Understanding paediatric COVID-19 vaccination during the pandemic: a prospective cohort and a population-based registry study.

Background: Despite the early demonstrated safety and effectiveness of COVID-19 vaccines in children, uptake was slow throughout the pandemic and remains low globally. Understanding vaccine refusal could provide insights to improving vaccine uptake in future pandemics. Methods: In a population-wide registry of all COVID-19 paediatric vaccination appointments, we used interrupted time series analysis to evaluate the impact of public policies. In a population-based cohort of adults, we used population attributable fractions to assess the individual and joint contributions of potential determinants to paediatric COVID-19 vaccination, and used mediation analysis to identify modifiable mediators between political views and paediatric vaccination. Findings: School vaccination requirements were associated with an increase in vaccination appointments by 278.7% (95% CI 85.3-673.9) in adolescents aged 12-17 and 112.8% (27.6-255.0) in children aged 5-11. Government-mandated vaccine pass, required for entry into restaurants, shopping malls and supermarkets, was associated with increased vaccination appointments by 108.7% (26.6-244.0) in adolescents. The following four determinants may explain 82.5% (63.5-100.0) of the reasons why children were unvaccinated: familial political views, vaccine hesitancy for children, mistrust in doctors and academics, and vaccine misconceptions. The influence of political views may be mitigated since 95.9% (76.4-100.0) of its association with vaccine reluctance for adolescents was mediated by modifiable factors such as mistrust in health authorities and low vaccine confidence. Interpretation: School vaccination requirements and vaccine passes were associated with increased vaccine uptake. Clinicians should recognise that factors beyond health, such as political views, can influence paediatric vaccine uptake to a significant extent. Nonetheless, such influences could be mitigated by targeted interventions and public policies. Funding: Hong Kong Jockey Club Charities Trust, Research Grants Council, University Grants Committee, and Health Bureau.

Deficits in neural encoding of speech in preterm infants.

Preterm children show developmental cognitive and language deficits that can be subtle and sometimes undetectable until later in life. Studies of brain development in children who are born preterm have largely focused on vascular and gross anatomical characteristics rather than pathophysiological processes that may contribute to these developmental deficits. Neural encoding of speech as reflected in EEG recordings is predictive of future language development and could provide insights into those pathophysiological processes. We recorded EEG from 45 preterm (≤ 34 weeks of gestation) and 45 term (≥ 38 weeks) Chinese-learning infants 0-12 months of (corrected) age during natural sleep. Each child listened to three speech stimuli that differed in lexically meaningful pitch (2 native and 1 non-native speech categories). EEG measures associated with synchronization and gross power of the frequency following response (FFR) were examined. ANCOVAs revealed no main effect of stimulus nativeness but main effects of age, consistent with earlier studies. A main effect of prematurity also emerged, with synchronization measures showing stronger group differences than power. By detailing differences in FFR measures related to synchronization and power, this study brings us closer to identifying the pathophysiological pathway to often subtle language problems experienced by preterm children.

Improving Consistency and Accuracy of Neonatal Amplitude-Integrated Electroencephalography.

OBJECTIVE: This study aimed to improve the utilization of amplitude-integrated electroencephalography (aEEG) in a neonatal unit by improving aEEG documentation, aEEG knowledge, and pattern recognition ability of neonatal staff. METHODS: A quality improvement (QI) program comprising the two Plan-Do-Study-Act (PDSA) cycles was conducted in a level-3 neonatal intensive care unit. The first cycle was focused on improving aEEG documentation with the primary outcome indicator being compliance with aEEG documentation. The second cycle was focused on aEEG interpretation in a health care professional education program with the outcome indicators being accuracy of seizure identification on aEEG and change in conventional EEGs (cEEG) performed. Other outcome indicators included accuracy in identification of background pattern, sleep-wake cycles and artifacts. Process indicators included improvement in aEEG-related knowledge. RESULTS: First PDSA cycle includes lectures on aEEG interpretation, a bedside key, and documentation form. Second PDSA cycle includes online aEEG education pack and detailed aEEG guideline. There was a significant improvement in aEEG documentation after the implementation of both PDSA cycles. Seven of the 46 patients (15.2%) had isolated electrographic seizures which would not have been identified in the pre-aEEG monitoring era. There was an increase in the number of patients with cEEGs done but a steady decrease in number of cEEGs per patient. CONCLUSION: With the successful application of standardized QI methods, improvements in outcome indicators, such as correct aEEG pattern recognition and improved coverage of at risk infants with cEEGs, were observed. Our QI measures were associated with improvement in aEEG pattern recognition. KEY POINTS: · Consistent and accurate use of aEEG is challenging.. · Standardized forms and guidelines improve aEEG interpretation consistency and documentation.. · Interactive self-paced online education packs can improve aEEG knowledge and pattern recognition..

