Lung function deficits and bronchodilator responsiveness at 12 years of age in children born very preterm compared with controls born at term.

INTRODUCTION: Very preterm birth is associated with lung function impairment later in life, but several aspects have not been studied. We aimed to comprehensively assess lung function at school age in very preterm infants and term controls, with special emphasis on bronchopulmonary dysplasia (BPD), sex, and bronchodilator response. METHODS: At 12 years of age, 136 children born very preterm (85 with and 51 without BPD) and 56 children born at term performed spirometry, body plethysmography, impulse oscillometry, measurement of diffusion capacity, and multiple breath washout, before and after bronchodilator inhalation. RESULTS: Airway symptoms and a diagnosis of asthma were more common in children born very preterm. These children had more airflow limitation, seen as lower forced expiratory volume in 1 s (FEV1 ) (p < .001), FEV1 /forced vital capacity (FVC) (p = .011), and mean forced expiratory flow between 25% and 75% of FVC (p < .001), and a higher total and peripheral airway resistance compared with term-born controls. There was no difference in total lung capacity but air trapping and lung clearance index were higher in children born very preterm. Diffusion capacity was lower in children born very preterm, especially in those with a diagnosis of BPD. In most other tests, the differences between preterm-born children with or without BPD were smaller than between children born preterm versus at term. Boys born preterm had more lung function deficits than preterm-born girls. In children born very preterm, airway obstruction was to a large extent reversible. CONCLUSION: At 12 years of age, children born very preterm had lower lung function than children born at term in most aspects and there was only little difference between children with or without BPD. Airway obstruction improved markedly after bronchodilator inhalation.

Patterns of Respiratory Support by Gestational Age in Very Preterm Infants.

INTRODUCTION: A detailed understanding of respiratory support patterns in preterm infants is lacking. The aim was to explore and visualize this practice in Sweden. METHODS: Preterm infants with gestational ages of 22-31 weeks, admitted to neonatal units reporting daily to the Swedish Neonatal Quality Register and discharged alive in November 2015-April 2022, were included in this descriptive cohort study. Proportions receiving mechanical ventilation, noninvasive support, or supplemental oxygen were calculated and graphically displayed for each gestational week and postnatal day (range 0-97) up to hospital discharge or 36 weeks of postmenstrual age. RESULTS: Respiratory support in 148,515 days of care (3,368 infants; 54% males; median [interquartile range] birthweight = 1,215 [900-1,525] g) was evaluated. Trajectories showed distinct nonlinear patterns for each category of respiratory support, but differences in respiratory support over the gestational age range were linear: the proportion of infants on mechanical ventilation decreased by -11.7 to -7.3% (variability in estimates related to the postnatal day chosen for regression analysis) for each week higher gestational age (r = -0.99 to -0.87, p ≤ 0.001). The corresponding proportions of infants with supplemental oxygen decreased by -12.4% to -4.5% for each week higher gestational age (r = -0.98 to -0.94, p < 0.001). At 36 weeks of postmenstrual age, dependencies on mechanical ventilation, noninvasive support, and supplemental oxygen varied from 3%, 84%, and 94% at 22 weeks to 0%, 3%, and 5% at 31 weeks of gestational age, respectively. CONCLUSIONS: Respiratory support patterns in very preterm infants follow nonlinear, gestational age-specific postnatal trajectories in a dose-response-related fashion.

Perinatal inflammation relates to early respiratory morbidity and lung function at 12 years of age in children born very preterm.

AIM: Very preterm birth may be associated with lung function impairment later in life. It is not known if this is caused by prematurity per se or by associated perinatal events, such as maternal-foetal inflammation and severity of early neonatal lung disease. We assessed these factors in a prospective cohort of very preterm infants followed from birth to middle school age. METHODS: In 71 infants with a gestational age of median 27.4 (range 23.9-31.7) weeks, pro-inflammatory and modulatory cytokines were measured in umbilical cord blood and in arterial blood sampled at 6, 24 and 72 h after birth, and cumulated cytokine concentrations were calculated as area under the curve (AUC). At median 12.6 (range 12.3-13.5) years of age, pulmonary function testing was done in 53 children. RESULTS: There was a positive correlation between days on mechanical ventilation and AUC for IL-6 (p = 0.001), IL-8 (p = 0.015) and IL-10 (p = 0.006). Infants with bronchopulmonary dysplasia (BPD; n = 32) had higher AUC for the cytokines IL-6, IL-8 and IL-10 than those without BPD (all p < 0.01). Higher levels of AUC for IL-6 at birth correlated with lower forced expiratory volume in 1 s (p = 0.030) and lower mean expiratory flow rate between 25 and 75% of forced vital capacity (p = 0.034). CONCLUSION: Perinatal inflammation, assessed by circulating cytokines in the first three days of life, was associated with BPD and with airway obstruction at 12 years of age.

Association Between Year of Birth and 1-Year Survival Among Extremely Preterm Infants in Sweden During 2004-2007 and 2014-2016.

