Are the severity of obstruction and the apnea-hypopnea index related to orofacial anatomy in children with obstructive sleep apnea? a kinetic MRI study.

OBJECTIVES: The proportionality between anatomical characteristics and disease severity in children and adolescents with obstructive sleep apnea (OSA) has not been well characterized. The present study investigated the relationship between the dentoskeletal and oropharyngeal features of young patients with OSA and either the apnea-hypopnea index (AHI) or the amount of upper airway obstruction. METHODS: MRI of 25 patients (8- to 18-year-old) with OSA (mean AHI = 4.3 events/h) was retrospectively analyzed. Sleep kinetic MRI (kMRI) was used to assess airway obstruction, and static MRI (sMRI) was used to assess dentoskeletal, soft tissue, and airway parameters. Factors related to AHI and obstruction severity were identified with multiple linear regression (significance level α = 0.05). RESULTS: As evidenced by kMRI, circumferential obstruction was present in 44% of patients, while laterolateral and anteroposterior was present in 28%; as evidenced by kMRI, obstructions were retropalatal in 64% of cases and retroglossal in 36% (no nasopharyngeal obstructions); kMRI showed a higher prevalence of retroglossal obstructions compared to sMRI(p = 0.037); the main obstruction airway area was not related to AHI; the maxillary skeletal width was related to AHI (ß = -0.512, p = 0.007) and obstruction severity (ß = 0.625, p = 0.002); and the retropalatal width was related to AHI (ß = -0.384, p = 0.024) and obstruction severity (ß = 0.519, p = 0.006). CONCLUSIONS: In children and adolescents, the severity of OSA and obstruction were inversely proportional to the maxillary basal width and retropalatal airway width. Further studies are needed to assess the benefits of targeted clinical treatments widening the transverse dimension of these structures.

Changes in all-cause and cause-specific excess mortality before and after the Omicron outbreak of COVID-19 in Hong Kong.

Background: While coronavirus 2019 (COVID-19) deaths were generally underestimated in many countries, Hong Kong may show a different trend of excess mortality due to stringent measures, especially for deaths related to respiratory diseases. Nevertheless, the Omicron outbreak in Hong Kong evolved into a territory-wide transmission, similar to other settings such as Singapore, South Korea, and recently, mainland China. We hypothesized that the excess mortality would differ substantially before and after the Omicron outbreak. Methods: We conducted a time-series analysis of daily deaths stratified by age, reported causes, and epidemic wave. We determined the excess mortality from the difference between observed and expected mortality from 23 January 2020 to 1 June 2022 by fitting mortality data from 2013 to 2019. Results: During the early phase of the pandemic, the estimated excess mortality was -19.92 (95% confidence interval (CI) = -29.09, -10.75) and -115.57 (95% CI = -161.34, -69.79) per 100 000 population overall and for the elderly, respectively. However, the overall excess mortality rate was 234.08 (95% CI = 224.66, 243.50) per 100 000 population overall and as high as 928.09 (95% CI = 885.14, 971.04) per 100 000 population for the elderly during the Omicron epidemic. We generally observed negative excess mortality rates of non-COVID-19 respiratory diseases before and after the Omicron outbreak. In contrast, increases in excess mortality were generally reported in non-respiratory diseases after the Omicron outbreak. Conclusions: Our results highlighted the averted mortality before 2022 among the elderly and patients with non-COVID-19 respiratory diseases, due to indirect benefits from stringent non-pharmaceutical interventions. The high excess mortality during the Omicron epidemic demonstrated a significant impact from the surge of COVID-19 infections in a SARS-CoV-2 infection-naive population, particularly evident in the elderly group.

Effect of surgical intervention for childhood OSA on blood pressure: A randomized controlled study.

