hypopnea 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 not indistinguishable impact" on the negative outcomes of sleep breathing disorders. 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 because they did not get the right kind of sleep. 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. symptoms 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. consequences 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. causes among the causes of hypopnea are: anatomical defects such as nasal septum deformation or congenital narrowness of nasal meatus and the gullet acute tonsillitis and/or adenoiditis obesity or being overweight neuromuscular disease or any condition that entails weakened respiratory muscles hypoventilation syndromes involving compromised or failed respiratory drive use of sedatives, for example sleeping pills hazardous alcohol use smoking aging others, most of which are also typical causes of airway obstruction, snoring and sleep apnea diagnosis 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. treatment obstructive hypopnea