THE ELECTRONIC NOSE ARISES INTO THE 21st CENTURY

Electronic noses (eNoses) are instruments designed to imitate the sense of smell. These devices are used to detect and precisely distinguish odours within complex samples at a relatively low cost, and these properties make them very useful in a diverse range of clinical scenarios. An eNose is typically composed of a multisensor array, an information-processing unit, and a pattern-recognition algorithm. The multisensor array combines to respond globally to a wide range of volatile organic compounds (VOCs) and the output provides a distinct digital response pattern. Clinical ‘breathprints’ or ‘smellprints’ contain VOCs and respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, and lung cancer can be detected by this novel technique. Moreover, patients with exacerbated COPD and a positive microbiological culture can be differentiated from those with stable disease. The eNose displays high accuracy in detecting obstructive sleep apnoea syndrome, and common conditions in the intensive care unit such as acute respiratory distress syndrome and ventilator-associated pneumonia have also been studied in relation to the use of eNoses. Information contained within breathprints interpreted by eNoses may serve as non-invasive biomarkers in respiratory medicine and infectious diseases, as well as other branches of medicine.