Sleep Duration and Adiposity in Children and Adults: Observational and Mendelian Randomization Studies.

OBJECTIVE: This study used two complementary designs, an observational and a Mendelian randomization (MR) study, to assess whether sleep duration causes adiposity in children and adults. METHODS: In Hong Kong's "Children of 1997" birth cohort, the adjusted cross-sectional associations of sleep duration with BMI z score and obesity and overweight were assessed at ~11 years of age. Generalized estimating equations were also used to examine longitudinal associations of sleep duration at ~11 years with annual BMI z score and obesity and overweight at about 11 to 16 years of age. Using MR, this study assessed the association of genetically predicted sleep duration, based on 54 single-nucleotide polymorphisms, applied to genetic studies of adiposity in children (n = 35,668), men (n = 152,893), and women (n = 171,977). RESULTS: Longer sleep was cross-sectionally associated with lower BMI z score at ~11 years of age (-0.13 per category, 95% CI: -0.22 to -0.04) and at about 11 to 16 years of age longitudinally in girls (-0.39, 95% CI: -0.66 to -0.13). Using MR, sleep duration was inversely associated with BMI in children (-0.29 SD per hour, 95% CI: -0.54 to -0.04), but was not clearly associated with BMI in adults, particularly for women. CONCLUSIONS: A small beneficial effect of sleep on BMI in children cannot be ruled out.

Life-Threatening Hemolytic Anemia after Intrapleural Instillation of OK-432 for Treatment of Congenital Chylothorax.

Recent reports have advocated treatment of congenital chylothorax with chemical pleurodesis via intrapleural administration of OK-432. Severe complications have not been reported, but recently we have encountered a life-threatening case of massive hemolysis after the procedure. The hemoglobin of the infant decreased from 8.7 to 3.1 g/dl within 48 h, with concomitant severe hyperbilirubinemia (472 µmol/l) requiring exchange transfusion. Frontline neonatologists should be aware of this rare but potentially life-threatening adverse reaction. In addition, it is possible that a longer indwelling time (3.5 vs. 0.5 h) for OK-432 pleurodesis may alter the therapeutic response.

Gestational Age, Birthweight for Gestational Age, and Childhood Hospitalisations for Asthma and Other Wheezing Disorders.

BACKGROUND: Preterm birth, early term birth, and low birthweight are associated with childhood wheezing disorders in developed Western settings, but observed associations could be confounded by socio-economic position. This study aims to clarify such associations in a developed non-Western setting with a different confounding structure. METHODS: Using Cox regression, we examined the adjusted associations of gestational age and birthweight for gestational age with time to first public hospital admission for asthma, bronchitis, and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490, and 493) from 9 days to 12 years in a population-representative birth cohort of 8327 Chinese children in Hong Kong, a developed setting with less clear social patterning of prematurity or birthweight. Analyses were adjusted for infant and parental characteristics and socio-economic position. RESULTS: Children born late preterm (34 to <37 weeks) had higher risk of hospitalisation for asthma and other wheezing disorders [hazard ratio (HR) 1.99, 95% confidence interval (CI) 1.48, 2.67] than children born full term (39 to <41 weeks). Early term births (37 to <39 weeks) had HR 1.01 (95% CI 0.84, 1.22), late term births (41 to <42 weeks) had HR 0.77 (95% 0.59, 1.01), and post-term births (≥42 weeks) had HR 0.56 (95% CI 0.32, 0.98). Large for gestational age was associated with lower risk of hospitalisation (HR 0.76, 95% CI 0.57, 0.99). CONCLUSION: The association of preterm birth with childhood wheezing could be biologically mediated. We cannot rule out an association for early term births.

