Postnatal changes in adrenal size in very low-birth-weight infants: sonographic evaluation for the prediction of late-onset glucocorticoid-responsive circulatory collapse.

We investigated the postnatal pattern of changes in adrenal size in very low-birth-weight (VLBW) infants and its relation to late-onset glucocorticoid-responsive circulatory collapse (LGCC) that may be associated with adrenal insufficiency. In 36 VLBW infants born at <33 weeks' gestation, ultrasound examinations of postnatal changes in adrenal size during the first 3 weeks of life were performed. VLBW infants were classified into three groups: group A (N = 6), the actual adrenal area was greater than or equal to the predicted value at birth and unchanged at 3 weeks; group B (N = 24), the actual adrenal area was greater than or equal to the predicted value and decreased at 3 weeks; and group C (N = 6), the actual adrenal area was less than the predicted value and unchanged at 3 weeks. Five infants developed LGCC, and all five were in group A. These observations suggest that the life of the adrenal fetal zone might be extended beyond 3 weeks after birth in some VLBW infants and that prolonged fetal zone activity might correlate with LGCC. On the other hand, adrenal maturation might have already occurred at birth in some VLBW infants. Sonographic evaluation of adrenal size may enable prediction of subsequent LGCC in VLBW infants.

Clinical patterns in extremely preterm (22 to 24 weeks of gestation) infants in relation to survival time and prognosis.

We investigated time-related predictors of death or neurological sequelae in extremely preterm infants (EPI) born at 22 to 24 weeks' gestation by categorizing clinical patterns according to their survival time and morbidity. Data on 113 infants born at 22 to 24 weeks' gestation from January 1991 through April 2006 were analyzed by a case-control approach. Cesarean section, Apgar score or= 24 hours, pulmonary hemorrhage and intraventricular hemorrhage (IVH) were significantly associated with death by day 6. Among those surviving >or= 7 days, sepsis and severe IVH were significantly associated with death. Assessment of survivors at a minimum follow-up period of 2 years revealed that protracted mechanical ventilation was significantly associated with a poor neurological outcome. There are various characteristic key events in relation to the outcome at different ages of life in EPI born at 22 to 24 weeks' gestation. Clinicians and parents should discuss management options for the infant on the basis of these findings.

Gastrointestinal perforation in very low-birthweight infants.

BACKGROUND: Spontaneous isolated gastrointestinal perforation (SIP) in very low-birthweight infants has been reported as a different disease entity from necrotizing enterocolitis (NEC). The objective of this study was to investigate the incidence and risk factors of NEC and SIP. METHODS: The authors reviewed the medical records of very low-birthweight infants who were admitted to Toho University Perinatal Center, Tokyo, Japan, between 1 January 1991 and 31 December 2002. The diagnosis of NEC was made with the finding of bloody gastric fluid or stool, abdominal distention, and abnormal abdominal X-ray findings such as pneumatosis intestinalis or fixed dilated intestinal loops. SIP was defined at laparotomy as the presence of an isolated gastrointestinal perforation surrounded by normal appearing bowel. RESULTS: A total of 556 very low-birthweight infants were included in this study. Of those, 15 infants were excluded because of major anomalies. Out of 541 infants, 14 were diagnosed to have NEC or gastrointestinal perforation. In total, 13 infants had gastrointestinal perforation and 10 were confirmed as SIP. Two SIP suggestive cases were included in SIP cases. There was only one case of NEC (0.2%) during 12 years in the authors' institute. Eight SIP cases had antenatal nonsteroidal anti-inflammatory drugs (NSAID). The treatment with antenatal NSAID was significantly associated with the incidence of SIP (p<0.001). CONCLUSION: The authors experienced only one proven case of NEC (0.2%), 12 cases of SIP (2.2%) among 556 very low-birthweight infants admitted during 12 years. Antenatal NSAID were strongly associated with SIP.

Elevation of cytokine concentrations in asphyxiated neonates.

BACKGROUND: Various cytokines are reportedly associated with many neonatal diseases. Asphyxia is considered to result in ischemia-reperfusion injuries and induces abnormal inflammatory responses involving excessive cytokine production. OBJECTIVES: To evaluate alteration in sera levels of various cytokines/chemokines in case of perinatal asphyxia at birth. METHODS: In order to determine the concentrations of various cytokines/chemokines in sera, we used a highly sensitive fluorescence microsphere method. We measured the concentration of 8 types of cytokines/chemokines in sera obtained from 17 cases of asphyxia, 10 normal neonates, and 6 healthy adults. RESULTS: The concentrations of IL-6, IL-8, and IL-10 in the sera of asphyxiated neonates were higher than those in the normal neonates. Irrespective of the presence or absence of asphyxia, sera concentrations of IL-2, IL-4, IFN-gamma, and TNF-alpha were higher in the neonates than those in the adults. The concentration of IFN-gamma in the asphyxiated neonates was lower than that in the normal neonates. Sera levels of IL-10 were higher in the asphyxiated cases than those in the normal neonates. The sera levels of IL-6, IL-8, and IL-10 in asphyxiated neonates with either a poor outcome or death were higher than those without poor outcomes. CONCLUSIONS: The concentrations of various types of cytokines/chemokines were different in neonatal sera and some of them increased drastically during asphyxia. The concentration of an anti-inflammatory cytokine IL-10 was elevated in asphyxiated neonates immediately after birth, thereby suggesting that IL-10 might be associated with neuroprotective functions.

