From scanning to surgery and superbug control, UK hospitals are trialling potentially revolutionary medical technologies, report Jon Excell and Stuart Nathan
Newspaper headlines frequently paint a picture of an NHS hospital system in crisis. With bed shortages, seemingly indestructible superbugs, and general wards full of patients who would once have been on the critical list, doctors are perhaps stretched as never before.
But things may be changing for the better. Across the UK, a range of diagnostic, therapeutic and patient monitoring systems are beginning to enter trials, and advanced medical technology could be poised to shape the NHS hospital of the future.
From X-ray to ultrasound, most current scanning and diagnostic techniques have been around for years, although improvements in performance have led to increased levels of detail.
One area of diagnostics that is growing in popularity and power is Positron Emission Tomography (PET) scanning. Later this year London’s Charing Cross Hospital will take delivery of a scanner that, according to its developers, will take PET to a whole new level.
The technology has been around since the 1970s. It acquires images by detecting radiation emitted by sub-atomic particles which are themselves emitted by a radioactive material administered to the patient. The technique is most commonly used to detect cancers and monitor their treatment, but it can also scan the brain, and is increasingly being used to determine whether heart-attack victims could benefit from surgery.
But with the launch of its high-definition (HD) PET scanner, Siemens believes that improved resolution will enable doctors to image tumours and lesions with unprecedented detail. The company also says it will have a major impact on establishing the extent of a patient’s disease so that a treatment regime can be decided on.
According to Lawrence Foulsham, product manager for molecular imaging with Siemens Medical Solutions, the scanner benefits from two technological developments. First, an extra detecting ring has boosted machine sensitivity by about 70 per cent, which can be used to either reduce scanning time or cut the dose of radiation given to the patient.
Siemens has also developed an image reconstruction technique that generates more clearly defined images across the entire field of view. Historically, the image quality of PET scans typically falls from 3.5mm at the centre to 5.5mm toward the edges, but the resolution of the HD system is claimed to be just 2mm.
This, said Foulsham, means doctors will be able to spot smaller lesions and provide earlier, and more targeted, treatment for many cancer patients.
At an earlier stage, a Manchester Royal Infirmary team is developing an imaging system to allow doctors to visualise processes, rather than structures, within the brain. Funded by the Wellcome Trust, the functional Electrical Impedance Tomography by Evoked Response (fEITER) project is developing a scanner that will be portable and cheap, yet powerful enough to observe the effects of drugs in real time.
The technology uses electrical impulses. A ring of 16 or 32 electrodes is placed on the patient’s head, a current is passed from one electrode to the one directly opposite it, and the voltages between all the neighbouring pairs of electrodes measured. Then the current injection direction is switched to the adjacent set of electrodes.
During scanning, the patient is given some kind of sensory stimulus. The brain secretes neurotransmitters to allow nerve impulses to be transmitted across synapses, and this changes the conductivity of the active areas in the brain. The scanner gives a picture of this pattern of changing electrical resistance.
‘We’re looking at the mass actions of millions of synapses in a dynamically changing picture,’ said Dr Chris Pomfrett from Manchester’s anaesthesia department. ‘What’s different about fEITER is that we look at those changes on a scale of about a hundred milliseconds.’ This is faster than any other method for looking at changes in the brain: functional MRI works on a six-second timescale, while PET takes a few minutes.
Also, fEITER doesn’t require the huge magnets and cooling systems or radiation management equipment of either of these technologies. And because it doesn’t expose patients to radiation, it can be carried out an unlimited number of times and for long periods.
The project will compare a patient’s brain activity pattern with healthy ones. This technique of comparing ‘activity maps’ will be a major advance on what is currently possible, said Pomfrett.
The first tests on patients, which the team hopes to begin this autumn, will look at the effects of anaesthesia. Pomfrett said anaesthesia is effectively switching off large areas of the brain, then letting it switch back on. ‘We’ll use it to calibrate fEITER, to give us a zero-to-100 per cent activity picture,’ he added.
This will allow doctors to look at the brain activity of stroke patients, for example. There are two types of stroke — one caused by blood clots, the other by bleeding blood vessels. It is currently difficult to distinguish one from the other quickly. This is a huge problem because giving drug therapies early in the course of a stroke is highly effective at limiting damage. But giving blood-clotting agents to someone who already has blood clots, or coagulation inhibitors to someone with bleeding, will increase the damage or even kill the patient.
