Central sleep apnea (CSA) or central sleep apnea syndrome (CSAS) is a
sleep
Sleep is a sedentary state of mind and body. It is characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity and reduced interactions with surroundings. It is distinguished from wakefulness by a de ...
-related
disorder
Disorder may refer to randomness, non-order, or no intelligible pattern.
Disorder may also refer to:
Healthcare
* Disorder (medicine), a functional abnormality or disturbance
* Mental disorder or psychological disorder, a psychological pattern a ...
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
Respiration may refer to:
Biology
* Cellular respiration, the process in which nutrients are converted into useful energy in a cell
** Anaerobic respiration, cellular respiration without oxygen
** Maintenance respiration, the amount of cellul ...
.
Central sleep apnea can also be an indicator of
Arnold–Chiari malformation
Chiari malformation (CM) is a structural defect in the cerebellum, characterized by a downward displacement of one or both cerebellar tonsils through the foramen magnum (the opening at the base of the skull). CMs can cause headaches, difficulty ...
.
Signs and symptoms
In a healthy person during sleep, breathing is regular so
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
levels and
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
levels in the bloodstream stay fairly constant: After
exhalation
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing.
This happens due to elastic properties of the lungs, ...
, the blood level of oxygen decreases and that of carbon dioxide increases. Exchange of gases with a lungful of fresh air is necessary to replenish oxygen and rid the bloodstream of built-up carbon dioxide. Oxygen and carbon dioxide receptors in the body (called
chemoreceptors
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
) send
nerve impulses
An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, ...
to the brain, which then signals for reflexive opening of the
larynx
The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...
(enlarging the opening between the
vocal cords
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speech ...
) and movements of the rib cage muscles and
diaphragm. These muscles expand the
thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
(chest cavity) so that a partial vacuum is made within the lungs and air rushes in to fill it.
In the absence of central apnea, any sudden drop in oxygen or excess of carbon dioxide, even if small, strongly stimulates the brain's respiratory centers to breathe; the respiratory drive is so strong that even conscious efforts to hold one's breath do not overcome it.
In pure central
sleep apnea
Sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. Each pause can last for a few seconds to a few minutes and they happen many times ...
, the brain's respiratory control centers, located in the region of the human brain known as the
pre-Botzinger complex, are imbalanced during sleep and fail to give the signal to
inhale
Inhalation (or Inspiration) happens when air or other gases enter the lungs.
Inhalation of air
Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...
, causing the individual to miss one or more cycles of breathing. The neurological feedback mechanism that monitors blood levels of
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
and in turn stimulates respiration fails to react quickly enough to maintain an even respiratory rate, allowing the entire respiratory system to cycle between apnea and hyperpnea, even for a brief time following an awakening during a breathing pause. The sleeper stops breathing for up to two minutes and then starts again. There is no effort made to breathe during the pause in breathing: there are no chest movements and no muscular struggling, although when awakening occurs in the middle of a pause, the inability to immediately operate the breathing muscles often results in cognitive struggle accompanied by a feeling of panic exacerbated by the feeling associated with
excessive blood CO2 levels. Even in severe cases of central sleep apnea, however, the effects almost always result in pauses that make breathing irregular rather than cause the total cessation of breathing over the medium term. After the episode of apnea, breathing may be faster and/or more intense (
hyperpnea
Hyperpnea, or hyperpnoea (forced respiration) is increased volume of air taken during breathing. It can occur with or without an increase in respiration rate. It is characterized by deep breathing. It may be physiologic—as when required by oxygen ...
) for a period of time, a compensatory mechanism to blow off retained waste gases, absorb more oxygen, and, when voluntary, enable a return to normal instinctive breathing patterns by restoring oxygen to the breathing muscles themselves.
Secondary effects
The conditions of
hypoxia
Hypoxia means a lower than normal level of oxygen, and may refer to:
Reduced or insufficient oxygen
* Hypoxia (environmental), abnormally low oxygen content of the specific environment
* Hypoxia (medical), abnormally low level of oxygen in the tis ...
and
hypercapnia
Hypercapnia (from the Greek ''hyper'' = "above" or "too much" and ''kapnos'' = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous pro ...
