Comparison of foam and hydrocolloid dressings in the management of
wounds: a review of the published literature 1.0April 2010PhilDaviesBSc (Hons)Clinical and Scientific Information Manager, Mölnlycke
Health Care, Gothenburg, Swedenphil.davies@molnlycke.comMarkRipponPhDMedical Marketing Manager,
Mölnlycke Health Care, Gothenburg, Swedenmark.rippon@molnlycke.comfoamshydrocolloidsreviewhealingin-use characteristicspatient-centred outcomesFoam and
hydrocolloid dressings possess many of the characteristics expected of modern
dressings.Recently, there has been an increase in the
awareness of the need for clinicians involved in wound care to consider
patient-centred outcomes such as avoiding dressing-related trauma and pain and
minimising wound malodour.A review of the literature
identified 11 randomised controlled trials that have been undertaken to compare
foams and hydrocolloids in the treatment of a variety of wound types.The review compared published data relating to a number of different
products, possibly with very different performance characteristics.Only one study demonstrated a significant difference between the two
dressing types in terms of wound healing rates (in favour of foam
dressings).The majority of the identified studies indicate
that, when used in the treatment of exuding wounds, foam dressings are superior
to hydrocolloids in terms of exudate management, conformability, and ease of
use, as well as being associated with less dressing-related trauma and pain,
discomfort and malodour, although some studies demonstrated the two dressing
types to be comparable in relation to these parameters. AbstractAppropriate
dressing selection plays a key role in promoting and maintaining a wound
environment that is conducive to healing. A wide range of modern products is
available to clinicians. The objective of this study was to compare the clinical
performances of the two most commonly used dressing types (foams and
hydrocolloids) by means of a literature review.The literature
search identified 12 articles describing the results of 11 comparative studies
(all randomised controlled trials) in which a number of different foam and
hydrocolloid dressings were evaluated on a variety of wound types. Outcomes
measured in the studies included those relating to wound healing, in-use
dressing characteristics and patient-centred outcomes. While
recognising that both foam dressings and hydrocolloids satisfy many of the
requirements of modern dressings, the available evidence suggests that the
former are associated with better in-use characteristics and are more likely to
meet the requirements of the patient, particularly in terms of preventing
dressing-related trauma and minimising dressing-related pain, discomfort and
malodour, in the management of exuding wounds. IntroductionMore than 40 years have passed since the
principle of ‘moist wound healing’ was established ref1. Since then, a large
number of modern wound dressings have been developed and are now readily
available for use. With such a plethora to choose from, it is vital that
clinicians have an extensive knowledge of the properties of different dressing
types, together with an understanding of the tissue repair process, in order to
select those products that will help to deliver optimum wound care ref2. As shown in Table 1, the ability to create (and maintain) a moist wound
environment is just one of the many characteristics that an ‘ideal’ dressing
should possess ref3. The research and development of modern wound dressings has
traditionally focused on healing as the major outcome of treatment, with little
attention paid to other outcomes that are undoubtedly of concern to patients,
such as wound-related trauma and pain, exudate management and malodour ref4. In
recent years, however, an increasing awareness of the need for clinicians to
consider patient-centred outcomes has been very much in evidence. For example,
the problems of wound-related trauma and pain are now well documented. In
addition to increasing the size of wounds and delaying healing, trauma to the
wound itself (caused by the removal of dressings that adhere to the wound bed),
stripping of the peri-wound skin (caused by the repeated application and removal
of adhesive dressings), and tissue excoriation and maceration of the peri-wound
skin (as a consequence of inadequate management of exudate) can all exacerbate
wound pain ref5 and impair the quality of life of patients ref6. Wound-related
pain is also known to cause psychological stress which, in turn, can delay
healing ref7ref8. A recently published World Union of Wound Healing Societies
consensus document ref9 advises clinicians to select appropriate dressings to
minimise wound-related pain based on wear time, moisture balance, healing
potential and peri-wound maceration.
Table 1: Performance requirements of the ‘ideal’ dressing ref3Primary requirementsFree of toxic/irritant extractablesDoes not release particles/non-biodegradable fibres
into the woundForms an effective bacterial
barrier (effectively contains exudate or cellular debris to prevent the
transmission of micro-organisms into or out of the wound) If self-adhesive, forms an effective water-resistant seal to
the peri-wound skin, but is easily removed without causing trauma or skin
strippingMaintains the wound and the
surrounding skin in an optimum state of hydration (this implies the ability to
function effectively under compression)Requires minimal disturbance or replacementProvides protection to the peri-wound skin from potentially irritant wound
exudate and excess moistureProduces minimal
pain during application or removal as a result of adherence to the wound
surfaceMaintains the wound at the optimum
temperature and pH.Secondary requirementsPossesses antimicrobial activity – capable of containing localised
infectionHas odour absorbing/combating
propertiesHas ability to remove or
inactivate proteolytic enzymes in chronic wound fluidPossesses haemostatic activityExhibits effective wound cleansing (debriding) activity.