End-of-life decision-making for newborns: a 12-year experience in Hong Kong.

SETTING: Neonatal end-of-life decisions could be influenced by cultural and ethnic backgrounds. These practices have been well described in the West but have not been systematically studied in an Asian population. OBJECTIVES: To determine: (1) different modes of neonatal death and changes over the past 12 years and (2) factors influencing end-of-life decision-making in Hong Kong. DESIGN: A retrospective study was conducted to review all death cases from 2002 to 2013 in the busiest neonatal unit in Hong Kong. Modes of death, demographical data, diagnoses, counselling and circumstances around the time of death, were collected and compared between groups. RESULTS: Of the 166 deaths, 46% occurred despite active resuscitation (group 1); 35% resulted from treatment withdrawal (group 2) and 19% occurred from withholding treatment (group 3). A rising trend towards treatment withdrawal was observed, from 20% to 47% over the 12-year period. Similar number of parents chose extubation (n=44, 27%) compared with other modalities of treatment limitation (n=45, 27%). Significantly more parents chose to withdraw rather than to withhold treatment if clinical conditions were 'stable' (p=0.03), whereas more parents chose withholding therapy if treatment was considered futile (p=0.03). CONCLUSION: In Hong Kong, a larger proportion of neonatal deaths occurred despite active resuscitation compared with Western data. Treatment withdrawal is, however, becoming increasingly more common. Unlike Western practice, similar percentages of parents chose other modalities of treatment limitation compared with direct extubation. Cultural variance could be a reason for the different end-of-life practice adopted in Hong Kong.

The neonatal resuscitation algorithm organized cart is more efficient than the airway-breathing-circulation organized drawer: a crossover randomized control trial.

INTRODUCTION: Although there is consensus on the resuscitation of newborns, there is no standardization on how resuscitation equipment should be organized. This might lead to difficulty and inefficiency in retrieval of the right equipment during resuscitation. The neonatal resuscitation carts organized in accordance with the American Academy of Pediatrics (AAP) Neonatal Resuscitation Program (NRP) algorithm might result in more efficient retrieval of resuscitation equipment. OBJECTIVES: To compare user preference and lengths of time required to retrieve standard resuscitation equipment from an NRP Cart versus a generic storage drawer. STUDY DESIGN: A prospective, randomized, controlled, and crossover trial was conducted during simulation-based NRP provider courses in the Accident & Emergency Training Centre from September to October 2013. The mean time of accurate equipment retrieval and ease of use, which was rated by the participants using a five-point Likert scale (1=most difficult, 5=easiest to use), were compared using the Wilcoxon signed-rank test because of right skew. RESULTS: A total of 55 individuals participated in this study. The mean length of time required for equipment retrieval from the NRP Cart was significantly less than that from the drawer (Z=-3.90, P<0.01, median=36.23 s, interquartile range=97 s). In general, the NRP Cart was 32% faster than the drawer when extensive resuscitation equipment was required. All the participants rated the NRP Cart as easier to use than the drawer, with a median score of 4 for NRP Cart and 3 for the drawer (Z=-4.10, P<0.01, interquartile range=2). CONCLUSION: The NRP Cart was superior to the generic drawer in terms of the speed of equipment retrieval and user acceptability.

Late prematurity and adiposity in adolescents: Evidence from "Children of 1997" birth cohort.