OBJECTIVE: To investigate the effect of surgical intervention on 24-h ABP in children with OSA. It was hypothesized that blood pressure would improve following adenotonsillectomy. METHODS: This was a two-centered investigator-blinded randomized controlled trial. Non-obese pre-pubertal children aged 6-11 years with OSA (obstructive apnea-hypopnea index, OAHI >3/h) underwent 24-h ABP monitoring at baseline and 9 months after the randomly assigned intervention, i.e. Early Surgery (ES) or Watchful Waiting (WW). Intention-to-treat analysis was performed. RESULTS: 137 subjects were randomized. Sixty-two (Age: 7.9y ± 1.3, 71% boys) and 47 (Age: 8.5y ± 1.6, 77% boys) participants from the ES and WW groups, respectively completed the study. Changes in ABP parameters were similar in the ES and WW groups (nighttime systolic BP z-scores: +0.03 ± 0.93 vs. -0.06 ± 1.04, p = 0.65; nighttime diastolic BP z-scores: -0.20 ± 0.95 vs. -0.02 ± 1.00, p = 0.35) despite a greater improvement in OSA in the ES group. However, a reduction in nighttime diastolic BP z-score correlated with improvements in OSA severity indexes (r = 0.21-0.22, p < 0.05), and a significant improvement in nighttime diastolic BP z-score [-0.43 ± 1.01, p = 0.027] following surgery was observed in participants with severe preoperative OSA (OAHI ≥10/h). The ES group had a significant increase in body mass index z-score after surgery [+0.27 ± 0.57, p < 0.001], which correlated with the increase in daytime systolic BP z-score (r = 0.2, p < 0.05). CONCLUSION: Surgical treatment did not lead to significant improvements in ABP in OSA children except in those with more severe disease. The improvement in BP was partially masked by the weight gain following surgery. CLINICAL TRIAL REGISTRATION: The trial was registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn. REGISTRATION NUMBER: ChiCTR-TRC-14004131).

Determining meteorologically-favorable zones for seasonal influenza activity in Hong Kong.

Investigations of simple and accurate meteorology classification systems for influenza epidemics, particularly in subtropical regions, are limited. To assist in preparing for potential upsurges in the demand on healthcare facilities during influenza seasons, our study aims to develop a set of meteorologically-favorable zones for epidemics of influenza A and B, defined as the intervals of meteorological variables with prediction performance optimized. We collected weekly detection rates of laboratory-confirmed influenza cases from four local major hospitals in Hong Kong between 2004 and 2019. Meteorological and air quality records for hospitals were collected from their closest monitoring stations. We employed classification and regression trees to identify zones that optimize the prediction performance of meteorological data in influenza epidemics, defined as a weekly rate > 50th percentile over a year. According to the results, a combination of temperature > 25.1℃ and relative humidity > 79% was favorable to epidemics in hot seasons, whereas either temperature < 16.4℃ or a combination of < 20.4℃ and relative humidity > 76% was favorable to epidemics in cold seasons. The area under the receiver operating characteristic curve (AUC) in model training achieved 0.80 (95% confidence interval [CI], 0.76-0.83) and was kept at 0.71 (95%CI, 0.65-0.77) in validation. The meteorologically-favorable zones for predicting influenza A or A and B epidemics together were similar, but the AUC for predicting influenza B epidemics was comparatively lower. In conclusion, we established meteorologically-favorable zones for influenza A and B epidemics with a satisfactory prediction performance, even though the influenza seasonality in this subtropical setting was weak and type-specific.

Feasibility of long-term home noninvasive ventilation program in a general pediatric unit: 21 years' experience in Hong Kong.

BACKGROUND: Long-term home noninvasive ventilation (NIV) is increasingly employed in children with sleep-disordered breathing and chronic respiratory failure. While studies suggest its successful implementation in tertiary care centers, little is known about the situation in a general care setting. Hence, we aim to evaluate the clinical profiles of these children in a general pediatric unit over the past two decades. METHODS: Data collected retrospectively on patients younger than 18 years old receiving long-term home NIV from January 1, 1997 to December 31, 2017 in a Hong Kong regional general pediatric unit were reviewed. RESULTS: The number of children on home NIV increased more than 10-fold over the past two decades. In total, 114 children were commenced on NIV during the 21-year period. Upper airway obstruction was the most common cause (77%), followed by neuromuscular diseases (16%), pulmonary disorders (4%), and abnormal ventilatory control (3%). Continuous positive airway pressure was the most common NIV type (59%). To date, 46% of the children remained in our NIV program, while 18% discontinued NIV support. NIV adherence increased significantly with follow-up (median of 78.6% and 82.5% at baseline and last follow-up, respectively). Sixty-five percent of the children used NIV for at least 4 h on 70% of the days monitored. Higher body mass index was associated with lower adherence. CONCLUSION: Pediatric home NIV is feasible in the general care setting with good outcomes and adherence. As the demand for NIV service grows, input from local hospitals will be of increasing importance and should be considered upon healthcare planning.

Short-term association among meteorological variation, outdoor air pollution and acute bronchiolitis in children in a subtropical setting.