, whether caused by apnea or not, trigger additional effects on the body. The immediate effects of central sleep apnea on the body depend on how long the failure to breathe endures, how short is the interval between failures to breathe, and the presence or absence of independent conditions whose effects amplify those of an apneic episode.
* Brain cells need constant oxygen to live, and if the level of blood oxygen remains low enough for long enough, brain damage and even death will occur. These effects, however, are rarely a result of central sleep apnea, which is a chronic condition whose effects are usually much milder.
* Drops in blood oxygen levels that are severe but not severe enough to trigger brain-cell or overall death may trigger
seizure
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...
s even in the absence of
epilepsy
Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...
.
* In severe cases of sleep apnea, the more translucent areas of the body will show a bluish or dusky cast from
cyanosis
Cyanosis is the change of body tissue color to a bluish-purple hue as a result of having decreased amounts of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Body tissues that show cyanosis are usually in locations ...
, the change in hue ("turning blue") produced by the deoxygenation of blood in vessels near the skin.
* Compounding effects of independent conditions:
:* In persons with epilepsy, the hypoxia caused by apnea may be powerful enough to trigger seizures even in the presence of medication that otherwise controls those seizures well.
:* In adults with
coronary artery disease
Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pla ...
, a severe drop in blood oxygen level can cause
angina
Angina, also known as angina pectoris, is chest pain or pressure, usually caused by ischemia, insufficient blood flow to the Cardiac muscle, heart muscle (myocardium). It is most commonly a symptom of coronary artery disease.
Angina is typical ...
,
arrhythmia
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...
s, or heart attacks (
myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
).
:* Longstanding and recurrent episodes of apnea may, over months and years, have the cumulative effect of increasing blood carbon-dioxide levels to the point that enough carbon dioxide dissolves in the blood to form
carbonic acid in overall proportions sufficient to cause
respiratory acidosis
Respiratory acidosis is a state in which decreased ventilation (hypoventilation) increases the concentration of carbon dioxide in the blood and decreases the blood's pH (a condition generally called acidosis).
Carbon dioxide is produced continuou ...
.
:* In persons who have either or both forms of sleep apnea, breathing irregularities during sleep can be dangerously aggravated by taking respiration-depressing drugs, especially
sedative
A sedative or tranquilliser is a substance that induces sedation by reducing irritability or excitement. They are CNS depressants and interact with brain activity causing its deceleration. Various kinds of sedatives can be distinguished, but t ...
drugs that operate by depressing the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
generally; respiratory depressants include
opiate
An opiate, in classical pharmacology, is a substance derived from opium. In more modern usage, the term ''opioid'' is used to designate all substances, both natural and synthetic, that bind to opioid receptors in the brain (including antagonis ...
s,
barbiturate
Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as we ...
s,
benzodiazepines
Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, i ...
, and, in large quantities,
alcohol
Alcohol most commonly refers to:
* Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom
* Alcohol (drug), an intoxicant found in alcoholic drinks
Alcohol may also refer to:
Chemicals
* Ethanol, one of sev ...
, the last three of which are broad-spectrum CNS depressants. Quantities that are normally considered safe may cause the person with chronic sleep apnea to stop breathing altogether. Should these individuals have general
anaesthesia
Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), am ...
, for example, they require prolonged monitoring after initial recovery, as compared against a person with no history of sleep apnea, because apnea is likely to occur with even low levels of the drugs in their system.
:*
Sudden infant death syndrome
Sudden infant death syndrome (SIDS) is the sudden unexplained death of a child of less than one year of age. Diagnosis requires that the death remain unexplained even after a thorough autopsy and detailed death scene investigation. SIDS usuall ...
is sometimes theorized to be attributable to sleep apnea; the recommendation, prevalent since the mid-1980s, of placing infants on their backs rather than their stomachs for sleep represents an attempt to prevent those instances of breathing cessation that are attributable to compressive obstruction.
