Changes in cerebral perfusion in extremely LBW infants during the first 72 h after birth.

Cerebral perfusion and its relation with systemic circulation in extremely LBW (ELBW) infants in the early neonatal period are not well understood. The cerebral tissue oxygenation index (TOI) and cerebral fractional tissue oxygen extraction (FTOE) were monitored in stable 16 ELBW infants (GA <29 wk) using near-infrared spectroscopy (NIRS) at 3-6, 12, 18, 24, 36, 48, and 72 h after birth. The left ventricular end-systolic wall stress (ESWS), left ventricular ejection fraction (LVEF), left ventricular cardiac output (LVCO), and superior vena cava (SVC) flow were also measured simultaneously using echocardiography. The ESWS increased till 18 h and then decreased; LVEF, LVCO, and SVC flow decreased till 12 h and increased thereafter. The TOI decreased till 12 h and correlated with SVC flow; FTOE increased until 12 h and then decreased. These changes in variables of NIRS and echocardiographic measurements contrasted to changes in mean arterial blood pressure (MABP), which showed trends of continuous and gradual increase after birth. We conclude that even stable ELBW infants undergo evident transitional changes in cerebral oxygenation and perfusion in the early postnatal period, which may reflect changes in cardiac function and cardiac output.

Usefulness of indomethacin for patent ductus arteriosus in full-term infants.

The aim of this retrospective study was to evaluate the effectiveness of indomethacin therapy for patent ductus arteriosus (PDA) in full-term infants. The patients were 41 full-term infants with a PDA birth weight (BW) > or =2500 g and a gestational age (GA) > or =37 weeks. The echocardiographic evaluation and medical management of PDA in these infants was similar to that for PDA in low-birth-weight infants. Indomethacin (0.2-0.25 mg/kg/dose) was given intravenously at 12-24-hour intervals within 23 days of birth. Of the 41 infants, 12 showed complete closure, and 13 showed improvement of clinical symptoms. These 25 infants were classified as the responder group (61%). The other 16 infants, who did not show improvement in clinical symptoms, were classified as the nonresponder group. Statistical analysis revealed no difference between the two groups regarding GA, BW, Apgar score at 1 minute, minimum diameter of the DA before treatment, the average age at the initiation of treatment, and DA flow pattern. No severe adverse reactions were observed in any infant. Indomethacin therapy appears to be an effective medical treatment option for PDA in full-term symptomatic infants prior to considering surgical treatment.

Monitoring of cerebral oxygenation during hypoxic gas management in congenital heart disease with increased pulmonary blood flow.

In the preoperative management of congenital heart disease (CHD) with increased pulmonary blood flow, hypoxic gas management to control pulmonary blood flow is useful. However, the cerebral oxygenation state has rarely been studied, and there is concern about neurologic development. In eight infants with CHD accompanied by increased pulmonary blood flow, hypoxia was induced after a 1-h baseline period in room air (FiO2, 0.21). The infants were simultaneously monitored in both the front-temporal region and the right-brachial region for 90 min using near-infrared spectroscopy (NIRS). The minimum SaO2 (pulse oximetry) after hypoxic gas administration was 80.8 +/- 2.9% when the minimum FiO2 was 16.2 +/- 1.1%. With a decrease in SaO2, oxy-Hb (O2Hb) decreased and total Hb [cHb: O2Hb + deoxy-Hb (HHb)] increased in both regions in the majority of infants. HHb increased in both regions with a decrease in SaO2. The maximum change in the tissue oxygenation index (TOI: O2Hb/cHb x 100) was -8.3 +/- 2.6% in the front-temporal region and -3.6 +/- 2.3% in the right-brachial region. Cerebral oxygenation decreased despite an increase in cerebral blood flow during hypoxic gas management. The change in TOI was < or =10% when the SaO2 was > or =80%. Safer control of SaO2 should be maintained over 80% for hypoxia management in CHD based on the results of the present study.