OBJECTIVES: To examine the association among acute bronchiolitis-related hospitalisation in children, meteorological variation and outdoor air pollution. METHODS: We obtained the daily counts of acute bronchiolitis-related admission of children≤2 years old from all public hospitals, meteorological data and outdoor air pollutants' concentrations between 1 January 2008 and 31 December 2017 in Hong Kong. We used quasi-Poisson generalised additive models together with distributed lag non-linear models to estimate the associations of interest adjusted for confounders. RESULTS: A total of 29 688 admissions were included in the analysis. Increased adjusted relative risk (ARR) of acute bronchiolitis-related hospitalisation was associated with high temperature (ambient temperature and apparent temperature) and was marginally associated with high vapour pressure, a proxy for absolute humidity. High concentration of NO2 was associated with elevated risk of acute bronchiolitis admission; the risk of bronchiolitis hospitalisation increased statistically significantly with cumulative NO2 exposure over the range 66.2-119.6 µg/m3. For PM10, the significant effect observed at high concentrations appears to be immediate but not long lasting. For SO2, ARR increased as the concentration approached the 75th percentile and then decreased though the association was insignificant. CONCLUSIONS: Acute bronchiolitis-related hospitalisation among children was associated with temperature and exposure to NO2 and PM10 at different lag times, suggesting a need to adopt sustainable clean air policies, especially to target pollutants produced by motor vehicles, to protect young children's health.

A 21-year retrospective analysis of environmental impacts on paediatric acute gastroenteritis in an affluent setting.

BACKGROUND: Extreme weather events happen more frequently along with global warming and they constitute a challenge for public health preparedness. For example, many investigations showed heavy rainfall was associated with an increased risk of acute gastroenteritis. In this study, we examined the associations between different meteorological factors and paediatric acute gastroenteritis in an affluent setting in China controlling for pollutant effects. METHODS: Aggregated total weekly number of intestinal infection-related hospital admissions, and meteorological and air pollution data during 1998-2018 in Hong Kong were collected and analysed by a combination of quasi-Poisson generalized additive model and distributed lag nonlinear model. Study population was restricted to children under 5 years of age at the time of admission. RESULTS: While heavy rainfall did not exhibit a statistically significant association with the risk of paediatric admission due to intestinal infections, low temperature and humidity extremes (both relative humidity and vapour pressure) did. Compared with the temperature at which the lowest risk was detected (i.e. 22.5 °C), the risk was 6.4% higher (95% confidence interval: 0.0% to 13.0% at 15.1 °C (i.e. the 5th percentile)). We also found the risk of paediatric admission was statistically significantly associated with an increase in the number of extreme cold days in a week over the study period. CONCLUSION: Cold condition may have greater impact on disease transmission through increased stability and infectivity of enteric viruses in affluent settings like Hong Kong and thus resulted in an increased risk for paediatric acute gastroenteritis. On the contrary, an insignificant impact from heavy rainfall and high temperature may indicate a minor effect on disease transmission through bacterial growth in contaminated food and water. With the identified impacts of weather factors, extreme weather events are likely to distort the prevalence and seasonal pattern of diarrhoeal diseases in the future.

Use of heated humidified high flow nasal cannula for obstructive sleep apnea in infants.

OBJECTIVE: Heated humidified high flow nasal cannula (HHHFNC) has gained popularity in the treatment of children with respiratory distress and bronchiolitis in the past decade. Its efficacy as a mode of non-invasive respiratory support has been demonstrated in both adults and children. However, reports on its use in the treatment of obstructive sleep apnea (OSA) in infants are limited. We aimed to evaluate the efficacy of HHHFNC therapy as treatment in infants with OSA. METHODS: A retrospective analysis of OSA infants who had undergone polysomnographic titration between 2015 and 2017 was undertaken. Data about the age, gender, AHI, co-morbid conditions and flow used for each patient were retrieved. RESULTS: Ten infants were included in this study (median age 34 weeks; IQR 27-38 weeks). The median optimal HHHFNC flow rate was 8.0 L/min (IQR 6.7-8.0 L/min). HHHFNC significantly reduced median obstructive apnea-hypopnea index (OAHI) from 9.1 (IQR 5.1-19.3) to 0.9 (IQR 0-1.6; P = 0.005) events/h; median obstructive apnea index (OAI) from 5.8 (IQR 1.1-13.4) to 0 (IQR 0-0.9; P = 0.021) events/h; median obstructive hypopnea index (OHI) from 4.1 (IQR 0.9-6.8) to 0.1 (0-0.9; P = 0.017) events/h; and median oxygen saturation (SpO2) nadir increased from 88% (IQR 83-94%) to 94% (IQR 93-96%; P = 0.040). CONCLUSION: HHHFNC significantly reduced respiratory events and improved oxygenation in infants with OSA.