:*
Premature infants
Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between 2 ...
with immature brains and reflex systems are at high risk for central sleep apnea syndrome, even if these babies are otherwise healthy. Premature babies who have the syndrome will generally outgrow it as they mature, provided that they receive careful enough monitoring and supportive care during infancy to survive. Because of premature infants' propensity toward central apnea, medications that can cause respiratory drive depression are either not given to them or administered to them only under careful monitoring, with equipment for resuscitation immediately available. Such precautions are routinely taken for premature infants after general anesthesia; administration of
caffeine
Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is mainly used recreationally as a cognitive enhancer, increasing alertness and attentional performance. Caffeine acts by blocking binding of adenosine t ...
has been found not only to aid in maintenance of respiratory function after
general anaesthesia
General anaesthesia (UK) or general anesthesia (US) is a medically induced loss of consciousness that renders the patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general ...
but to reduce apnea for preterm infants regardless of context.
Diagnosis
A diagnosis of sleep apnea requires determination by a physician. The examination may require a study of an individual in a sleep lab, although the AAST has said a two belt IHT (In Home Test) will replace a PSG for diagnosing obstructive apnea. There, the patient will be monitored while at rest, and the periods when breathing ceases will be measured with respect to length and frequency.
During a PSG (
polysomnography
Polysomnography (PSG), a type of sleep study, is a multi-parameter study of sleep 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 Gree ...
) (a sleep study), a person with sleep apnea shows breathing interruptions followed by drops/reductions in blood oxygen and increases in blood carbon dioxide level.
* In adults, a pause must last 10 seconds to be scored as an apnea. However, in young children, who normally breathe at a much faster rate than adults, shorter pauses may still be considered apneas.
* Hypopneas in adults are defined as a 30% reduction in air flow for more than ten seconds, followed by oxygen-saturation declines of at least 3% or 4% per the AASM standards. and/or
EEG arousal. The
Apnea-Hypopnea Index (AHI) is expressed as the number of apneas or
hypopnea
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 n ...
s per hour of sleep.
As noted above, in central sleep apnea, the cessation of airflow is associated with the absence of physical attempts to breathe; specifically, polysomnograms reveal correlation between absence of rib cage and abdominal movements and cessation of airflow at the nose and lips. By contrast, in
obstructive sleep apnea
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 episod ...
, pauses are not correlated with the absence of attempts to breathe and may even be correlated with more effortful breathing in an instinctive attempt to overcome the pressure on the affected person's airway. If the majority of a sleep-apnea patient's apneas/hypopneas are central, their condition is classified as central; likewise, if the majority are obstructive, their condition is classified as obstructive.
Criteria
CSA is divided in 6 categories, Primary CSA,
Cheyne–Stokes respiration
Cheyne–Stokes respiration is an abnormal pattern of breathing characterized by progressively deeper, and sometimes faster, breathing followed by a gradual decrease that results in a temporary stop in breathing called an apnea. The pattern repe ...
, High-altitude periodic breathing, CSA due to a medical condition without CSB, Central sleep apnea due to a medication or substance and Treatment Emergent Central Apnea (also called Complex Sleep Apnea). The following symptoms are present in the Primary CSA: excessive daytime sleepiness, frequent arousals and awakenings during sleep or insomnia complaints, awakening short of breath, snoring, witness apneas.
[American Academy of Sleep Medicine (2014). ''International Classification of Sleep Disorders'', 3rd edition. Darien, IL: American Academy of Sleep Medicine] His polysomnography shows ≥5 central apneas and/or central hypopneas per hour of sleep, representing at least 50% of total respiratory events in the apnea-hypopnea index.
CSA with Cheyne-Stokes breathing is characterized by at least one of the criteria of Primary CSA or the presence of atrial fibrillation/flutter, CHF, or a neurologic disorder.
His polysomnography looks like the Primary CSA polysomnography with the addition of a ventilatory pattern compatible with CSB.
High-Altitude Periodic Breathing requires that the patient has recently been at least 2500 meters.
In the CSA due to a medication or substance, opioid or respiratory depressants must had been taken.