Pomfrett hopes fEITER will be able to identify the type of stroke, and whether the neuroprotective agents are having a genuine effect while they are being administered. The real-time monitoring of drug effects could also be useful in intensive care units (ICUs), where it may be days before the effectiveness can be gauged.
Ultrasound is another scanning technique that has made huge leaps in recent years. Although we’ve all seen the images of babies moving in the womb, perhaps the most exciting development is the use of high-intensity beams of focused ultrasound (HIFU) to destroy cancer cells.
Non-invasive, with fewer side-effects than radio- and chemotherapy and potentially cheaper, HIFU’s effect is akin to ‘a magnifying glass in the sun,’ according to one of the technology’s pioneers, Dr Gail ter Haar, head of therapeutic ultrasound at the Institute of Cancer Research in Sutton.
The technique has been approved for treatment of prostate cancer by the National Institute for Clinical Excellence (NICE) and Ter Haar’s team is collaborating in a clinical trial at the Royal Marsden NHS Foundation Trust for HIFU’s use in recurrent prostate cancer.
The team built a prototype machine, which has been used in clinical trials to treat abdominal tumours, and is currently working with a £5m EPSRC grant to develop a smaller, faster system that should be ready for use this year.
Meanwhile, Ter Haar is also overseeing trials of HAIFU, a Chinese-developed system being tested on liver and kidney cancers at Oxford’s Churchill Hospital.
Dr David Wild of Stockport-based Ultrasound Therapeutics — responsible for bringing this technology to the UK —said the system has been used to treat thousands of patients in the Far East where, in the absence of UK-style clinical trials, there is a huge amount of anecdotal evidence that the procedure can have a major impact.
Sutton’s Ter Haar is keen to see whether it can have a similar impact when exposed to the rigours of the UK medical establishment. ‘The potential for the technology is huge,’ she said. ‘we’re not there yet — exactly what we’ll be able to do with it will depend on improving our targeting and imaging. If it proves successful, it could be a front-line treatment for single tumours of the liver or kidney. But that’s a long way off.’
Non-invasive procedures are attractive for a variety of reasons, but invasive surgery is still sometimes the only option.
Fortunately, advances in robotic surgery, in which tele-operated devices enable surgeons to perform minimally invasive procedures, mean surgery is potentially not as traumatic as it was.
Perhaps the best-known technology is Intuitive Surgical’s DaVinci system, the use of which in the UK was pioneered by Prof Ara Darzi (click hereto read this issue’s Interview with Prof Darzi.)
Currently used in seven UK hospitals, the £1.28m system’s most recent customer is Manchester’s Christie Hospital, where surgeons hope to use it to treat prostate cancer.
But DaVinci is not the only robotic system being used by the NHS.
Thanks to £2m of British Heart Foundation funding, surgeons at University College London Hospital(UCLH) are pioneering the UK use of Stereotaxis, a system that could revolutionise the treatment of life-threatening heart arrhythmias and abnormalities.
These conditions are traditionally treated manually, with surgeons feeding catheters through a sheath in the femoral vein at the top of the patient’s leg and up into the heart, before ablating specific tissues.
This is time-consuming and, for the surgeon, physically and mentally arduous.
With Stereotaxis, which has so far been used on about 40 patients, surgeons place the sheath in the femoral vein, attach a magnet-tipped catheter and retire to a console in a separate room. They then use a joystick to operate magnets either side of the patient and drag the catheter up from the groin and into the heart.
Dr Martin Lowe, the consultant in charge of UCLH’s facility, said that as well as enabling more precise positioning of the catheter, the technology can also halve procedure time.
New medical devices are not necessarily derived from new technologies, however. Doppler oesophogeal monitoring, which uses an ultrasound probe inserted down a patient’s throat or nose to measure the amount of blood being pumped out of the heart, has been used in ICUs for many years, but is only now being taken up within the NHS to monitor surgery.
A device called the CardioQ, made by West Sussex-based Deltex, was tested at Newcastle’s Freeman Hospital by colorectal surgeon Alan Horgan in late 2005, and is now being taken up by NHS trusts across the country.
