A device held against the side of the neck for 90 seconds may be a new way to tackle asthma attacks. The battery-powered gadget, which resembles a remote control, sends out low-level electrical signals to stimulate a nerve under the skin in the neck.
This triggers a series of changes that leads to the muscles in the airways relaxing, allowing more air to pass through, and easing symptoms of breathlessness.
NHS figures suggest that 5.4 million people in the UK are being treated for asthma. In an asthma attack, the smooth muscles of the bronchi — the small tubes that branch out from the windpipe and carry air in and out of the lungs — contract. This causes the airways to narrow and, together with inflammation in the linings of the airways, leaves a patient short of breath and with a tight feeling in their chest.
Asthma attacks are often sparked by an irritant in the environment. These triggers vary and include pollens, dust mites, viral infections and even stress.
Patients are typically offered two main types of treatment, in the form of drug inhalers, which act to widen the airways. However, in some cases the symptoms may not improve, despite this treatment, and immediate medical attention is needed.
The new device is designed to treat attacks by using low-level electrical stimulation of the nerve that runs up the side of the neck, called the vagus nerve.
When symptoms appear, it is held next to the skin, against the carotid artery, which is next to this nerve.
The weak electrical signal is then transmitted through the skin. The vagus nerve is crucial for co-ordinating the body’s ‘fight or flight response’ and increasing heart rate and oxygen levels in the body.
When stimulated, part of the nerve’s response is to trigger the release of the hormone adrenaline.
Asthma
This acts to relax the muscles in the walls of the airway, widening the tubes that connect to the lungs, allowing more air in and out of the body.
The treatment lasts for 90 seconds at a time and is used by the patient whenever they feel breathless. Early stage animal research suggests that the approach may provide an especially effective option for patients who suffer side-effects from common asthma medications — which can include a sore throat and muscle shakes — or who fail to respond to the drugs.
A new study in the Journal of Academic Emergency Medicine showed that stimulation of the nerve was highly effective in acute asthma attacks.
Other studies have shown the treatment widens airways by more than 60 per cent.
Previously, scientists have inserted electrodes into the neck of asthma patients, in direct contact with the vagus nerve.
One study using this approach, published in The Internet Journal of Asthma, Allergy and Immunology, revealed that the technique reduced breathlessness in a patient admitted to hospital with a severe asthma attack.
However, the newer system will not require doctors to implant electrodes in the body, say the researchers, as the symptoms in the patients using it would not have reached such a severe stage. This means that the electrical signals produced by the device will be strong enough to trigger some degree of relaxation in the airways.
A new clinical trial with 30 men and women is underway at a number of centres in the U.S., including the California Allergy and Asthma Center.
Commenting on the research, Leanne Metcalf, assistant director of research at charity Asthma UK, says: ‘Despite having a number of effective treatments for asthma in the UK, they don’t work for everyone and even those who are taking regular medication can still find themselves in trouble.
‘The potential of this device to tackle asthma attacks has yet to be proven, but the results of the clinical trial will help to tell us whether this is a viable new treatment.’
