Pressure injuries: showing a clean pair of heels...

1 September 2012

CLINICALLY APPRAISED TOPIC (CAT): Can elevating the heels help prevent pressure injuries?

CLINICAL BOTTOM LINE:

A heel offloading device may reduce pressure injuries in patients already treated with pressure redistribution surfaces. Cost-effectiveness of the device has not been established.

CLINICAL SCENARIO:

An improvement specialist on a pressure injury prevention project asks about the effectiveness of practises and devices for preventing pressure injuries on heels, as they are the second leading site of injury in a hospital–wide audit. Existing pressure injury prevention guidelines and a Cochrane review provide limited guidance or do not address the issue. A PubMed clinical query search reveals one randomised controlled trial of a heel offloading device.

QUESTION:

Among patients in acute hospital, does a heel offloading device reduce the incidence of pressure injury compared to standard practice?

SEARCH STRATEGY:

PubMed – Clinical queries (therapy/broad search): pressure injury AND heels.

CITATION:

Donnelly J, Winder J, Kernohan WG, Stevenson M. AN RCT to determine the effect of a heel elevation device in pressure ulcer prevention post-hip fracture.

J Wound Care 2011;20(7):309-18.

STUDY SUMMARY:

A two-arm parallel group, randomised controlled trial conducted in a Belfast tertiary hospital. Inclusion criteria were age 65 years or more and suffered a hip fracture within the previous 48 hours. Exclusion criteria were patients not consenting, existing heel pressure damage, and history of previous pressure ulceration.

All patients were nursed on pressure-redistributing surfaces, including high specification foam mattress, AlphaExcel or AutoExcel overlay, and Nimbus 3 alternating pressure mattresses. Choice of surface was clinically determined, recorded, and entered as covariate in regression analyses.

Heel-offloading device (HOLD) (n=119): Heelift suspension boot applied to both lower limbs of the patient. Device wraps around the foot and lifts heels off surfaces by redistributing pressure over the lower leg.

Standard care (n=120): Usual care not described although patients nursed on pressure-redistributing surfaces.

Outcomes: Primary – presence of any pressure injury grade 1 or greater at any site at point of censor (death, discharge, or transfer). Pressure points inspected daily.

STUDY VALIDITY:

A randomised trial using a computer-generated sequence method. The allocation of the randomisation was concealed as managed by a senior nurse separate from the study. There was not complete follow-up as three participants (2.5 per cent) were lost to follow-up in each group. The intention-to-treat analysis included all participants. The nature of the trial meant it could not be blinded. The groups received equal treatment and the baseline groups were comparable, although there were differences in time to surgery (that favoured the intervention group) and time in surgery (that favoured the control group). Not clear if these differences were adjusted for in the Cox regression. Overall validity – reasonably high quality study, although with an absence of blinding.

RESULTS:

In all, 705 patients were screened and 239 randomised. Main reasons for exclusion were age, non-consenting, or time since injury. Mean age of the study population was 81 years and 55 per cent were female. Thirty nine patients developed 48 pressure injuries. Frequency of any pressure injury was lower in HOLD group (table). The main finding was robust to sensitivity analyses that excluded grade 1 pressure injuries or where all patients lost to follow-up were considered to have developed a pressure injury. There were 17 heel injuries in the control group compared to none in the treatment group. Frequency of adverse events was similar in both groups, with one adverse event possibly related to the HOLD device (bruising).

Image:image1.jpg

HR = hazard ratio; NNT = number needed to treat; NS = not significant

Comments:

Pragmatic trial with few exclusion criteria. Although study population was limited to people with hip fractures, there is no reason to suppose a device might be less effective in other at-risk patient groups, although differences in age distribution need to be considered.

Trial stopped early when interim analysis at half the proposed recruitment (480) by an independent statistician found a highly significant difference between the groups that exceeded the stopping rule of p<0.01.

No indication as to whether or how the device’s manufacturer was involved in the study or what the sources of funding might have been.

Cost-effectiveness has not been established.

Reviewer: Dr Andrew Jull, RN PhD, Nurse Advisor – Quality, Auckland District Health Board & Associate Professor (School of Nursing).