Most modern dressings can be grouped into one of five different
categories: alginates, films, foams, hydrocolloids and hydrogels. The two
dressing types with the biggest share of the global moist wound dressings market
are hydrocolloids and foams (Figure 1) ref10. First launched in the early 1980s,
hydrocolloids are now readily available in sheet, fibrous, paste and powder
forms. The development of foam dressings (either polyurethane- or
silicone-based) was aimed at overcoming the problem posed by the limited
absorbency of film dressings. First introduced in the 1970s, foam dressings are
now available in sheet form and cavity versions; they are widely used by
clinicians in the management of a variety of different wound types. Based on
observations reported in the literature ref11ref12, Table 2 summarises the
description, composition, key properties and uses of these two dressing types.
Table 2: Comparison of the properties and uses of foams and
hydrocolloids ref11ref12FoamsHydrocolloidsDescriptionAbsorptive,
sponge-like polymer dressings (with or without adhesive borders)Dressings consisting of adhesive, carbohydrate-based wafers (most
have a waterproof backing)CompositionPolyurethane and other
componentsMicrogranular suspensions of natural or
synthetic polymers (such as gelatin or pectin) in an adhesive matrix (such as
polyisobutylene)Key
propertiesAbsorptiveProvide a moist wound
environmentPromote autolytic
debridementProvide cushioning effect
against mechanical forces (shear and friction)Can be used in combination with topical agentsTurn to gel as
they absorb moistureProvide a moist wound
environmentPromote autolytic
debridementImpermeable to oxygen, water and
water vapour UsesPrimary or secondary dressings on
wounds (flat or cavity) with minimal to high exudate, where a non-adherent
surface is important.Dressings for wounds with
minimal to moderate exudate, including necrotic and sloughy wounds. Sheets may
also be used as secondary dressings.
When it comes to selecting dressings,
clinicians should go further than simply considering the basic properties of
different dressing types and, in doing so, should examine the published results
of clinical evaluations of different products. By way of an example, this
article provides a summary of the clinical evaluations that have been undertaken
to compare the two dressing types that account for over half of the global moist
wound dressings market. AimsThis
paper summarises the results of a literature search that was undertaken to
identify comparative data on which foam dressings and hydrocolloids can be
compared in terms of their clinical effectiveness and safety. Parameters
relating to wound healing, dressing performance and patient-centred outcomes are
included. MethodologySearches of
the bibliographic databases and authoritative internet sites listed in Table 3
were undertaken to identify published articles in which reference is made to
comparative clinical data relating to the two dressing types. The scope of the
search included clinical evaluations involving patients but excluded data
generated from in vitro and animal studies. The following search terms were
used: ‘wound(s)’ or ‘ulcer(s)’ or ‘burn(s)’; ‘foam(s)’ or ‘polyurethane(s)’;
‘hydrocolloid(s)’ and ‘clinical study’ or ‘clinical trial’ or ‘clinical
evaluation’. The search was restricted to articles published between January
1970 and December 2008, written in English. In addition, manual searches of
peer-reviewed journals of relevance to wound management were performed.
Table 3: Electronic data
sourcesTypeSourcesBibliographic databasesMEDLINE, National Library of Medicine, Bethesda, USA EMBASE, Elsevier BV,
Amsterdam, NetherlandsAMED, British Library, London, UKInternet sitesCochrane LibraryWorld Wide Wounds
ResultsComparative clinical data relating to the two dressing types were
identified in 12 articles, all of which describe the outcomes of randomised
controlled trials (RCTs) involving patients with a variety of different wound
types, for example leg ulcers of arterial ref13ref14, diabetic ref14, and venous
aetiology ref13ref14ref15ref16ref17ref18ref19, pressure ulcers ref14ref16ref20ref21ref22ref23 and skin tears ref24. Two of the articles refer to the same study
ref18ref19. Details of the study populations, therapeutic interventions, and
outcome measures reported in the identified articles are presented in Table 4.
