This article needs additional citations for verification .(September 2018) |
Hypopnea is overly shallow breathing or an abnormally low respiratory rate. Hypopnea is defined by some to be less severe than apnea (the complete cessation of breathing), while other researchers have discovered hypopnea to have a "similar if not indistinguishable impact" on the negative outcomes of sleep breathing disorders [1] . In sleep clinics, obstructive sleep apnea syndrome or obstructive sleep apnea–hypopnea syndrome is normally diagnosed based on the frequent presence of apneas and/or hypopneas rather than differentiating between the two phenomena. Hypopnea is typically defined by a decreased amount of air movement into the lungs and can cause oxygen levels in the blood to drop. It commonly is due to partial obstruction of the upper airway.
Hypopnea during sleep is classed as a sleep disorder. With moderate to severe hypopnea, sleep is disturbed such that patients may get a full night's sleep but still not feel rested. The disruption in breathing causes a drop in blood oxygen level, which may in turn disrupt the stages of sleep.
Daytime hypopnea events, however, are mostly limited to those with severely compromised respiratory muscles, as occurs in certain neuromuscular diseases or compromised central respiratory drive, as occurs in conditions such as acquired or congenital central hypoventilation syndrome (ACHS or CCHS). Daytime hypopnea can also cause a drop in blood oxygen level.
The most common hypopnea symptom is excessive sleepiness, which results from constant sleep interruption. People with hypopnea due to airflow obstruction often have loud, heavy snoring that is interrupted with choking sounds or loud snorts followed by periods of silence, because not enough air can flow into the lungs through the mouth and nose. The periods of silence can last 20 seconds or longer and can happen many times each hour, resulting in poor sleep and reduced levels of oxygen in the blood.
Other symptoms of hypopnea may include depression, forgetfulness, mood or behaviour changes, trouble concentrating, loss of energy, nervousness, and morning headaches. Not all people with hypopnea experience all of these symptoms and not everyone who has these symptoms has hypopnea.
Hypopnea is a disorder that may result in excessive daytime sleepiness and compromised quality of life, including traffic accidents, diminished productivity in the workplace, and emotional problems.
Cardiovascular consequences of hypopnea may include myocardial infarction, hypertension, coronary heart disease as well other problems such as stroke, psychiatric problems, impotence, cognitive dysfunction and memory loss.
Among the causes of hypopnea are:
In the context of diagnosis and treatment of sleep disorders, a hypopnea is not considered to be clinically significant unless there is a 30% or greater reduction in flow lasting for 10 seconds or longer and an associated 4% or greater desaturation in the person's O2 levels, or if it results in arousal or fragmentation of sleep.
The direct consequence of hypopnea (as well as apnea) is that the CO2 in the blood increases and the oxygen level in the patient's blood decrease is proportionate to the severity of the airway obstruction. This disruptive pattern of breathing generates disruptive sleep patterns, the consequences of which being that those individuals may exhibit increased fatigability, lethargy, decreased ability to concentrate, increased irritability, and morning headaches. Basically, those individuals are extremely tired due to their inability to get a good night's sleep.
Hypopneas can be either central i.e., as part of a waxing and waning in breathing effort, or obstructive in origin. During an obstructive hypopnea, in comparison to an obstructive apnea, the airway is only partially closed. However, this closure is still enough to cause a physiological effect i.e., an oxygen desaturation and/or an increase in breathing effort terminating in arousal.
A Hypopnea Index (HI) can be calculated by dividing the number of hypopnea events during the sleep period by the number of hours of sleep. The Apnea-Hypopnea Index (AHI) is an index of severity that combines apneas and hypopneas. Combining them both gives an overall severity of sleep apnea including sleep disruptions and desaturations (a low level of oxygen in the blood). The apnea-hypopnea index, like the apnea index and hypopnea index, is calculated by dividing the number of apneas and hypopneas by the number of hours of sleep. Another index that is used to measure sleep apnea is the Respiratory Disturbance Index (RDI). The RDI is similar to the AHI, however, RDI also includes respiratory events that do not technically meet the definitions of apneas or hypopneas, such as a Respiratory Effort Related Arousal (RERA), but do disrupt sleep.
One treatment for obstructive hypopnea is continuous positive airway pressure (CPAP). CPAP is a treatment in which the patient wears a mask over the nose and/or mouth. An air blower forces air through the upper airway. The air pressure is adjusted so that it is just enough to maintain the oxygen saturation levels in the blood.
Another treatment is sometimes a custom fitted oral appliance. The American Academy of Sleep Medicine's protocol for obstructive sleep apnea (OSA) recommends oral appliances for those who prefer them to CPAP and have mild to moderate sleep apnea or those that do not respond to/cannot wear a CPAP. Severe cases of OSA may be treated with an oral appliance if the patient has had a trial run with a CPAP. Oral appliances should be custom made by a dentist with training in dental sleep medicine. [2]
Mild obstructive hypopnea can often be treated by losing weight or by avoiding sleeping on one's back. Also quitting smoking, and avoiding alcohol, sedatives and hypnotics (soporifics) before sleep can be quite effective. Surgery is generally a last resort in hypopnea treatment, but is a site-specific option for the upper airway. Depending on the cause of obstruction, surgery may focus on the soft palate, the uvula, tonsils, adenoids or the tongue. There are also more complex surgeries that are performed with the adjustment of other bone structures - the mouth, nose and facial bones.
