Negative pressure dressings are no better than standard dressings for open fracturesBMJ 2019; 364 doi: https://doi.org/10.1136/bmj.k4411 (Published 13 March 2019) Cite this as: BMJ 2019;364:k4411
All rapid responses
Dear Dr Goh,
Matthew Costa usefully outlines the reasons for the headline message that not using negative pressure dressings could save costs. This is based on another publication from this study and the detailed analysis supporting this claim can be found in the HTA study itself, our full Signal on the NIHR website and the BMJ summary found here.
The complete Signal also includes commentary from a clinician, in this case a vascular surgeon, who highlights the potential for cost savings in this particular use, while reminding us of other benefits of negative pressure dressings (for instance, in accelerating the healing of open wounds).
Readers can find more information on our approach to summarising the conclusions and context of NIHR research (ref 1).
Competing interests: Guarantor of the summary Signal on behalf of the NIHR dissemination centre editorial team
I welcome Dr Costa to the discussion.
It is a curious yet perplexing observation that Dr Costa invoked the NICE guidelines NG37 (ref 1) to justify the basis of “this level of care” (involving definitive wound closure within 72 hours of injury including open fractures), particularly when the said document was not published until Feb 2016, several months after the last patient of the WOLFF trial was recruited (July 2012 to December 2015); hence the guideline itself cannot be the reason for this standard since it did not exist when the trial was started. Of course there may be other guidelines pointing to this 72hr recommendation but certainly no reason to quote NG37 here.
It is even more confusing to read Dr Costa stating NICE guidelines were based on “strong evidence” that early definitive wound management reduces the risk of wound healing complications including infection and in support of recommendation 1.2.29 (ref 1) considering that the entire section 6.8 of the full guidelines addressing the evidence behind this recommendation lists all the considered studies leading this decision are all very low quality evidence and all had GRADE rating as VERY LOW (emphasis by NICE within own NG37 document).
Finally, Dr Costa believes that his other research (ref 3) addressed the issue of health economic evaluation of NPWT vs Standard dressing raised by myself. Again I would like to state that a key indication of NPWT use is “reduced need for wound dressing changes with ability to perform toileting and wound washing without time-consuming (and painful) removal and changing of dressings in the ward or operating theatre”. I had pointed out that “study design by the WOLLF Collaboration does not and cannot address these issues particularly when all patients are deemed to require definitive wound coverage within 72 hours”; it is unlikely that dressing change (standard or NPWT) is required within 72 hours and hence the benefit of one NPWT dressing change vs multiple standard dressing change over 7-10 days is not realised in a typical scenario.
The same Health Technology Assessment (HTA) paper clearly compares the cost of NPWT dressing to only one standard dressing cost. Upon reading the HTA paper, I am puzzled to find that of the detailed cost analysis of NPWT only group vs Standard dressing group, including GP, nursing, clinic outpatient and emergency attendance costing, the initial £1223.10 extra costs of NPWT group over Standard dressing dwindled down to £76.80, although the suggestion of NPWT group requiring a mean of 2.05 NPWT dressing change requires explanation; surely these 2 NPWT dressing change did not occur within the 72 hours period before definitive skin closure?
More questions are raised than answered here.
It is possible we are looking at here a mismatch in values and outlook in clinical practice and healthcare goals, but I am certainly not disappointed about the conclusions from the NPWT evaluation.
After all such considerations can be applicable only to healthcare system organised for definitive wound closure of all open fracture in 72 hours, a standard even NICE admits to be based on very low quality evidence.
Aspirations can be desirable, but the reality and practicality of spending beyond the means will ultimately result in unsustainable goals and unnecessary waste of resources in austere times, when even the 4 hour A&E target is coming off the table (ref 4)
3. Negative-pressure wound therapy versus standard dressings for adults with an open lower limb fracture: the WOLLF RCT. Health Technol Assess. 2018 Dec;22(73):1-162
Competing interests: No competing interests
Dr Goh is correct in that not all healthcare economies can provide definitive wound closure within 72 hours of injury. The lack of appropriately trained surgeons in many low to middle income countries is well-documented.
However, the NICE guideline for complex fractures (www.nice.org.uk/guidance/ng37) are based upon strong evidence that early definitive wound management reduces the risk of wound healing complications including infection:
"1.2.29 Perform fixation and definitive soft tissue cover: at the same time as debridement" or "within 72 hours of injury if definitive soft tissue cover cannot be performed at the time of debridement."
Those of us privileged to work in advanced healthcare economies should clearly aspire to this level of care.
With regard to the number of dressing changes and length of hospital stay. These are indeed important issues and are fully documented in the health economic evaluation which was an integral part of the WOLLF trial. (Negative-pressure wound therapy versus standard dressings for adults with an open lower limb fracture: the WOLLF RCT. Health Technol Assess. 2018 Dec;22(73):1-162). Disappointing as it may be, the evaluation concludes that "NPWT dressings do not provide a clinical or an economic benefit for patients with an open fracture of the lower limb".
Competing interests: Chief Investigator
I have concerns about how the authors of this NIHR Signals paper reached their conclusions
They wrote that the UK WOLLF randomised clinical trial (ref1) found
"There were no clinically important differences in disability, deep infections, or healing between the group that received negative pressure dressings and the group that received standard dressings."
"Quality of life was similar in both groups throughout."
However the authors of the NIHR Signals paper suggest the implications of the UK WOLLF Collaboration research are:
"The findings from this trial have been incorporated into an updated Cochrane review, plus two other small trials completed in 2016. This is the only randomised controlled trial to date that provides 12 month outcomes for disability and quality of life and indicates that the more expensive negative wound pressure dressings are no better. The pooled data show uncertainty about whether negative wound pressure reduces deep infections for open wounds following open fractures. These findings are likely to be important for orthopaedic practice.
Not offering this treatment would potentially save money for use on other therapies and would simplify the care pathway. Negative pressure dressings are used in other surgical contexts, and these might be suitable for a similar study."
While it may be true, based on the evidence of the Costa et al study, that there is no obvious difference in the measured outcome featured in the study, it is important to remember that the basis of the study is they recruited patients with an open fracture of the lower limb that could not be closed primarily at time of first operation to apply comparison dressings; the same patients had a second operation at 48 to72 hours, when a further wound assessment and debridement was performed and the wound closed either primarily with sutures or by soft-tissue reconstruction as necessary.
Hence these delayed primary closure or plastic reconstruction occurs within 48 to 72 hours. Not all hospitals can provide these reconstructive service, not all patients requires definitive wound closure within 48-72 hrs.
A key indication of negative pressure dressings had always been reduced need for wound dressing changes with ability to perform toileting and wound washing without time-consuming (and painful) removal and changing of dressings in the ward or operating theatre. The study design by the WOLLF Collaboration does not and cannot address these issues particularly when all patients are deemed to require definitive wound coverage within 72 hours. Nor did they look at the effects on length of stay.
Therefore in my view, the authors should not suggest that not offering negative pressure dressings can be money saving when the costs of more frequent dressing change of standard care involving materials and nursing expertise has not be seriously accounted for. The applicability of this study to centres without reconstructive service or easy access to operating time in order to achieve wound closure within 72 hours ultimately limits its relevance to many non-tertiary hospitals who account for a majority of care of patients with open fracture
1. Costa ML, Achten J, Bruce J, et al. Effect of negative pressure wound therapy vs standard wound management on 12-month disability among adults with severe open fracture of the lower limb: the WOLLF randomised clinical trial. JAMA. 2018 Jun 12;319(22):2280-2288. doi: 10.1001/jama.2018.6452.
Competing interests: No competing interests