Table 4: Randomised
clinical trials of foam dressings and hydrocolloidsReferenceWound type(s)InterventionsWound/dressing-related outcome
measuresPatient-centred outcome measuresCollier, 1992 ref13AU/VU (n=71)Foam (Tielle, Johnson &
Johnson) (n=39) or hydrocolloid (unspecified) (n=32) for up to eight
weeksWound conditionDressing wear
timeEase of dressing applicationEase of dressing
removal Wound odourBanks et al, 1994a ref20PU (grade 2
or 3*) (n=29)Foam (Spyrosorb, BritCair) (n=13) or
hydrocolloid (Granuflex E, ConvaTec) (n=16) for up to six weeks Proportion of wounds healedTime to complete
healingWound conditionDressing wear timeNumber of dressings usedEase of dressing removalPain at dressing removalPatient
comfort/acceptability of dressingBanks et al, 1994b ref21PU (grade 2 or 3*)
(n=40)Foam (Spyrosorb, BritCair) (n=20) or
hydrocolloid (n=20) (Granuflex E, ConvaTec) for up to six weeksProportion of wounds healedWound conditionDressing wear timeNumber of dressings usedEase
of dressing removalPain at dressing
removalPatient comfort/acceptability of dressingBowszyc et al, 1995 ref15VU (n=82)Foam (Lyofoam, Molnlycke) (n=41)
or hydrocolloid (Granuflex, ConvaTec) (n=41) plus compression for up to 16
weeksProportion of wounds healedTime to complete healingWound conditionNumber
of dressings usedEase of dressing applicationEase of
dressing removalPain at dressing removalPatient comfortBale et al,
1997 ref22PU (grade 2 or 3*) (n=60)Foam (Allevyn, Smith & Nephew) (n=29) or hydrocolloid
(Granuflex (ConvaTec) (n=31) for up to six weeksProportion of wounds healedDressing wear timeDressing absorbencyDressing leakageEase of
dressing applicationEase of dressing removalDressing
conformabilityThomas et al, 1997 ref16PU (n=99)VU (n=100)PU: foam (Tielle, Johnson &
Johnson) (n=49) or hydrocolloid (Granuflex, ConvaTec) (n=50) for up to six
weeksVU: foam (n=50) or hydrocolloid (n=50) plus compression for
up to 13 weeks Proportion of wounds healedReduction in wound sizeDressing wear timeExudate productionDressing leakageEase of
dressing removalPatient comfortWound odourBale et al, 1998
ref14PU (grade 2 or 3*) (n=32)Leg
ulcers (AU/DU/VU/ other) (n=30)Other wounds (n=34)Foam (Allevyn, Smith & Nephew) (n=50) or hydrocolloid
(Granuflex, ConvaTec) (n=46) for up to eight weeksProportion of wounds healedReduction in wound sizeDressing wear timeNeed for wound cleansingDressing leakagePatient comfortEdwards et al, 1998 ref24ST (n=30)Foam (Lyofoam, Molnlycke)
(n=3) or hydrocolloid (DuoDerm Extra Thin (ConvaTec) (n=3) for up to two weeks
Proportion of wounds healedTime to
change dressingsEase of dressing applicationEase of
dressing removalPain at dressing removalSeeley et al, 1999 ref23PU (n=39)Foam (Allevyn, Smith &
Nephew) (n=20) or hydrocolloid (DuoDerm, ConvaTec) (n=19) for up to eight
weeksProportion of wounds healedDressing wear timeTime to change dressingsDressing leakageEase of dressing application Ease of dressing removalWound-related
painWound odourCharles
et al, 2002 ref17VU (n=91)Foam (Cutinova, Beiersdorf) (n=31) or hydrocolloid – either Comfeel
(Coloplast) n=29) or Granuflex (ConvaTec) (n=31) – plus compression for up to 12
weeks Proportion of wounds healedReduction in wound sizeTime to complete healingWound-related painEase of dressing useKarlsmark, 2006 ref18Zillmer et al, 2006 ref19(two papers reporting the same
study)VU (n=45) Peri-ulcer skin treated for up to 14 days with either:Biatain (Coloplast) DuoDerm Extra (ConvaTec)Mepilex Border (Molnlycke)Tielle (Johnson &
Johnson)None givenTrauma to peri-wound skin
* = Stirling classification ; AU = arterial ulcer; DU =
diabetic ulcer; ST = skin tear; PU = pressure ulcer; VU = venous ulcer
Table 5: Proportion of completely healed wounds following treatment with foam dressings or hydrocolloidsPercentage of healed wounds at study end ReferenceFoamHydrocolloidStatistical significance (p value)Banks et al, 1994a ref207769Not reportedBanks et
al, 1994b ref216050Not reportedBowszyc et al, 1995 ref156060NoneBale et al, 1997 ref224116Not
reportedThomas et al, 1997
ref162735NoneBale et
al, 1998 ref1446330.045Edwards et al, 1998 ref243333NoneSeeley et al, 1999 ref234040NoneCharles et al, 2002
ref175854-59None
The literature review identified
the results of 11 RCTs that set out to compare foam dressings and hydrocolloids
in terms of:Wound healing (that is the
proportion of wounds healed, time to complete healing, the percentage reduction
in wound size, wound condition and the need for wound cleansing)In-use characteristics (that is wear time, number
of dressings used, time required to change dressings, absorbency, leakage, ease
of application, conformability and ease of removal)Patient-centred outcomes (that is wound odour, trauma, pain at
dressing removal and patient comfort/acceptability). The key findings of these studies are presented
below.Wound healing The proportion of
wounds that were completely healed (that is fully re-epithelialised) at the end
of the treatment period is reported in nine of the 11 studies. As shown in Table
5, only one study ref14 observed a statistically significant larger proportion of
healed wounds in the foam dressing-treated group (23 out of 50, 46%) than in
those treated with the hydrocolloid dressing (15 out of 46, 33%) (p=0.045).
