What does apneic mean?

Definition of Apneic

Apneic refers to a temporary cessation of breathing characterized by a ≥90% reduction in airflow that lasts for 10 seconds or longer. 1

Clinical Definition and Classification

According to the American Academy of Sleep Medicine (AASM) guidelines, apnea is defined by two key criteria:

1. A drop in peak signal excursion by ≥90% of pre-event baseline using an oronasal thermal sensor, positive airway pressure device flow, or an alternative apnea sensor
2. The duration of this ≥90% drop in sensor signal must be ≥10 seconds 1

Apneas are further classified into three distinct types based on respiratory effort:

• Obstructive apnea: Characterized by continued respiratory effort despite airflow cessation, indicating upper airway obstruction
• Central apnea: Characterized by absence of respiratory effort during the cessation of airflow
• Mixed apnea: Begins as a central apnea (no respiratory effort) and transitions to include respiratory effort (obstructive component) 1

Clinical Significance

Apneic events have significant clinical implications:

• In adults, they are a hallmark feature of sleep apnea disorders, which when left untreated can lead to cardiovascular disease, metabolic disorders, and increased mortality 2
• In premature infants, apnea is defined as breathing pauses lasting >20 seconds, or >10 seconds if associated with bradycardia or oxygen desaturation 3
• Repeated apneic events can cause intermittent hypoxia, leading to serious adverse outcomes including:
  • Systemic and pulmonary hypertension
  • Cardiac arrhythmias
  • Stroke
  • CNS dysfunction
  • Metabolic disorders 4

Diagnostic Context

In sleep medicine, apneas are distinguished from hypopneas, which are defined as:

• A ≥30% reduction in airflow (rather than ≥90%)
• Lasting ≥10 seconds
• Associated with either ≥3% oxygen desaturation or an arousal 1

Clinical Applications

Understanding apneic periods is critical in several clinical scenarios:

• Airway management: During intubation, apneic oxygenation techniques can be employed to maintain oxygenation during periods when ventilation is not possible, particularly important in difficult airway scenarios 5
• Neonatal care: Apnea of prematurity is a common disorder in premature infants that requires monitoring and intervention 6
• Sleep medicine: Identification and classification of apneic events is essential for diagnosing sleep-disordered breathing 1

Important Considerations

• The duration of apnea is measured from the nadir in flow preceding the first breath that is clearly reduced to the start of the first breath that approximates baseline breathing 1
• If a portion of a respiratory event that would otherwise meet criteria for hypopnea meets criteria for apnea, the entire event should be scored as an apnea 1
• Apneic events that occur during sleep studies must be properly identified and classified to determine appropriate treatment strategies 1, 2