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OSA terms
These are some terms for OSA. Hope they are helpful.
Apnea- defined as the cessation of airflow at the nostrils and mouth for at least 10 seconds. Literally means "no breath."
Apnea index (AI)-the number of apnea events per hour. A measure of the severity of sleep apnea.
Apnea plus hypopnea index (AHI)-the number of apneas and hypopneas in an hour of sleep. Criterion: 5-20=mild, 21-50=moderate, above 51 severe
RDI = Respiratory Disturbance Index, includes all respiratory events per hour.
Central apnea- absence of both airflow and inspiratory effort. Apnea caused by irregularity in the brain's control of breathing.
Excessive daytime sleepiness or somnolence-a subjective report of difficulty in maintaining the awake state, accompanied by a ready entrance into sleep when the individual is sedentary; may be quantitatively measured by use of subjectively defined rating scales of sleepiness.
Hypercapnia-too much carbon dioxide in the blood. Elevated carbon dioxide level in blood.
Hypersomnia- excessive or prolonged sleep. Sometimes associated with difficulty in awakening or sleep drunkenness.
Hypopnea-shallow breathing in which the air flow in and out of the airway is less than half of normal. Usually associated with oxygen desaturation.
Hypoxemia-a abnormal lack of oxygen in the blood in the arteries. Symptoms of acute hypoxemia are the patient turning blue, restlessness, stupor, coma, increased blood pressure, too-rapid heart beat, and an initial increase in heart output that later falls, resulting in low blood pressure and irregular heart beat or heart stoppage. Chronic hypoxemia stimulates red blood cell production by the bone marrow, leading to an excess of red cells. Hypoxemia caused by decreased oxygen pressure in the blood or too little oxygen intake improves with oxygen therapy. Hypoxemia resulting from shunting of blood from the right side of the heart to theleft side of the heart without exchange of gases in the lungs is treated with bronchial hygiene and breathing therapy.
Laser assisted uvulopalatoplasty (LAUP)-may eliminate or decrease snoring but has not been shown to be effective in treating sleep apnea.
Mandibular Maxillary Osteotomy and Advancement (MMOA)- is a procedure developed for those patients with retrolingual obstruction, or those patients with retropalatal and retrolingual obstruction who have not responded to CPAP and uvulopalatopharyngoplasty (UPPP).
Micro-arousal-partial awakening from sleep of which the sleeper is unaware.
Micro-sleep- a period lasting up to a few seconds during which the polysomnogram suddenly shifts from waking characteristics to sleep and external stimuli are not perceived; associated with excessive daytime sleepiness and automatic behavior, which are symptoms of DOES. Or a lapse from wakefulness into sleep that lasts just a few seconds, typically experienced by sleep-deprived persons.
Mixed (sleep) apnea-interruption in breathing during sleep which begins as a central apnea then becomes an obstructive apnea.
Multiple sleep latency test (MSLT)- a series of measurements of the interval from "lights out" to sleep onset that is utilized in the assessment of excessive daytime sleepiness. Subjects are allowed a fixed number of opportunities to fall asleep during their customary awake period. Long latencies are helpful in distinguishing physical tiredness or fatigue from true sleepiness. Or measures how sleepy you are by observing how long it takes you to fall asleep.
NREM or non-REM sleep-quiet sleep, slow-wave sleep; about 80 percent of sleep;characterized by slower and larger brain waves and little or not dream behavior.
Obstructive apnea- a cessation of airflow (10 seconds) in the presence of continued inspiratory effort. Or apnea caused by blockage of the airway. 2, cessation of breathing during sleep, due to a mechanical obstruction, such as a semi-collapsed trachea, tongue relaxed to back of the throat, or a large amoung of tissue in the uvula area.
O2- Chemical symbol for oxygen. Criterion lowest percent O2 saturation: Greater than 85%=mild, 80% to 85%=moderate, less than 80%=severe
PO2- partial pressure of oxygen (O2) in the blood. Any value for PO2 above 60 is usually considered a safe level:lower than 60 indicated hypoxemia and potential danger for the patient.
Polysomnogram- the continuous and simultaneous recording of physiological variables during sleep, i.e., EEG, EOG, EMG (these are the three basic stage scoring parameters), EKG, respiratory air flow, respiratory excursion, lower limb movement, and other electrophysiological variables.
Pulse Oximetry- a non-invasive measure of one's oxygen saturation; that is the amount of oxygen saturated in the hemoglobin in terms of percentage. This is not as accurate as the values obtained from an arterial blood gases (ABG) test and should only be used as a gauge of oxygenation. Normal ranges are between 95-100%. Supplemental oxygen is not generally instituted unless Sa02 is less that 88-90% at rest.
