Treatment and persistence/recurrence of sleep-disordered breathing in children with Down syndrome.

OBJECTIVE: Sleep-disordered breathing (SDB) is common in children with Down syndrome, but the trajectory and long-term outcomes are not well-described. In a retrospective longitudinal cohort of children with Down syndrome, study objectives were to (1) characterize polysomnography (PSG), treatments received, and persistence/recurrence of SDB and (2) explore predictors of SDB persistence/recurrence. METHODS: A retrospective cohort study was conducted of children who underwent PSGs between 2004 and 2014. SDB was defined as obstructive sleep apnea (OSA)-mixed (apnea-hypopnea index [AHI] >5 events/hour), central sleep apnea or hypoventilation. PSGs, interventions, and trajectory of SDB were described. Age, body mass index (BMI) Z-score and AHI at first SDB diagnosis were evaluated as predictors of persistent/recurrent SDB. RESULTS: Of 506 children, 120 had ≥1 PSG; 54 had subsequent PSGs. Children with ≥2 PSGs were more likely to have higher total AHI (P = .02) and obstructive-mixed AHI (P = .01). Thirty-five of fifty-four (65%) were initially diagnosed with OSA-mixed SDB. After first PSG, 67 of 120 had OSA-mixed SDB, of whom 25 (37.3%) underwent adenotonsillectomy (T&A), 13 (19.4%) received positive airway pressure (PAP). Those who underwent T&A after PSG were significantly younger than those who received PAP (median age 6.2 vs 12.5 years; P = .005). OSA-mixed SDB persisted/recurred in 33 of 54 (73.3%) with ≥2 PSGs. Persistence/recurrence was not associated with age, AHI or BMI Z-score at first SDB. CONCLUSION: Children with Down syndrome undergoing T&A for SDB were significantly younger than those treated with PAP. SDB persisted/recurred in three of four and was not predicted by age, SDB severity or BMI Z-score. Longitudinal PSG assessment for persistence/recurrence of SDB is required in this population.

Predicting the presence of sleep-disordered breathing in children with Down syndrome.

OBJECTIVE: Sleep-disordered breathing (SDB) is highly prevalent in children with Down syndrome. Given the scarcity of resources and the presence of risk factors for SDB in this population, the objective of this study is to identify the clinical predictors of SDB, which would assist prioritization of children with Down syndrome for SDB evaluation. METHODS: A retrospective cohort study was conducted on children enrolled in the Down syndrome clinic at CHEO who underwent polysomnography in 2004-2014. Total apnea-hypopnea index (AHI) or obstructive AHI (OAHI) > 5 events/hour was considered clinically significant. Associations between SDB and concurrent diagnoses, referral reasons, and sleep symptoms assessed by questionnaire were examined using Pearson's chi-square test or Fisher's exact test as appropriate. Univariate and multivariate logistic regression analyses were used to examine the predictors of SDB. RESULTS: SDB was present in 42.9% of 119 children, with its highest prevalence at age 8 years. Symptoms were not significantly associated with AHI > 5 events/hour or OAHI > 5 events/hour. Gastroesophageal reflux was associated with lower odds of OAHI > 5 events/hour on univariate testing (odds ratio 0.16, 95% CI 0.04-0.72; p = 0.02) and multivariate analysis (odds ratio 0.05, 95% CI 0.0006-0.50; p = 0.002). CONCLUSIONS: SDB is highly prevalent at all ages in children with Down syndrome. Symptoms did not predict SDB in this population, although gastroesophageal reflux may mimic SDB, which indicates that clinicians should continue to perform ongoing surveillance for SDB throughout the lifespan of children with Down syndrome.

Neck circumference percentile: A screening tool for pediatric obstructive sleep apnea.

RATIONALE: Large neck circumference (NC) is associated with obstructive sleep apnea (OSA) in adults, especially males. Since NC changes with age and sex, a lack of reference ranges makes neck size difficult to assess as a screening tool in children. METHODS: Using a population-based dataset of 1,913 children, we developed reference ranges for NC by age and sex for children aged 6-17 years. In this study, we collected NC data on 245 children aged 6-17 years presenting to the Children's Hospital of Eastern Ontario for polysomnography. The association between NC>the 95th percentile and OSA (total apnea-hypopnea-index>5 events/hr and/or obstructive-apnea-index ≥ 1 event/hr) was explored. Thresholds of BMI percentile and waist circumference were also examined. RESULTS: Individuals with NC>95th percentile for age and sex had increased risk of OSA (relative risk 1.7 [95% CI 1.0-3.0], P=0.04), compared to those with NC ≤ 95th percentile. BMI ≥ 95th percentile gave similar results (relative risk 1.8 [95% CI 1.1-2.9], P=0.02). When examined by sex, the association was significant in males ≥ 12 years (relative risk 3.3 [95% CI 1.0-10.4], P=0.04), but not females (P=0.63). Neither BMI ≥ 95th percentile nor waist circumference>95th percentile was significant. CONCLUSIONS: Children and youth with NC>95th percentile for age and sex have significantly increased risk of OSA. This effect is significant in males ≥ 12 years, whereas BMI is not. NC percentile may be an additional screening tool for OSA in children and youth.

Inter- and intra-rater reliability of neck circumference measurements in children.

RATIONALE: Increased neck circumference is a risk factor for obstructive sleep apnea in adults. With rising obesity prevalence in children, it may be an important identifier of obstructive sleep apnea in children. The reliability of measuring neck circumference in children has not been systematically evaluated. OBJECTIVE: To determine the inter- and intra-rater reliability of neck circumference measurements in children aged 2-16 years. METHODS: Children aged 2-16 years with limb fractures were recruited. Neck circumference was measured by three investigators each using two separate unmarked paper tapes in the 2-5 year age group (N = 43), and three separate tapes in the 6-10 and 11-16 year age groups (N = 18 and 40). RESULTS: Neck circumference measurements showed excellent inter-rater reliability for children 6-10 and 11-16 years (ICC = 0.952 and 0.989). Substantial variation was observed for the 2-5 year age group (ICC = 0.701). Good intra-rater reliability was demonstrated for the three groups (ICC range: 0.776, 0.950). Repeatability coefficients were 2.5-3.4 cm in the youngest age group and were 1.2-1.4 cm in the 6-16 year age group. CONCLUSION: In children 6-16 years old, neck circumference shows very good inter and good intra-rater reliability. Multiple measurements are not required for precision and reliability.

Preventing sensitization with mycophenolate mofetil in a pediatric kidney recipient.

Sensitization, as measured by panel reactive antibodies (PRAs), occurs as a result of previous organ transplantation, blood transfusions, or pregnancy. The high-PRA levels increase the risk of complications during transplantation and may result in long time duration for future transplants. Mycophenolate mofetil (MMF) has been shown to decrease lymphocyte proliferation and antibody formation. We report the use of prophylactic MMF in preventing the formation of PRAs in a pediatric renal transplant recipient with multiple donor exposures. A four-yr-old girl received an unsuccessful living-related renal transplant in February 2003 and was subject to multiple blood transfusions in the perioperative period. MMF, 500 mg/m2/day in two divided doses, achieved suppression of PRAs to less than 20% and allowed successful renal transplantation within nine months. No side effects occurred. This approach may reduce the risk of sensitization in future potential organ donor recipients in similar situations.