Effects of rapid rewarming on cerebral nitric oxide production and cerebral hemodynamics after hypothermia therapy for kainic acid-induced seizures in immature rabbits.

BACKGROUND: The aim of the present study was to investigate whether rapid rewarming after hypothermia therapy during seizures alters the endogenous nitric oxide (NO) production in and around hippocampus, cortical cerebral blood flow (cCBF), and mean arterial blood pressure (MABP) in immature rabbits. METHODS: The hypothermic rabbits (rectal temperatures, 33 degrees C) were given kainic acid (KA; 12 mg/kg, i.v; at 0 min), followed by cooling (33 degrees C) for 60 min (at 60 min), then either rewarming (RW; 33-37 degrees C) was started (KA[+]RW[+] group, n = 7) or cooling was continued (KA[+]RW[-] group, n = 7) for another 60 min (at the end 120 min). In the KA(-)RW(+) group (n = 5), 0.5 mL normal saline was given (at time 0 min), followed by cooling (33 degrees C) for 60 min (at 60 min), then rewarming to 37 degrees C was started with observation for another 60 min (at the end 120 min). NO production in and around hippocampus was continuously measured by an NO-selective electrode, cCBF by laser Doppler flowmetry, cortical electroencephalogram (EEG), rectal and cerebral temperatures, and MABP during the experiment. Comparisons were made of these parameters between the values at 60 min and 120 min after the KA administrations. RESULTS: KA administration induced abnormal discharges in both KA(+)RW(+) and KA(+)RW(-) groups at the same degree. The KA(+)RW(+) group had a significant increase in %NO, and significant decreases in %cCBF and MABP after rapid rewarming, compared with before rewarming. In the KA(+)RW(-) group, there were no significant changes in %NO, %cCBF, and MABP between values at 60 and 120 min. These changes after rapid rewarming in the KA(+)RW(+) group were different from those with only elevation in brain temperature from 33 to 37 degrees C without seizures (KA[-]RW[+] group). CONCLUSIONS: These results suggest that rapid rewarming after hypothermia therapy induces an increase in the NO production in and around hippocampus and the decreases in cCBF and MABP during seizures in immature rabbits.

Hypothermia during kainic acid-induced seizures reduces hippocampal lesions and cerebral nitric oxide production in immature rabbits.

We investigated (1) whether cerebral hypothermia during kainic acid (KA)-induced seizures was neuroprotective; and (2) whether nitric oxide (NO) production in the brain during seizures was altered by cerebral hypothermia in immature rabbits. Twelve female rabbits, aged 2 weeks, were anesthetized, paralyzed and mechanically ventilated. We continuously measured NO production in the brain by NO-selective electrode, cortical electroencephalogram (EEG), regional cerebral blood flow (rCBF) by laser Doppler flowmetry, rectal and cerebral temperatures and mean arterial blood pressure (MABP) during KA (12 mg/kg, i.v.)-induced seizures in the hypothermic group (n = 6; rectal temperature, 33 degrees C), and in the normothermic group (n = 6; rectal temperature, 37 degrees C). The normothermic group showed a gradual increase in NO generation in the brain, which was significantly inhibited in the hypothermic group. There were no significant differences in the increases in rCBF, MABP, arterial blood gases, blood glucose, or EEG abnormalities between the two groups. Neuronal damages in the hippocampus (CA3) were significantly lower in hypothermia than in normothermia. These results suggest that hypothermia attenuates NO production during drug-induced seizures and decreases hippocampal brain lesions in the immature rabbit brain. These results may help to explain the neuroprotective effects of hypothermia.

Characteristics of 11 neonates with atrial septal defects detected by heart murmurs.

