Respirology/ ICU

Mechanism of a Mixed Apnea

Mixed apneas are characterized by absent respiratory effort and airflow in the first section of the event and respiratory effort without airflow in the later portion [1].

Proposed Mechanism:

An initial obstructive apnea is followed by a post-apnea hyperpnea/hyperventilation once the upper airway opens. Carbon dioxide is blown off (hypocapnia), and CO2 levels drop below the apneic threshold at the termination of the obstructive apnea.

The subsequent apneic event starts as central apnea until the CO2 level rises, reaching the apneic threshold, and respiratory effort resumes [2].

References:

  1. Simon Herkenrath, Katja Pavsic, Marcel Treml, Lars Hagmeyer, Winfried Randerath. Mixed apnea metrics during diagnostic polysomnographies in obstructive sleep apnea patients with/without treatment-emergent central sleep apnea. European Respiratory Journal 2019 54: PA824; DOI: 10.1183/13993003.congress-2019.PA824
  2. Iber C, Davies SF, Chapman RC, Mahowald MM. A possible mechanism for mixed apnea in obstructive sleep apnea. Chest. 1986 Jun;89(6):800-5. doi: 10.1378/chest.89.6.800. PMID: 3086045.
Get Medical Pearls directly to your inbox every week!
Weekly posts with high yield medical knowledge, directly to your mailbox!
Dr. C Humphreys

Internal Medicine

Share
Published by
Dr. C Humphreys

Recent Posts

Nocturia and OSA: Mechanism

Nocturia is a common symptom associated with obstructive sleep apnea. [1] Img Cred: Am J…

6 months ago

ASD vs. VSD Murmur Difference

ASD (Atrial Septal Defect) Wide, Fixed split S2 (in contrast to the normal variation in…

6 months ago

How Does Hypothyroidism Cause Hypoventilation?

Although rare, the differential diagnosis of hypoventilation and hypercapnia respiratory failure includes hypothyroidism. It is…

1 year ago

Why is Pro-BNP/ BNP lower in Obesity?

B-type natriuretic peptide (BNP) is a hormone created in response to cardiac wall stretch due…

2 years ago

What is Peribronchovascular Distribution on CT imaging?

A common finding described on computed tomography (CT) imaging. A disease with a peribronchovascular distribution…

3 years ago

Trapped Lung vs. Lung Entrapment

Though often used synonymously; Trapped Lung and Lung Entrapment technically describe separate entities along the…

3 years ago

This website uses cookies.