Criticality of human breath detection with a portable device III: integration with other devices for health care and self-monitoring

Human breath is largely composed of oxygen, carbon dioxide, water vapor, nitric oxide, and numerous volatile organic compounds (VOCs) [1, 2]. Changes in the concentration of the molecules in VOCs could suggest various diseases or at least changes in the metabolism. Indeed, breath gases are recognized to be excellent indicators of the presence of diseases and clinical conditions. Such gases have been identified as biomarkers using accurate but expensive benchtop instrumentations such as gas chromatography (GC) or electronic nose (e-nose) [1]. As a consequence, in recent years, it has been stimulated the necessity to develop a portable device for breath analysis, easy to use, and feasible for patients living far from medical structures or physicians. In the framework of SEMEOTICONS (SEMEiotic Oriented Technology for Idividual's CardiOmetabolic risk self-assessmeNt and Self-monitoring) European Project, we developed a low cost, portable, easy-to- use device for the analysis of breath composition: the Wize Sniffer (WS). The WS captures breath samples, the chemical selective sensors sense the sample and accordingly form a sort of odor-print of healthy people or patients with known and specific diseases, in order to evaluate the well-being state of a human subject [3, 4]. It should be noted that does not exist a general definition of "well-being state", rather some indices for well-being that can be correlated to cardio-metabolic risk, which is representing the leading cause of worldwide mortality [3, 5]. The breath molecules detected by the Wize Sniffer are the following, all related to those noxious habits for cardio-metabolic risk (alcohol intake, smoking, wrong diet): ï,· Carbon Monoxide (CO): CO is present in cigarette smoke (it is the major component, 75,95%). Mean carbon monoxide concentration in exhaled breath is about 3,5 ppm. Increasing levels of exhaled carbon monoxide can be detected in smoking subjects: 13.8 - 29 ppm. ï,· Carbon Dioxide (CO2) and Oxygen (O2): Exhaled air has a decreased amount of oxygen and an increased amount of CO2. These amounts show how much O2 is retained within the body for use by the cells and how much CO2 is produced as a by-product of cellular metabolism. CO2 is also one of constituents of tobacco smoke (13%). Exhaled O2 amount is about 13.6%-16% while mean CO2 concentration in exhaled breath is about 4% (= 40000ppm). Lower values may be due to respiration disorders. ï,· Ethanol: Exogenous Ethanol comes from alcoholic drink. It is important to note that it is recognized that ethanol breakdown leads to an accumulation of free radicals into the cells, a clear example of oxidative stress. Ethanol may cause arrhythmias and depresses the contractility of cardiac muscle. ï,· Nitrogen (di)Oxide (NOx): it is a vasodilator and it modulates inflammatory response (operating in combination with CO and Hydrogen Sulfide). It is also a good indicator for asthma diseases. ï,· Hydrogen Sulfide (H2S): it is a vascular relaxant agent, and has a therapeutic effect in various cardiovascular diseases (myocardial injury, hypertension). In general, H2S could have therapeutic effect against oxidative stress due to its capability to neutralize the action of free radicals. ï,· Ammonia (NH3): Mean baseline levels of ammonia in exhaled gas are about 0.42ppm. Elevated breath ammonia usually could be due to liver disease, such also to kidney disease. Ammonia is also one of the major compounds, together with CO, of tobacco fumes (approximately 22,15%). ï,· Hydrogen (H2): The production of hydrogen is a metabolic consequence of carbohydrate fermentation by anaerobic bacteria. This hydrogen traverses the gut wall, and is transported via the circulation to the lungs, where is execrated in exhaled breath. Not only, a certain amount of exhaled hydrogen is the result of fermentation by oropharingeal bacteria. As a consequence, increased values of breath hydrogen may be due to overweight problems, intestinal diseases, improper life-style. The baseline value is about 9.1ppm. In this report, we describe briefly the hardware/software architecture of the Wize Sniffer, and how it can be integrated in other multisensory platform for health care and self-monitoring.