People with neuromuscular disorders or hypoventilation syndromes involving failed respiratory drive experience central hypoventilation. The most common treatment for this form is the use of non-invasive ventilation such as a bilevel positive airway pressure (BPAP) machine.
The word hypopnea uses combining forms of hypo- + -pnea , from the Greek roots hypo- (meaning low, under, beneath, down, below normal) and pnoia (meaning breathing). See pronunciation information at dyspnea.
Sleep apnea is a sleep-related breathing disorder in which repetitive pauses in breathing, periods of shallow breathing, or collapse of the upper airway during sleep results in poor ventilation and sleep disruption. Each pause in breathing can last for a few seconds to a few minutes and occurs many times a night. A choking or snorting sound may occur as breathing resumes. Common symptoms include daytime sleepiness, snoring, and non restorative sleep despite adequate sleep time. Because the disorder disrupts normal sleep, those affected may experience sleepiness or feel tired during the day. It is often a chronic condition.
Snoring is the vibration of respiratory structures and the resulting sound due to obstructed air movement during breathing while sleeping. The sound may be soft or loud and unpleasant. Snoring during sleep may be a sign, or first alarm, of obstructive sleep apnea (OSA). Research suggests that snoring is one of the factors of sleep deprivation.
Obesity hypoventilation syndrome (OHS) is a condition in which severely overweight people fail to breathe rapidly or deeply enough, resulting in low oxygen levels and high blood carbon dioxide (CO2) levels. The syndrome is often associated with obstructive sleep apnea (OSA), which causes periods of absent or reduced breathing in sleep, resulting in many partial awakenings during the night and sleepiness during the day. The disease puts strain on the heart, which may lead to heart failure and leg swelling.
Positive airway pressure (PAP) is a mode of respiratory ventilation used in the treatment of sleep apnea. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, in newborn infants (neonates), and for the prevention and treatment of atelectasis in patients with difficulty taking deep breaths. In these patients, PAP ventilation can prevent the need for tracheal intubation, or allow earlier extubation. Sometimes patients with neuromuscular diseases use this variety of ventilation as well. CPAP is an acronym for "continuous positive airway pressure", which was developed by Dr. George Gregory and colleagues in the neonatal intensive care unit at the University of California, San Francisco. A variation of the PAP system was developed by Professor Colin Sullivan at Royal Prince Alfred Hospital in Sydney, Australia, in 1981.
Generalized hypoxia is a medical condition in which the tissues of the body are deprived of the necessary levels of oxygen due to an insufficient supply of oxygen, which may be due to the composition or pressure of the breathing gas, decreased lung ventilation, or respiratory disease, any of which may cause a lower than normal oxygen content in the arterial blood, and consequently a reduced supply of oxygen to all tissues perfused by the arterial blood. This usage is in contradistinction to localized hypoxia, in which only an associated group of tissues, usually with a common blood supply, are affected, usually due to an insufficient or reduced blood supply to those tissues. Generalized hypoxia is also used as a synonym for hypoxic hypoxia This is not to be confused with hypoxemia, which refers to low levels of oxygen in the blood, although the two conditions often occur simultaneously, since a decrease in blood oxygen typically corresponds to a decrease in oxygen in the surrounding tissue. However, hypoxia may be present without hypoxemia, and vice versa, as in the case of infarction. Several other classes of medical hypoxia exist.
Upper airway resistance syndrome (UARS) is a sleep disorder characterized by the narrowing of the airway that can cause disruptions to sleep. The symptoms include unrefreshing sleep, fatigue, sleepiness, chronic insomnia, and difficulty concentrating. UARS can be diagnosed by polysomnograms capable of detecting Respiratory Effort-related Arousals. It can be treated with lifestyle changes, functional orthodontics, surgery, mandibular repositioning devices or CPAP therapy. UARS is considered a variant of sleep apnea, although some scientists and doctors believe it to be a distinct disorder.
Polysomnography (PSG) is a multi-parameter type of sleep study and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Greek πολύς, the Latin somnus ("sleep"), and the Greek γράφειν.
A mandibi splint or mandibi advancement splint is a prescription custom-made medical device worn in the mouth used to treat sleep-related breathing disorders including: obstructive sleep apnea (OSA), snoring, and TMJ disorders. These devices are also known as mandibular advancement devices, sleep apnea oral appliances, oral airway dilators, and sleep apnea mouth guards.
Non-invasive ventilation (NIV) is the use of breathing support administered through a face mask, nasal mask, or a helmet. Air, usually with added oxygen, is given through the mask under positive pressure; generally the amount of pressure is alternated depending on whether someone is breathing in or out. It is termed "non-invasive" because it is delivered with a mask that is tightly fitted to the face or around the head, but without a need for tracheal intubation. While there are similarities with regard to the interface, NIV is not the same as continuous positive airway pressure (CPAP), which applies a single level of positive airway pressure throughout the whole respiratory cycle; CPAP does not deliver ventilation but is occasionally used in conditions also treated with NIV.
