Objective. To determine whether upper airway resistance syndrome (UARS
) can be recognized and distinguished from obstructive sleep apnea syn
drome (OSAS) in prepubertal children based on clinical evaluations, an
d, in a subgroup of the population, to compare the efficacy of esophag
eal pressure (Pes) monitoring to that of transcutaneous carbon dioxide
pressure (tcPCO(2)) and expired carbon dioxide (CO2) measurements in
identifying UARS in children. Study Design. A retrospective study was
performed on children, 12 years and younger, seen at our clinic since
1985. Children with diagnoses of sleep-disordered breathing were drawn
from our database and sorted by age and initial symptoms. Clinical fi
ndings, based on interviews and questionnaires, an orocraniofacial sca
le, and nocturnal polygraphic recordings were tabulated and compared.
If the results of the first polygraphic recording were inconclusive, a
second night's recording was performed with the addition of Pes monit
oring. In addition, simultaneous measurements of tcPCO(2) and end-tida
l CO2 with sampling through a catheter were performed on this second n
ight in 76 children. These 76 recordings were used as our gold standar
d, because they were the most comprehensive. For this group, 1848 apne
ic events and 7040 abnormal respiratory events were identified based o
n airflow, thoracoabdominal effort, and Pes recordings. We then analyz
ed the simultaneously measured tcPCO(2) and expired CO2 levels to asce
rtain their ability to identify these same events. Results. The first
night of polygraphic recording was inconclusive enough to warrant a se
cond recording in 316 of 411 children. Children were identified as hav
ing either UARS (n=259), OSAS (n=83), or other sleep disorders (n=69).
Children with small triangular chins, retroposition of the mandible,
steep mandibular plane, high hard palate, long oval-shaped face, or lo
ng soft palate were highly likely to have sleep-disordered breathing o
f some type. If large tonsils were associated with these features, OSA
S was much more frequently noted than UARS. In the 76 gold standard ch
ildren, Pes, tcPCO(2) and expired CO2 measurements were in agreement f
or 1512 of the 1848 apneas and hypopneas that were analyzed. Of the 70
40 upper airway resistance events, only 2314 events were consonant in
all three measures. tcPO(2) identified only 33% of the increased respi
ratory events identified by Pes; expired CO2 identified only 53% of th
e same events. Conclusions. UARS is a subtle form of sleep-disordered
breathing that leads to significant clinical symptoms and day and nigh
ttime disturbances. When clinical symptoms suggest abnormal breathing
during sleep but obstructive sleep apneas are not found, physicians ma
y, mistakenly, assume an absence of breathing-related sleep problems.
Symptoms and orocraniofacial information were not useful in distinguis
hing UARS from OSAS but were useful in distinguishing sleep-disordered
breathing (UARS and OSAS) from other sleep disorders. The analysis of
esophageal pressure patterns during sleep was the most revealing of t
he three techniques used for recognizing abnormal breathing patterns d
uring sleep.