OSA or Obstructive Sleep apnea disease is a widely prevalent disorder. In this sleep disorder, apnea occurs due to the obstruction of upper airway while sleeping. Let we try to understand exactly what is OSA?
Obstructive Sleep Apnea Definition
The partial or complete obstruction of the upper airway during sleep is termed as Obstructive sleep apnea disease (OSA). During OSA episode, shallow respiration happens. Moreover, the breathing may pause for a while. The OSA conversely impacts oxygen saturation level in a blood. Typically, the OSA episode happens for 20 to 40 seconds. Usually, the episode follows loud snoring.
The upper airway obstruction can be of mild or severe intensity. Snoring represents ill-health of the individual. First, it results in low-quality sleep to the sufferer. Second, it may annoy nearby individuals often disturbing their sleep. As a matter of fact, the snorer often becomes the subject of a joke, ridicule or even anger.
Anatomically, snoring involves the soft palate and nearby tissues. The pharyngeal muscles and tongue base narrow the airway passage. Tonsils and adenoids play an additional role in obstructing the airflow. Inflammation of these parts also has the catastrophic effect on air exchange. Hope you would have got some brief outline of what is OSA or obstructive sleep apnea definition.
In fact, lack of rigid support in collapsible upper airway portion is the cause of Obstructive sleep apnea disease. As a matter of fact, Oronasopharynx at a palatal level and Orohypopharynx at the base of tongue are the anatomical portions where the snorer usually has some weakness.
Around 2 to 6% of adults and 2% children population suffering from OSA. Although OSA can happen at any age, individuals in the age group 50 to 60 are more affected.
What is OSA? What are the causes of OSA?
We are more familiar with this apnea disease due to the symptom of snoring. Snoring can be disruptive and may the reason of anguish. It may be the reason of insomnia especially for the people who have to sleep nearby the snorer. While defining Obstructive Sleep Apnea disease, we have discussed how the breathing mechanism behaves for the snorer while sleeping. In short, intermittent relaxation of throat muscles while sleeping is the true answer to the question what is OSA.
Looking at the wider number of people affected with obstructive sleep apnea disease, one may tend to ask what is different in these snoring individuals? or what are the common obstructive sleep apnea causes?
Obstructive Sleep Apnea Causes
There are five major factors which differentiate the snorers from remaining population. Either acting alone or in combination, these five factors cause Obstructive sleep apnea disease in the snorers.
- Lack of muscle tone in the region of palate, tongue, and pharynx
- Space occupying mass in an airway passage
- Receding chin that fails to keep tongue forward while sleeping
- Excessive length of uvula and soft palate which narrows the nasopharyngeal aperture
- Airway vacuum created due to the intra-nasal restriction of airflow
In addition to above obstructive sleep apnea causes, below disorders may cause OSA while sleeping.
- Deformities of nose
- Deformities of nasal septum
- Turbinate tumors or overgrowth
- Nasal polyps
- Obesity or weight gain
- Old age
- Brain injury
- Recurrent tonsillitis or adenoiditis
Obstructive Sleep Apnea Symptoms
Obstructive Sleep Apnea Causes snoring during the sleep. Snoring indicates poor quality of sleep. Obstructive sleep apnea may cause a detrimental impact on person’s health. Although the person has taken sleep for enough duration he may suffer from Obstructive sleep apnea (OSA) symptoms. Below is the list of OSA symptoms
- Snoring while sleeping
- Excessive daytime sleepiness
- In-between sleep disturbances
- Early morning headache
- Difficulty in focusing mind
- Diminishing memorizing power
- Anxiety, Depression, and Sadness
- Eye strain, Periorbital headache
- Mood changes
- Decreased libido
- Difficulty in performing keen tasks
- Fluctuations in blood pressure, blood sugar
- Gasping or choking episodes
Obstructive Sleep Apnea Diagnosis
OSA symptoms may remain unnoticed for years. Sometimes even the individuals suffering from mild obstructive sleep apnea symptoms remain in a dark. Snoring, although the reason of anguish, hardly considered as the medical problem. Hence, people would not prefer to visit a doctor, unless they suffer from a burden of this disorder. In fact, OSA can be fatal if not taken care of.
Medical history of patient’s symptoms plays a vital role in confirming Obstructive Sleep Apnea Disease. Each sign and symptom of the snorer would be evaluated. Information obtained from family members is crucial in confirming the apnea disease. Ideally, sleep specialist should evaluate the data and conclude the necessity of actual lab investigation. Below lab tests are required to differentiate obstructive sleep apnea symptoms from rest of the sleep disorders.
