Inhaled nitric oxide therapy for preterm infants after 7 days of age: a scoping review protocol.

INTRODUCTION: Inhaled nitric oxide (iNO) use is recommended for persistent pulmonary hypertension of the newborn in term and late preterm infants. Recently, iNO therapy to prevent bronchopulmonary dysplasia (BPD) or rescue for hypoxic respiratory failure and pulmonary hypertension secondary to BPD has increasingly been used in preterm infants after 7 days of postnatal age (in the postacute phase), despite its off-label use. However, the initiation criteria of iNO therapy for preterm infants in the postacute phase are varied. The aim of this scoping review is to identify the clinical and/or echo findings at the initiation of iNO therapy in preterm infants in the postacute phase. METHODS AND ANALYSIS: We will search PubMed, Embase and the Japanese database 'Ichushi.' The following studies will be included in the review: randomised controlled trials, prospective/retrospective cohort studies, case-control studies and case series on iNO therapy for preterm infants in the postacute phase; studies published between January 2003 and August 2023; studies conducted in developed countries and studies written in English or Japanese. We will independently screen, extract and chart data using the population-concept-context framework following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. We will summarise the characteristics and findings of the included studies. ETHICS AND DISSEMINATION: Obtaining an institutional review board approval is not required because of the nature of this review. A final report of review findings will be published and disseminated through a peer-reviewed journal and presentation at relevant conferences. TRIAL REGISTRATION NUMBER: UMIN000051498.

Early changes in serum interleukin-6 levels in extremely premature newborns for detecting fetal inflammation.

BACKGROUND: Fetal inflammatory response syndrome (FIRS) is defined by elevated levels of inflammatory cytokines circulating in fetal blood, which may result in preterm morbidities. Serum interleukin-6 (IL-6) level has been reported to be a good indicator of FIRS; however, changes in IL-6 levels after birth remain to be elucidated. Herein, we characterized early changes in serum IL-6 levels in extremely premature newborns (EPNs, < 28 wks gestation), and then determined the cut-off values for detecting fetal inflammation at each postnatal epoch. METHODS: In this single-center study, 49 EPNs were retrospectively studied. Serum IL-6 measurements are routinely performed at delivery, 1-3, 6-12, and 24-36 h of life. Receiver operating characteristic (ROC) curve analyses were performed for detecting the presence of funisitis, the histologic counterpart of FIRS. RESULTS: Overall, serum IL-6 levels were significantly elevated at 1-3 (298 [31-4719] pg/mL) and 6-12 (29 [2-12,635] pg/mL) hours of life, then returned to at-delivery levels at 24-36 h of life. When comparing serum IL-6 levels at each postnatal epoch, the levels at delivery, 1-3, and 6-12 h of life were significantly higher in the EPNs with funisitis. Serum IL-6 cut-off values at delivery, 1-3, 6-12, and 24-36 h of life for the presence of funisitis were 20, 572, 290, and 13 pg/mL with area under ROCs of 0.75, 0.71, 0.68, and 0.53, respectively. CONCLUSIONS: Serum IL-6 levels in EPNs significantly increase early after birth, then decrease to at-delivery levels by 24-36 h of life. Therefore, postnatal age-dependent cut-off values of serum IL-6 might be considered for detecting fetal inflammation with confirmed funisitis.

Second nationwide survey of bilirubin encephalopathy in preterm infants in Japan.

OBJECTIVES: To determine the clinical features of bilirubin encephalopathy in preterm infants (pBE) in Japan. METHODS: We performed a retrospective, nationwide questionnaire-based survey. The initial survey determined the number of children with pBE who were born after 2000. Using a structured questionnaire, the second survey clarified the clinical manifestations and characteristics of children with pBE, including demographic data, neurological symptoms, and MRI and auditory brainstem response (ABR) findings. RESULTS: The initial survey identified 41 pBE infants from 18 institutions. After exclusion of patients included in previous studies, clinical information was collected from 30 patients (21 boys and 9 girls) during the secondary survey. The median gestational age was 26 weeks and the median birthweight was 846 g. Chronic lung disease and symptomatic patent ductus arteriosus were common neonatal complications. Head control was observed in 63% and functional gait in 17% of patients. Purposeful hand use was seen in 57% and verbal communication in 50% of patients. MRI showed T2 hyperintensities in the globus pallidus of 29 of 30 patients. ABR abnormalities were present in 11 of 15 patients. None of the variables were significantly different between the 2017 and 2021 surveys. CONCLUSIONS: The pBE infants had severely impaired gross motor function and relatively preserved manual function and verbal communication. MRI and ABR findings aid in the diagnosis of pBE.

