interviews

The positive potential of negative pressure therapy

Matthew Costa, Professor of Trauma and Orthopaedics at the Warwick Clinical Trials Unit and consultant orthopaedic surgeon at University Hospitals Coventry & Warwickshire, spoke to NHE about a new type of treatment with the potential to cut infection rates in open wounds.

Open wounds can pose significant risk of infection to patients. A new type of pressure therapy could reduce this dramatically, compared to the traditional treatment approach, and is currently being trialled across the UK’s major trauma centres.

The trial is funded by the National Institute for Health Research (NIHR) and the Health Technology Assessment Programme and is taking place over four years to determine both the clinical and cost effectiveness of the new treatment.

While it is important to measure the number of infections found in each case, the primary test for the new technology is how it affects patients, and whether it improves their ability to manage their injury.

Professor of Trauma and Orthopaedics at the Warwick Clinical Trials Unit, Matthew Costa, explained the detail behind the trial and how it could change policy.

Broken barriers

Patients participating in the trial have serious injuries to their legs, with open fractures. Without the skin to act as a barrier to infection, there is a risk of serious complications, including infection of the bone, which can even lead to amputation.

The existing treatment is a standard dressing where sterile gauze with antiseptic is placed over the wound and secured with a bandage.

The new intervention being studied is known as negative pressure wound therapy (NPWT) and consists of a constant, yet gentle, suction on the surface of the wound to reduce the bacterial load and remove blood to encourage the healing process.

The risk of infection is a huge challenge for any operation, and especially in cases where the wound is open, Prof Costa explained.

“Whenever we do any operation there’s a risk of infection because the bacteria live on the skin and in the air and everywhere around us,” he said.

“There’s a risk with any fracture, but the risk is much greater if the skin barrier is breached and bones are exposed to that contamination at the point of injury. The risk for fractures varies hugely on the nature of the injury; it’s only about 3 or 4% if the injury is closed but it can be up to 25-30% if the injury is open, so it’s a much bigger problem for open fractures.”

Military technology

Such technology has been in use for the past five or ten years, particularly with military medics tending serious leg injuries to soldiers in Iraq and Afghanistan.

Prof Costa said: “We want to know if that same technology can be effective in the civilian world in the NHS.”

Previous research suggested that infection risk may be reduced with NPWT, but as a single centre study, did not provide enough evidence to definitively suggest it was the better treatment option.

He explained: “The honest answer is we don’t know which is best. We hope that this new treatment will improve the outcomes for this group of patients, save some legs and get people walking again more quickly; but we won’t know, until the end of this study, firstly whether it works and secondly if it’s cost effective and worth the NHS spending the extra money.”

If the trial is successful, these results will then be taken up by regulators such as NICE to determine whether guidance should be issued recommending NPWT across the NHS.

A measure of success

To measure the success of the trial, a disability rating index is being used. Patients will selfreport, filling in a simple questionnaire that captures how easily they are able to carry out daily activities. Pictures are also taken to mark progress of wound healing and the number of deep infections associated with a fracture is also counted as a secondary outcome measure.

Prof Costa said: “How many infections is not really the issue – it’s how they affect patients, so that’s why we’re asking the patients themselves what they feel is the best treatment.”

If the new treatment received approval from NICE, this could improve the cost ratio of procurement, as if all trusts invested in the equipment, the cost could be shared and therefore reduced.

“It’s all about scale. The units themselves are quite expensive at the moment, thousands of pounds for the actual unit, but as soon as they become a recommended treatment they become a mass produced product and that will hopefully bring down costs across the board,” he said.

Prof Costa added that the trial would give researchers a better idea about which specific groups of patients would benefit most, enabling investment to be targeted.

Fractures and open wounds come in a range of severity known as grades, and he suggested that it may be that the NPWT is most effective with the group with the most serious injuries. This information could impact on future policy and help the NHS to tailor their funding to those who need it the most.

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