REM sleep, rapid eye movement sleep-sleep characterized by the active brain waves, flitting motions of the eyes, and weakness of the muscles; most dreaming occurs in this stage, which accounts for about 20% of sleep in adults.
Sleep- a state marked by lessened consciousness, lessened movement of the skeletal muscles, and lowed-down metabolism. People normally sleep in patterns that follow four definite, gradual stages. These four stages make up three fourths of a periods of typical sleep and are called as a group, nonrapid eye movement(NREM) sleep. The remaining time is usually occupied with rapid eye movement(REM) sleep. The REM sleep periods, lasting from a few minutes to half an hour, alternate with the NREM periods. Dreaming occurs during REM time. Individual sleep patterns change throughout life because daily need for sleep gradually diminish from s much as 20 hours a day in infancy to as little as 6 hours a day in old age. Infants tend to begin a sleep period with REM sleep, whereas REM activity usually follows the four stages of NREM sleep in adults.
Sleep hygiene- the conditions and practices that promote continuous and effective sleep. These include regularity of bedtime and arise time: conformity of time spent in bed to the time necessary for sustained and individually adequate sleep (i.e., the total sleep time sufficient to avoid sleepiness when awake); restriction of alcohol and caffeine beverages in the period prior to bedtime; employment of exercise,nutrition, and environmental factors so that they enhance, not disturb, restful sleep.
Sleep stage NREM (NREMS)- the major sleep state apart from REMS; comprises sleep stages 1-4, which constitute areas in the spectrum of NREMS "depth" or physiological intensity.
Sleep stage 1 (NREMS stage 1)- a stage of NREMS sleep that ensues directly from the awake state. Its criteria consist of a low-voltage EEG with slowing to theta frequencies, alpha activity less than 50%, EEG vertex spikes, and slow rolling eye movements; no sleep spindles, K-complexes, or REMS. Stage 1 normally assumes 4-5% of total sleep.
Sleep stage 2 (NREMS stage 2)- a stage of NREM sleep characterized by the advent of sleep spindles and K complexes against a relatively low-voltage, mixed-frequency EEG background; high-voltage delta waves may comprise up to 20% of stage 2 epochs; usually accounts for 45-55% of total sleep time.
Sleep stage 3 (NREMS stage 3)- a stage of NREM sleep defined by at least 20 and not more than 50% of the period consisting of EEG waves less than 2 Hz and more than 75 uV(high -amplitude delta waves); a "delta" sleep stage; with stage 4, it constitutes "deep "NREM sleep; and often combined with stage 4 into NREMS stage ¾ because of the lack of documented physiological differences between the two; appears usually only in the first third of the sleep period; usually comprises 4-6% of total sleep time.
Sleep stage 4 (NREMS stage 4)- all statements concerning NREMS stage 3 apply to stage 4 except that high-voltage, slow EEG waves, cover 50% or more of the record: NREMS stage 4 usually takes up 12-15% of total sleep time. Somnambulism, sleep terror, and sleep-related enuresis episodes generally start in stage 4 or during arousals from this stage. See Sleep stage 3.
Sleep stage REM (REMS)- the stage of sleep (i.g. state of the CNS) found in all mammals studies, including man, in which brain activity is extensive, brain metabolism is increased, and vivid hallucinatory imagery, or dreaming occurs (in humans). It is also called "paradoxical sleep" because, in the face of this intense excitation of the CNS and presence of spontaneous rapid eye movements, resting muscle activity is suppressed. The EEG is a low-voltage, fast-frequency, nonalpha record. Stage REMS is usually 20 25% of total sleep time.
Titration-a progressive ,stepwise increase in CPAP pressure applied during a polysomnogram to establish the optimal treatment pressure.
Uvulopalatopharyngoplasty-operation Performed on the throat to treat snoring and sleep apnea: abbreviated as UPPP, UPP, or UP3. 2. UPPP is an accepted means of surgical treatment for ODA, but is curative in less than 50% of patients. Scientific evidence suggests that UPPP works best in retropalatal and combination retropalatal and retrolingual obstruction
Most people with OSA have built up a huge sleep debt. Once you have your apnea treated, you start to pay off the sleep debt. REM sleep and Delta (Slow Wave Sleep) are "paid off" preferentially. You may find yourself groggy for a while. Also remember that even though you've got your apnea under control, you will still need 8 to 8.5 hours of sleep a night. Less than this (except for very rare cases) and you will continue to accumulate a sleep debt.
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