Accurately Measuring the Temperature of Exhaled Breath

A new device that easily and accurately measures the temperature of a patient's exhaled breath offers a breakthrough in the management of asthma and other respiratory diseases.

The X-Halo Breath Thermometer measures exhaled respiratory temperature during free voluntary tidal breathing. The device includes an environmental chamber, an air inlet for receiving a stream of exhaled respiratory breath, and an air outlet for permitting the escape of the exhaled breath. To use the device the patient inhales through the nose and exhales into the device through a disposable mouthpiece; each exhalation increases the temperature inside the reservoir until equilibrium is reached and the temperature is then measured by a thermal sensor, which is accurate to 0.03 degrees Celsius. The device automatically displays and stores the final temperature. A maximum of 122,400 individual data points can be stored and then downloaded via a universal serial bus (USB) port from the device to a personal computer (PC). The breath thermometer is powered by two AAA batteries and it can run continuously for 11 days. The X-Halo Breath Thermometer is a product of Delmedica (Singapore). Due to limited initial production, the company is now offering the device exclusively to researchers and clinicians. The device has not yet been approved by the U.S. Food and Drug Administration (FDA).

"The temperature of the exhaled breath turns out to be an unexplored area on the map of human physiology and disease,” said device inventor allergologist Professor Todor Popov, M.D., of the Medical University of Sofia (Bulgaria). "There are preliminary reports that increased exhaled breath temperature could be a marker for viral and bacterial infections of the respiratory system, but there is a vast territory to systematically cover in order to figure out the utility of this simple and cheap approach.”

A number of recent medical studies have concluded that an asthma sufferer's exhaled breath temperature is related to the degree of airway inflammation, due to an increased vascularity of the airway mucosa, which alters heat loss in the airways. Exhaled breath temperature can increase by up to 1.2 degrees Centigrade before an asthma attack. Furthermore, exhaled breath temperature is different from core body temperature, as determined by otic or axillar thermometers.

Related Links:
Delmedica
Medical University of Sofia