For the CSA due to a medical condition without CSB, the criteria are the same as Primary CSA, but the symptoms are caused by a disease.
In the Treatment Emergent Central Apnea, there was firstly some obstructive respiratory events but after their disappearance, the CSA has appeared.
Differential diagnosis
Although central and obstructive sleep apnea have some signs and symptoms in common, others are present in one but absent in another, enabling
differential diagnosis
In healthcare, a differential diagnosis (abbreviated DDx) is a method of analysis of a patient's history and physical examination to arrive at the correct diagnosis. It involves distinguishing a particular disease or condition from others that p ...
as between the two types:
Signs and symptoms of sleep apnea generally
*
Sign
A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or me ...
s:
:* Observed breathing pauses during sleep
:*
High carbon-dioxide saturation of blood, especially just before awakenings during which a patient experiences urgent need to breathe (see "Symptoms" below)
:*
Low oxygen saturation of blood
:*
Heart rate
Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...
increase (response to both hypercapnia and hypoxemia/hypoxia), unless there also exist problems with the heart muscle itself or the autonomic nervous system severe enough to make this compensatory increase impossible
*
Symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an disease, illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormali ...
:
:* High frequency of urgent need to breathe upon awakening (symptom created by
hypercapnia
Hypercapnia (from the Greek ''hyper'' = "above" or "too much" and ''kapnos'' = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous pro ...
), especially among subset of awakenings occurring at times other than normal for an individual's sleep schedule and
circadian rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogeno ...
s
Signs and symptoms of central sleep apnea
*
Signs:
:* Lack of abdominal and thoracic movement for 10 seconds or longer during sleep and coincident with breathing pauses
*
Symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an disease, illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormali ...
:
:* Inability, either complete or without excessive effort, to voluntarily operate diaphragm and other thoracic muscles upon awakening
::* The combination of this symptom with a high frequency of urgent need to breathe upon awakening is especially specific in that the co-presence of the latter symptom differentiates central sleep apnea's presentation from that of
sleep paralysis
Sleep paralysis is a state, during waking up or falling asleep, in which one is conscious but is completely paralyzed. During an episode, one may hallucinate (hear, feel, or see things that are not there), which often results in fear. Episodes ...
generally.
Signs and symptoms of and conditions associated with obstructive sleep apnea
*
Signs:
:* Observably ineffective respiratory movements (observable lack of air flow despite observable muscle movements indicating efforts to breathe)
:* Snoring (high-sensitivity but low-specificity)
:* Observably dry mouth or throat (high-sensitivity but low-specificity)
*
Symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an disease, illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormali ...
:
:* Sleepiness, fatigue, or tiredness, often rising to the level of
excessive daytime sleepiness
Excessive daytime sleepiness (EDS) is characterized by persistent sleepiness and often a general lack of energy, even during the day after apparently adequate or even prolonged nighttime sleep. EDS can be considered as a broad condition encompass ...
:* Frequent feelings of choking (airway and/or lung compression), as distinguished from mere feeling of suffocation nonspecific with respect to presence/absence of pressure, upon awakening
*
Associated conditions Associated may refer to:
*Associated, former name of Avon, Contra Costa County, California
* Associated Hebrew Schools of Toronto, a school in Canada
*Associated Newspapers, former name of DMG Media, a British publishing company
See also
*Associat ...
:
:*
Opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid us ...
medication use
:* Large neck circumference (>16" for females, > 17" for males) (frequent causal factor and possible indirect symptom; see "Obesity" below)
:* Obesity (frequent causal factor and possible, albeit low-specificity, sign both direct and indirect): Obesity frequently involves accumulation of fat below the chin and around the neck, depressing the
trachea
The trachea, also known as the windpipe, is a Cartilage, cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends ...
when one is in the supine position, and
central obesity
Abdominal obesity, also known as central obesity and truncal obesity, is a condition when excessive visceral fat around the stomach and abdomen has built up to the extent that it is likely to have a negative impact on health. Abdominal obesity has ...
