Age-related changes in baroreflex sensitivity and cardiac autonomic tone in children mirrored by regional brain gray matter volume trajectories.

BackgroundThe baroreflex and central autonomic brain regions together control the cardiovascular system. Baroreflex sensitivity (BRS) decreases with age in adults. Age-related changes in brain regions for cardiovascular control in children are unknown. We studied age-related changes in BRS, cardiac autonomic tone, and gray matter volume (GMV) of brain regions associated with cardiovascular control.MethodsBeat-to-beat blood pressure and heart rate (HR) were recorded in 49 children (6-14 years old). Spontaneous BRS was calculated by the sequence method. Cardiac autonomic tone was measured by spectral analysis of HR variability. GMV was measured using voxel-based morphometryin 112 healthy children (5-18 years old).ResultsAge-related changes in BRS were significantly different in children <10 years and ≥10 years. Age-related changes in GMV in regions of interest (ROI) were also significantly different between children <10 and ≥10 years and between children <11 and ≥11 years. However, age-related changes in cardiac autonomic tone were progressive.ConclusionsSignificant changes in BRS trajectories between <10 and ≥10 years may be associated with similar age-related changes of GMV in brain ROI. This new knowledge will guide future studies examining whether childhood cardiovascular disruption manifests as deviated maturation trajectories of specific brain regions.

Polysomnographic Oxygen Saturation Findings for Preteen Children versus Adolescents.

Objective Home oximetry is commonly used to screen for obstructive sleep apnea (OSA) in children; however, normal oxygen desaturation levels by disease severity are not well known. It was our objective to determine if oxygen saturation levels differed by OSA severity category in children and if these differences were similar for preteen children and adolescents. Study Design Retrospective case series of children undergoing polysomnography from September 2011 to July 2015. Setting Tertiary pediatric hospital. Subjects and Methods Six- to 18-year-olds (preteen, 6-12 years old; adolescent, 13-18 years old). Chi-square, Wilcoxon rank sum test, and Kruskal-Wallis testing were used to compare variables between age groups. Results The study included 342 children with a mean age of 11.3 ± 2.4 years (range, 6.5-17.5) and a mean body mass index of 25.6 ± 9.2 kg/m2 (78 ± 29 percentile); 61% were white, 35% were black, and 4% were other or unknown. Of the children, 48% were female, and this was not a significant difference between age groups ( P = .81). Overall, 50% of the children had no OSA, 32% mild, 10% moderate, and 8% severe. When compared with the younger children, the adolescents had a longer sleep time ( P = .014) and a higher mean obstructive apnea-hypopnea index (3.53 ± 5.1 vs 3.03 ± 6.1 events per hour, P = .02). The 3% and 4% oxygen desaturation indices were not significantly different between age groups when accounting for OSA severity. Conclusion Adolescents have longer sleep times and higher obstructive apnea-hypopnea indexes than preteens, but oxygen saturations and desaturation indices were similar. This supports current triage algorithms for children with OSA, as we found no significant age-based differences.

Dynamic Volume Computed Tomography Imaging of the Upper Airway in Obstructive Sleep Apnea.

STUDY OBJECTIVES: To describe a dynamic three-dimensional (3D) computed tomography (CT) technique for the upper airway and compare the required radiation dose to that used for common clinical studies of a similar anatomical area, such as for subjects undergoing routine clinical facial CT. METHODS: Dynamic upper-airway CT was performed on eight subjects with persistent obstructive sleep apnea, four of whom were undergoing magnetic resonance imaging and an additional four subjects who had a contraindication to magnetic resonance imaging. This Health Insurance Portability and Accountability Act-compliant study was approved by our institutional review board, and informed consent was obtained. The control subjects (n = 41) for comparison of radiation dose were obtained from a retrospective review of the clinical picture-archiving computer system to identify 10 age-matched patients per age-based control group undergoing facial CT. RESULTS: Dynamic 3D CT can be performed with an effective radiation dose of less than 0.38 mSv, a dose that is less than or comparable to that used for clinical facial CT. The resulting data- set is a uniquely complete, dynamic 3D volume of the upper airway through a full respiratory cycle that can be processed for clinical and modeling analyses. CONCLUSIONS: A dynamic 3D CT technique of the upper airway is described that can be performed with a clinically reasonable radiation dose and sets a benchmark for future use.