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| CSIRO | SOLVE | Issue 6 Feb 06 | |
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ARTICLE
FIBRE OPTICS:
Fibre Optics Ease the Hard Swallow By Whitney MacDonald
Doctors and their patients will benefit from a more comfortable catheter. Experiencing the symptoms of any disease is hard enough, but for young children and patients recovering from stroke, added discomfort comes from a condition called dysphagia, which inhibits swallowing. Dysphagia is a serious disorder that affects five per cent of the population, and although it is most common among small children and recovering stroke victims, it can affect anyone with impaired muscular function. It can lead to malnutrition, lung inflammation from inhaling foreign material, choking, or even death.
The new diagnostic tool incorporates a novel application of optical fibre, resulting in a catheter barely three millimetres in diameter containing a series of optical-fibre pressure sensors, which use some smart physics and modern telecommunications technology to measure the waves of pressure when the patient swallows. This creates a comprehensive representation of the pressure wave travelling down the oesophagus as the patient swallows. The technique used is no stranger to the technology world, as it forms the premise for nearly every modern telecommunications system. However, its introduction into medical use is a result of some handy serendipity. One of the two project leaders for this research, Dr John Arkwright, worked in the telecommunications industry for 15 years before joining CIP. His co-leader in the project, Simon Doe, brings more than 15 years of experience in the microjoining and assembly field to this work at CMIT’s South Australian site. They were approached by research fellow Dr Taher Omari and speech therapist Dr Nathalie Rommel, both from the Adelaide Women’s and Children’s Hospital, to devise a diagnostic tool for dysphagia that overcame the limitations of tools such as catheters, which can be painful, uncomfortable and far from accurate. One of the more commonly used techniques for diagnosing dysphagia – when results from initial bedside examinations indicate further testing is required – is oesophageal manometry. Like the objective of the CSIRO-developed device, oesophageal manometry measures the muscular function of the oesophagus to detect abnormalities in the upper and lower oesophageal responses to swallowing. The pressure sensors that detect any muscular deficiencies are encased in a catheter, which is inserted into the patient’s oesophagus through either the nose or mouth. Using traditionally available water-perfused catheters, the accuracy of the test relies upon the patient remaining still for its duration, often for 30 minutes to an hour. This can be difficult for small children, and thus oesophageal manometry only has about a 25 per cent accuracy rate. Dr Arkwright says one of the advantages of the fibre-optic-based diagnostic tool is that it greatly reduces the discomfort to the patient – thus making it easier for the patient to remain still. A smaller catheter also means being able to use the diagnostic device in even younger children than is currently possible, Dr Arkwright explains. “In addition to being smaller, and thus less intrusive, the fibre-optic technology doesn’t require the patient to sit still for a long time.” The scientists have been able to reduce the diameter of the fibre-optic catheter to about three OPTICSmillimetres, which is almost half of the diameter of some of the commonly used catheters. “The real advantage of using the fibre-optic technology is that because it uses wavelengths of light, we only need a single fibre,” Dr Arkwright says. “That means we can have up to 50 pressure sensors in the one optical fibre without increasing the diameter of the catheter, whereas with current technology an increase in sensor numbers equates to more complex manufacturing, and an increase in catheter diameter.”
Dr Arkwright: "In addition to being smaller and less intrusive, the fibre-optic technology doesn’t require the patient to sit still for a long time." Most catheters used in oesophageal manometry typically contain one to 12 sensors, with an increase in sensor number associated with an improvement in diagnostic ability. The CSIRO team has designed its device to contain four sensors, with plans to produce a model with 12 by next year.The fibre-optic diagnostic technology has had a whirlwind ride, going from drawing board to pre-clinical trials in just one year, a blink of an eye in the medical instrumentation world. After positive results at the pre-clinical level, the researchers are ready to move to the next phase: clinical trials on a patient cohort assembled by Dr Omari and Dr Rommel. The CSIRO team is also looking towards the commercialisation process, and expects the device will be ready within a year. “It is a very strong product, and we anticipate that the commercialisation process will run smoothly, especially because we have chosen a product that is minimally invasive and made up of component parts that are substantially equivalent to parts that have already gone through regulatory approval,” says Mr Doe. Having the clinicians' support is also expected to be helpful throughout the commercialisation process. “The clinicians are very happy with our fibre-optic device because it meets all of the original requirements with which they approached us. Not only is the catheter smaller, but the associated electronics used to operate the device are much smaller and can be positioned on the other side of the room from the patient.” Dr Arkwright says currently used devices often add to a young patient’s distress by their daunting size and proximity. The CSIRO device is also much easier to use than the commonly used devices to diagnose swallowing abnormalities, which typically require the test to be carried out at a specialist centre. “Right now there are only two oesophageal motility specialist centres in Australia and 18 sub-centres,” Mr Doe says. “We are aiming to make the entire diagnostic procedure simpler so as to increase the accessibility of the diagnostic test. Our fibre-optic diagnostic tool is very simple to use, to the point that it is almost plug-and-play. “So limited training is required, making the testing procedure more widely available, although expert clinicians will still be required to analyse the results.” Dr Omari has been impressed with the simplicity of the CSIRO device. “The simplicity of use is one of the key advantages to this device. It offers the ability to record pressures at many more sites throughout the entire gastrointestinal tract, resulting in more accurate and reliable diagnosis than currently available. If successful, the device will revolutionise the way we approach functional disorders of the gastrointestinal system.” Along with being easier to use, the fibre-optic-based tool takes significantly less time to set up, requiring only 10 minutes for calibration compared to the two hours that traditional water-perfused oesophageal manometry equipment requires. The fibre-optic catheter is also pitched as a disposable device, so it should win acceptance with centres that wish to reduce risk from improper sterilisation. Although the team is initially focusing on improving the diagnostic tools for detecting swallowing disorders in small children, it will be useful for anyone who suffers from a malfunctioning swallowing mechanism. The device could also be used to assess patients before and after throat surgery. The pressure sensor platform technology may expect to be used in other catheters through the length of the gastrointestinal tract. “We are still perfecting the sensor, but in the near future we hope this technology will improve the quality of healthcare for those affected by dysphagia and, consequently, improve their quality of life,” says Dr Arkwright. APPLICATION Fibre-optic sensors create a representation of the pressure wave travelling down the oesophagus as a patient swallows For further information contact: |
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Now, in a lateral application of fibre-optic technology, researchers at two CSIRO divisions, Industrial Physics (CIP) and Manufacturing and Infrastructure Technology (CMIT), have developed a diagnostic tool that detects differences in pressure along a patient’s oesophagus when swallowing. This in turn is used to construct a profile of the swallowing action and allows doctors to more accurately identify what is causing the problem.
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