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Interpreting CPAP device respiratory indices in children
Rebecca Mihai1, Kirsten Ellis1, Margot J Davey1,2
1Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, Australia.
Insights
Automatic respiratory indices from CPAP devices are not accurate enough to guide treatment for pediatric obstructive sleep apnea (OSA). These devices may overestimate apneas and underestimate hypopneas, potentially missing residual OSA in children.
Area of Science:
- Pediatric Pulmonology
- Sleep Medicine
- Medical Device Technology
Background:
- Obstructive sleep apnea (OSA) in children is increasingly treated with continuous positive airway pressure (CPAP).
- Accurate assessment of respiratory events during CPAP therapy is crucial for effective treatment management.
Purpose of the Study:
- To evaluate the accuracy of automatic respiratory indices generated by a CPAP device compared to manual polysomnography (PSG) scoring in children.
- To determine if CPAP device data can reliably predict residual OSA in pediatric patients.
Main Methods:
- A comparative study involving 46 children undergoing CPAP titration with a ResMed VPAP ST-A (S9) device.
- Automatic respiratory indices (AHICPAP, AICPAP, HICPAP) were compared against manually derived indices (RDIPSG, OAHIPSG, AIPSG, HIPSG) from PSG using statistical analysis.
Main Results:
- While RDIPSG and AHICPAP showed no significant difference, AIPSG was lower than AICPAP, indicating overestimation of apneas by the CPAP device.
- OAHIPSG was significantly lower than AHICPAP, suggesting underestimation of hypopneas by the device.
- The CPAP device's AHICPAP demonstrated high specificity but low sensitivity for detecting residual OSA (OAHIPSG ≥ 5 events/hr).
Conclusions:
- Automatic respiratory indices from the ResMed S9 CPAP device are insufficient for guiding pediatric OSA treatment decisions.
- The device's metrics may fail to identify residual OSA in symptomatic children, necessitating careful clinical interpretation.
- A low AHICPAP should be interpreted cautiously as it might mask ongoing hypopneas.
Study Objectives:
An increasing number of children with obstructive sleep apnea (OSA) require treatment with continuous positive airway pressure (CPAP). This study aimed to determine whether automatic respiratory indices from a CPAP device accurately predict manually determined respiratory indices derived from overnight polysomnography (PSG) in children.
Methods:
Consecutive children undergoing manual CPAP titration PSG using a ResMed VPAP ST-A (S9) were included. The apnea-hypopnea index (AHI), apnea index (AI), and hypopnea index (HI) from automatic analysis of the CPAP device for that night (AHICPAP, AICPAP, and HICPAP) were compared with manually derived respiratory indices (RDIPSG, OAHIPSG, AIPSG, and HIPSG) using the Wilcoxon matched-pairs signed-ranks test.
Results:
Forty-six children (32 boys; median age, 13.5 years; range, 4.6-20.0 years) were included. There was no difference between RDIPSG and AHICPAP (P = .6) nor between HIPSG and HICPAP (P = .2). AIPSG was significantly lower than AICPAP (mean difference -1.3 events/hr, P < .001). AIPSG and AICPAP were strongly correlated (r² = .72, P < .01), but the CPAP machine overestimated the number of apneas at higher AIs. OAHIPSG was significantly lower than AHICPAP (P = .003) but strongly correlated (r² = .87, P < .01). The CPAP device significantly underestimated the number of hypopneas at higher indices. Using the manually scored OAHIPSG of ≥5 events/hr to define significant residual OSA, the AHICPAP had a high specificity (0.95) but low sensitivity (0.20).
Conclusions:
The ResMed S9 respiratory indices are not accurate enough to guide treatment decisions in children; in particular, they do not rule out the presence of residual OSA in children that remain symptomatic on CPAP. A low AHICPAP is reassuring in the context of a stable patient but may miss ongoing hypopneas.
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