| C | Cataplexy |
| Cannula | A flexible tube that is inserted into your nose. It is used with a nasal pressure transducer to measure airflow. |
| Cardiac Arrest | Sudden cessation of the heart beat. |
| Cardiovascular | Pertaining to blood vessels and the heart |
| Cataplexy | Sudden dramatic decrement in muscle tone and loss of deep reflexes that leads to muscle weakness paralysis or postural collapse. Usually caused by outburst of emotion: laughter startle or sudden physical exercise; one of the tetrad of symptoms of narcolepsy. |
| CATAPLEXY (cat-ar-plex-ee) | Sudden loss of muscle power with collapse onto the ground but no loss of consciousness. A feature of narcolepsy that occurs particularly during moments of excitement or anticipation. |
| CDC | Center for Disease Control |
| Central apnea | Absence of airflow and inspiratory effort; apnea caused by irregularity in the brain's control of breathing. |
| CENTRAL APNOEA | Episodes of stopping breathing not due to obstruction of the upper airway but due to the brain simply failing to ask for a breath. Much less common than obstructive sleep apnoea and needs nasal intermittent positive pressure ventilation (NIPPV) as a treatment rather than nasal CPAP. |
| Central Nervous System (CNS) | Brain and spinal cord. |
| Central Sleep Apnea | Also CSA. A sleep related breathing disorder that occurs when the brain fails to tell the lungs to breathe. It is most common in the elderly and in patients who have heart disease or have had a stroke. In contrast to OSA it is unrelated to an obstructed airway. |
| CFIDS | Chronic Fatigue Immune Dysfunction Syndrome |
| CFS | Chronic Fatigue Syndrome |
| Cheyne-Stokes respiration | Breathing pattern typified by regular "crescendo-decrescendo" or waxing and waning fluctuations in respiratory rate and tidal volume. |
| CHEYNE-STOKES-BREATHING | Breathing that cycles up and down also know as periodic breathing. Found in people with heart failure and neurological problems. |
| CHF | Congestive Heart Failure |
| CHIN SUPPORT / STRAP | A strap or loop of material passing under the chin sometimes needed to hold the mouth closed to prevent air leaks during nasal CPAP or nasal ventilation. |
| Chronotherapy | Treatment for circadian rhythm sleep disorder by systemically changing sleeping and waking times to reset the biological clock. |
| Circadian rhythm | Innate daily fluctuation of behavioral and physiological functions including sleep waking generally tied to the 24 hour day-night cycle but sometimes to a different (e.g. 23 or 25 hour) periodicity when light/dark and other time cues are removed. |
| CNS | Central nervous system |
| Compliance | Adhering to or conforming with a regimen of treatment such as CPAP |
| CPAP | Continuous Positive Airway Pressure (a nasal device to relieve obstructed breathing in a sleeping patient) |
| CPAP | Continuous Positive-Airway Pressure. These PAP units provide one fixed level of air pressure. These PAP units provide one fixed level of air pressure. |
| CPAP - Continuous Positive Airway Pressure | The device used to treat sleep apnea by sending positive airway pressure at a constant continuous pressure to help keep an open airway allowing the patient to breathe normally through his/her nose and airway |
| CPAP Pressure | Pressure needed to maintain an open airway in a sleep apnea patient treated with CPAP expressed in centimeters of water (cm H20). The positive pressure can range from 5 - 20 cm H20. Different patients require different pressures. The value is determined in a CPAP titration study. |
| CPAP Study | Continuous Positive-Airway-Pressure Study. A sleep study that evaluates the effectiveness of CPAP therapy. It involves the titration of the CPAP device by a sleep technologist. |
| cps | cycles per second |
| CSA | Central Sleep Apnea |
| CSR | Cheyne-Stokes respiration |
| CYANOSIS (sigh-an-o-sis) | The bluey colour one goes when low in oxygen. |