can, depending on an individual's fat distribution, lead to increased direct pressure on the thoracic cavity and/or compressive anterior (headward) displacement of the abdominal organs, in the second case reducing space for and increasing difficulty of the motion of the
diaphragm. Poor breathing during sleep ''a''] reduces oxygen available for metabolism and may therefore depress
basal metabolic rate
Basal metabolic rate (BMR) is the rate of food energy, energy expenditure per unit time by endotherm, endothermic animals at rest. It is reported in energy units per unit time ranging from watt (joule/second) to ml O2/min or joule per hour per kg b ...
during sleep, increasing the difference between supply of food energy and demand for it during that time and thereby promoting weight gain, and ''b''] reduces sleep quality and recovery per time unit of sleep, resulting in sleepiness or fatigue that may prompt affected people to eat more in an attempt to increase short-term energy levels.
:* Correlation with cardiac disorders:
::*
Atrial fibrillation (AF): A study in the medical journal ''Sleep'' found that the prevalence of atrial fibrillation among patients with idiopathic central sleep apnea was significantly higher than the prevalence among patients with obstructive sleep apnea or no sleep apnea (27%, 1.7%, and 3.3%, respectively). The study was based on 180 subjects with 60 people in each of the 3 groups. Possible explanations for the association between CSA and AF include a causal relationship in one direction or the other between the two conditions or a common cause involving an abnormality of central cardiorespiratory regulation.
::* Adults with
congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
are at risk for a form of central apnea called
Cheyne-Stokes respiration, which manifests itself both during sleep and during waking hours. Cheyne-Stokes respiration is characterized by
periodic breathing
Periodic breathing is clusters of breaths separated by intervals of apnea or near-apnea. As opposed to normal breathing which is usually regular, periodic breathing is defined as three or more episodes of central apnea lasting at least 4 seconds, s ...
featuring recurrent episodes of apnea alternating with episodes of rapid breathing. There is good evidence that replacement of the failing heart (
heart transplant
A heart transplant, or a cardiac transplant, is a surgical transplant procedure performed on patients with end-stage heart failure or severe coronary artery disease when other medical or surgical treatments have failed. , the most common proce ...
) cures central apnea in these patients. Temporary measures (''e.g.'', those taken pending the availability of an
organ donor
Organ donation is the process when a person allows an organ of their own to be removed and transplanted to another person, legally, either by consent while the donor is alive or dead with the assent of the next of kin.
Donation may be for re ...
) include the administration of drugs whose effects include
respiratory stimulation, although these drugs are not universally effective in reducing the severity of Cheyne-Stokes apneas.
Congenital central hypoventilation syndrome
Congenital central hypoventilation syndrome
Central hypoventilation syndrome (CHS) is a sleep-related breathing disorder that causes ineffective breathing, apnea, or respiratory arrest during sleep (and during wakefulness in severe cases). CHS can either be congenital (CCHS) or acquired ( ...
(CCHS), often referred to by its older name "
Ondine's curse
Central hypoventilation syndrome (CHS) is a sleep-related breathing disorder that causes ineffective breathing, apnea, or respiratory arrest during sleep (and during wakefulness in severe cases). CHS can either be congenital (CCHS) or acquired ( ...
," is a rare and very severe inborn form of abnormal interruption and reduction in breathing during sleep. This condition involves a specific
homeobox
A homeobox is a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. For instance, mutations in a homeobox may change large-scale anatomical features of the full- ...
gene,
PHOX2B
PHOX was an American six-piece alternative folk / indie pop band from Baraboo, Wisconsin. Active from 2011 until 2017, they released their self-titled debut LP on June 24, 2014.
History
Prior to the formation of PHOX, many eventual members col ...
, which guides maturation of the autonomic nervous system; certain loss-of-function mutations interfere with the brain's development of the ability to effectively control breathing. There may be a recognizable pattern of facial features among individuals affected by this syndrome.