Three other studies ref20ref21ref22 reported higher proportions of completely
healed wounds in patients assigned to treatment with foam dressings compared to
those treated with hydrocolloids; however, the statistical significance of these
findings are not included in the respective articles. The remaining five studies
ref15ref16ref23ref24ref17 did not detect any difference between the two dressing
types in terms of the percentage of healed wounds. It is worth noting that, in
one study ref15, the mean age of the patients receiving treatment with the foam
dressing was significantly higher than that of the group of patients treated
with the hydrocolloid dressing (p=0.01); therefore the ulcers of patients
randomised to treatment with the foam dressing would have been expected to take
longer to heal. In terms of the time taken for wounds to heal, no significant
differences between foam dressings and hydrocolloids were observed in the three
studies that reported on this parameter ref15ref17ref20. As only one of the
studies ref14 which evaluated wound healing rates demonstrated a difference
between the dressing types (in favour of foams), too much reliance should not be
placed on its findings. Moreover, based on the reported confidence level
(p=0.046), there is almost a 1 in 20 chance that this study found a
statistically significant result when, in reality, no real difference
exists.Bearing in mind the longevity of many leg
ulcers and pressure ulcers, the adoption of treatment periods of insufficient
length (for example, as short as two weeks in one instance) ref24 is the most
likely explanation for the low healing rates cited in Table 5. In view of this,
it is worth highlighting that other wound-healing parameters were evaluated in a
number of the studies. For example, at the end of an eight-week treatment
period, Collier ref13 observed a significant difference in wound condition
between the two treatment groups: a 74% improvement in ulcer condition was
recorded in the group of patients assigned to a foam dressing, compared to 50%
in those treated with a hydrocolloid dressing (p≤0.05). In order
to allow comparisons to be made for wounds which do not heal completely during
the treatment period of a study, the mean percentage change in wound area at the
time of each dressing change can be measured. In the study reported by Thomas et
al ref16, wounds treated with the foam dressing reduced in area more quickly than
those in the hydrocolloid-treated group, although the result was not
statistically significant. Significantly more leg ulcers treated with the foam
dressing (44 out of 49, 90%) reduced in area compared to those treated with the
hydrocolloid (33 out of 47, 70%) (p=0.028). Conversely, Charles et al ref17 noted
a non-statistically significant trend in favour of hydrocolloid dressings in
their study. In the second of two studies reported by Bale et al ref14, the
percentage reduction in wound area was significantly greater for wounds assigned
to treatment with foam dressings than in those treated with hydrocolloids
(p=0.013). In-use characteristicsDressing wear timeDressing wear time is of
importance to both patients and clinicians. Increased wear times are associated
with fewer dressing changes, decreased procedure-related pain and reduced wound
care costs in relation to nursing time and improved healing rates ref25. Of the
seven studies that reported on dressing wear time, four ref13ref20ref22ref23
indicated trends in favour of the foam dressings, compared to three ref21ref16ref14 which revealed trends in favour of the hydrocolloid dressings: none of the
differences were statistically significant, however. On a related theme, three
of the identified articles ref20ref21ref15 report on the number of dressings used
during the treatment phase of the respective studies but found no statistically
significant difference between the two dressing types.Exudate managementOne of the factors that influence the
wear time of a dressing is its ability to manage (absorb and retain) wound
exudate. It is imperative that, in providing an optimum moist wound healing
environment, dressings are used that achieve the delicate balance between an
excess of wound exudate (which may lead to maceration) and the drying out of the
wound (which could lead to cell and tissue death). It is important that
dressings can also achieve this when used under compression in the treatment of
venous ulcers, for example ref3. Exudate from chronic wounds has been shown to be
detrimental to the normal process of wound healing ref26. It is thought that this
is because chronic wound fluid contains high levels of proteases, which lead to
a breakdown of wound and skin tissue matrix components ref27. Exudate management
is also relevant to patient quality-of-life issues. Failure to control exudate
production will lead to leakage and malodour, as well as impacting on health
economics, due to increased management costs and patient morbidity ref28. The ability of foam dressings and hydrocolloids to manage wound exudate
was evaluated in five of the identified studies ref16ref20ref21ref22ref23,
including one evaluation in which the performance of the dressings under
compression therapy was compared ref16. In the earlier of the two
studies undertaken by Bale and co-workers ref22, dressing absorbency (assessed
subjectively based on the researchers’ perceptions of the frequency of dressing