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episodes are termed "apneas" with complete or near-complete cessation of breathing, or "hypopneas" when the reduction in breathing is partial. In either case, a fall in blood oxygen saturation, a disruption in sleep, or both, may result. A high frequency of apneas or hypopneas during sleep may interfere with the quality of sleep, which – in combination with disturbances in blood oxygenation – is thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime.
Apnea of prematurity is a disorder in infants who are preterm that is defined as cessation of breathing by that lasts for more than 20 seconds and/or is accompanied by hypoxia or bradycardia. Apnea of prematurity is often linked to earlier prematurity. Apnea is traditionally classified as either obstructive, central, or mixed. Obstructive apnea may occur when the infant's neck is hyperflexed or conversely, hyperextended. It may also occur due to low pharyngeal muscle tone or to inflammation of the soft tissues, which can block the flow of air though the pharynx and vocal cords. Central apnea occurs when there is a lack of respiratory effort. This may result from central nervous system immaturity, or from the effects of medications or illness. Many episodes of apnea of prematurity may start as either obstructive or central, but then involve elements of both, becoming mixed in nature.
Continuous positive airway pressure (CPAP) is a form of positive airway pressure (PAP) ventilation in which a constant level of pressure greater than atmospheric pressure is continuously applied to the upper respiratory tract of a person. The application of positive pressure may be intended to prevent upper airway collapse, as occurs in obstructive sleep apnea, or to reduce the work of breathing in conditions such as acute decompensated heart failure. CPAP therapy is highly effective for managing obstructive sleep apnea. Compliance and acceptance of use of CPAP therapy can be a limiting factor, with 8% of people stopping use after the first night and 50% within the first year.
The Apnea–Hypopnea Index or Apnoea–Hypopnoea Index (AHI) is an index used to indicate the severity of sleep apnea. It is represented by the number of apnea and hypopnea events per hour of sleep. Apnea is the complete absence of airflow through your nose and mouth. Hypoapnea is a partial collapse of your airway, limiting breathing. Apneas must last for at least 10 seconds and be associated with a decrease in blood oxygenation to be considered. Combining AHI and oxygen desaturation gives an overall sleep apnea severity score that evaluates both the number of sleep breathing disruptions and the degree of oxygen desaturation during said disruptions.
The respiratory disturbance index (RDI)—or respiratory distress Index—is a formula used in reporting polysomnography findings. Like the apnea-hypopnea index (AHI), it reports on respiratory distress events during sleep, but unlike the AHI, it also includes respiratory-effort related arousals (RERAs). RERAs are arousals from sleep that do not technically meet the definitions of apneas or hypopneas, but do in some way disrupt breathing during sleep and cause respiratory symptoms that may cause an arousal.
Rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation (ROHHAD) is a rare condition whose etiology is currently unknown. ROHHAD mainly affects the endocrine system and autonomic nervous system, but patients can exhibit a variety of signs. Patients present with both alveolar hypoventilation along with hypothalamic dysfunction, which distinguishes ROHHAD from congenital central hypoventilation syndrome (CCHS). ROHHAD is a rare disease, with only 100 reported cases worldwide thus far.
Central sleep apnea (CSA) or central sleep apnea syndrome (CSAS) is a sleep-related disorder in which the effort to breathe is diminished or absent, typically for 10 to 30 seconds either intermittently or in cycles, and is usually associated with a reduction in blood oxygen saturation. CSA is usually due to an instability in the body's feedback mechanisms that control respiration. Central sleep apnea can also be an indicator of Arnold–Chiari malformation.
Nasal expiratory positive airway pressure is a treatment for obstructive sleep apnea (OSA) and snoring.
A sleep-related breathing disorder is a sleep disorder in which abnormalities in breathing occur during sleep that may or may not be present while awake. According to the International Classification of Sleep Disorders, sleep-related breathing disorders are classified as follows:
Sleep surgery is a surgery performed to treat sleep disordered breathing. Sleep disordered breathing is a spectrum of disorders that includes snoring, upper airway resistance syndrome, and obstructive sleep apnea. These surgeries are performed by surgeons trained in otolaryngology, oral maxillofacial surgery, and craniofacial surgery.
Infantile apnea is a rare disease that is characterized by cessation of breathing in an infant for at least 20 seconds or a shorter respiratory pause that is associated with a slow heart rate, bluish discolouration of the skin, extreme paleness, gagging, choking and/or decreased muscle tone. Infantile apnea occurs in children under the age of one and it is more common in premature infants. Symptoms of infantile apnea occur most frequently during the rapid eye movement (REM) stage of sleep. The nature and severity of breathing problems in patients can be detected in a sleep study called a polysomnography which measures the brain waves, heartbeat, body movements and breathing of a patient overnight. Infantile apnea can be caused by developmental problems that result in an immature brainstem or it can be caused other medical conditions. As children grow and develop, infantile apnea usually does not persist. Infantile apnea may be related to some cases of sudden infant death syndrome (SIDS) however, the relationship between infantile apnea and SIDS is not known.