admitted to the pediatric ward or NICU in Asan Medical Center from May 1990 to January 2002. They had proven GBS in culture or latex agglutination test in CSF. Results : The male to female ratio was 1 : 1.9. There were two cases of early onset type and 27 cases of late onset type. All cases had normal birth weight with full term at delivery. The perinatal predisposing factors were premature rupture of membrane(two cases), and maternal colonization(two cases). The most common presenting symptoms were fever and irritability. Associated diseases were GBS sepsis(21 cases). There was relatively high sensitivity to penicillin derivatives. There were abnormal brain CT or MRI findings in 16 cases(64%), such as infarction, encephalomalatic change, effusion, hydrocephalus, hemorrhage and abscess. The intensive care unit admission rate and the incidence of DIC were higher in the group with complications. Two cases were discharged against advice. Conclusion : We recommend early detection and active treatment in Group B streptococcal meningitis to improve the prognosis.

• Neonatal Medicine
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• v.17 no.2
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• pp.245-249
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• 2010

Purpose: Numerous false alarms by pulse oximetry, which is widely used in neonatal intensive care unit, can delay response to true alarms. Masimo $SET^{(R)}$ was introduced lately, to overcome false alarms by motion. We compared the clinical performance of two devices (Nellcor $N-595^{(R)}$ and Masimo $SET^{(R)}$) for the evaluation of the false alarm frequency during usual motion artifacts and stable state. Methods: A total of 20 preterm infants weighing 1,000-2,500 g were enrolled in the study. The sensors of two devices were placed on the different feet on the same infants, and both devices were programmed to emit an alarm for episode of hypoxemia (SpO2$\leq$85%). The false alarms were defined as episodes of poor correlation with ECG heart rate, poor waveforms, and the absence of obvious signs of hypoxia. We compared the frequency of false alarms between the two devices. Results: The mean chronological age was 20.8 days and the mean body weight was 1,668 g on the study day. The frequency of total false alarm was significantly fewer for Masimo $SET^{(R)}$ pulse oximetry (48 in Nellcor $N-595^{(R)}$, 27 in Masimo $SET^{(R)}$) although the false alarm during usual motion artifacts was not significantly between two devices (32 in Nellcor $N-595^{(R)}$, 19 in Masimo $SET^{(R)}$). Conclusion: The Masimo $SET^{(R)}$ pulse oximetry has fewer false alarm rates and identified more true hypoxic events than Nellcor $N-595^{(R)}$ pulse oximetry. Therefore, it is useful for adequate oxygen therapy and helps to decrease unnecessary handling by clinicians and nurses.

• Neonatal Medicine
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• v.18 no.1
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• pp.89-95
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• 2011

Purpose: Hypernatremia most frequently occurs in the immature newborn and be severe in association with intraventricular hemorrhage (IVH). This study examined the frequency, onset and risk factors of hypernatremia, and the relationship between hypernatremia and IVH in very low birth weight (VLBW; <1,250 g) infants. Methods: We retrospectively reviewed the medical records of 55 VLBW infants admitted between January 2006 and December 2009 to the neonatal intensive care unit of Wonkwang University Hospital and who survived over 7 days. Serum sodium concentration, sodium intake, fluid and weight loss, as suggested risk factors of hypernatremia, and the incidence of IVH were evaluated. The infants were divided into a hypernatremia group (${\geq}$150 mEq/L) and nonhypernatremia group, and were compared. Results: Incidence of hypernatremia in the VLBW infants was 52.7%, and mean starting time of hypernatremia was 2.8${\pm}$1.3 days. There were no differences in the sodium and fluid intake between the two groups. Weight loss at day 3 after birth was significantly higher in the hypernatremia compared to the nonhypernatremia group (P<0.05); thereafter weight loss was non-significantly higher. The incidence of IVH in VLBW infants was 38.2%, and the difference between the two groups was not significant. Conclusion: Hypernatremia occurs commonly in VLBW infants and is most commonly caused by weight loss in the early days after birth. Incidence of IVH is not likely influenced by hypernatremia with marginally elevated sodium concentration.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1324-1329
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• 2005

Purpose : The aim of this study was to evaluate recent improvements in the survival rate of extremely low birth weight (ELBW) infants and to identify perinatal and management factors that are associated with improved survival. Methods : Two groups of ELBW infants who were admitted to our neonatal intensive care unit (NICU) during two distinct eras : November 1994-December 1999 (Period 1 : n=100) and January 2000-April 2004 (Period 2 : n=166) were retrospectively reviewed. Results : Despite the younger gestational age and smaller birth weight of the ELBW infants in period 2, not only did their survival rate increased to 75 percent from 60 percent in period 1, but their incidence of morbidities such as bronchopulmonary dysplasia, confimed sepsis and intraventricular hemorrhage (${\geq}$Grade III) also declined. Factors significantly associated with improved survival included the use of antenatal steroids, a longer duration of nasal continuous positive airway pressure and the absence of intraventricular hemorrhage (${\geq}$Grade III). Conclusion : We believe that optimized clinical practice, that emphasized less invasive care, contributed to the recent improvements in the survival rate of ELBW infants.