Ventilatory response to CO2 with Read's rebreathing method in normal infants.

BACKGROUND: Methods of evaluating the ventilatory response to CO2 (VRCO2 ) of the respiratory center include the steady-state and the rebreathing method. Although the rebreathing method can evaluate the ventilatory response continuously to gradually increasing CO2 , the rebreathing method has been rarely performed in infants. The aim of this study was to investigate whether we could perform the VRCO2 with the rebreathing method in normal infants. METHODS: The subjects were 80 normal infants. The gestational age was 39.9 (39.3-40.3) weeks, and the birth body weight was 3142 (2851-3451) grams. We performed the VRCO2 with Read's rebreathing method, measuring the increase in minute volume (MV) in response to the increase in EtCO2 by rebreathing a closed circuit. The value of VRCO2 was calculated as follow: VRCO2 (ml/min/mmHg/kg) = ΔMV/ΔEtCO2 /body weight. RESULTS: We performed the examination without adverse events. The age in days at examination was 3 (2-4), and the examination time was 150 ± 38 s. The maximum EtCO2 was 51.1 (50.5-51.9) mmHg. The value of VRCO2 was 34.6 (29.3-42.8). The intraclass correlation coefficient of the VRCO2 of cases with multiple measurements was 0.79. CONCLUSION: This study suggests that the rebreathing method can evaluate the ventilatory response to high blood CO2 in a short examination time. We conclude that the rebreathing method is useful even in infants. In the future, we plan to measure the VRCO2 of preterm infants, and evaluate the respiratory center of infants in more detail.

Impact of pre-eclampsia in extremely premature infants: Population-based study.

BACKGROUND: The relationship between chorioamnionitis (CAM) and neonatal mortality has been extensively investigated, but that of maternal pre-eclampsia and neonatal mortality is unclear. We investigated neonatal mortality and morbidity of maternal pre-eclampsia and clinical CAM in extremely premature infants using data from a population-based cohort study. METHODS: We retrospectively analyzed data obtained from the Neonatal Research Network in Japan, a population-based cohort study (n = 18 900) conducted to clarify the clinical characteristics and morbidity of very low-birthweight infants. Patients were divided into four diagnosis-based groups for comparative analysis: sole pre-eclampsia; sole clinical CAM; concurrent pre-eclampsia and clinical CAM; and non-diagnosis (of pre-eclampsia and clinical CAM). RESULTS: Mortality was higher in the pre-eclampsia groups compared with the groups without (18.3%, 84/459 vs 14.0%, 567/4059; OR, 1.38; 95%CI: 1.07-1.78). In contrast, mortality was not affected by presence of clinical CAM (with, 13.7% 182/1328 vs without, 15.0% 469/3190; OR, 0.92; 95%CI: 0.77-1.11). With regard to small for gestational age, the mortality rate increased by two-three-fold as gestational week decreased. The complication survival rate in the whole group was 35% (1135/3218). CONCLUSIONS: Maternal pre-eclampsia is associated with poor prognosis in extremely premature infants. We also need to deliberate on the trade-off between the advantages of early rescue from pre-eclampsia and risk of prematurity.

Effect of hemodiafiltration therapy in a low-birthweight infant with congenital sepsis.

The clinical course of congenital neonatal sepsis due to Streptococcus pneumoniae progresses rapidly and results in multiorgan failure with high mortality. The swift progression of the disease limits the timeframe for conventional treatment, which often requires waiting for antibiotics to show efficacy. Here, we describe the case of a very low-birthweight (VLBW) female infant with congenital sepsis due to S. pneumoniae who was treated with continuous hemodiafiltration (CHDF) and polymyxin B-immobilized fiber column-direct hemoperfusion (PMX-DHP). The infant was born at 30 weeks' gestation and diagnosed with hypotension, disseminated intravascular coagulation, and pulmonary hypertension. CHDF and PMX-DHP were initiated approximately 11 h after birth. Mean blood pressure, oxygenation, and blood interleukin-6 began to improve after dialysis commencement, and the patient survived with mild sequelae. Combined CHDF and PMX-DHP may be effective in treating VLBW infants with severe septic shock.