RESUMO
STUDY OBJECTIVES: Few studies have examined the validity of actigraphy in school-aged children. The objective of this study was to examine the validity of a commonly used actigraph compared to polysomnography (PSG) in a sample of children age 5 to 12 y born prematurely, sleeping in their natural home environment. METHODS: 148 children born preterm (85 boys and 63 girls), ages 5-12 y (mean = 9.3 y, standard deviation = 2.0) wore the Philips Respironics Actiwatch-2 for 1 night concurrently with comprehensive, ambulatory PSG in the child's home. Sleep outcome variables were sleep onset latency, total sleep time (TST), and sleep efficiency. Epoch-by-epoch comparisons were used to determine sensitivity, specificity, and accuracy. Secondary analyses examined differences between children with no sleep issues, obstructive sleep apnea syndrome, and periodic limb movements in sleep (PLMS). RESULTS: Actigraphy significantly underestimated TST (30 min) and sleep efficiency (5%). Actigraphy underestimated or overestimated sleep onset latency by at least 10 min for a third of the children. Sensitivity and accuracy were good at 0.88 and 0.84, respectively, whereas specificity was lower at 0.46. Differences between actigraphy and PSG for TST and sleep efficiency were greatest for children with PLMS. CONCLUSIONS: This study adds to the small existing literature demonstrating the validity of actigraphy in middle childhood. Although actigraphy shows good sensitivity (ability to detect sleep), specificity (ability to detect wake) is poor in this age group. Further, the results highlight the importance of considering whether a child has PLMS when interpreting actigraphic data, as well as the difficulties in accurately capturing sleep onset latency with actigraphy.
Assuntos
Actigrafia/normas , Sono/fisiologia , Criança , Pré-Escolar , Meio Ambiente , Feminino , Humanos , Masculino , Síndrome da Mioclonia Noturna/fisiopatologia , Polissonografia , Nascimento Prematuro , Sensibilidade e Especificidade , Apneia Obstrutiva do Sono/fisiopatologia , Fatores de Tempo , Vigília/fisiologiaRESUMO
OBJECTIVE: To test the hypothesis that concentrations of adropin, a recently discovered peptide that displays important metabolic and cardiovascular functions, are lower in obstructive sleep apnea (OSA), especially when associated with endothelial dysfunction. STUDY DESIGN: Age-, sex-, and ethnicity-matched children (mean age, 7.2 ± 1.4 years) were included into 1 of 3 groups based on the presence of OSA in an overnight sleep study, and on the time to postocclusive maximal reperfusion (Tmax >45 seconds) with a modified hyperemic test. Plasma adropin concentrations were assayed using a commercial enzyme-linked immunosorbent assay kit. RESULTS: Among controls, the mean morning adropin concentration was 7.4 ng/mL (95% CI, 5.2-16.3 ng/mL). Children with OSA and abnormal endothelial function (EF) (OSA(+)/EF(+) group) had significantly lower adropin concentrations (2.7 ± 1.1 ng/mL; n = 35) compared with matched controls (7.6 ± 1.4 ng/mL; n = 35; P < .001) and children with OSA and normal EF (OSA(+)/EF(-) group; 5.8 ± 1.5 ng/mL; n = 47; P < .001). A plasma adropin concentration <4.2 ng/mL reliably predicted EF status, but individual adropin concentrations were not significantly correlated with age, body mass index z-score, obstructive apnea-hypopnea index, or nadir oxygen saturation. Mean adropin concentration measured after adenotonsillectomy in a subset of children with OSA (n = 22) showed an increase in the OSA(+)/EF(+) group (from 2.5 ± 1.4 to 6.4 ± 1.9 ng/mL; n = 14; P < .01), but essentially no change in the OSA(+)EF(-) group (from 5.7 ± 1.3 to 6.4 ± 1.1 ng/mL; n = 8; P > .05). CONCLUSION: Plasma adropin concentrations are reduced in pediatric OSA when endothelial dysfunction is present, and return to within normal values after adenotonsillectomy. Assessment of circulating adropin concentrations may provide a reliable indicator of vascular injury in the context of OSA in children.
Assuntos
Proteínas Sanguíneas/análise , Endotélio Vascular/fisiopatologia , Apneia Obstrutiva do Sono/sangue , Índice de Massa Corporal , Estudos de Casos e Controles , Criança , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Hiperemia/complicações , Hiperemia/diagnóstico , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Oxigênio/metabolismo , Peptídeos , Polissonografia , Curva ROC , Sensibilidade e EspecificidadeRESUMO
OBJECTIVES: To determine alveolar and airways nitric oxide (NO) levels in children with sickle cell disease (SCD). STUDY DESIGN: Multiple flows fractional exhaled NO (FE(NO)), bronchial NO flux (J'aw(NO)), and alveolar NO concentration (Ca(NO)) were determined prospectively in 16 non-atopic children with SCD in a tertiary ambulatory clinic and compared with those in 10 children with primary ciliary dyskinesia and 22 healthy control subjects. Differences in FE(NO), J'aw(NO), and Ca(NO) were compared with mixed model analysis and Mann-Whitney tests. RESULTS: Children with SCD had reference range FE(NO) at 50 mL/sec, but FE(NO) was elevated across all flows compared with healthy control subjects (mean difference=2.10±0.91 parts per billion, P=.03). Subjects with SCD had increased J'aw(NO) (1177±533 picoliters per second versus 833±343 picolitres per second, P=.03), and Ca(NO) was no different from control subjects. In contrast, children with primary ciliary dyskinesia had decreased FE(NO) (mean difference=3.36±1.24 parts per billion, P<.01) and J'aw(NO) (507±259 picoliters per second versus 833±343 picoliters per second, P<.01). CONCLUSIONS: Lower airways NO is increased in children with SCD. Elevation of J'aw(NO) may represent dysregulation of NO metabolism or subclinical airways inflammation.