changes and the level of dressing saturation) was rated as ‘good’ for 100 out of
124 (81%) of the foam dressings, compared to just 30 out of 117 (26%) of the
hydrocolloid dressings. At the other end of the scale, none of the foam
dressings were rated as having ‘poor’ absorbency compared to 26 out of 117 (22%)
of the hydrocolloid dressings (Figure 2). In the same study, levels of
absorbency in the group treated with foam dressings were significantly superior
to the levels of absorbency associated with the hydrocolloid dressings
(p<0.001). Soiling of clothes and bedclothes was reported in only five out of
125 (4%) cases in the group assigned to treatment with the foam dressing,
compared to 29 out of 118 (25%) cases in the group treated with hydrocolloid
dressings: this also reached statistical significance (p=0.002). Four of the other
studies ref16ref20ref21ref23 reported on the proportion of dressing changes that
were undertaken because of leakage and detachment. Thomas et al ref16 observed
that, at the first dressing change, 27 out of 50 patients with leg ulcers that
were treated with a hydrocolloid dressing had their dressings removed because of
leakage compared with seven out of 50 in those assigned to treatment with a foam
dressing (p<0.0001). Similarly, leakage was significantly less frequent for
patients with pressure ulcers in the foam-treated group (four out of 49), than
in the hydrocolloid-treated group (15 out of 50) (p=0.007). Seeley et al ref23
recorded leakage on only four occasions with a foam dressing compared to 23
occasions with the hydrocolloid dressing. In terms of actual patient numbers,
leakage affected only one patient in the foam group and six patients in the
hydrocolloid group (p=0.04), although there was no significant difference
between the treatment regimens in terms of the number of wounds that became
macerated or inflamed. In the first of two studies undertaken by
Banks et al ref20, the proportion of dressing changes undertaken because of
leakage and detachment in the group assigned to treatment with foam dressings
was 5% (leakage) and 44% (detachment), compared with 9% (leakage) and 53%
(detachment) in those assigned to hydrocolloids. In the subsequent study by
Banks et al ref21, the proportion of dressing changes undertaken because of
leakage and detachment was 27% and 25% respectively in those treated with foam
dressings; in the group assigned to hydrocolloids, 5% of dressing changes were
carried out because of leakage and 61% due to detachment. Bearing in mind that
the two studies undertaken by Banks and co-workers ref20ref21 evaluated the same
two dressings, it may seem a little surprising that the observed incidences of
leakage and detachment varied so much between the two trials. Unfortunately, the
authors do not offer an explanation for this but it may be relevant to note that
the mean dressing wear times in the two studies were different (3.5 and 3.1 days
for the foam and hydrocolloid dressings in the initial study ref20 compared to
4.2 and 3.7 days for the foam and hydrocolloid dressings in the subsequent
study ref21). All of the studies which evaluated exudate
management properties demonstrated statistically significant differences
between the two dressing types which strongly indicate that foams are
generally able to cope with higher levels of wound fluid than hydrocolloids.
ConformabilityThe ability of
a dressing to conform to the contours of a wound is important to reduce
areas of non-contact where micro-organisms may proliferate ref29. A dressing
should also be sufficiently flexible and conformable to stay securely in
place, even when applied to wounds in awkward locations, otherwise it will
fail to provide effective exudate management, leading to leakage and the
risk of maceration. In the one study that looked at conformability, the foam
dressing was found to be significantly better at conforming to body contours
than the hydrocolloid dressing (p=0.018) ref22. Some 88% of applications (121
out of 138) were rated as conforming to body contours in the foam
dressing-treated group, compared with 76% (99 out of 131) in the patients
assigned to treatment with the hydrocolloid dressing ref22. The proportion
of applications rated as showing ‘good’ initial adhesion to the skin was 96%
(132 out of 138) in the group treated with the foam dressing and 92% (121
out of 131) in those assigned to the hydrocolloid dressing. Tape bandages
were used to secure the foam dressing on five occasions (4%) and on 38
occasions to help retain the hydrocolloid dressing (29%). Ease of use If a dressing is easy to apply and
remove, then it will generally take less nursing time to undertake dressing
changes with that product than it would with one that is more difficult to
use. This dressing characteristic, therefore, has economic implications for
healthcare providers. Five studies included an evaluation of foams and
hydrocolloids in terms of their ease of application ref13ref15ref22ref23ref24. Two studies ref15ref24 observed no significant different between the
two dressing types. Collier ref13 observed that a foam dressing was
significantly easier to use than a hydrocolloid dressing (p<0.005),
particularly during application. In another study ref22, it
was reported that both foam dressings and hydrocolloids were easy to apply
in the majority of cases. The foam dressing was reported to be awkward to
apply in five out of 29 patients (10 out of 138 dressing applications, 7%).