Importance: Since 2004-2007, national guidelines and recommendations have been developed for the management of extremely preterm births in Sweden. If and how more uniform management has affected infant survival is unknown. Objective: To compare survival of extremely preterm infants born during 2004-2007 with survival of infants born during 2014-2016. Design, Setting and Participants: All births at 22-26 weeks' gestational age (n = 2205) between April 1, 2004, and March 31, 2007, and between January 1, 2014, and December 31, 2016, in Sweden were studied. Prospective data collection was used during 2004-2007. Data were obtained from the Swedish pregnancy, medical birth, and neonatal quality registries during 2014-2016. Exposures: Delivery at 22-26 weeks' gestational age. Main Outcomes and Measures: The primary outcome was infant survival to the age of 1 year. The secondary outcome was 1-year survival among live-born infants who did not have any major neonatal morbidity (specifically, without intraventricular hemorrhage grade 3-4, cystic periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity stage 3-5, or severe bronchopulmonary dysplasia). Results: During 2004-2007, 1009 births (3.3/1000 of all births) occurred at 22-26 weeks' gestational age compared with 1196 births (3.4/1000 of all births) during 2014-2016 (P = .61). One-year survival among live-born infants at 22-26 weeks' gestational age was significantly lower during 2004-2007 (497 of 705 infants [70%]) than during 2014-2016 (711 of 923 infants [77%]) (difference, -7% [95% CI, -11% to -2.2%], P = .003). One-year survival among live-born infants at 22-26 weeks' gestational age and without any major neonatal morbidity was significantly lower during 2004-2007 (226 of 705 infants [32%]) than during 2014-2016 (355 of 923 infants [38%]) (difference, -6% [95% CI, -11% to -1.7%], P = .008). Conclusions and Relevance: Among live births at 22-26 weeks' gestational age in Sweden, 1-year survival improved between 2004-2007 and 2014-2016.

Club cell secretory protein (CC16) in gastric fluid at birth and subsequent lung disease in preterm infants.

BACKGROUND: Club cell secretory protein (CC16) probably has a role in protecting the lung from inflammation. AIM: To evaluate if low levels of CC16 in gastric fluid at birth, reflecting low levels of CC16 in the lung, would be associated with lung inflammation and respiratory morbidity. METHODS: A study of 64 infants with mean gestational age 26.1 weeks. CC16 was analyzed in gastric fluid at birth. CC16, pro-inflammatory cytokines, and MMP-9 were analyzed in tracheal aspirate within 24 h from birth. RESULTS: CC16 in gastric fluid increased with gestational age (P = 0.033). Lower concentrations of CC16 in gastric fluid at birth were associated with higher concentrations of IL-1ß (P = 0.028), TNF-α (P = 0.034), and MMP-9 (P = 0.015) in tracheal aspirate. Infants who needed mechanical ventilation at 24 and 72 h of age had lower CC16 in gastric fluid than those not ventilated at these ages (P = 0.011 and P = 0.024, respectively). Lower CC16 in gastric fluid was associated with higher FiO2 at 6 h (P = 0.009), higher PaCO2 at 24 h (P = 0.03), more ventilator days (P = 0.012) and more days with supplemental oxygen (P = 0.03). Infants who had either died or were still treated with supplemental oxygen at 36 weeks postmenstrual age had lower CC16 in gastric fluid than infants with none of these outcomes (P = 0.049). CONCLUSION: A low CC16 concentration in gastric fluid at birth was associated with increased inflammation in the trachea within the first 24 h of life and with more need for respiratory support in the neonatal period.

Rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted respiratory distress syndrome with high sensitivity.

AIM: Respiratory distress syndrome (RDS) is a major cause of mortality and morbidity in premature infants. By the time symptoms appear, it may already be too late to prevent a severe course, with bronchopulmonary dysplasia or mortality. We aimed to develop a rapid test of lung maturity for targeting surfactant supplementation. METHODS: Concentrations of the most surface-active lung phospholipid dipalmitoylphosphatidylcholine and sphingomyelin in gastric aspirates from premature infants were measured by mass spectrometry and expressed as the lecithin/sphingomyelin ratio (L/S). The same aspirates were analysed with mid-infrared spectroscopy. Subsequently, L/S was measured in gastric aspirates and oropharyngeal secretions from another group of premature infants using spectroscopy and the results were compared with RDS development. The 10-minute analysis required 10 µL of aspirate. RESULTS: An L/S algorithm was developed based on 89 aspirates. Subsequently, gastric aspirates were sampled in 136 infants of 24-31 weeks of gestation and 61 (45%) developed RDS. The cut-off value of L/S was 2.2, sensitivity was 92%, and specificity was 73%. In 59 cases, the oropharyngeal secretions had less valid L/S than gastric aspirate results. CONCLUSION: Our rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted RDS with high sensitivity.

Clinical experience of urine D-arabinitol/L-arabinitol ratio in the early diagnosis of invasive candidiasis in paediatric high risk populations.

In 2 prospective studies, we previously reported on the early and accurate diagnosis of invasive candidiasis by determining the D-arabinitol/L-arabinitol (DA/LA) ratio in urine in neutropenic children with cancer at the paediatric oncology unit (POU) and in premature infants at the neonatal intensive care unit (NICU) at our hospital. In this retrospective study at the same units, we report how the DA/LA assay was implemented in clinical practice immediately after the prospective study periods. We found that, in the POU, the recommendation of regularly monitoring urine DA/LA ratios in patients at risk and considering antifungal therapy in the case of elevated ratios had been followed. A significant decrease in the incidence of culture positive invasive candidiasis may have been attributed to the introduction of the DA/LA assay. At the NICU, where the DA/LA assay was recommended only as an adjunct to other diagnostic tools, morbidity in invasive candidiasis remained unchanged. While regular monitoring of the urine DA/LA ratio probably facilitates the early detection of invasive candidiasis in paediatric oncology, it remains to be determined if the test can be used in a similar way in neonatal intensive care.