OBJECTIVE: The association of late prematurity with later adiposity is unclear, and the mediating role of infant growth is seldom studied. We assessed the association of late prematurity with markers of adiposity in adolescence and tested whether accelerated infant weight gain mediated the association. METHODS: In the Chinese birth cohort "Children of 1997," we used multivariable linear regression to assess the adjusted association of late premature (n = 295), compared to term (n = 6874), births with markers of adiposity at 14 years. We tested whether any association was mediated by accelerated weight gain from birth to 12 months, i.e., a change in weight z-score ≥0.67. RESULTS: Late premature births had greater body mass index (BMI) z-score (0.21, 95% confidence interval (CI) 0.07, 0.35), waist-hip ratio z-score (0.16, 95% CI 0.03, 0.29), and waist-height ratio z-score (0.27, 95% CI 0.14, 0.40) than term births in adolescence. The association of late prematurity with higher adolescent BMI, but not waist ratios, was mediated by accelerated infant weight gain. CONCLUSIONS: Late prematurity was associated with higher BMI and waist ratios in adolescence, but only the association with BMI was mediated by infant weight gain, suggesting vulnerability to metabolic risk in late premature births may arise through multiple pathways.

Intranasal corticosteroids for mild childhood obstructive sleep apnea--a randomized, placebo-controlled study.

BACKGROUND: The use of non-surgical treatment for childhood obstructive sleep apnea (OSA) is gaining popularity, especially in children with mild disease. OBJECTIVE: To test the hypothesis that intranasal corticosteroids reduce disease severity in children with mild OSA. STUDY DESIGN: A randomized, double-blinded, placebo-controlled trial of intranasal mometasone furoate (MF) versus placebo in children aged 6 to 18 years with mild OSA. The primary outcome was the change from baseline obstructive apnea hypopnea index (OAHI), as documented by overnight polysomnography, after four months of treatment. RESULTS: Sixty-two children were recruited but 12 dropped out. This left 24 and 26 children for final analysis in the MF and placebo group, respectively. The OAHI and oxygen desaturation index (ODI) improved significantly in the MF group only. The OAHI decreased from 2.7 ± 0.2 to 1.7 ± 0.3 in the MF group, but increased from 2.5 ± 0.2 to 2.9 ± 0.6 in the placebo group (p = 0.039). The mean changes in ODI in the MF group and placebo group were -0.6 ± 0.5 and +0.7 ± 0.4, respectively (p = 0.037). CONCLUSION: Four months of treatment with intranasal mometasone furoate effectively reduces the severity of mild OSA in children.

Endothelial function in children with OSA and the effects of adenotonsillectomy.

BACKGROUND: The association between childhood OSA and endothelial function as measured by flow-mediated dilation (FMD) and its response to OSA treatment are uncertain. The objective of this study was to compare FMD in children with OSA with nonsnoring control subjects and to examine its response to treatment. METHODS: Index cases were children aged 6 to 18 years with habitual snoring and polysomnography (PSG)-confirmed OSA (obstructive apnea hypopnea index [OAHI] > 1 events/h). Each case was paired with an age-, sex-, and BMI-matched nonsnoring control subject recruited from our previous community growth survey. All subjects underwent FMD measurement in the morning after overnight PSG. Adenotonsillectomy (AT) was offered to subjects who satisfied predefined AT operation criteria. All cases underwent repeat PSG and FMD assessment 6 months later. RESULTS: A total of 63 case-control pairs were recruited. The OSA group had a significantly higher OAHI (median, 5.3 events/h [interquartile range (IQR), 2.6-11.7] vs 0.2 events/h [IQR, 0-0.5], P < .001) and lower FMD (mean ± SD, 7.9% ± 1.3% vs 8.3% ± 0.8%; P = .04) than the control group. Thirty-two case subjects underwent AT. A significant reduction in OAHI was documented in the AT group (-8.8 events/h [IQR, -13.7 to -4.7]; P < .001) accompanied by a significant increase in FMD (+0.6% [IQR, 0.4-1.4]; P < .001), which was not observed in subjects who did not undergo AT. CONCLUSIONS: Children with OSA had reduced FMD, which was reversible with treatment.