The hydrocolloid dressing was awkward to apply in 11 out of 31 patients (24
out of 131 dressing applications, 18%). In the study reported by Seeley et
al ref23, 106 out of 107 (99%) dressings in the foam group and 87 out of 92
(95%) in the hydrocolloid group were assessed as being easy to apply.
Conversely, one patient in the foam group and four patients in the
hydrocolloid group experienced at least one difficult dressing application,
but the difference was not significant (p=0.18). In addition
to the economic implications described above, a dressing that is difficult
to remove is likely to cause trauma to the wound and surrounding skin and,
as discussed earlier, this can lead to increased wound-related pain, reduced
quality of life for the patient, and delayed healing ref5ref6.The ease of removal of the two dressing types has been compared in
eight studies ref13ref15ref16ref20ref21ref22ref23ref24. In the earlier of the
two studies reported by Bale et al ref22, the foam dressing was significantly
easier to remove than the hydrocolloid (p<0.001) Dressing removal was
reported as being ‘easy’ in 97% of cases (113 out of 117) in the foam group
compared to 73% (85 out of 116) in the hydrocolloid group. Removal was
reported as being difficult or awkward in 7% (eight out of 116) and 20% (24
out of 116) respectively for hydrocolloid dressings compared to 0% and 3% (4
out of 117) respectively for foam dressings (Figure 3). Similar observations were reported by Seeley et al ref23. A total of
5/102 (5%) dressings in the foam group and 49/82 (62%) dressings in the
hydrocolloid group were assessed as being difficult to remove.
Statistically significant differences in favour of the foam dressings were
observed with respect to the number of patients who experienced at least one
difficult dressing removal (p<0.0001) and the time taken to change the
dressings (p<0.001). The mean dressing change times were 7.6 minutes and
12.3 minutes for the foam and hydrocolloid dressing groups, respectively. In
contrast, one study reported that approximately 60% of dressings with
hydrocolloids took five minutes or less to complete, whereas 75% of those
undertaken with foams took longer than five minutes to complete ref24.While both foam and hydrocolloid dressing removal was rated ‘easy’ in
the majority of cases at the first dressing change in the study reported by
Thomas et al ref16, more hydrocolloid dressings in the pressure ulcer group
(85 out of 509, 17%) were rated ‘difficult to remove’ compared to foam
dressings (11 out of 537, 2%) as the evaluation progressed. The foam dressings were shown to be significantly easier to remove in
four other studies; three of which reported confidence levels of p≤0.005
ref13ref20ref21 and one which cited a confidence level of p≤0.016 ref15. One
study detected no difference between the two dressing types in terms of ease
of removal ref24. In terms of ease of application and removal,
statistically significant differences in favour of foam dressings are
reported in the majority (5/8) of the cited studies. On the other hand, no
studies observed statistically significant differences in favour of
hydrocolloid dressings. Overall, the available evidence strongly indicates
that foam dressings are easier to use than hydrocolloids. Patient-centred outcomesDressing-related painAs discussed earlier,
dressing-related pain is a major concern to patients. For example, a
cross-sectional, international survey of more than 2000 patients from
approximately 15 countries revealed that more than 50% of respondents
experienced pain at dressing change either ‘quite often’, ‘most of the
time’, or ‘all of the time’. Forty-three per cent of those surveyed stated
that pain at dressing change was the worst part of living with a wound ref30.