Prophylactic calcium administration for hyperkalemia in extremely low birthweight infants.

The objective of this study was to clarify the relationship between the blood potassium and calcium levels, and the efficacy of prophylactic calcium (Ca) administration early in life for nonoliguric hyperkalemia in extremely low birthweight (ELBW) infants. This was a retrospective study including 55 ELBW infants with gestational age less than 26 weeks (mean, 24.4 weeks; mean body weight, 681 g). The plasma potassium concentration and whole blood ionized calcium (iCa) concentration were measured every 2 to 3 hours. Laboratory data obtained up to 24 hours after birth were collected. The infants were divided into two groups based on whether or not Ca gluconate was administered prophylactically starting at admission (prophylactic and nonprophylactic group). There was a negative correlation between the plasma potassium and iCa levels at 12 and 24 hours, and the maximum plasma potassium level was higher in the hypocalcemia group (minimum iCa level, < 0.9 mmol/L) than in the normocalcemia group. The iCa level was significantly higher and the plasma potassium level was significantly lower in the prophylactic group than in the nonprophylactic group at 12 and 24 hours. The increment in the plasma potassium level at 24 hours compared with that at admission was significantly lower in the prophylactic than in the nonprophylactic group. Nonoliguric hyperkalemia may be attenuated by maintaining the iCa level within normal limits by prophylactic Ca administration early in life. Prospective studies are needed to confirm this.

Nitric oxide inhalation therapy in very low-birthweight infants with hypoplastic lung due to oligohydramnios.

BACKGROUND: Although nitric oxide inhalation (iNO) therapy improves arterial oxygenation and reduces the rate of extracorporeal membrane oxygenation in term neonates, the efficacy of this therapy in premature infants is controversial. The objective of the present study was to determine whether iNO therapy improves the survival of very low-birthweight infants with pulmonary hypoplasia due to prolonged rupture of membrane. METHODS: A retrospective comparative study of very low-birthweight infants with pulmonary hypoplasia due to oligohydramnios who had or had not been treated with iNO therapy, was performed (iNO-treated group, eight infants; control group, 10 infants). A neonate was considered to have pulmonary hypoplasia due to oligohydramnios if the following conditions were satisfied: (i) artificial surfactant treatment did not improve the respiratory distress; (ii) prolonged rupture of membrane (PROM) continued for more than 5 days with oligohydramnios; and (iii) sufficient arterial oxygenation did not occur even after giving 100% oxygen, and more than 8 cm H(2)O of mean airway pressure was needed to maintain arterial oxygenation. RESULTS: Nitric oxide inhalation improved arterial oxygenation rapidly and consistently in all eight infants with pulmonary hypoplasia. All eight iNO-treated infants survived longer than 28 days, while five of the 10 control infants died within 24 h of birth (P < 0.05). Before starting iNO, seven of the eight treated infants had shown persistent pulmonary hypertension, which was confirmed by echocardiography. No iNO-treated infant had IVH greater than grade 1, while one control infant had grade 2 IVH. All six long-term survivors in the iNO-treated group are developing normally, while only two of the control infants are developing normally as of February 2002. CONCLUSIONS: The majority of the infants with pulmonary hypoplasia due to oligohydramnios had persistent pulmonary hypertension. iNO improved the arterial oxygenation and significantly improved the survival rate. A controlled study to determine whether iNO therapy improves the survival rate of preterm infants with pulmonary hypoplasia due to oligohydramnios is necessary.

Antenatal steroid treatment prevents severe hyperkalemia in very low-birthweight infants.

BACKGROUND: Hyperkalemia is seen quite often in very low-birthweight (VLBW) infants and concentrations sometimes become high enough to cause cardiac arrhythmia. The purpose of the present study was to identify factors that increase serum concentrations of potassium in VLBW infants. METHODS: Retrospective comparative analysis was performed on 140 VLBW infants who had been admitted to the Toho University Perinatal Center between January 1993 and December 1999 and needed mechanical ventilation for respiratory distress. Serum concentrations of potassium at 24 and 48 h of age were compared in two groups of infants, those whose mothers did and did not receive antenatal steroid treatment. Risk factors for severe hyperkalemia were analyzed by multiple linear regression models and Pearson's partial correlation analysis. RESULTS: Antenatal steroid treatment reduced serum potassium concentrations significantly at 24 and 48 h, as well as the incidence of cardiac arrhythmia and necessity for glucose insulin treatment for severe hyperkalemia. Multiple linear regression showed the serum potassium concentration at 24 h of age was associated with antenatal steroid hormone treatment, 24 h fluid intake volume, serum sodium concentrations at 24 h, gestational weeks and sampling site. Serum concentration of potassium at 48 h of age was associated with blood urea nitrogen, gestational week, serum sodium concentration at 48 h of age and fluid intake between 24 and 48 h of age. Urine output volume and serum creatinine concentrations were not correlated with potassium concentrations at either age. CONCLUSION: Antenatal steroid hormone treatment can reduce early hyperkalemia in VLBW infants and also the incidence of cardiac arrhythmia and the use of glucose insulin treatment.