Mixed Apnea in Newborns
This newborn has mixed apnea, characterized by the combination of absent respiratory effort (central component) followed by upper airway obstruction (obstructive component) during the same apneic episode.
Classification of Apnea Types
The American Academy of Sleep Medicine defines three distinct types of apnea based on respiratory effort 1:
- Obstructive apnea: Greatly diminished or absent airflow in the presence of continued respiratory effort (thoracoabdominal excursions persist throughout the event) 1
- Central apnea: Complete cessation of airflow with absent respiratory effort due to temporary loss of ventilatory drive 1
- Mixed apnea: Events that begin with a central component (absent respiratory effort) followed by an obstructive component (respiratory effort resumes but airflow remains absent due to upper airway obstruction) 1
Why This is Mixed Apnea
The clinical description explicitly states both absent respiratory effort and upper airway obstruction occur during these episodes 1. This dual pathophysiology is the defining characteristic of mixed apnea, distinguishing it from purely obstructive or purely central events 1.
Mixed apneas are particularly common in newborns and infants, representing a significant proportion of respiratory events in this age group 2. In one longitudinal study of normal infants, obstructive and mixed-type apneas were specifically identified as clinically significant events that may indicate sleep apnea syndrome, especially when episodes exceed 15 seconds duration 2.
Clinical Significance in Newborns
- Mixed apneas lasting 10-15 seconds occurring several times per hour warrant careful evaluation, as they indicate respiratory regulation instability 3
- The presence of mixed events (rather than purely obstructive or central) suggests dysfunction in both central respiratory drive and upper airway patency mechanisms 4
- Episodes of this duration and frequency may be associated with oxygen desaturation or bradycardia, which significantly increases clinical concern 2
Important Caveats
While respiratory pauses under 15 seconds are common in normal infants, the combination of central and obstructive components (mixed type) is more concerning than isolated central pauses 2. The frequency described (several times per hour) also exceeds what is typically seen in normal newborns, where apneas >10 seconds are rare 2.
The scoring methodology from the American Academy of Sleep Medicine maintains separate definitions for obstructive, central, and mixed apneas specifically because mixed events have distinct pathophysiologic and prognostic implications 1.