Doppler monitoring has been used to help patients get over serious illnesses, but the innovation with the CardioQ is to use it in the operating theatre to prevent problems before they occur, picking up changes in blood volumes more quickly than traditional methods such as monitoring pulse and blood pressure. At the start of the operation, the anaesthetist gives fluids until the patient reaches the optimal level of circulating blood, then maintains that level throughout the operation.
‘This decreases post-operative complications — such as heart attacks and lung and abdomen infections — admissions to intensive care, and reduces recovery times,’ said Horgan. His patients were discharged after seven days on average if the CardioQ was used, and nine if not; there was also a significant reduction in serious complications, he added.
‘I think in five to 10 years’ time, we’ll be saying it’s incredible that we were anaesthetising patients without the help of this technique,’ said Horgan. ‘It’s not that expensive — £50-60 per probe per patient — and if it saves two hospital days, major complications and ICU stays, then it pays for itself many times over.’
One reason for reducing hospital stays for post-operative patients is to limit their exposure to hospital-borne infections. Reducing infections and cleaning hospitals is a major focus for UK research funding, but according to Clive Beggs, professor of medical technology at Bradford University, the much-vaunted ‘deep cleaning’ strategy will not be as effective as hoped.
According to Beggs, there is a major knowledge gap about hospital infections. ‘MRSA is not the same as C. difficile, and they’re not the same as acinetobacter,’ he said. ‘We don’t know the routes through which infections are transmitted, and we’ve assumed they’re mostly handborne. but when beds are made, clouds of infectious particles are sent up into the air and they’ll land on surfaces.’ This means the current policy of attempting to eradicate infection by enforcing stricter handwashing protocols will never be completely effective, he said.
Deep cleaning isn’t the whole answer, either. ‘In ICUs, for example,’ said Beggs, ‘the only way to get rid of some bacteria has been to clear all the patients out, and before they are allowed back, clean everything using steam or hydrogen peroxide. But bacteria such as acinetobacter seed the environment, creating a reservoir of infectious agents. Infection almost always arrives with people, and the first person in the ward carrying the infection just re-seeds the environment.’
Beggs is currently developing new methods to identify the key pieces of hospital equipment that pass on infections, and find effective methods for cleaning them. Some surfaces will be more important than others. ‘There might be a few bugs on the ceiling, but that’s much less important than a ventilator tube and almost certainly less so than the bedrails.’
One method for controlling vital surfaces might be to coat them in an antibacterial material, such as copper or silver, but then the time it takes to kill the bacteria becomes important. ‘If you identify a tap as a key surface and make it bactericidal, the surface takes 12 hours to kill MRSA,’ said Beggs. ‘So what’s the likelihood that someone will touch it again before 12 hours?’
Some technologies are showing potential for reducing the amount of infectious particles in the environment. ‘One that looks exciting uses hydroxyl radicals in a kind of aerosol, which allows you to keep all the patients in hospital, which is the biggest goal,’ said Beggs, who saw acinetobacter infection eliminated by installing ionisers in ICUs at St James’s Hospital in Leeds. ‘We think it changed the electromagnetic field around plastic equipment on the ward, so they repelled the particles. We suspect the ventilator tubes were crucial because the bacteria were getting into patients’ lungs.’
Another method showing promise in controlling gram-negative bacteria is by manipulating humidity, to which they are very sensitive. ‘If you reduce humidity rapidly, the bacteria die of osmotic shock. You could leave patients on the ward, take the air conditioning down to dry the air for a few hours overnight, kill the bacteria, then take it back to normal during the day.’
The need to react quickly to MRSA has given the NHS a stark reminder of the pressures it faces. Thanks to a heady mix of superbugs, an increasing reliance on outpatient procedures and an ageing population, our hospitals have never been so full of seriously ill patients.
According to Prof Gary Smith, a consultant in critical care medicine at Portsmouth’s Queen Alexandra (QA) hospital, this means there is a pressing need for more effective patient monitoring. ‘Patients on general wards are sicker now than they have been in the past,’ he said. ‘When I was a house officer, I looked after people who were well enough to push round the coffee trolley. Those people are now operated on as day patients and we have people on general wards who 20 years ago might have been in an ICU — so we’ve got to start monitoring them.’