Once almost uniformly fatal, CCHS is now treatable. Children who have it must have
tracheotomies and access to mechanical ventilation on
respirator
A respirator is a device designed to protect the wearer from inhaling hazardous atmospheres including fumes, vapours, gases and particulate matter such as dusts and airborne pathogens such as viruses. There are two main categories of respir ...
s while sleeping, but most do not need to use a respirator while awake. The use of a
diaphragmatic pacemaker may offer an alternative for some patients. When pacemakers have enabled some children to sleep without the use of a mechanical respirator, reported cases still required the tracheotomy to remain in place because the vocal cords did not move apart with inhalation.
Persons with the syndrome who survive to adulthood are strongly instructed to avoid certain condition-aggravating factors, such as alcohol use, which can easily prove lethal.
Treatment
After a patient receives a diagnosis, the diagnosing physician can provide different options for treatment. If central sleep apnea is medication-induced (e.g., opioids), reducing the dose or eventual withdrawal of the offending medication often improves CSA.
* The FDA has recently approved a pacemaker-like implantable device called the remedē System for adult patients with moderate to severe central sleep apnea. After a commonly performed procedure, the device stimulates a nerve in the chest (phrenic nerve) to send signals to the large muscle that controls breathing (the diaphragm). It monitors respiratory signals during sleep and helps restore normal breathing patterns. The device is silent, activates automatically during the night, and does not require the patient to wear a mask.
* Mechanical regulation of airflow and/or airway pressure:
:* Treatment for central sleep apnea differs in that the device is set not at one constant optimal pressure but rather at two different settings, one for inhalation (IPAP) and for exhalation (EPAP), maintaining normal breathing rhythm by inflating the patient's lungs at regular intervals whose specifics, such as the breathing rate and the duration of a single breath, can be programmed. Devices tailored to this purpose are known as BiPAP ("
bilevel positive airway pressure
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), ...
") devices.
:* Both CPAP and BiPAP devices can be connected to a humidifier to humidify and heat the inhaled air, thus reducing unpleasant symptoms such as a sore throat or blocked nose that can result from inhaling cold, dry air.
:*CPAP and BiPAP devices can trigger central Apneas in those with obstructive sleep apnea requiring the use of an ASV (adaptive servo ventilation) device, which is also the proper machine for those who have central sleep apnea or mixed/complex apnea.
Epidemiology
Central sleep apnea is less prevalent than
obstructive sleep apnea
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 episod ...
. In one study, CSA is stated to have a prevalence of 0.9% in comparison to OSA.
There are many factors that increase the risk of developing CSA. Chronic opioid use produces a mean prevalence in central sleep apnea development of 24%. An estimate of 10% of
chronic kidney disease
Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...
(CKD) patients have a CSA diagnosis. Cohort studies of
stroke
A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
patients show a 70% development rate of CSA within 72 hours of the stroke event, although CSA was detected in less than 17% after 3 months of follow-up. Another cohort study from the Sleep Heart Healthy study showed incidence of CSA in
heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
patients to be 0.9%.
Infancy
Central sleep apnea is common in preterm, newborn, and infancy stages but a decrease in risk is found with aging and maturity of the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
. Underlying neurological disorders are the most common cause of CSA in full term infants. Of the apnea related events in preterm infants born at less than 29 weeks, 25% are central in origin.
Childhood
CSA is less common after 2 years of age. The prevalence of CSA in healthy children aging 10 to 18 years is 30%. Children with underlying medical conditions fall under a prevalence rate of 4-6%. For children diagnosed with
Prader-Willi syndrome (PWS), CSA is more common and can occur in up to 53% of cases.
Adulthood
Research shows that rates of sleep apnea are higher in adults over the age of 65 years,
due to older individuals having higher risks of developing CSA due to pre-existing medical conditions. Recorded prevalence in a cohort study of 2,911 men over the age of 65 was 7.5%.
There is reduced risk of CSA in women, and a higher incidence in men. One study showed the incidence of CSA in men was 7.8% and 0.3% in women, stating a difference in hormones have an effect on the apneic threshold (AT) for apnea.
References
Further reading
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External links
{{DEFAULTSORT:Central Sleep Apnea
Sleep disorders