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Oximetry and carbon dioxide screening for ventilatory requirements in children with spinal muscular atrophy type 1-3
Archana Chacko1, Peter D Sly2, Robert S Ware3
1Centre for Child Health Research, University of Queensland, Brisbane, Australia.
Insights
Oxygen desaturation index (ODI4) ≥20 events/hour effectively screens for Non-Invasive Ventilation (NIV) needs in untreated children with Spinal Muscular Atrophy (SMA). However, TcCO2 monitoring and oximetry are not useful in children treated with disease-modifying treatments (DMT).
Area of Science:
- Pediatric Pulmonology
- Neuromuscular Disorders
- Sleep Medicine
Background:
- Children with Spinal Muscular Atrophy (SMA) often require assisted ventilation, even with disease-modifying treatments (DMT).
- Screening for sleep-disordered breathing (SDB) using oximetry and transcutaneous carbon dioxide (TcCO2) is recommended.
Purpose of the Study:
- To evaluate the effectiveness of pulse oximetry and TcCO2 in screening for SDB and the need for Non-Invasive Ventilation (NIV) in children with SMA types 1-3.
- To assess diagnostic accuracy of these screening methods compared to polysomnography (PSG).
Main Methods:
- A prospective cohort study involving 47 untreated and 36 treated children with SMA (types 1-3) in Queensland, Australia.
- Full diagnostic polysomnography (PSG) was performed, with pulse oximetry and TcCO2 data extracted.
- Receiver operating characteristic (ROC) curves and diagnostic statistics were calculated to assess screening utility.
Main Results:
- In untreated children, an Oxygen Desaturation Index ≥4% (ODI4) ≥20 events/hour showed 82.6% sensitivity for predicting NIV need.
- TcCO2 monitoring, alone or combined with oximetry, demonstrated low diagnostic ability in both untreated and treated groups.
- Oximetry and TcCO2 monitoring were not useful screening tests for children receiving DMT.
Conclusions:
- ODI4 ≥20 events/hour can predict the need for NIV in untreated children with SMA.
- TcCO2 monitoring does not improve the positive predictive value for NIV need.
- Diagnostic PSG may still be necessary even with normal screening results; screening is ineffective in DMT-treated children.
Introduction:
Despite disease modifying treatments (DMT), assisted ventilation is commonly required in children with Spinal Muscular Atrophy (SMA). Guidelines suggest screening with oximetry and transcutaneous carbon dioxide (TcCO2) for sleep disordered breathing (SDB).
Aim:
To determine the utility of pulse oximetry and TcCO2 as a screen for SDB and the need for Non-Invasive Ventilation (NIV) in children with SMA type 1-3.
Methods:
A prospective cohort study was conducted in Queensland, Australia. Full diagnostic PSG was completed in DMT naïve children with SMA. Pulse oximetry and TcCO2 were extracted from PSG. Apnoea-hypopnoea indices (AHI) criteria were applied to PSG results to define the need for NIV. Abnormal was defined as: ≤3 months of age [mo] AHI≥10 events/hour; >3mo AHI ≥5 events/hour. Receiver operating characteristic curves were calculated for abnormal PSG and pulse oximetry/TcCO2 variables, and diagnostic statistics were calculated.
Results:
Forty-seven untreated children with SMA were recruited (type 1 n = 13; 2 n = 21; 3 n = 13) ranging from 0.2 to 18.8 years old (median 4.9 years). Oxygen desaturation index ≥4 % (ODI4) ≥20events/hour had sensitivity 82.6 % (95 % CI 61.2-95.0) and specificity of 58.3 % (95 % CI 36.6-77.9). TcCO2 alone and combinations of oximetry/TcCO2 had low diagnostic ability. The same methodology was applied to 36 children who were treated (type 1 n = 7; type 2 n = 17; type n = 12) and oximetry±TcCO2 had low diagnostic ability.
Conclusion:
ODI4 ≥20events/hour can predict the need for NIV in untreated children with SMA. TcCO2 monitoring does not improve the PPV. If normal however, children may still require a diagnostic PSG. Neither oximetry nor TcCO2 monitoring were useful screening tests in the children treated with DMT.
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