A double-blind randomised controlled trial of fish oil-based versus soy-based lipid preparations in the treatment of infants with parenteral nutrition-associated cholestasis.

BACKGROUND: Infants receiving prolonged parenteral nutrition (PN) are at risk of PN-associated cholestasis (PNAC). This can progress to hepatic failure and death if PN cannot be discontinued. Fish oil-based parenteral lipid preparation (FOLP) has been shown to be beneficial in case studies. OBJECTIVES: (1) To evaluate whether FOLP could halt or reverse the progression of PNAC compared with soy-based parenteral lipid preparation (SLP) and (2) to assess the effects of FOLP on liver function and physical growth. DESIGN: double-blind randomised controlled trial. SETTING: level III neonatal intensive care unit. PARTICIPANTS: infants with PNAC (plasma-conjugated bilirubin concentration ≥ 34 µmol/l or 2 mg/dl) expected to be PN-dependent for >2 weeks. INTERVENTION: to receive either FOLP or SLP at 1.5 g/kg/day. PRIMARY OUTCOME MEASURE: reversal of PNAC within 4 months after commencement of lipid treatment; secondary outcomes: rate of change of weekly liver function tests, infant growth parameters, blood lipid profile and episodes of late-onset sepsis. RESULTS: A total of 9 infants were randomised to the FOLP group and 7 to the SLP group. There was no significant difference in reversal of PNAC at 4 months between groups. Rates of increase of plasma-conjugated bilirubin and alanine aminotransferase in the SLP group were significantly greater than the FOLP group (13.5 vs. 0.6 µmol/l per week and 9.1 vs. 1.1 IU/l per week, respectively, p = 0.03). Increased enteral nutrition was associated with significant improvement of PNAC in infants receiving FOLP compared with SLP (-8.5 vs. -1.6 µmol/l per 10% increase in enteral nutrition, respectively). The study was terminated prematurely. CONCLUSIONS: progression of PNAC in PN-dependent infants can be halted by replacing SLP with FOLP and reversed by increasing the proportion of enteral nutrition in infants receiving FOLP. Replacement of SLP with FOLP in PN-dependent infants who develop PNAC may be considered.

A 4-year prospective follow-up study of childhood OSA and its association with BP.

BACKGROUND: Childhood OSA is a prevalent condition associated with raised BP as documented in cross-sectional studies. This study aimed to determine whether baseline or change in OSA severity was associated with ambulatory BP at 4-year follow-up. METHODS: Children who participated in our previous OSA prevalence research were invited to undergo a repeat overnight sleep study and 24-h ambulatory BP monitoring in this 4-year follow-up study. BP parameters of subjects with differing baseline OSA severity, that is, obstructive apnea-hypopnea index (OAHI) < 1/h, 1 to 5/h, and > 5/h, were compared. Overweight and normal-weight children were analyzed separately. RESULTS: One hundred eighty-five of 306 subjects (60%) were included in the analysis, of whom 58 were overweight at baseline. Linear increasing trends of wake systolic BP (SBP), wake diastolic BP (DBP), and sleep SBP z scores at follow-up were found across groups of increasing baseline OSA severity in the normal weight but not in the overweight subgroup. After adjusting for BMI z score, baseline OAHI was independently associated with all BP z scores at follow-up but not associated with changes in BP z scores across 4 years. On the other hand, change in OAHI was independently associated with sleep SBP and DBP z scores at follow-up and with changes in sleep SBP and DBP z scores across 4 years. CONCLUSIONS: This study provides longitudinal data as additional proof that childhood OSA is associated with elevated BP independent of obesity.

Sleep architecture in school-aged children with primary snoring.

