• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.317-325
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• 2006

Purpose : This study was carried out to elucidate the effects of nitric oxide synthase(NOS) inhibitor, NG-monomethyl-L-arginine(L-NMMA) and nitric oxide precursor, L-arginine(L-Arg) on cerebral hemodynamics and energy metabolism during reoxygenation-reperfusion(RR) after hypoxia-ischemia(HI) in newborn piglets. Methods : Twenty-eight newborn piglets were divided into 4 groups; Sham normal control(NC), experimental control(EC), L-NMMA(HI & RR with L-NMMA), and L-Arg(HI & RR with L-Arg) groups. HI was induced by occlusion of bilateral common carotid arteries and simultaneously breathing with 8 percent oxygen for 30 mins, and followed RR by release of carotid occlusion and normoxic ventilation for one hour. All groups were monitored with cerebral hemodynamics and cytochrome $aa_3$ (Cyt $aa_3$) using near infrared spectroscopy(NIRS). $Na^+$, $K^+$-ATPase activity, lipid peroxidation products, and tissue high energy phosphate levels were determined biochemically in the cerebral cortex. Results : In experimental groups, mean arterial blood pressure, $PaO_2$, and pH decreased, and base excess and blood lactate level increased after HI compared to NC group(P<0.05). These variables subsequently returned to baseline after RR except pH. There were no differences among the experimental groups. In NIRS, oxidized hemoglobin($HbO_2$) decreased and hemoglobin(Hb) increased during HI(P<0.05) but returned to base line immediately after RR; 40 min after RR, the $HbO_2$ had decreased significantly compared to NC group(P<0.05). Changes of Cyt $aa_3$ decreased significantly compared to NC after HI and recovered at the end of the experiment. Significantly reduced cerebral cortical cell membrane $Na^+$, $K^+$-ATPase activity and increased lipid peroxidation products(P<0.05) were not improved with L-NMMA or L-Arg. Conclusion : These findings suggest that NO is not involved in the mechanism of HI and RR brain damage during the early acute phase of RR.

• Clinical and Experimental Pediatrics
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• v.45 no.5
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• pp.596-602
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• 2002

Purpose : The purpose of this study was to analyze the association of peripheral neutrophil count with the development of respiratory failure in preterm infants. Methods : A retrospective study was conducted from January 1993 to December 1999 on 44 preterm infants, who were admitted to the neonatal intensive care unit of St. Francisco hospital. Preterm infants(birth weight 500 to 1,350 gm) who had a complete blood count obtained within 2 hours after delivery. Patients in the lowest of neutrophil count(early neutropenia, < $1.0{\times}10^9/L$) were compared with patients in the remaining group. Results : Low neutrophil count were transient in early neutropenia group. The concentration the circulating neutrophil count rose from $0.85{\pm}0.11{\times}10^9/L$ at average of 2 hours after delivery to $5.3{\pm}2.7{\times}10^9/L$ at 24 hours after delivery in the early neutropenia group and from $3.6{\pm}1.6{\times}10^9/L$ to $5.8{\pm}3.2{\times}10^9/L$ in the non-neutropenia group during the same time period. Compare to the non-neutropenia group, the neutropenia group had a lower birth weight($1,046.50{\pm}180.76gm$ Vs $1,156.70{\pm}124.99gm$), a lower Apgar score(1 min : $3.41{\pm}1.18$ Vs $4.30{\pm}1.46$, 5 min : $5.41{\pm}0.87$ Vs $6.15{\pm}0.95$), and a higher incidence of bronchopulmonary dysplasia(27.27% Vs 7.0%). Patients who had early neutropenia were more likely to require mechanical ventilation, supplemental oxygen and hospital stay. Also, main effect factors for the two groups were birth weight(Odds ratio=5.457, 95% CI=1.551-27.525), initial peripheral blood white cells(odds ratio=8.308, 95% CI=2.054-52.699), and bronchopulmonary dysplasia(odds ratio=0.099, 95% CI=0.017-0.397). Conclusion : A low count of neutrophil in the systemic circulation of premature infants within 2 hours of birth is associated with more severe respiratory distress.

• Clinical and Experimental Pediatrics
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• v.45 no.10
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• pp.1204-1212
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• 2002

Purpose : Early surfactant therapy with either gentle ventilation, high-frequency ventilation or aggressive weaning of mechanical ventilation are principles for the treatment of respiratory distress syndrome(RDS). We studied to determine the accessibility of noninvasive nasal continuous positive airway pressure(CPAP) rather than mechanical ventilation by invasive intubation after early surfactant therapy. Methods : The study group consisted of 14 infants who were born and diagnosed with moderate respiratory distress syndrome and received early surfactant therapy with nasal CPAP of PEEP 5-6 cm $H_2O$ within two hours after birth in the Fatima neonatal intensive care unit for two years from January 1999 to August 2001. The control group consisted of 15 infants who were diagnosed with the disease and could be weaned from mechanical ventilator within five days after birth during the same period. Results : The characteristics, the severity of clinical symptoms and laboratory findings in the two groups at birth showed no significant difference. Neither did the interim analysis of laboratory data in two groups. Of 14 infants in the study group who received nasal CPAP after early surfactant therapy, only two infants showed weaning failure with this therapy. In the response cases, duration of CPAP was five days and mean airway pressure was $5.4{\pm}0.5cm$ $H_2O$. Two had the complication of CPAP with abdominal distension. Final complications and outcomes in the two groups showed no signifcant difference(P>0.05). Conclusion : The clinical courses in the two groups showed no significant difference. Therefore, we suggest that early surfactant therapy with noninvasive nasal CPAP is a simple and safe method rather than aggressive weaning after invasive mechanical ventilation in moderate respiratory distress syndrome.