- Polysomnography (PSG): This sleep study monitor patient’s brain (EEG), heart (ECG), skeletal muscle activities (EMG), eye movements (EOG) and lung activities during sleep. Breathing patterns are evaluated. Additionally, blood oxygen saturation levels compared. The study can be conducted for the full night or for few night hours. The polysomnogram helps to differentiate sleep apnea from other sleep disorders like Narcolepsy, Idiopathic hypersomnia, PLMD or Periodic Limb Movement Disorders and Parasomnias.
- Home Oximetry: This is a non-invasive method of monitoring oxygen saturation level in blood during sleep. However, it fails to measure actual apneic episodes as far as sleep apnea is concerned
- Home based Sleep Apnea Testing is the at-home version of Polysomnography. The test monitors airflow, breathing patterns and blood oxygen saturation levels.
Warning signs of OSA
As discussed, the symptoms of Obstructive Sleep Apnea may go unnoticed. However, below is the list of symptoms which should not be ignored.
- Loud snoring: The sound disturbing sleep of patient or the persons sleeping nearby
- Intermittent sleep disturbances: Frequent awakening due to stoppage of breathing for a brief period
- Choking: The person wakes up abruptly and gasps, gets frightened or strives for a breath.
- Excessive daytime sleepiness: The person remains drowsy throughout the day. He carries the risk of accident and lack of attention. He may fell asleep while performing his daily activities.
What is hypopnea?
Hypopnea or hypopnoea is defined as shallow breathing i.e. inhalation of minimum breath. Rather than a diaphragm, intercostal muscles play the major role in inhaling air. Hypopnea signifies partial rather than complete cessation of breathing. In conclusion, air movement in lungs decreases considerably. Hypopnea may cause a decrease in oxygen saturation level in the blood.
Medically hypopnea is a reduction of airflow by 30% or greater. It may also be defined as the thoracoabdominal movement with the decrease in oxygen saturation of 4% or greater in blood.
Hypopnea Index: Hypopnea can be of central origin i.e. central hypopnea may occur as a part of waxing or waning as a breathing effort. The number of hypopnea episodes divided by total sleep hours gives Hypopnea Index (HI). In like manner, the number of apnea episodes divided by total sleep hours gives Apnea Index (AI). The apnea-hypopnea index (AHI), calculated as the way individual HI or AI calculated, provides the index of severity as it combines apneas and hypopnea episodes.
Similarly, Sleep Disturbance Index (SDI), is another index used for measuring Sleep Apnea Disease.
Hypopnea vs bradypnea: Bradypnea is abnormally slow respiration from its normal rate while hypopnea is characterized by shallow respiration. In hypopnea respiratory rate may or may not decrease.
Apnea also termed as apnoea, is the temporary suspension of breathing activity. Sleep apnea or Sleep apnoea stands for temporary cessation of breathing while sleeping.
Medically, apnea is a pause in breathing lasting at least 10 seconds. At this point of time, no airflow activity measured on the airflow sensor.
Typical sleep apnea pause stands for 10 to 40 seconds. Such pause episodes happen frequently during the night. Usually, snoring sound follows after each episode. It is probably an involuntary effort of the body to inhale more oxygen.
There are 3 forms of sleep apnea.
- Obstructive Sleep Apnea or OSA
- Central Sleep Apnea or CSA
- Mixed form of Sleep Apnea
In obstructive sleep apnea disease, there is persistent respiratory effort present on the chest or abdominal belt sensors. On the contrary, in central sleep apnea disease, there is no such effort present on the chest or abdominal belt sensors. The mixed or combination form of sleep apnea disease exhibits the combination of both varieties. Meaning in mixed form there may be or may not be the effort exhibition on the chest or abdominal belt sensors depending on the active apnea form at given moment.
Out of the 3 forms, OSA or obstructive sleep apnea is very common.
Sleep Apnea Causes
Obstructive sleep apnea causes are already explained in above discussion. The reasons for central sleep apnea are different from OSA. Central sleep apnea disease occurs because brain fails to send proper signals to breathing muscles. Common Central Sleep Apnea causes are as listed below.
- Heart failure
- Sleeping at high altitude
- Cerebral trauma
- Drugs like morphine sulfate
- Idiopathic Central Sleep Apnea
The mixed form of sleep apnea is very rare. Usually, above medical conditions, when accompanied by certain kind of airway obstruction, cause the mixed form of sleep apnea.
Hope you would have understood above information regarding apnea meaning, what is OSA and what is hypopnea. We will discuss this sleep disorder with further details in the next letter.