Smith has been working with healthcare informatics specialist The Learning Clinic on developing a system for collecting vital signs data that replaces the clipboard at the end of the bed with PDAs linked wirelessly to the hospital’s intranet.
Patient details are entered on to the PDA, where software called VitalPac interprets the data, recommends a course of action, and ensures the appropriate clinical staff are alerted. This represents a fundamental reversal of the traditional paper process, said Smith. ‘It’s pushing data to people rather than people having to pull data.’
The initial driver behind the project was the 23,000 in-hospital heart attacks and 20,000 ICU admissions a year in the UK that are thought to be preventable through improved monitoring. But as staff have got used to the system, its use is spreading. It is, for instance, now being used to identify patients at risk of deep vein thrombosis, and identifying new admissions who could be at an increased risk of carrying MRSA.
With the system currently used on only 10 per cent of beds at QA, it is hard to quantify its success, but with further trials under way in Shrewsbury and Telford, Coventry and Warwick and Chelsea and Westminster health trusts, Smith hopes there will soon be statistics to back up the anecdotal evidence. ‘There is evidence that patients moving out of an area covered by the system are deteriorating and conditions are not being picked up in the way they were being picked up in a VitalPac area,’ he said.
Smith added: ‘I think we’ve been successful because we started with the ward staff. We said that if we’re going to use this device, how will it fit in with your work rather than disrupt it?’ He suggested that those responsible for the NHS’s controversial £12.4bn IT project, Connecting for Health, would do well to heed the lessons of this bottom-up approach.
The next step for VitalPac, said Smith, and for patient monitoring systems in general, is to take the pressure off nurses by integrating wireless devices that can monitor a patient’s vital signs continuously. Smith is about to begin clinical trials of a radar system for measuring breathing rate — and there are many other devices in development. Particularly promising, said Smith, is the Digital Plaster, a wireless, disposable sensing device developed by Imperial college spin-out Toumaz.
Due to enter clinical trials later this year, the device can continuously monitor a range of vital signs and can be programmed to extract and transmit only significant data. Toumaz co-founder Keith Errey agrees about the urgent need for patient-monitoring systems. ‘There is a growing concern that there aren’t sufficient critical care beds in the UK. In the event of a major outbreak of SARS or something like that, the healthcare system would collapse because you can’t monitor people.’
And while in the short term, devices such as the digital plaster will help improve critical care in hospitals, the technology could ultimately be used to take further strain off the NHS by monitoring patients at home.
Remote monitoring (or telemedicine) is a very different challenge for the sensor manufacturers now moving into medical devices. One example is a system in which Philips, Sheffield Hallam, Bath and Ulster universities are collaborating to help stroke patients recover arm mobility.
The technology comprises three small sensor packages strapped around the wrist, upper arm and trunk, which communicate wirelessly with a PC-based touchscreen display and control system. All of these can be attached to the body and operated with only one good hand. They can also be used by people with the kind of cognitive disability resulting from strokes.
The display system guides patients through their physiotherapy routines and is linked via the internet to a terminal at a clinic.
The sensors contain accelerometers, gyroscopes and magnetometers, and transmit readings to the control unit, which calculates a patient’s relative positions and enables the system to analyse their movements.
This gives instant evidence of patient progress. ‘Motion sensors are more accurate than the naked eye and much more accurate than the patient’s own perceptions,’ said Philips’ signal processing specialist Richard Willmann. ‘When patients improve, they often forget how ill they were. If you show them their recovery history, it’s a powerful motivating factor.’
This is the underlying rationale for the system — it allows the patients to do their physio without the direct supervision of a physiotherapist. ‘Rehab is expensive: it’s a one-to-one relationship between patient and therapist,’ said Willmann. ‘If you can automate that but still keep the patient motivated, you can break the one-to-one relationship, which would allow the therapist to deal with many more people.’
At the clinic, the therapist reviews each patient’s record and can easily notice an improvement or dropping-off of performance.
The system is now undergoing trials. Bath is using it in a clinic to treat brain injuries, while Sheffield Hallam has two units that are being taken to stroke patients’ homes.
From improved scanning techniques to new surgical systems, advanced technology is already helping to save lives and speed recovery in UK hospitals. As this helps hospitals focus on the sickest, and the telemedicine revolution gathers pace, it could be that the hospital of the future isn’t actually a hospital at all, but our own homes.