Perinatal factors contributing to intellectual impairment in a cohort of Japanese children with very low birth weight.

BACKGROUND: To determine whether prematurity, intrauterine growth restriction (IUGR), or neonatal stress affects intellectual impairment in children with very low birth weight (VLBW). METHODS: This national historical cohort study evaluated children with VLBW cared for in perinatal medical centers throughout Japan. Factors assessed included three latent variables (prematurity, IUGR, and stress during the neonatal period) and eight observed variables during perinatal period. The primary endpoint was intellectual or developmental quotient (IQ/DQ) at age ≥3 years. Structural equation model (SEM) was used to examine factors associated with IQ/DQ. RESULTS: The study included 248 VLBW children, who were of mean age 5.7±2.0 years and mean IQ/DQ of 85.5 at last encounter. SEM showed that stress during the neonatal period (ß=-0.37) contributed more to IQ/DQ than intrauterine malnutrition (ß=0.25) and prematurity (ß=0.15) and that the duration of mechanical ventilation was an important contributor to stress during the neonatal period. CONCLUSIONS: Neonatal stress was more harmful to future intellectual impairment of VLBW neonates, with IUGR contributing more than prematurity. Duration of mechanical ventilation was an important risk factor in neonatal stress. Neonatologists should minimize neonatal stress in VLBW neonates, and obstetricians should monitor fetal growth restriction to prevent intellectual impairment in later life.

Perinatal factors contributing to chronic kidney disease in a cohort of Japanese children with very low birth weight.

BACKGROUND: Developmental programming of chronic kidney disease (CKD) in young adults is linked to preterm birth and intrauterine growth restriction (IUGR). Which confers a higher risk of progression to chronic kidney damage in children with very low birth weight (VLBW; born weighing < 1500 g): prematurity or IUGR? METHODS: This is a national historical cohort study of children with VLBW cared for in perinatal medical centers in Japan. Predictive factors included three latent variables (prematurity, IUGR, stress during neonatal period) and eight observed variables (gestational age, birth weight Z-score, maternal age, duration of treatment with antibiotics and diuretics, maternal smoking, late-onset circulatory collapse, kidney dysfunction) during the perinatal period. The primary endpoint was estimated glomerular filtration rate (eGFR) at age ≥ 3 years. A structural equation model was used to examine the pathologic constitution. RESULTS: The 446 children with VLBW included 253 boys and 193 girls, of mean age 5.8 ± 2.6 years and mean eGFR 111.7 ml/min/1.73 m2 at last encounter. Pathway analyses showed intrauterine malnutrition (ß = 0.85) contributed more to chronic kidney damage than stress during the neonatal period (ß = - 0.19) and prematurity (ß = 0.12), and kidney dysfunction and late-onset circulatory collapse were important observed variables in stress during the neonatal period. CONCLUSIONS: IUGR was more harmful to future kidneys of VLBW neonates. Neonatal kidney dysfunction and late-onset circulatory collapse were important risk factors for subsequent CKD development. This emphasizes the need for obstetricians to monitor for fetal growth restriction and neonatologists to minimize neonatal stress to prevent CKD in later life.

Visual function scale for identification of infants with low respiratory compliance.

AIM: Precise estimation of respiratory function is essential to optimise neonatal respiratory care. However, current clinical scores have not been validated with quantitative measures of respiratory function. The aim of this study was to develop a physiological scoring system to predict low respiratory dynamic compliance of <0.6 ml/cmH2O/kg. METHODS: Forty-four newborn infants were studied before (dynamic compliance) and shortly after scheduled extubation (physiological signs). A novel scoring system was developed based on the association between physiological signs and dynamic compliance. RESULTS: The respiratory rate was identified as the primary independent variable for dynamic compliance in the univariate analysis. The prediction score for low dynamic compliance comprised the presence of nasal flaring, see-saw respiration, suprasternal/intercostal retraction, and the respiratory rate ranks (0-3). The area under the receiver-operating characteristics curve of the composite score had discriminatory capability of 0.86 (95% confidence interval: 0.75-0.97) to predict low dynamic compliance with the optimal cut-off value of ≥3 (sensitivity, 0.882; specificity, 0.667). CONCLUSION: Our novel scoring system might help predict newborn infants with low dynamic compliance, who may require escalation of respiratory support, or transfer to higher level units.

Methylxanthines inhibit late-onset circulatory collapse in preterm infants.

BACKGROUND: Several drugs, when used chronically in very preterm infants, are considered to be associated with the development of late-onset circulatory collapse (LCC), which can lead to neurodevelopmental impairment. Despite its clinical importance, conclusive risk factors for LCC have yet to be identified. The aim of the present study was to investigate the relationship between LCC and diuretics, methylxanthines, levothyroxine, and sodium chloride. METHODS: Infants born at <28 weeks gestational age were enrolled and divided into two groups: the LCC group and the non-LCC group. Use of diuretics, methylxanthines, or levothyroxine, and the sodium intake in each infant were recorded. We then determined if these represented primary risk factors associated with the development of LCC, using multivariate analysis to exclude confounding factors. RESULTS: Thirty-seven preterm infants were eligible for this study. LCC developed in 10 infants; 27 infants did not develop the disease. Only methylxanthine was significantly associated with a decrease in the incidence of LCC (odds ratio, 0.04; P < 0.05). We also observed a significant positive correlation between sodium intake and the period from diuretic treatment to LCC onset. CONCLUSIONS: Methylxanthine use was significantly associated with LCC onset. Diuretics may have the ability to provoke LCC through sodium wasting, resulting in a negative balance of the electrolyte. The incidence of LCC could be lowered by paying particular attention to infants' sodium balance, and by aggressive methylxanthine treatment.

Airway lavage with exogenous surfactant in an animal model of meconium aspiration syndrome.

BACKGROUND: Meconium aspiration syndrome (MAS) is a major cause of respiratory morbidity and mortality in term infants, and occasionally causes serious respiratory disturbance. Viscous meconium debris in the trachea interferes with ventilation, and chest physiotherapy (CPT) is effective for removing secretions from the trachea. The effects of conventional exogenous diluted surfactant lavage combined with CPT were evaluated in a MAS animal model in a randomized controlled study. METHODS: Twenty-three MAS model adult Japanese rabbits were randomized into three groups and artificially ventilated for 3 h with the following treatments: group 1, suction only (n = 7); group 2, surfactant lavage (n = 7); group 3, surfactant lavage with CPT (n = 7). Surfactant lavage was performed by infusing 2 mL/kg of diluted Surfactant TA (Surfacten; 6 mg/mL) into the trachea over approximately 5 s, then performing gentle manual bagging six times, and aspirating the tracheal contents using a suction catheter. This procedure was performed four times in four different positions (total, 8 mL/kg). In group 3, CPT (squeezing) was performed during expiration of manual bagging in surfactant lavage. RESULTS: In group 3, PaO(2) improved significantly (P < 0.05) at all time points compared with those in the other groups. Oxygenation index (OI) in group 3 improved significantly (P < 0.05) at all time points except after 0.5 h compared with that in group 1, and at 2, 2.5, and 3 h compared with that in group 2. CONCLUSIONS: A combination of exogenous surfactant lavage and CPT (squeezing) improves respiratory disturbance in MAS.