What is Obstructive Sleep Apnea (OSA)?
Obstructive sleep apnea (OSA) is a disorder in which breathing is repeatedly interrupted or decreased during sleep when muscles in the throat and tongue fail to keep the airway open despite efforts to breathe, preventing air to flow into the lungs and causing oxygen starvation.
When this occurs, sleep becomes a threat to life, the brain is required to momentarily awaken and breathing can be restored. In some individuals the brain has a very low tolerance to decreased airflow even if the airway is not intensely compromised, with resulting frequent arousals and sleep disruption.
What are the symptoms of OSA?
This process in which breathing stops and starts can be repeated up to hundreds of times during one night. The combination of disturbed sleep and oxygen starvation may cause:
- Daytime sleepiness and tiredness
- Morning headaches
- Cognitive impairment
Also, snoring is strongly associated with OSA, resulting in one of the most common reasons why patients search for treatment in the first place. However, it is worth pointing out that not all who snore have OSA and vice-versa. That’s why the best way to discover and treat this important problem is with a thorough evaluation by a sleep medicine physician/surgeon in conjunction with a sleep test.
How do I know I have OSA?
The gold standard for diagnosis is a Polysomnography (PSG), or, sleep study. This test is performed while the patient is asleep at a sleep laboratory, and monitors brain waves, blood oxygen levels, heart rate and breathing, as well as eye and leg movements. A home monitoring device may be a useful alternative for some patients under the guidance of a knowledgeable sleep professional.
However, the sleep test itself does not provide the location of the obstruction, so evaluation methods of the upper airway are necessary to identify potential sites of collapse that lead to OSA.
Nasopharyngoscopy is an office procedure in which a flexible fiberoptic endoscope is introduced through the nose and throat to observe anatomical structures that narrow the airway and compromise airflow and cause snoring.
Sleep Endoscopy is similar to Nasopharyngoscopy, however it is performed under mild sedation (with an hypnotic drug, such as propofol) and it is an outpatient procedure. The objective of this test is to reproduce what occurs to the patient’s upper airway in a sleep state, and identify structures and areas causing the obstruction.
Still under our research protocols, imaging methods such as computadorized tomography scans (CTs), awake and sleep magnetic resonance imaging (MRI) may provide useful information as well in select candidates. CTs are routinely used in the pre-operative evaluation of patients who undergo any surgery that involves the facial skeleton such as maxillomandibular advancement.
These tools should be used together to establish a diagnosis and guide the physician’s decision-making towards the appropriate treatment for each patient.
L: Narrowed airway in OSA patient R: Airway on normal patient
Airway Blocked During Sleep
Why treat my OSA?
There are three main reasons why we treat OSA:
Snoring is frequently a source of distress for both the patient and their bedpartner at night.
The drop in oxygen levels at night has been associated with increased risk of high blood pressure, cardiac arrhythmia(s) and stroke. OSA has been described as causing insulin resistance, which may cause difficulty of glucose control in diabetic patients and achieving weight loss.
While it varies in individual patients and subject to interaction with other ailments such as lack of sleep and psychological comorbidities, it is generally accepted that sleep fragmentation prevents the brain from having complete restorative sleep and may result in daytime sleepiness and drowsiness, deficits in attention, concentration, memory and executive functioning. Worsening of mood symptoms and increased risk of automobile accidents have also been described in association with OSA.