How accurate is pulse oximetry in diagnosing obstructive sleep apnoea in children with Down’s syndrome?

Date First Published:
January 15, 2015
Last Updated:
January 15, 2015
Report by:
Dr C Flanagan, ST8 Paediatrics (Belfast Trust)
Search checked by:
Dr C Flanagan, Belfast Trust
Three-Part Question:
In [children with Down's syndrome] is [pulse oximetry effective in diagnosing obstructive sleep apnoea] when compared with [polysomnography]?
Clinical Scenario:
In community paediatric clinic you review a 4 year old boy with Down’s syndrome with attention difficulties. Parents report no concern with his sleep. At a recent meeting you remember a respiratory physician discussing screening for OSA in children with Down’s syndrome. Polysomnography is difficult to access in your area, you wonder whether overnight pulse oximetry would be an appropriate alternative.

You realise you require three main questions answered:
1.tWhat is the baseline prevalence of OSA in children with Down’s syndrome?
2.tHow accurate is pulse oximetry in diagnosing OSA in children with Down’s syndrome?
3.tWhat is the post-test probability of OSA using pulse oximetry in my patient with Down’s syndrome?
Search Strategy:
Medline (clinical queries)


Search Details:
1. child down syndrome AND sleep apnea: 116 studies
Those studies that were recruited from sleep investigation centres were dismissed.

2. pulse oximetry AND sleep apnea children AND Down syndrome (diagnosis) = 4

pulse oximetry AND sleep apnea children (diagnosis) = 161
Outcome:
1. This search strategy retrieved a total of 116 articles, of which 6 were appropriate.

2. This search strategy retrieved a total of 165 articles, 1 of which was identified as able to answer the question of how accurate pulse oximetry was in all children, not specifically children with Down’s syndrome.
Relevant Paper(s):
Study Title Patient Group Study type (level of evidence) Outcomes Key results Study Weaknesses
Obstructive sleep apnoea in children with Down syndrome. Ng DK et al. 2006 Singapore 22 children with Down’s syndrome (mean age 10 +/- 5.9) recruited Down’s Syndrome Association matched with controls with habitual snoring referred to sleep disorder service Case-control Detailed clinical evaluation overnight polysomnography (PSG). Prevalence of OSA was 59% in children with Down’s syndrome. 40% of these children were asymptomatic potential selection bias
Prevalence of sleep-disordered breathing in children with Down syndrome: polygraphic findings in 108 children. de Miguel-Diez J, Villa-Asensi JR, Alvarez-Sala JL. 2003 Spain 108 consecutive unselected children with Down’s syndrome (mean age, 7.9 years; range, 1-18 years) Case-control 1.History and physical examination 2.Lateral radiographs of the nasopharynx 3.Overnight cardiorespiratory polygraphy Prevalence of sleep-disordered breathing was 54.6%
Sleep apnea and Down's syndrome. Dahlqvist A, Rask E, Rosenqvist CJ, Sahlin C, Franklin KA. 2003 Sweden 21 children with Down’s syndrome from a geographically defined area were invited aged 2-10, with their siblings acting as controls. 17/21 Down’s syndrome and 21 controls completed the study. Population based study: case control 1. Overnight polysomnography 2. Echocardiography No increase in rate of OSA in Down’s syndrome when compared with controls. Snoring, restless sleep and hypertrophy of the tonsils were common among children with Down's syndrome but not OSA.
Prospective polysomnographic analysis of obstructive sleep apnea in Down syndrome. Dyken ME, Lin-Dyken DC, Poulton S, Zimmerman MB, Sedars E. 2003 United States 19 children with Down’s syndrome who were seen for routine developmental assessment. Mean age 9.1yrs +/- 4.7 Case control 1. Standard overnight polysomnography. Prevalence of OSA was 79%
Obstructive sleep apnea in children with Down syndrome. Marcus C, Keens T, Bautista D, et al. 1991 United States 53 children recruited from Down’s syndrome parents association and specialty clinics including 17 referred by physician for clinically suspected OSA . Mean age 7.4 +/- 1.2 years Case-control 1.Parental history 2. All had 1-2 hr nap polysomnography 3. 16 children had night-time polysomnography Prevalence of obstructive sleep apnoea was 45%. Nap studies were found to underestimate abnormalities compared to overnight studies Parental history alone was not a significant test for OSA Possible selection bias
Sleep-related upper airway obstruction in a cohort with Down’s syndrome. Stebbens VA, Dennis J, Samuels MP, Croft CB, Southall DP. 1991 United Kingdom 36 children with Down's syndrome under the age of 5 from a geographically defined area invited. 34/36 completed study. Median age 1.4 Case-control 1.Parental questionnaire 2.Overnight tape recordings of arterial oxygen saturation (Sao2) and breathing movement 3.Clinical assessment Prevalence of upper airway obstruction was 31%
A diagnostic approach to suspected obstructive sleep apnoea in children. Brouillette RT, Hanson D, David R, et al. 1984 349 children between the ages of 6 months and 18 years who were referred to their sleep laboratory with suspected OSA. Six out of the total population had Down’s syndrome. The overall pre-test probability of this population was 60%, the incidence of OSA in the study population. case-control 1. polysomnography 2. pulse oximetry The results confirm that pulse oximetry is highly specific (97%) and most useful when it is positive. The sensitivity is relatively low (43%) which means that a negative test does not effectively rule out OSA – not ideal in a screening test. The likelihood ratio for a positive test was 19.4; a negative test 0.58.
Author Commentary:
OSA is common in children with Down’s syndrome and the complications of undiagnosed and unmanaged are significant, potentially affecting the child’s general health and developmental potential. The challenge to clinical practice is finding a safe, cost-effective method of assessing children with Down’s syndrome. Polysomnography is the gold standard for diagnosing OSA but is time-consuming, expensive and often not accessible. Pulse oximetry has many benefits, including reduced cost and potential for home monitoring. However while oximetry is useful when positive in confirming OSA in the general childhood population, a negative oximetry result cannot be used to rule out OSA therefore limiting its role in screening for OSA.
Bottom Line:
Clinical bottom-line:
•tObstructive sleep apnoea is common in children with Down syndrome with estimated prevalence between 31-79%
•tPolysomnography is the gold standard for diagnosing OSA
•tPositive pulse oximetry increases the probability of OSA to ~ 90%
•tNegative pulse oximetry decreases the probability of OSA to ~ 40%
References:
  1. Ng DK et al.. Obstructive sleep apnoea in children with Down syndrome.
  2. de Miguel-Diez J, Villa-Asensi JR, Alvarez-Sala JL.. Prevalence of sleep-disordered breathing in children with Down syndrome: polygraphic findings in 108 children.
  3. Dahlqvist A, Rask E, Rosenqvist CJ, Sahlin C, Franklin KA.. Sleep apnea and Down's syndrome.
  4. Dyken ME, Lin-Dyken DC, Poulton S, Zimmerman MB, Sedars E. . Prospective polysomnographic analysis of obstructive sleep apnea in Down syndrome.
  5. Marcus C, Keens T, Bautista D, et al. . Obstructive sleep apnea in children with Down syndrome.
  6. Stebbens VA, Dennis J, Samuels MP, Croft CB, Southall DP. . Sleep-related upper airway obstruction in a cohort with Down’s syndrome.
  7. Brouillette RT, Hanson D, David R, et al.. A diagnostic approach to suspected obstructive sleep apnoea in children.