This important parameter was assessed in four of the identified studies ref15ref20ref21ref23. In the first of the two evaluations reported by Banks et al
ref20, the foam dressing was associated with significantly less pain at
dressing change (p <0.005); the proportion of patients experiencing
pain-free dressing removal was 80% in the foam-treated group and 40% in the
group treated with the hydrocolloid dressing. Although their second study
did not detect a significant difference between groups in terms of pain on
dressing removal, there were approximately 25% more pain-free dressing
changes in the foam-treated group ref21. The authors offer no explanation for
the difference in findings between their two studies but it is worth noting
that there is nothing in the respective articles to indicate that the pain
assessment method employed by the researchers involved a validated tool such
as a visual analogue scale. Two other studies ref15ref23
detected no significant difference between the two dressing types in terms
of pain on dressing removal and overall wound-related pain, but the former
did reveal a slight, but not statistically significant, trend in favour of
the foam dressing ref15. Patients were asked to score on a scale of 1 to 4
(where 1 = very painful and 4 = no pain) if the dressings caused pain on
removal. The mean score for the foam dressing was 3.72 and 3.63 for the
hydrocolloid group ref15. As none of the studies utilised validated pain
assessment tools, the relevance of the results presented above is
questionable. Patient comfortDressing comfort is likely to contribute to patient concordance with
treatment. In the first of two studies that measured patients’ subjective
assessment of dressing comfort ref15, participants were asked to score on a
scale of 0 to 10 (where 0 = uncomfortable and 10 = very comfortable)
according to whether they felt the dressings were comfortable while in
place. The mean score for the foam dressing was 8.72 compared with 8.18 for
the hydrocolloid dressing (difference not statistically significant). In the
more recent study ref16, it was noted that, at the first dressing change in
patients with leg ulcers, the foam dressing was significantly more likely to
be scored as comfortable than the hydrocolloid dressing (comfortable vs
otherwise, p=0.023). In addition to the above, the proportion
of dressing changes undertaken in the first of the two studies reported by
Banks et al ref20 because of patient discomfort was 21% in the foam-treated
group and 34% in the hydrocolloid-treated group. Similar findings were
observed in their second study ref21: the proportion of dressing changes
undertaken because of patient discomfort was 18% in the foam group, compared
with 45% in the hydrocolloid-treated group. Interestingly, of the patients
who were withdrawn from the study, two were withdrawn due to discomfort in
the hydrocolloid group and none in the foam group. Unfortunately, no
statistical analyses of these observations are reported.Wound odourThe management of malodour in
fungating wounds and chronic ulcers presents a number of challenges, not
least of which is the impact it may have on the quality of life of patients
ref31. This issue was considered in the design of three of the identified
studies ref13ref16ref23. For example, Collier ref13 observed that odour levels
at dressing change were significantly lower in the foam dressing-treated
group than in those treated with the hydrocolloid dressing (p<0.005); of
particular note is that odour was absent at over 70% of dressing changes on
the foam-treated group, compared with under 40% of those treated with the
hydrocolloid dressing. Thomas et al ref16 noted that, at the first dressing
change in patients with leg ulcers, the foam dressing was significantly less
likely to produce odour than the hydrocolloid dressing (no odour vs
otherwise, p=0.023. The third study ref23 did not observe a significant
difference in wound odour between groups (p=0.11). The mean wound odour
value was 0.16 and 0.47 for the foam and hydrocolloid groups respectively
(scored as 0 = none, 1 = mild, 2 = moderate, 3 = severe).These
findings are consistent with other reports in the literature that refer to
some hydrocolloid dressings interacting with wound exudate, resulting in
liquefied material that is frequently associated with malodour, can resemble
pus and may cause leakage, all of which can cause great distress to patients
ref32ref33. For these reasons, it has been argued that foam dressings are a
better choice than hydrocolloid dressings for exudating and/or malodorous
wounds ref34. Dressing-related traumaIn the first of two studies reported by Bale and co-workers ref22,
there was no report of foam dressing removal causing damage to the wound,
but there were three such reports in the group treated with the hydrocolloid
dressings (3%). There were three cases of damage to the surrounding skin
reported in the group treated with the foam dressing (2%); this compared
favourably to the eight reports in the group assigned to the hydrocolloid
dressings (7%). More recently, Karlsmark ref18 and Zillmer et
al ref19 reported on the results of a randomised controlled trial involving
45 patients with venous leg ulcers that specifically set out to determine
the effect of repeated removal of four different dressings on peri-ulcer
skin. The test products included: a foam dressing with hydrocolloid
adhesive, a hydrocolloid dressing with hydrocolloid adhesive, a foam
dressing with soft silicone adhesive and a foam dressing with polyurethane
adhesive. Adhesive patches of the dressings were replaced every second day
over a two-week period. Skin barrier function and stratum corneum hydration
were assessed by measuring transepidermal water loss (TEWL) and electrical
conductance, respectively. As shown in Figure 4, peri-wound skin treated
with hydrocolloid-based adhesive dressings was associated with significantly
increased TEWL and conductance (see Fig 4 for details), compared with
non-treated peri-ulcer skin. By comparison, the foam dressings with soft
silicone and polyurethane adhesives did not have any significant effect on
TEWL and conductance. These findings, which are very
much in line with those obtained from a series of volunteer studies ref35ref36ref37, indicate that hydrocolloid dressings or products incorporating
hydrocolloid adhesives have a tendency to damage both the wound bed and