OBJECTIVE: We aimed to examine if sleep architecture was altered in school-aged children with primary snoring (PS). METHODS: Children ages 6 to 13 years from 13 primary schools were randomly recruited. A validated obstructive sleep apnea (OSA) screening questionnaire was completed by their parents. Children at high risk for OSA and a randomly chosen low-risk group were invited to undergo overnight polysomnography (PSG) and clinical examination. Participants were classified into healthy controls, PS, mild OSA, and moderate to severe OSA (MS OSA) groups for comparison. RESULTS: A total of 619 participants underwent PSG (mean age, 10.0 ± 1.8 years; 396 (64.0%) boys; 524 (84.7%) prepubertal). For the cohort as a whole, there were no significant differences in measures of sleep architecture between PS and nonsnoring healthy controls. In the multiple regression model, percentage of nonrapid eye movement (NREM) stage 1 (N1) sleep had a significantly positive association, whereas percentage of slow-wave sleep (SWS) had a significantly negative association with sleep-disordered breathing (SDB) severity after controlling for age, gender, body mass index (BMI) z score, and pubertal status. In prepubertal children with PS, no significant disruption of sleep architecture was found. However, pubertal adolescent PS participants had significantly higher adjusted percentage of N1 sleep and wake after sleep onset (WASO) compared to healthy controls. CONCLUSIONS: PS did not exert significant adverse influences on normal sleep architecture in prepubertal school-aged children. Nevertheless, pubertal adolescents with PS had increased N1 sleep and WASO.

Gut-associated biomarkers L-FABP, I-FABP, and TFF3 and LIT score for diagnosis of surgical necrotizing enterocolitis in preterm infants.

OBJECTIVES: To evaluate the use of gut barrier proteins, liver-fatty acid binding protein (L-FABP), intestinal-fatty acid binding protein (I-FABP), and trefoil factor 3 (TFF3), as biomarkers for differentiating necrotizing enterocolitis (NEC) from septicemic/control infants and to identify the most severely affected surgical NEC from nonsurgical NEC infants. BACKGROUND: Clinical features and routine radiologic investigations have low diagnostic utilities in identifying surgical NEC patients. METHODS: The diagnostic utilities of individual biomarkers and the combination of biomarkers, the LIT score, were assessed among the NEC (n = 20), septicemia (n = 40), and control groups (n = 40) in a case-control study for the identification of proven NEC and surgical NEC infants. RESULTS: Plasma concentrations of all gut barrier biomarkers and the LIT score were significantly higher in the NEC than in the septicemia or control group (P < 0.01). Using median values of biomarkers and the LIT score in the NEC group as cutoff values for identifying NEC from septicemic/control cases, all had specificities of 95% or more and sensitivities of 50%. Significantly higher levels of biomarkers and the LIT score were found in infants with surgical NEC than in nonsurgical NEC cases (P ≤ 0.02). The median LIT score of 4.5 identified surgical NEC cases with sensitivity and specificity of 83% and 100%%, respectively. A high LIT score of 6 identified nonsurvivors of NEC with sensitivity and specificity of 78% and 91%, respectively. CONCLUSIONS: The LIT score can effectively differentiate surgical NEC from nonsurgical NEC infants and nonsurvivors of NEC from survivors at the onset of clinical presentation. Frontline neonatologists and surgeons may, therefore, target NEC infants who are most in need of close monitoring and those who may benefit from early surgical intervention.

Reduced flow-mediated vasodilation of brachial artery in children with primary snoring.

BACKGROUND: Sleep disordered breathing, especially obstructive sleep apnea, is associated with endothelial dysfunction in both adults and children. However, the role of primary snoring (PS) on endothelial function has not been investigated. This study aimed to examine flow-mediated vasodilation (FMD) in both normal weight and overweight children with PS. METHODS: Children aged 6-18 years with habitual snoring were recruited from our sleep disorder clinic. Non-snoring controls were recruited from participants of a community growth survey. All subjects underwent polysomnography and FMD evaluation on the same day. Children with body mass index of greater than the 85th percentile of the local reference were defined as overweight. Subjects were divided into groups of normal weight, overweight, non-snorers and PS for comparisons. RESULTS: Two hundred and one children, of whom 83 were overweight, with a mean ± SD age of 11.3 ± 2.7 years were recruited. Seventy three out of 201 children had PS. Both normal weight (7.9 ± 1.3 vs. 8.5 ± 0.9, p=0.012) and overweight subjects (7.4 ± 1.4 vs. 8.1 ± 1.1, p=0.006) with PS had significantly reduced FMD than the non-snoring controls. Multivariate linear regression model showed that PS was independently associated with reduced FMD in both normal weight (p=0.014) and overweight subgroups (p=0.016) after controlling for obstructive apnea hypopnea index. CONCLUSIONS: PS in children is associated with reduced FMD, independent of obesity.

