Cerebral Blood Flow Response to Hypercapnia in Children with Obstructive Sleep Apnea Syndrome.
STUDY OBJECTIVES
Children with obstructive sleep apnea syndrome (OSAS) often experience periods of hypercapnia during sleep, a potent stimulator of cerebral blood flow (CBF). Considering this hypercapnia exposure during sleep, it is possible that children with OSAS have abnormal CBF responses to hypercapnia even during wakefulness. Therefore, we hypothesized that children with OSAS have blunted CBF response to hypercapnia during wakefulness, compared to snorers and controls.


METHODS
CBF changes during hypercapnic ventilatory response (HCVR) were tested in children with OSAS, snorers, and healthy controls using diffuse correlation spectroscopy (DCS). Peak CBF changes with respect to pre-hypercapnic baseline were measured for each group. The study was conducted at an academic pediatric sleep center.


RESULTS
Twelve children with OSAS (aged 10.1 ± 2.5 [mean ± standard deviation] y, obstructive apnea hypopnea index [AHI] = 9.4 [5.1-15.4] [median, interquartile range] events/hour), eight snorers (11 ± 3 y, 0.5 [0-1.3] events/hour), and 10 controls (11.4 ± 2.6 y, 0.3 [0.2-0.4] events/hour) were studied. The fractional CBF change during hypercapnia, normalized to the change in end-tidal carbon dioxide, was significantly higher in controls (9 ± 1.8 %/mmHg) compared to OSAS (7.1 ± 1.5, P = 0.023) and snorers (6.7 ± 1.9, P = 0.025).


CONCLUSIONS
Children with OSAS and snorers have blunted CBF response to hypercapnia during wakefulness compared to controls. Noninvasive DCS blood flow measurements of hypercapnic reactivity offer insights into physiopathology of OSAS in children, which could lead to further understanding about the central nervous system complications of OSAS.
['Busch|David R|DR|', 'Lynch|Jennifer M|JM|', 'Winters|Madeline E|ME|', 'McCarthy|Ann L|AL|', 'Newland|John J|JJ|', 'Ko|Tiffany|T|', 'Cornaglia|Mary Anne|MA|', 'Radcliffe|Jerilynn|J|', 'McDonough|Joseph M|JM|', 'Samuel|John|J|', 'Matthews|Edward|E|', 'Xiao|Rui|R|', 'Yodh|Arjun G|AG|', 'Marcus|Carole L|CL|', 'Licht|Daniel J|DJ|', 'Tapia|Ignacio E|IE|']
D000293:Adolescent D002245:Carbon Dioxide D002560:Cerebrovascular Circulation D002648:Child D005260:Female D006801:Humans D006935:Hypercapnia D008297:Male D017286:Polysomnography D012890:Sleep D020181:Sleep Apnea, Obstructive D012913:Snoring D014851:Wakefulness
cerebral blood flow hypercapnia obstructive sleep apnea child humans