False-positive SARS-CoV-2 serology in 3 children with Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is an acute febrile and eruptive disease with systemic vasculitis predominantly affecting young East Asian children. Recent reports showed that children with KD-like disease from KD low prevalence regions had positive SARS-CoV-2 serology despite a negative SARS-CoV-2 polymerase chain reaction (PCR) in respiratory samples. OBJECTIVES: To describe 3 pediatric Kawasaki Disease patients with false positive SARS-CoV-2 serology. STUDY DESIGN: We retrospectively recruited children with KD diagnosed during the COVID-19 outbreak in Hong Kong. Clinical characteristics and laboratory test results including SARS-CoV-2 PCR results were retrieved. We performed a microparticle-based immunoassay for the detection of IgG against nucleoprotein (NP) and spike protein receptor binding domain (RBD), and a microneutralization assay for the detection of neutralizing antibodies. RESULTS: Three Chinese children with typical KD were identified. They had no epidemiological links with COVID-19 patients and tested negative for SARS-CoV-2 NPA PCR. They were treated with IVIG and aspirin, and were discharged without complications. Subsequently 2 of them were tested positive against anti-RBD and anti-NP antibodies and 1 was tested positive against anti- RBD antibodies. However, microneutralization assay showed that neutralizing antibodies were absent, suggesting a false-positive IgG result. CONCLUSION: Detection of neutralizing antibodies is recommended to confirm previous SARS-CoV-2 infection in IgG-positive but PCR-negative patients.

Palivizumab for Infants < 29 Weeks in Hong Kong without a Clear-Cut Season for Respiratory Syncytial Virus Infection-A Cost-Effectiveness Analysis.

AIM: To evaluate the cost-effectiveness of palivizumab prophylaxis for premature infants born <29 weeks in Hong Kong. METHOD: We evaluated the hospitalization rate for respiratory syncytial virus (RSV) infection within the first 12 months of discharge of a cohort of preterm infants born between 2010 and 2014 at two local hospitals. RESULTS: In total, 40 of 135 infants were given palivizumab. The hospitalization rate for premature infants <29 weeks was reduced from 15.8 to 5% (p = 0.096) and that for infants <27 weeks was reduced from 33.3 to 8.7% (p = 0.046). In the former group, the incremental cost-effectiveness ratio per hospital admission prevented (ICER/HAP) was US dollar (USD) 24 365. In the latter subgroup, the ICER/HAP was USD 3108. CONCLUSION: The cost-effectiveness as measured for infants <27 weeks is more favorable than that for infants <29 weeks.

Heart rate variability in childhood obstructive sleep apnea.

The identification of patients with obstructive sleep apnea (OSA) is important because of morbidities associated with OSA. A previous adult study demonstrated the use of heart rate variability (HRV) as a tool to identify patients with moderate to severe OSA. Either a reduction in time parameters or an increase in LF/HF ratio was seen at overnight or 24-hr studies suggestive of increased sympathetic modulation. To study the feasibility of daytime HRV as a screening tool, a short-term recording of HRV is studied. Since it was shown in adult study that increased normalized LF, decreased normalized HF and increased LF/HF ratio could be detectable during supine rest at daytime awake period, the authors hypothesize that the differences are also detectable in children. Children who underwent sleep polysomnography for suspected OSA were recruited. Subjects were classified OSA if apnea-hypopnea index (AHI) > 1.5/hr and non-OSA if AHI ≤ 1.5/hr. Continuous 1-hr electrocardiographic monitoring was recorded in awake children during the day. Parameters from time domain and frequency domain were analyzed. Seventy-four male and 17 female snoring subjects were included in this study. Fifty-one (56%) and 40 (44%) of them were classified as "non-OSA" and "OSA," respectively. pNN50, a parameter for parasympathetic modulation, was significantly reduced in the OSA group when compared with the non-OSA group. Using multiple regression, all time domain variables were shown to be decreased in OSA group. Our results suggest that 1-hr study of HRV may be a feasible tool in identifying children with OSA.

Maternally inherited Leigh syndrome: an unusual cause of infantile apnea.

INTRODUCTION: Leigh Syndrome is an uncommon cause of infantile apnea. CASE SUMMARY: We report a 5-month-old girl with sudden respiratory arrest followed by episodic hyper- and hypo-ventilation, encephalopathy, and persistent lactic acidosis. Computed tomography of the brain revealed symmetric low densities over the basal ganglia, internal capsule, thalami, and midbrain. Cardiac echocardiogram was suggestive of hypertrophic cardiomyopathy. DISCUSSION: Diagnosis of Leigh syndrome due to T8993G mutation was confirmed with polymerase chain reaction and direct DNA sequencing of mitochondrial genome. To our knowledge, this is the first report of proven maternally inherited Leigh syndrome in Hong Kong.