the skin surrounding wounds. Other adverse eventsThree studies reported on
dressing-related adverse events ref16ref22ref23. In the first of these
studies ref16, seven patients in the hydrocolloid dressing group and 10 in
the foam dressing group were reported to have experienced adverse events
that suggested a link to the dressing. Most frequently, these related to
problems with the adhesive nature of the dressings causing minor trauma or
areas of erythema on removal. In addition, other minor dressing-related
events were observed. For example, maceration occurred in ten patients in
the hydrocolloid group. Maceration was not reported for any wounds in the
foam group. Bleeding from the wound area was reported in three patients in
the hydrocolloid group. No bleeding was recorded in the foam group. Wound
dehydration and problems with dressing adhering to the wound surface were
encountered in two patients in the foam group but no such problems were
encountered in the hydrocolloid group. Excess granulation tissue developed
in three patients in the hydrocolloid group. No excess granulation tissue
was recorded in the foam group. In relation to the latter finding, it is
worthy of note that, in the second of two studies reported by Banks et al
ref21, 10% of the patients treated with hydrocolloid dressings were withdrawn
due to overgranulation of the wound. A study in which overgranulating wounds
were treated with a foam dressing demonstrated a decrease in height of 2mm
of granulation tissue from initial measurements to measurements taken two
weeks later (p<0.01) ref38. In the two other studies that
refer to dressing-related adverse events, Seeley et al ref23 described one
patient in the foam-treated group who developed blisters beneath the
adhesive border and two adverse events in the hydrocolloid group in which
the edges of one patient’s ulcer became macerated, while the other patient
developed a rash beneath the dressing. Finally, Bale et al ref22 describe
just one adverse event, a localised skin rash in a patient treated with a
foam dressing.A number of studies have compared
patient-centred outcomes associated with the use of foam and hydrocolloid
dressings. Some did not demonstrate significant differences between the two
dressing types: this could be due to the general accepted view that it is
very difficult to demonstrate clear differences between wound dressings in
small-scale clinical trials or it could reflect that there is no real
difference between certain dressings. Either way, it is just as important
to point out that for each of the parameters discussed above
(dressing-related pain, patient comfort, wound odour, and dressing-related
trauma), significant differences in favour of foam dressings have been
observed but not for hydrocolloids. DiscussionWhile this article does not attempt to provide an
in-depth critique of the design and methodology of each of the studies
described earlier, it is important to point out a number of deficiencies
with them. For example, although all the studies were designed as RCTs, the
method of randomisation was not stated for three of them ref13ref20ref24.
Furthermore, full randomisation was not possible in one of the studies ref24.
On this basis, it is important to bear in mind that poor methodology could
account, at least in part, for the wide variation in the clinical
observations. Another criticism that could be levelled at a number of the
studies is the size of the respective study populations. For example, in the
first of the studies undertaken by Banks et al ref20 and the clinical
evaluation described by Edwards et al ref24, the study populations were 29
and 30, respectively. It is generally accepted that it is extremely
difficult to design clinical studies to detect differences between wound
care interventions, particularly in the case of those involving relatively
small patient populations.In considering the findings of the
cited studies, it is important to bear in mind that foams and hydrocolloids
are broad categories and that there are significant differences between the
characteristics of dressings within these categories. Furthermore, it is
not uncommon for dressings to be redeveloped so that some of those evaluated
in the identified studies may now have been replaced by improved versions.
It could also be argued that, in certain situations, foam and hydrocolloid
dressings are not directly comparable. For example, hydrocolloids may offer
some advantages over foam dressings in the management of dry wounds, whereas
foam dressings may offer some advantages over hydrocolloids in the treatment
of exuding wounds ref39. Nevertheless, this article has identified that
there would appear to be important differences between foam dressings and
hydrocolloids in terms of their in-use characteristics (such as exudate
management) and patient-centred characteristics (such as the severity of
trauma and pain associated with their removal). ConclusionsWhile most clinicians
would argue that both foams and hydrocolloids satisfy many of the
characteristics of an ‘ideal’ dressing, this literature review indicates
that there are a number of studies assessing clinical performance in which
foam dressings outperform hydrocolloids, although there are other studies in
which the dressings appear to be comparable. The explanation for this may
be due to the wide range of products used in these studies, which may
exhibit clinically significant differences within the product groups.Only one study demonstrated a significant difference between the two
dressing types in terms of wound healing rates ((in favour of foam), but due
to the number of studies showing no significant difference, this is possibly
a statistically anomaly arising by chance. However, a number of comparative
studies have highlighted that foam dressings are superior to hydrocolloids
in terms of exudate management and in-use characteristics (such as ease of
use, ease of removal and conformability) in the treatment of exuding wounds
although other studies report no real difference between the two product
types. This paper highlights the importance of considering
the likely effects of different dressing types not only on the actual
wounds, but also on patients. The ability of dressings to help maintain (and
improve) the quality of life of patients is something that clinicians must
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