Determination and verification of reference intervals of serum immunoglobulin G at birth.

BACKGROUND: To accurately assess hypogammaglobulinemia at birth, it is essential to determine the reference intervals of serum immunoglobulin (IgG) levels in newborns. In the present study, we determined the gestational age (GA)-/birth weight (BW)-dependent percentile-based reference intervals of serum IgG levels and converted them into simple formulas for practical use. METHODS: Serum IgG levels were measured in cord blood from 2902 newborns delivered at 22 to 41 weeks of GA or 264 to 4642 g of BW after exclusion of those with congenital disorders. Linear regression analysis was used to correlate GA and UC-IgG levels and BW and UC-IgG levels. After calculation of the percentile values of UC-IgG levels for each GA or BW, the distributions were approximated by the least-squares method. Fitness was evaluated by the coefficient of determination (R2). RESULTS: Significant positive correlations were found both between GA and UC-IgG levels (rs = 0.790, P < 0.001) and BW and UC-IgG levels (rs = 0.626, P < 0.001). The distribution of the 5%ile of UC-IgG levels (Y) by GA or BW (X) was approximated as a straight line (Y = 37.5 *X - 775.8; Y = 0.161 *X + 95.34, respectively). The fitness was stronger in the GA-derived formula than the BW-derived formula (R2 = 0.973 vs 0.913). CONCLUSIONS: We established GA-/BW-dependent reference percentile-based intervals for serum IgG levels using cord blood from 2902 newborns without congenital disorders. Using GA-dependent reference intervals may be useful for assessing hypogammaglobulinemia at birth.

Corrigendum: Influences of Orogastric and Nasogastric Tubes on Sucking Pressure during Bottle Feeding in Immature Infants.

This corrects the article in Kobe J Med Sci. 2023 May 31; 69(1): E25-E32.

Impact of tracheostomies on the long-term survival of patients with trisomy 13 syndrome.

In this retrospective cohort study, we investigated the impact of tracheostomies on the long-term survival of children with trisomy 13 syndrome at a Japanese tertiary pediatric center. We compared survival and survival to discharge rates between patients who underwent tracheostomies during their NICU stays (T group, n = 8) and those who did not (non-T group, n = 11). A total of 19 patients enrolled. Median survival in all patients was 673 (266-1535) days. Significant differences in the 1-, 2-, and 3-year survival rates were found between the T and the non-T groups (100% vs. 46%, p = 0.018; 88% vs. 18%, p = 0.006; 63% vs. 9%, p = 0.041, respectively). The survival to discharge rate was higher in the T versus non-T group (75% vs. 45%, p = 0.352). This study highlights a significantly higher long-term survival of patients with trisomy 13 syndrome who underwent tracheostomies during their NICU stays.

Current status of neonatal jaundice management in Japan.

BACKGROUND: This nationwide survey aimed to determine the status of jaundice management in Japan. METHODS: A questionnaire about bilirubin level measurements and neonatal jaundice treatment was sent to 330 institutions providing neonatal care. The responses were analyzed according to institution level. RESULTS: Of 330 institutions, 172 responded (52.1% response rate). Total bilirubin levels were measured in the central laboratory using spectrophotometry at 134 institutions and a blood gas analyzer at 81 institutions. Unbound bilirubin (UB) levels were measured by 79 institutions, while transcutaneous bilirubin measurements were taken at 63 institutions. There was no association between institution level and UB or transcutaneous bilirubin measurement. For phototherapy criteria, the Murata-Imura criteria were adopted by 67 institutions, Nakamura criteria by 36, and Morioka criteria by 39. Light-emitting diodes (LED) were used by 160 institutions versus fluorescent lights by 31. When a blue LED was used, 119 institutions used the high mode. There is no standard for increasing light intensity. No association was found between institution level and phototherapy criteria. UB was measured in 14 of 63 institutions using the Murata-Imura criteria. CONCLUSIONS: There is a large variation in the management and treatment of neonatal jaundice among institutes in Japan.