Improvement in quality of life after adenotonsillectomy in a child with Prader Willi syndrome.

INTRODUCTION: We report a child with Prader Willi syndrome who developed obstructive sleep apnea (OSA). This patient underwent surgical treatment for OSA. There was improvement not only on her OSA but in her quality of life score as well. This report highlights the need for a comprehensive assessment in the management of patients with Prader Willi syndrome.

Modified Epworth Sleepiness Scale in Chinese children with obstructive sleep apnea: a retrospective study.

BACKGROUND AND OBJECTIVE: The purpose of this study is to assess whether Chinese children with high apnea-hypopnea index (AHI) are sleepier by a modified Epworth Sleepiness Scale (ESS). MATERIALS AND METHODS: Records were retrospectively reviewed. We included children who were between 3 and 12 years old, admitted for overnight polysomnogram because of suspected obstructive sleep apnea syndrome (OSAS). A modified ESS was used to assess excessive daytime sleepiness (EDS) of the children. RESULTS: One hundred ninety-two Chinese children were included. Children with high AHI, defined as AHI > 5.0, were sleepier than children with AHI less than or equal to 5. After adjustment by age, gender, and obesity, children with high AHI remained significantly sleepier. Modified ESS was significantly correlated with AHI (rho = 0.124, 95% CI = 0.004-0.281). Modified ESS score of >8 was the best cutoff point with the sensitivity and specificity of 0.29 and 0.91, respectively. The odds ratio of children with modified ESS > 10 having high AHI was 4.231 (95%CI = 1.248 to 14.338) and children with modified ESS > 8 had the highest odds ratio, 4.295(95%CI = 1.66 to 11.1), of having high AHI. CONCLUSION: Chinese children with high AHI appear to be sleepier than children with low AHI. Children with suspected OSAS and high modified ESS, i.e., ESS > 8, had significantly higher odds ratio of having high AHI. Increased sleepiness is a specific but not a sensitive symptom in snoring children with high AHI. Screening for EDS in snoring children may help us identify those with high AHI and prioritize the management of those children.

Cardiovascular changes in children with snoring and obstructive sleep apnoea.

INTRODUCTION: Adults with obstructive sleep apnoea (OSA) are well documented to be at high risk for cardiovascular abnormalities. Growing evidence suggests that OSA is also associated with cardiovascular consequences in children. The purpose of this review is to examine the available data on this association in children. METHODS: Primary studies were extracted from a MEDLINE search limited to those published between 1970 and 2008. The keywords used included child, sleep disordered breathing, sleep apnoea, snoring, blood pressure and hearts. The relevant articles were selected by consensus between 2 authors. RESULTS: The results suggested that OSA was consistently associated with hypertension. Meta-analysis of risk of hypertension in those with high apnoea-hypopnoea index was undertaken. A combined odds ratio equal to 3.15 was found (95% confidence interval, 2.01 to 4.93). There was evidence for increased sympathetic activation, decreased arterial distensibility and ventricular hypertrophy in children with OSA. CONCLUSION: Childhood OSA is associated with blood pressure dysregulation. The association of OSA with other cardiovascular morbidities requires further study in view of the limited data available currently.

Application of videotape in the screening of obstructive sleep apnea in children.

OBJECTIVE: To determine if watching a videotape that shows features of obstructive sleep apnea (OSA) will improve the accuracy of a verbally administered questionnaire in the prediction of OSA in pediatric snorers. PATIENTS AND METHODS: In a prospective single-blinded, randomized, controlled study at a pediatric clinic for sleep-disordered breathing, we studied children aged 0-18 years, who had been referred to a sleep laboratory for overnight polysomnography (PSG), and their parents from November 1999 to November 2000. The parents were randomized to answer a standard verbally administered panel of three questions (SQ) or a verbally administered panel of questions assisted by videotape (VQ). RESULTS: The parents of 52 and 56 pediatric snorers were assigned to answer SQ and VQ, respectively. The areas under the receiver operating characteristic [ROC] curves (AUCs) for screening of OSA in patients were similar at 0.709 (95% confidence interval (CI)=0.561-0.851) for SQ and 0.714 (95% CI=0.571-0.858) for VQ. The two questionnaires had a reasonable negative predictive value to rule out the presence of OSA (VQ=0.816 and 95% CI=0.726-0.885, SQ=0.828, 95% CI=0.714-0.913). CONCLUSION: The addition of a videotape showing important features of OSA achieved no better accuracy than a standard questionnaire.