Should respiratory effort related arousals (RERAs) be counted when calculating the apnea‑hypopnea index for pediatric sleep apnea?

Should RERAs Be Counted When Quantifying Sleep Apnea in Pediatrics?

Scoring RERAs in pediatric sleep apnea is optional, not mandatory, according to AASM guidelines, but including them provides a more comprehensive assessment of sleep-disordered breathing severity and may prevent underdiagnosis of clinically significant disease.

Guideline Recommendations

The American Academy of Sleep Medicine (AASM) 2012 update explicitly states that scoring RERAs in pediatric patients should be considered [Optional] (Consensus) 1. This means:

• RERAs can be scored but are not required for pediatric polysomnography
• When scored, RERAs should be included in the Respiratory Disturbance Index (RDI), not the standard Apnea-Hypopnea Index (AHI)
• The decision to score RERAs is left to the individual sleep specialist's discretion

Pediatric RERA Scoring Criteria

If you elect to score RERAs in children, the AASM defines them as 1:

• A sequence of breaths lasting at least 2 breaths (or the duration of two breaths during baseline breathing)
• Characterized by increasing respiratory effort, flattening of nasal pressure waveform, snoring, or elevation in end-tidal PCO₂
• Leading to arousal from sleep
• Does not meet criteria for apnea or hypopnea

Clinical Impact: Why This Matters

Evidence Supporting RERA Inclusion

Research demonstrates that excluding RERAs can lead to significant underestimation of disease severity 2:

• When comparing scoring methods, the AASM 2007 rules (which don't mandate RERAs) produced a lower OAHI and underestimated severity in 24% of cases compared to previous standards
• Including RERAs (AASM+RERA) produced an OAHI comparable to previous standards and prevented clinically significant underestimation of disease severity
• This is particularly important because morbidity has been demonstrated even in mild OSA in children 2

The Hypopnea Rule Change Context

Understanding the 2012 AASM update is crucial 1:

• The task force changed the pediatric hypopnea definition from requiring a 50% drop in airflow to 30%
• This change was specifically made because a 50% threshold would create a class of events (30-50% flow reduction with arousal/desaturation) that would only be captured as RERAs
• By lowering the hypopnea threshold to 30%, many events previously scored as RERAs are now captured as hypopneas

Practical Clinical Algorithm

When to Score RERAs:

Score RERAs if:

• You want the most comprehensive assessment of sleep-disordered breathing burden
• The child has symptoms suggestive of OSA but a low AHI
• You're evaluating treatment response and want to capture all respiratory events
• You're concerned about missing clinically significant disease

RERAs may be less critical if:

• Using the 30% hypopnea definition (many events will already be captured)
• The AHI is already clearly elevated (>5 events/hour)
• You're following standardized protocols that don't include RERA scoring

Reporting Strategy:

When RERAs are scored, report both indices 3:

• AHI: Apneas + hypopneas per hour of sleep
• RDI: Apneas + hypopneas + RERAs per hour of sleep

This allows for:

• Comparison with studies using different scoring methods
• More complete characterization of respiratory disturbance burden
• Better clinical decision-making, especially in borderline cases

Common Pitfalls

1. Inconsistent scoring: If you score RERAs, do so consistently across all studies for valid comparisons
2. Misunderstanding the 30% rule: The 2012 change to 30% hypopnea threshold already captures many events that would have been RERAs under older rules
3. Ignoring clinical context: A child with significant symptoms but low AHI may have substantial RERAs contributing to morbidity
4. Not reporting RDI when RERAs are scored: Always report RDI if you've scored RERAs to provide complete information

Bottom Line for Clinical Practice

While AASM guidelines make RERA scoring optional in pediatrics, the weight of evidence suggests that including RERAs provides more accurate disease characterization and prevents underdiagnosis 2. Given that even mild OSA causes morbidity in children, and that the 30% hypopnea rule already captures many borderline events, the decision should be based on:

• Your laboratory's standardized protocols
• The clinical context (symptomatic children with borderline AHI benefit most from RERA scoring)
• The need for comprehensive assessment versus streamlined reporting

If resources and expertise allow, scoring RERAs and reporting RDI alongside AHI provides the most complete clinical picture, particularly for children with symptoms disproportionate to their AHI.