Influences of Orogastric and Nasogastric Tubes on Sucking Pressure during Bottle Feeding in Immature Infants.

Orogastric (OG) and nasogastric (NG) tubes have been reported to delay breastfeeding initiation and affect respiratory function. However, the effects of feeding tubes on sucking pressure have not been well studied. Fourteen preterm infants were enrolled in this study, and their sucking pressures during bottle feeding with an OG tube, NG tube, and without any tube were measured. Sucking pressure significantly increased after changing the OG tube to an NG tube (p = 0.044). However, sucking pressure showed no significant differences after changing the feeding method from an NG tube to oral intake. Thus, NG tubes are superior to OG tubes in terms of sucking pressure.

Sustained lower bilirubin-binding affinity of albumin in extremely preterm infants.

BACKGROUND: Elevated albumin-free or unbound bilirubin (UB) levels beyond the first week of life have been associated with the development of bilirubin encephalopathy in preterm infants. However, the mechanism(s) that induces this prolonged unbound bilirubinemia has remained unknown. We hypothesized that it may due to a sustained lower bilirubin-binding affinity of albumin in extremely premature infants. METHODS: Twenty-two very preterm infants born at 28-31 weeks' gestational age (GA) (VPT Group) and 21 extremely preterm infants born at 22-27 weeks' GA (EPT Group) were retrospectively studied. On days 14, 21, and 28, bilirubin-binding affinity of albumin was assessed by calculating of the UB/total bilirubin ratio, bilirubin-albumin molar ratio (BAMR), and binding affinity (Ka). RESULTS: On days 14, 21, and 28, significantly higher UB/total bilirubin ratios were found in the EPT than in the VPT Group. Although BAMRs were comparable, significantly lower Ka values on days 14, 21, and 28 were observed in the EPT than those in the VPT Group (56.1 vs. 70.9 L/µmol, p < 0.001; 55.2 vs. 74.7 L/µmol, p < 0.001; 53.0 vs. 86.5 L/µmol, p < 0.001, respectively). CONCLUSIONS: EPT infants have a sustained lower bilirubin-binding affinity of albumin beyond the first week of life. IMPACT: Bilirubin encephalopathy is still reported in extremely preterm (EPT) infants. EPT infants often have prolonged unbound bilirubinemia beyond the first week of life. Sustained lower bilirubin-binding affinity of albumin, regardless of the bilirubin-albumin molar ratio (BAMR), is observed in EPT infants. BAMRs should not be used as a surrogate marker of unbound bilirubinemia, especially in EPT infants at a later postnatal period.

Decreased moderate admission hypothermia in extremely preterm newborns.

BACKGROUND: Admission temperature is inversely correlated with mortality and morbidity risk in extremely preterm newborns (EPNs). As almost all EPNs require advanced resuscitation at birth, we improved a simple and comprehensive management protocol to reduce admission hypothermia. This study reports the changes over the past 15 years in the rate of admission hypothermia in all EPNs. It clarified the distribution of admission temperature and the risk factors for developing admission hypothermia in recent EPNs. METHODS: This single-center study retrospectively analyzed the EPNs delivered at our institution between January 2006 and December 2020. The comprehensive management protocol, including warming equipment, plastic wrapping, aluminum-polyethylene sheet, and room temperature, was applied to avoid heat loss during resuscitation. On admission, the rectal temperature was measured and defined as moderate (32.0-35.9 °C) or mild (36.0-36.4 °C) hypothermia. RESULTS: Overall (n = 432), the rate of admission with moderate hypothermia decreased from 48% in 2006 to 8% in 2020. In the recent evaluation of 80 EPNs delivered in 2017-2020, 10 (13%) and 26 (33%) had moderate and mild hypothermia on admission, respectively. Extremely preterm newborns with moderate-to-mild hypothermia had a significantly smaller gestational age and lower birthweight than those without hypothermia. No significant differences in the other perinatal and environmental risk factors were observed between EPNs with and without hypothermia. CONCLUSIONS: Our comprehensive management protocol reduced the rate of moderate hypothermia on admission in EPNs to only 13%. However, eliminating mild hypothermia remains a challenge and requires continuous improvement, especially in smaller EPNs.