Air Flow Limitation - This is early collapse to the upper airway

Apnealink - Is a Type IV ambulatory tool for screening Sleep Disorder Breathing. It offers a high pre-test probability of sleep apnoea.

Arousal - Occurring during sleep an arousal is a brief awakening which can contribute to a decrease in cognitive performance, increase in daytime sleepiness & increase cardiovascular risk.

Adapative Servo-Ventilation (ASV) - Is a type of device designed to treat patients diagnosed with all forms of sleep apnoea. This type of device technology aims to normalise the breathing. For further information on how the algorithms operate please see the websites of manufactures of this technology.


Bi-Level Device - A device that is able to be programmed to adjust both inspiratory & expiratory pressures. It can be used for patients with OSA &/or other respiratory problems.

Bruxism - The grinding of teeth during sleep.


CHS (Centre for Healthy Sleep) - 2 centres, one based in Abingdon, Oxfordshire and one in London. Staffed by experienced clinicians working in partnership with other healthcare professionals. They offer an alternative pathway for screening, diagnosis, treatment and on-going support, which is affordable and available to all patients.

CPAP Tritration - To determine the required pressure to be set on a CPAP flow generator to abolish both apnoea & hypnoea events. This maybe attended to via use with an APAP device.

Cheyne-Stokes Respiration - This is a cyclinical pattern of breathing diagnosed with a sleep study, here waxing & waning of tidal volume will be observed. Patients here are at risk of sleep disturbance and consequently increase daytime sleepiness. Left side heart failure may also be present.

Compliance - Currently there is no universal definition to define compliance, though it is a term that is widely used by clinicians to describe a patient's usage of their CPAP treatment.


Desaturation - a patient with untreated sleep apnoea can show a decreased in oxygen levels following an apnoea or hyponoea event.

Deviated Nasal Septum - The nasal septum which separates the nasal passages is found not to be equally aligned. This is a diagnosed by an ENT surgeon. When using CPAP treatment this can create some discomfort, hence the correct mask is vital.

Diabetes Mellitus - This classified into two (2) categories: Type 1: a reduction in insulin production & Type 2: resistance to insulin. Both cause hyperglycaemia & thus require medical management to treat via either use of insulin injections, diabetic oral medication & diet.


Embletta - This is a pocket-size digital recorder that is a complete system for diagnosis of SDB in the sleep clinic, hospital or home


Flattening - The inspiratory flow curve begins to flatten indicating airway instability.


Heart Failure - Also known as 'Congestive Heart Failure'. The structure of the heart is impaired thus affecting its' pumping action to deliver a sufficient amount of blood around the body. Symptoms can include breathlessness, tiredness, oedema at legs, coughing and more.

Humidification - Involves attaching a separate unit to a CPAP machine in order to add moisture to the air pressure being delivered. There are two (2) types of humidifiers, a cold passover & a heated system. Heated humidification has been shown to be more effective in resolving adverse symptoms of CPAP treatment such as ie. nasal dryness & nasal congestion

Hypercapnia - This is where carbon dioxide levels in the blood are raised outside the normal parameters.

Hyperventilation - Is an increased rate of breathing. It can occur as a result of a panic attack, or the body's response to a medical event. This can caused alterations in carbon dioxide levels.

Hypothyroidism - The thyroid gland is underactive and therefore does not produce enough of the thyroid hormone. This is diagnosed via blood test and can cause a person to feel tired & lethargic.

Hypoventilation - When breathing is either too shallow or too slow this can cause alterations in both oxygen & carbon dioxide levels.

Hypoxia - This is where oxygen in the body is below the normal parameters.

Hypertension - This is a term for High Blood Pressure. Untreated sleep apnoea is a risk indicator for this disorder. A medical doctor will usually prescribe anti-hypertensive medication to treat this condition. CPAP treatment has also been shown to be effective in helping to provide further control here.


Manometer - A piece of equipment able to measure the pressure delivered by a CPAP machine, thus ensuring that the device is delivering accurate pressures.

Mixed Apnoea - An apnoea & hyponoea event has both respiratory effort & non-effort.

Multiple Sleep Latency Test (MSLT) - This is a test to measure how long it takes to fall asleep. The results are scored as normal, moderate or severe sleepiness.


Non Rapid Eye- Movement (NREM) - dreams are a rare occurrence here & the body also does not experience paralysis at this time, this occurs in REM sleep. There are four (4) stages of NREM sleep.


Obesity Hypoventilation Syndrome - This is generally found to be more common in people who are clinical obese. Here both blood oxygen & carbon dioxide levels are affected both during the day & at sleep.

Oximetry - This involves applying an oximeter to i.e. a finger - to show - oxygen saturations in the blood

Oxygen Desaturating Index (ODI) - This is a measurement to show then number of oxygen desaturations occurring each hour, this can be used to indicate the severity of OSA.


Peridoic Limb Movement (PLM) - 'jerking' & 'cramping' of legs is experienced whilst asleep. This is diagnosed whilst undergoing a sleep study. This can result in sleep disturbance & thus increased daytime sleepiness.

POS (Point of sale) - Process of payment and invoice to the patient. Used for stock control and to generate sales report; and Dr, patient information for correspondence.


Rapid Eye Movement (REM) - this stage of sleep displays rapid movements of the eye. It can be normal for a person to experience 4-5 stages of this sleep per night, comprising of 20-25% of total sleep time. Dreams can be recalled from this stage of sleep.

The RealSleep programme is a free facility designed to help patients get the most from their treatment at all times. Members have many benefits including 50% extended warranty on all ResMed products, support, advice and discount on selected items

ResScan - Is a patient management system. The system collects data from the flow generator in order to monitor and optimise the patient's therapy and allow clinicians to store data.

Restless Legs Syndrome - This can be an uncomfortable crawling & tingling sensation, accompanied by an urge to move limbs to alleviate these sensations. Usually occurring in the evenings, this can cause problems with falling asleep.

Rhinitis - This can be an adverse symptom of CPAP treatment. Here the internal membrane of the nose can become irritated & inflamed. Symptoms vary from person to person but may present in the form of increase mucus production, dryness or even a runny nose. There are three (3) types of rhinitis. Heated humidification & nasal medication will assist to resolve this symptom.

Risk Indicator (RI) - Untreated sleep apnoea is a risk indicator for the cardiovascular system, diabetes, traffic & workplace accidents plus others. Alternatively it may be used to highlight a patient at risk of suffering with sleep apnoea following assessment of symptoms & simple screening pre diagnosis.


Sinisitis - This is inflammation of the sinuses, there are several classifications here. Those on CPAP treatment ultimately will manage better with a full face mask system with heated humidification.

Sleep Study - This is an overnight test that involves wearing equipment attached to the body whilst asleep. A polysomnography or an ambulatory test will be carried out here. A diagnosis is then made by a medical doctor where an appropriate course of action or treatment will follow.

SleepVantage (now RealSleep) programme is a free facility designed to help patients get the most from their treatment at all times. Members have many benefits including 50% extended warranty on all ResMed products, support, advice and discount on selected items

Somnologica - This is the software that supports all polysomnography devices.

Stroke- Blood flow & supply to the brain is altered due to an event, this affects the brains ability to function normally, thus can lead to a deterioration in bodily actions.


Upper Airway Resistance Syndrome (UARS) - Increased resistance in the upper airway, thus increasing the work of breathing. Unlike OSA a patient with UARS will not experience apnoea & hyponoea events. Increased daytime sleepiness can be present as arousal events can follow trying to overcome the airway resistance.