Upper airway collapsibility during REM sleep in children with the obstructive sleep apnea syndrome.
OBJECTIVE
In children, most obstructive events occur during rapid eye movement (REM) sleep. We hypothesized that children with the obstructive sleep apnea syndrome (OSAS), in contrast to age-matched control subjects, would not maintain airflow in the face of an upper airway inspiratory pressure drop during REM sleep.


METHODS
During slow wave sleep (SWS) and REM sleep, we measured airflow, inspiratory time, inspiratory time/total respiratory cycle time, respiratory rate, tidal volume, and minute ventilation at a holding pressure at which flow limitation occurred and at 5 cm H2O below the holding pressure in children with OSAS and in control subjects.


METHODS
Sleep laboratory.


METHODS
Fourteen children with OSAS and 23 normal control subjects.


RESULTS
In both sleep states, control subjects were able to maintain airflow, whereas subjects with OSAS preserved airflow in SWS but had a significant decrease in airflow during REM sleep (change in airflow of 18.58 +/- 12.41 mL/s for control subjects vs -44.33 +/- 14.09 mL/s for children with OSAS, P = 0.002). Although tidal volume decreased, patients with OSAS were able to maintain minute ventilation by increasing the respiratory rate and also had an increase in inspiratory time and inspiratory time per total respiratory cycle time


CONCLUSIONS
Children with OSAS do not maintain airflow in the face of upper-airway inspiratory-pressure drops during REM sleep, indicating a more collapsible upper airway, compared with that of control subjects during REM sleep. However, compensatory mechanisms exist to maintain minute ventilation. Local reflexes, central control mechanisms, or both reflexes and control mechanisms need to be further explored to better understand the pathophysiology of this abnormality and the compensation mechanism.
Huang
Jingtao
J
Sleep Center, Children s Hospital of Philadelphia, University of Pennsylvania School ofMedicine, Philadelphia, PA, USA.
Karamessinis
Laurie R
LR
Pepe
Michelle E
ME
Glinka
Stephen M
SM
Samuel
John M
JM
Gallagher
Paul R
PR
Marcus
Carole L
CL
D000402:Airway Obstruction / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000150:complications / Q000503:physiopathology; D017286:Polysomnography / Q000379:methods; D012137:Respiratory System / Q000503:physiopathology*; D020181:Sleep Apnea, Obstructive / Q000150:complications* / Q000503:physiopathology*; D012895:Sleep, REM; D013990:Tidal Volume