Overnight Polysomnography versus Respiratory Polygraphy in the Diagnosis of Pediatric Obstructive Sleep Apnea
Overnight Polysomnography versus Respiratory Polygraphy in the Diagnosis of Pediatric Obstructive Sleep Apnea
Hui-Leng Tan 0 1 2
David Gozal 1 2
Helena Molero Ramirez 1 2
Hari P. R. Bandla 1 2
Leila Kheirandish-Gozal 1
0 Department of Paediatric Respiratory Medicine, Royal Brompton Hospital , London , UK
1 Polygraphy and Polysomnography in Children-Tan et al
2 Section of Pediatric Sleep Medicine, Department of Pediatrics, Pritzker School of Medicine, Biological Sciences Division, The University of Chicago , Chicago, IL , USA
Background: Substantial discrepancies exist in the type of sleep studies performed to diagnose pediatric obstructive sleep apnea (OSA) in different countries. Respiratory polygraphic (RP) recordings are primarily performed in sleep laboratories in Europe, whereas polysomnography (PSG) constitutes the majority in the US and Australia. Home RP show consistent apnea-hypopnea index (AHI) underscoring, primarily because the total recording time is used as the denominator when calculating the AHI compared to total sleep time (TST). However, laboratory-based RP are less likely affected, since the presence of sleep technicians and video monitoring may enable more accurate TST estimates. We therefore examined differences in AHI in PSG and in-lab RP, and whether RP-based AHI may impact clinical decision making. Methods: Of all the children assessed for possible OSA who underwent PSG evaluation, 100 were identified and divided into 4 groups: (A) those with AHI < 1/h TST (n = 20), (B) 1 ≤ AHI < 5/h TST (n = 40), (C) 5 ≤ AHI < 10/h TST (n = 20), and (D) AHI ≥ 10/h TST (n = 20). Electroencephalography, electrooculography, and electromyography channels were deleted from the original unscored recordings to transform them into RP, and then rescored in random sequence. AHI-RP were compared to AHI-PSG, and therapeutic decisions based on AHI-RP and AHI-PSG were formulated and analyzed using clinical details derived from the patient's clinic letter. Results: Bland Altman analysis showed that in lab RP underestimated the AHI despite more accurate estimates of TST. This underestimation was due to missed hypopneas causing arousals without desaturation. Basing the therapeutic management decision on RP instead of PSG results changed the clinical management in 23% of all patients. The clinical management for patients in groups A and D was unaffected. However, 27.5% of patients in group B would have been given no treatment, as they would be diagnosed as having no OSA (AHI < 1/h TST) when they should have received a trial of anti-inflammatory therapy or been referred for ear, nose, and throat (ENT) review. Sixty percent of patients in group C would have received either a trial of medical treatment to treat mild OSA or no treatment, instead of referral to ENT services or commencement of continuous positive airway pressure. Conclusion: Apnea-hypopnea index (AHI) is underestimated in respiratory polygraphy (RP), and the disparity in AHI-RP and AHI-polysomnography can significantly affect clinical management decisions, particularly in children with mild and moderate obstructive sleep apnea (1 < AHI < 10/h total sleep time).
INTRODUCTION
There is a significant discrepancy in the type of sleep studies
performed in the context of diagnosing pediatric
obstructive sleep apnea (OSA) in different countries. In the US and
Australia, polysomnography (PSG) is the accepted gold
standard, as recommended by the American Academy of
Pediatrics.1-3 In Europe, the vast majority of laboratories perform
respiratory polygraphy (RP).4-6 A substantial number of
physicians believe that RP is sufficient to diagnose OSA, and the
Royal College of Paediatrics and Child Health Working party
on Sleep Physiology and Respiratory Control Disorders in
Childhood has recommended that RP provides a
satisfactory approach to diagnose OSA in uncomplicated children
over the age of 2 years.7 However, if the 2 types of diagnostic
studies, i.e., RP and PSG, yield different results, then centers
that currently perform RP may need to change and adopt
PSG as the only valid gold-standard approach. Conversely,
if the results derived from RP and PSG are comparable, then
performing RP would be both simpler and more
cost-effective—a serious consideration in these current economically
constrained times.
Considering the potentially significant ramifications of such
dilemma, there have been surprisingly few pediatric studies
directly comparing RP and PSG,8-10 and none that have
examined the clinical management implications. Studies comparing
home RP with in-lab PSGs have shown that home RPs
underscore the apnea-hypopnea index (AHI), primarily because the
total recording time (TRT) is used as the denominator when
calculating the AHI, as compared to the use of the total sleep
time (TST) that can be derived from the PSG.11 However, sleep
and wakefulness can be quite accurately determined in children
using cardiorespiratory and videotape recordings,12 such that
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