Biomarkers in neonatology: the next generation of tests.

Over the past two decades, neonatal clinicians have commonly used host response biomarkers to diagnose and assess the severity of systemic infection. Most of these biomarkers, such as acute-phase proteins or cytokines, are non-specific immunomodulating mediators of the inflammatory cascade. With advances in biochemical/genetic research, it is anticipated that future biomarkers will be 'organ and/or disease specific'. There is also the quest for discovery of 'novel' biomarkers to assist diagnosis and prognosis of neonatal diseases using powerful mass-screening techniques, e.g. the next-generation sequencing, proteomics and arrays. This article aims to introduce the concept of the next generation of biomarkers to practising neonatal clinicians, and, hopefully, to integrate basic science research into day-to-day clinical practice in the future.

Follow up of aerobic capacity in children affected by severe acute respiratory syndrome.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the aerobic capacity of children 3 years after they were diagnosed with severe acute respiratory syndrome (SARS). METHODS: Twenty-seven patients who completed both pulmonary function and maximal aerobic capacity tests at 6 and 15 months after the acute illness were invited to return for reassessment. RESULTS: Twenty-one patients (median age 18.2 years, interquartile range (IQR) 16.5-19.7) completed all investigations at 36 months. Pulmonary function was normal in all patients. Maximal aerobic capacity, peak oxygen pulse (peak VO(2) ) and ventilatory anaerobic threshold showed significant improvements compared with values measured at 6 months in both boys and girls. In girls, ventilatory efficiency (ventilatory equivalents for oxygen and carbon dioxide) and perfusion of the lungs (end-tidal partial carbon dioxide pressure) had not increased further compared with the values measured at 15 months. Although peak VO(2) improved further at 36 months in patients with or without persistent radiological abnormalities, the values were 68% (IQR 50-84) and 74% (IQR 60-99), respectively, of those for normal control subjects. CONCLUSIONS: There were improvements in aerobic capacity at 36 months in children affected by SARS; however, the measured values remained suboptimal.

A prospective longitudinal study to estimate the "adjusted cortisol percentile" in preterm infants.

The normal range of serum cortisol concentrations and the appropriate levels of circulating cortisol in different clinical situations in preterm infants are not well defined. This study aimed to evaluate the impact of perinatal factors on circulating cortisol levels in preterm infants and to create a quantitative model that could estimate the "adjusted cortisol percentile." Serial serum cortisol concentrations were measured in 209 infants ≤ 32 wk gestation on d 1, 4, 7, 14, and 21 of life. Seven perinatal factors or conditions that could affect circulating cortisol level were identified. Serum cortisol levels were higher on d 4 (p = 0.007) and d 7 (p = 0.007) but lower on d 21 (p = 0.001) compared with d 1. Serum cortisol was also higher in infants on nasal continuous positive airway pressure (p = 0.003); requiring a second vasopressor (p < 0.001); with intraventricular hemorrhage (≥ grade 3; p < 0.001); with histologic chorioamnionitis (p = 0.007); with severe lung disease (p = 0.046); and with decreasing GA (p < 0.001). A mathematical equation was proposed based on factors derived in this preliminary study for estimating the adjusted cortisol percentile. Frontline neonatologists could now access the equation on our Web site (http://www.sta.cuhk.edu.hk/pswong/ACortP.html) to calculate the adjusted cortisol percentile, which could potentially improve the interpretation of circulating cortisol in different clinical situations.