(Philadelphia, PA) – Researchers at the University of Pennsylvania School of Medicine have recently completed three studies – the most comprehensive and largest to date – that demonstrate the effectiveness of an electronic nose device for diagnosing common respiratory infections, specifically pneumonia and sinusitis. Doctors hope that the device – called the Cyranose 320, or e-nose – will provide a faster, more cost-effective and easier-to-use method for accurately diagnosing pneumonia and, as a result, help reduce over-prescription of antibiotics. Their initial findings will be presented at the combined annual meetings of otorhinolaryngology (ear, nose and throat) experts – the Triologic Society and the American Broncho-Esophagological Association – on April 30th, 2004, in Phoenix, Arizona.
“Pneumonia is a serious bacterial infection that can cause serious injury or even death; indeed, it remains a leading cause of death in intensive care units (ICUs),” said lead author of the first study, C. William Hanson III, MD, Professor of Anesthesia and board-certified expert in critical care medicine. “Treating this illness is complicated because there are many kinds of pneumonia, and it can be commonly misdiagnosed in the ICU and confused with other diseases which cannot be treated using antibiotics. This is a leading cause of the overuse – through over-prescription – of antibiotics for false cases of pneumonia.”
The first two studies looked at pneumonia cases among patients who are on ventilators in the surgical intensive care unit (SICU). Here, diagnosis is made difficult by the patients’ limited ability to move, and they are vulnerable to infections from other compounding injuries. In the first study, researchers found that the e-nose effectively diagnosed 92 percent of pneumonia cases among 25 patients, as confirmed by computed tomography (CT) scans of the lungs. It successfully distinguished 13 positive cases from 12 other patients who did not have pneumonia. Similarly, in the second study, researchers found the e-nose effective in providing accurate diagnoses of pneumonia in 31 of 44 SICU patients (70 percent).
One quarter of ventilated SICU patients develop pneumonia – a serious complication that can threaten the patient’s life, requires immediate treatment with antibiotics, and also increases their hospital stay three-fold, with average additional hospital costs of $11,000 per patient.
The third study looked at sinusitis, the most common diagnosis from respiratory complaints by patients in outpatient clinics. The e-nose was effective at diagnosing 82 percent of sinusitis cases among 22 patients, one half infected and the other half not so.
All bacteria, as living organisms, produce unique arrays or mixtures of exhaled gases. The e-nose works by comparing “smellprints” from a patient’s breath sample to standardized, or known, readings stored on a computer chip. These “smellprints” are created from both electro-chemical and mathematical analysis of exhaled gases contained in a breath sample. Upon analysis, identifiable patterns emerge, and a patient’s “smellprint” can tell a physician whether or not bacteria are present and, if so, what kind. This can aid not just in the accuracy of diagnosis, but can also help physicians select the most effective antibiotic for treatment.
“The results confirm that exhaled breath can be analyzed for pneumonia and sinusitis using a commercially available e-nose device,” said lead investigator for the sinusitis study and co-investigator for the pneumonia studies, Erica Thaler, MD, an Associate Professor of Otorhinolaryngology: Head and Neck Surgery at Penn. “There is the potential with this device to radically change and improve the way we diagnose and treat both conditions – for which there is no gold-standard test. And, given that we can apply this sensory analysis to the detection of pneumonia and sinusitis, then, hopefully, it can be applied to common bacterial infections of the upper respiratory tract.”
The e-nose is also being studied for its possible use in diagnosing many other illnesses, including: lung cancer, kidney disease and cirrhosis of the liver, otitis media (middle ear infections) in children, or even detection of chemicals and biological agents. Manufactured by Smiths Detection of Pasadena, CA, the machines cost approximately $8,000 USD, and still require approval from the federal Food and Drug Administration before they can be widely used. Breath samples are taken with a hand-held sensor – about the size of child’s video game player – connected to a standard oxygen mask with cup, as the patient breathes normally. Readings are displayed by connecting the device to a laptop computer.
"Flexibility and ease-of-use are the greatest advantages of the e-nose," said lead researcher Neil Hockstein, MD, a clinical instructor and Penn otorhinolaryngologist. "They are miniaturized devices, provide quick results, are relatively inexpensive, non-invasive, safe for patients and they could be used in a doctor's office - or, potentially, even at home."
One big advantage of devices that can rapidly diagnose infectious diseases is that they can cut antibiotic overuse and therefore reduce the rate at which pathogens develop resistance to antibiotics. Another advantage is the more rapid diagnosis and treatment of infections. More generally the use of devices of this type will accelerate the speed of diagnosis of diseases of all types.
In the longer run automated diagnosis devices are going to drop in cost by orders of magnitude. The sensor systems are mostly electronics and the electronics will drop in price as the sensors become more powerful and automated. Check out the size of the Cyranose 320 e-nose. I bet the vast bulk of their costs are development costs (especially regulatory approval but clinical testing is expensive regardless of regulatory requirements) and that their manufacturing costs are a small fraction of product price. So in the long run this device and future devices like it will become much cheaper.
Many diagnostic devices will become so easy to use and widely available and cheap that it will become very common to do self-diagnosis for a large assortment of diseases. This will cause a radical change in how medical care is delivered. Most people will test themselves at home using cheap home diagnostic sensor kits and show up at a doctor's office already diagnosed. Also, the increasing power of over-the-counter (OTC) drugs will reduce the need to go to a doctor's office to seek treatment in the first place. Even when a doctor does choose the course of treatment in many cases there will be no need for an office visit as the diagnostic information will be passed to the doctor's computer for review with the doctor then electronically passing the chosen treatment information to a pharmacy.
Further in the future even the trip to the pharmacy will become unnecessary for some treatments. Cheap microfluidic devices available in many homes will be able to synthesis some drugs and some types of gene therapy. Just as an upscale home is not complete without a high tech home entertainment center and an assortment of other home appliances it will become common to have home medical appliances for testing, treatment synthesis, and treatment delivery.
Expect to see diagnostic devices embedded into houses. Chemical testers for toilets are an obvious possibility. Expect parents to eagerly buy such testers when the testers get the ability to instantly spot junior's illicit drug use. Also, sensors embedded in bathtub drains and kitchen sinks could check for patterns of secretions which indicate disease. Sensors at the head of a bed and in couches and chairs could check exhaled gasses for signs of disease.
Diagnostic and treatment appliances embedded in the human body will also become common. A person will be able to wear a watch that sounds an alarm if internal body sensors report something amiss. A watch or some other worn device could even make a cellular phone call to a medical facility with GPS information to warn of an especially urgent medical condition.
|Share |||Randall Parker, 2004 May 24 01:15 PM Biotech Assay Tools|