The aim of this prospective study was to investigate, using echocardiography, the relationship between heart murmurs found in the neonatal period and atrial septal defect (ASD). Heart murmurs were detected in 115 of 5124 term neonates within 1 month after birth. The babies were followed by echocardiographic examination with attention to the atrial septal area. Heart murmurs of 11 term neonates (9.6%) were associated with interatrial shunts consistent with ASD. The defect closed spontaneously in 7 out of the 11 neonates by 18 months of age. Two neonates showed evidence of right ventricular overload from early infancy. This study showed that nearly 1 neonate in 10 with a heart murmur up to 1 month after birth had an interatrial shunt associated with ASD. We concluded that the absence of a flap sign (valve-like openings of the defects) affects the development of the heart murmur of ASD found in the neonatal period.

Determination of enterovirus serotype inferred from sequence analysis of PCR products.

BACKGROUND: Enterovirus infections are common in neonates. Virus isolation is the only diagnostic method to confirm enterovirus serotype infections, however, is not always successful. OBJECTIVES: A new approach for the diagnosis of enterovirus infections was performed, using the reference strain inferred from sequence analysis of PCR products. STUDY DESIGN: Virus isolation, enterovirus RT-PCR and sequence analysis were performed from clinical samples or stored sera from two neonates with fever and rash. Neutralizing test (NT) antibodies against prototype reference virus were measured in paired sera. RESULTS: Virus isolation was negative in both patients but the enterovirus genome was amplified in the acute phase sera obtained from the two patients. From the results of sequence analysis of 109 nucleotides located in the 5'-noncoding of the conserved region of enteroviruses, a high homology to echovirus types 25 and 30 was found. More than a 4-fold increase in NT antibodies against reference viruses was demonstrated in the acute and convalescent phase sera. They were confirmed as echovirus type 25 and 30 infection, respectively. CONCLUSIONS: These virological examinations are practical and useful for clinical settings for a diagnosis of enterovirus infections because of an insufficient positive rate in virus isolation.

A case of Wilson-Mikity syndrome with high serum KL-6 levels.

KL-6 and surfactant protein D (SP-D) serum concentrations are known to rise in adult patients with various types of interstitial pneumonia. We evaluated the time course of serum KL-6, SP-D, and lactate dehydrogenase (LDH) levels in an infant with Wilson-Mikity syndrome. In this case, serum KL-6 levels correlated with clinical symptoms better than serum SP-D and LDH levels. The findings of this case suggest that high serum levels of KL-6 show activity of interstitial lung disease of Wilson-Mikity syndrome.

Nitric oxide donor increases cerebral blood flow and oxygenation during kainic acid-induced seizures in newborn rabbits.

BACKGROUND: We investigated the hypothesis that sodium nitroprusside (SNP), a nitric oxide (NO) donor, increased the cerebral blood flow and oxygenation during kainic acid (KA)-induced seizures in newborn rabbits. METHODS: After KA administration (i.v. 12 mg/kg)to induce seizures, either 1.2 mg/kg SNP (SNP group, i.v., n = 6) or 1 mL normal saline (vehicle group, i.v., n = 6)was given. Regional cerebral blood flow (rCBF), cerebral oxyhemoglobin(oxy-Hb), deoxyhemoglobin (deoxy-Hb), total hemoglobin (t-Hb), mean arterial blood pressure (MABP), heart rate (HR) and electroencephalography(EEG) were continuously monitored throughout the experiment, lasting at least 60 min after the KA administration. RESULTS: The value for rCBF was greatly increased during seizures in the SNP group than in the vehicle group. The values for oxy-Hb and t-Hb were significantly increased, and deoxy-Hb was significantly decreased. There were ameliorations of cerebral oxygenation in the SNP group during the acute phase of seizures in the neonatal animals, compared with the vehicle group. There were no significant differences in the MABP, HR, arterial blood gases, rectal and brain temperatures, blood hemoglobin concentrations,blood glucose levels, the latencies to first abnormal discharges in EEG, the total sum of the duration of abnormal discharges in EEG and the incidences of subclinical electric status epileptics between the two groups. CONCLUSIONS: These results suggest that the treatment with SNP contributed to the increases in cerebral blood flow and oxygenation, and that EEG abnormalities were unchanged by the treatment with SNP during neonatal seizures.