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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Congenital central hypoventilation syndrome (CCHS, Ondine's curse) is generally thought to be due to insensitivity of the central chemoreceptors to carbon dioxide. Children with CCHS have absent ventilatory responses to both hypercapnea and hypoxia, suggesting either abnormal central and peripheral chemoreceptor function or abnormal central integration of chemoreceptor input. Because ventilatory and arousal responses to respiratory stimuli are distinct from each other, if children with CCHS have complete chemoreceptor dysfunction, one would predict that both ventilatory and arousal responses to respiratory stimuli would be abnormal. However, if they have abnormal central integration of chemoreceptor input for ventilation, they may still arouse to respiratory stimuli despite the absence of a ventilatory response. Hypercapneic arousal responses were tested in eight children with CCHS, aged 5.8 +/- 1.2 (SEM) years, and seven healthy control subjects, aged 4.4 +/- 1.1 years. Children were studied during sleep while normal ventilation was maintained using their home ventilators. Hypercapneic challenges were performed by rapidly increasing the inspired carbon dioxide tension to 60 mm Hg and maintaining this level until the child aroused or for a maximum of 3 minutes. Of children with CCHS, 87.5% aroused to hypercapnea, compared with 100% of control children. There was no significant difference in arousal between children with CCHS and normal control subjects. It is concluded that most children with CCHS arouse to hypercapnea, indicating the presence of some central chemoreceptor function. It is speculated that because these children do respond to hypercapnea, the most probable mechanism for CCHS is a brainstem lesion in the area where input from both chemoreceptors is integrated.
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PMID:Hypercapneic arousal responses in children with congenital central hypoventilation syndrome. 194 41

The role of the central and peripheral chemoreceptors in the hyperpnea of exercise has been controversial. We studied five children, age 6 to 11 yr, with absent hypercapneic and hypoxic ventilatory responses during wakefulness (congenital central hypoventilation syndrome, CCHS). Each child performed an incremental treadmill exercise test. Maximal oxygen consumption (VO2) and minute ventilation (VE) at maximal exercise were lower than but not significantly different from these values in a group of nine normal control children of similar age, height, and weight (VO2/kg, 33.7 +/- 5.0 versus 45.4 +/- 2.9 ml/kg/min, mean +/- SEM, NS; VE 28.3 +/- 7.3 versus 43.8 +/- 3.9 L/min, NS). Oxygen tension and saturation fell and CO2 tension rose significantly at maximal exercise in CCHS but not in control subjects. In contrast to control subjects, CCHS subjects increased VE largely by increasing respiratory frequency (f) rather than tidal volume (VT). In the oldest child, submaximal exercise tests at 50% VO2, with varying pacing rate, showed a significant positive relation between pacing rate and f, but not VT. Thus, VE was higher at the faster pacing rate. Further incremental testing in the two oldest subjects with recording of the pacing rate showed positive linear relations between pacing frequency and breathing frequency and between pacing frequency and VE up to a maximum pacing rate of 48 to 50 paces per 15 s. VE beyond this level varied randomly around the maximum level. We conclude that exercise-induced hyperpnea can occur in the absence of chemoreceptor function. In the CCHS children, limb movement is an important determinant of the ventilatory response to exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ventilatory response to exercise in children with congenital central hypoventilation syndrome. 848 29