Continuous Asthma Monitoring System Helps Pinpoint Cause of Asthma Attacks

A personal sensor system which continuously monitors the environment air around persons prone to asthma attacks has been developed at Georgia Tech Research Institute. Designed to be worn in the pockets of a vest, the system should help researchers understand the causes of asthma attacks.

The system measures airborne exposure to formaldehyde, carbon dioxide, ozone, nitrogen dioxide, temperature, relative humidity and total volatile organic compounds (VOCs). VOCs are emitted as gases from products such as paints, cleaning supplies, pesticide formulations, building materials and furnishings, office equipment and craft materials.

In addition to sensing the seven compounds mentioned above, a special mesh filter collects particles. A pump pulls air through the filter so that the quantity of particles can be measured at the end of the sampling period, and the composition of the collected particulate can be analyzed in a laboratory.

The entire device weighs less than a pound including batteries. Every two minutes, it takes a measurement of air, stores the data in on-board memory and then goes to sleep mode to conserve power.

Searching For Causes

Although no one fully understands why certain people get asthma, doctors know that once a person has it, his/her lungs can overreact to environmental stimuli causing chest tightness or breathlessness, known as an asthma attack. According to CDC, 6.8 million children in the U.S. have asthma[1], and 3,884 died due to asthma[2].

“We are investigating whether we can go back after an asthma attack and see what was going on environmentally when the attack started,” said Charlene Bayer, Georgia Tech research scientist.

The sensor system is designed to be comfortably worn in the pockets of a vest throughout the day and kept at the bedside while sleeping at night. Another vest pocket contains an electronic peak flow meter to periodically measure pulmonary function. When experiencing an asthma attack, the vest wearer notes what time it occurred and Bayer can examine the levels of the chemical compounds at that time.

Six adult volunteers have tested the vest for comfort and the effectiveness of the sensor system under actual use conditions. And that has already brought benefits for one volunteer, whose vest detected higher volatile organic exposures in his home than anywhere else. That led researchers to discover a pollutant pathway from the volunteers basement garage into the living areas that was allowing automobile exhaust and gasoline fumes to invade the house.

With future funding, Bayer hopes to develop a smaller and more sensitive sensor system, test the current vest in population studies of asthmatic children and develop software to process the population studies data as it is collected.

“With this system we can determine what children are exposed to at home, at school and outside where they play,” said Bayer. “Chances are there are some overreaching compounds that seem to trigger asthma attacks in more children.”

Although it was developed specifically for use in researching asthma triggers, it seems to me this device, or a similar approach, could be useful in finding out causes of attacks for other problems, such as Multiple Chemical Sensitivity.

References:

1. Centers for Disease Control Report, Summary Health Statistics for U.S. Children: National Health Interview Survey, 2006
2. Centers for Disease Control Report, Deaths: Final Data for 2005