Technology overview

This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.

About the technology

CE marking

The Airsonett device is a class I medical device for which the manufacturer, Airsonett AB, received a CE mark in June 2010.


The Airsonett device is a temperature‑controlled laminar airflow device intended to be used as an add‑on to standard treatment for people whose asthma is affected by exposure to airborne allergens, particularly those with severe persistent allergic asthma. It was previously marketed under the name Protexo, and may also be referred to as Airsonett Airshower. All of these names refer to the same model of the device.

The device consists of a base unit containing an air intake, filter and cooler, neck pipes, and an air supply nozzle. The base unit stands next to the patient's bed and the air supply nozzle is positioned above their head.

The device is principally designed to operate by the bedside while the patient sleeps. The device draws air from the room through a filter that captures allergens and other particles. This filtered air is then cooled to 0.5–0.8ºC below the ambient room temperature, before being slowly expelled from the air supply nozzle. This cooler air is more dense than the ambient room air and so it descends into the patient's breathing zone. The device provides cooled, filtered air around the patient's face through the night, breaking the natural body convection without creating draught or dehydration. The manufacturer describes this as the key feature that differentiates the Airsonett device from other devices designed to supply filtered air to the breathing zone.

Intended use

The device is designed to reduce the level of allergens inhaled during the night. It does this by providing a temperature‑controlled laminar flow of filtered air, thereby alleviating the symptoms of allergy‑induced diseases.

Setting and intended user

The Airsonett is primarily intended for home use by people with poorly controlled persistent allergic asthma despite high‑intensity treatment. Such patients are typically described as having reached Step 4 of the Global Initiative for Asthma (GINA) and the British Thoracic Society/Scottish Intercollegiate Guidelines Network (BTS/SIGN) guidelines. This is defined as having poor control of asthma symptoms despite treatment with moderate doses of inhaled steroid and add‑on therapies. These patients can be further defined as having an Asthma Control Test (ACT) score of less than 18. The ACT provides an indication of how well a person's asthma has been controlled over the previous 4 weeks; scores range from 1 to 25, with any score below 20 indicating poor symptom control. Such patients are likely to be under the care of a hospital‑based respiratory physician as well as receiving regular primary care management. The device may also be considered for people with less severe conditions such as rhinitis and eczema, although these uses are outside the scope of this briefing.

Current NHS options

The Airsonett device is intended to be used for people who are at Step 4 or above of the BTS/SIGN stepwise treatment approach. The 2012 BTS/SIGN guidelines recommend that add‑on therapies can be considered for people who have reached Step 5, which means that continuous or frequent use of oral steroids is often necessary to control asthma symptoms.

Current add‑on treatment options for severe allergic asthma as recommended in the NHS are daily corticosteroid tablets and omalizumab. Other available options include bronchial themoplasty and immunosuppressants such as methotrexate and ciclosporin.

Omalizumab for treating severe persistent allergic asthma (NICE technology appraisal guidance 278) recommends omalizumab as an optional add‑on to standard therapy in people aged 6 years and older who need continuous or frequent treatment with oral corticosteroids.

Bronchial thermoplasty uses short pulses of radiofrequency energy to reduce the amount muscle in the airway. Bronchial thermoplasty for severe asthma (NICE interventional procedure guidance 419) states that the procedure shows some improvement in symptoms of severe asthma, including expiratory flow rate, beta‑2 antagonist use, and number of exacerbations and hospital admissions. There is also evidence of improvement in quality of life. The guidance goes on to state that although the evidence on short- and medium‑term safety are adequate, more evidence is needed on longer‑term safety. Therefore, bronchial thermoplasty should be used only with special arrangements for clinical governance, consent and audit or research, and patients should be chosen by a respiratory team with special expertise in managing severe asthma.

Treatment with immunosupressants can decrease long‑term steroid tablet requirements, but these drugs have significant adverse effects. As most immunosuppressants act non‑selectively, a common treatment effect is immunodeficiency, which results in increased susceptibility to infections.

NICE is aware of the following devices that appear to fulfil a similar function to the Airsonett:

  • PureZone Personal Air Filtration System (PureZone Technologies).

  • PureNight Pure Air System (Halo).

NICE has not investigated the regulatory status of these devices; it is the responsibility of healthcare professionals to check this status for any intended use.

Costs and use of the technology

The rental cost of Airsonett to the NHS is £174 (excluding VAT) per month, equivalent to £5.72 per night, on a managed service basis that includes replacement filters every 6 months. Replacement, repairs and technical support are included in the rental charge.

In cases of misuse or damage that necessitates repairs and replacements, the following charges (excluding VAT) apply:

  • Filter: £500.

  • Refurbishment followed by self‑installation: £250.

  • Refurbishment on site by Airsonett: £500.

  • Refurbishment at Airsonett facility: £1100.

The Airsonett device has an anticipated lifespan of 5 years when used every night for 8 to 10 hours. The cost of omalizumab ranges from £1665 per patient per year (75 mg dose every 4 weeks) to £26,640 per patient per year (600 mg dose – the recommended maximum dose in the summary of product characteristics – every 2 weeks), indicating a comparable daily cost per patient of £4.56 on the lower dose and £72.99 on the maximum dose. As part of the evidence preparation for Omalizumab for treating severe persistent allergic asthma (NICE technology appraisal guidance 278), a systematic review and economic evaluation by Norman et al. (2013) estimated the average daily cost per patient to be £23, based on the distribution of doses taken by people in the included trials. This included administration and monitoring costs.

Likely place in therapy

The technology is intended to be used as a long‑term add‑on therapy for children and adults with severe persistent allergic asthma whose disease, despite high‑intensity pharmacotherapy, remains poorly controlled. This includes people who have reached BTS/SIGN Step 4 or above who would otherwise be considered for long‑term oral steroids, omalizumab or bronchial thermoplasty.

Specialist commentator comments

One specialist commentator noted that the Airsonett device may be useful for patients whose immunoglobulin E concentration is too high for treatment with omalizumab. It is cheaper and less potentially harmful than omalizumab, although the evidence on effectiveness is limited.

One commentator suggested that dust mite pillow covers should be used with the Airsonett device, because they would reduce the inhalation of allergenic particles from pillows. However, these covers were not used in any of the clinical trials, so there is no measure of their potential benefit.

One commentator noted that a number of people with severe asthma experience multisystem allergic disease, in particular eczema and allergic rhinitis. When used to treat these patients, temperature‑controlled laminar airflow such as that provided by the Airsonett device shows multiple benefits. These include a reduction in topical treatment need, improvement in quality of life and reduction in healthcare resource use. However, this view was not supported by another commentator, who noted that there was no objective evidence to support the use of the Airsonett device in multisystem allergic disease.

Specialist commentators made generally positive comments about their experience of using the Airsonett device. They did, however, report difficulties in obtaining funding because the evidence on efficacy is limited, and severe asthma is not part of the NHS specialist commissioning arrangements.

Equality considerations

NICE is committed to promoting equality and eliminating unlawful discrimination. We aim to comply fully with all legal obligations to:

  • promote race and disability equality and equality of opportunity between men and women, and

  • eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief, in the way we produce our guidance. (NB these are protected characteristics under the Equality Act (2010)).

Some people with asthma are considered to have a disability according to the Equality Act (2010).