2_supr a h g 02 2005

SUPRASORB RANGE

RATIONALE AND EVIDENCE

A H - G

February 15, 2005

AC February 15, 2005 2

Contents page

1. SUPRASORB A 3

2. CLINICAL EVIDENCE OF ALGINATES 5

3. CONCLUSIONS ON ALGINATE DRESSINGS 8

3.1. Clinical Evidence gathered so far includes the following 8

3.2. Market Drivers for alginates are 8

3.3. Market Restraints for alginates are 8

3.4. Competitive Analysis 8

4. REFERENCES 10

5. SUPRASORB H 12

6. CLINICAL EVIDENCE ON HYDROCOLLOIDS 13

7. EXAMPLES OF HCD IN MORE DETAIL 15

8. CLINICAL POSITIONING 16

9. CONCLUSION ON HCD 18

10. REFERENCES 19

11. SUPRASORB G 22

12. CLINICAL EVIDENCE ON HYDROGELS 22

13. CONCLUSIONS ON AMORPHOUS GELS 24

14. REFERENCES 28


1. SUPRASORB A

Suprasorb A is a calcium alginate dressing, available as a wound sheet, for superficial wounds and as wound filler for deep wounds. Both presentations may be used together or may be combined.

Alginate dressings are developed from naturally occurring polysaccharides found in certain species of brown seaweeds, harvested from western Scotland and the west coast of Ireland. Alginic acid was first extracted from seaweed in 1881 by Stanford, a British chemist1. Calcium alginates have been available as wound dressings since 19842. Alginic acid is a polymer of mannuronic and guluronic acid molecules. The two types of alginate dressing that are generally available have differing proportions of these acid molecules which belong to the group of sugar acids, respectively aldehydes or uronic acids3,4.

Both types of alginate react with exudate to form a gel at the surface of the wound by exchanging calcium for sodium ions. Alginates contain different quantities of calcium and sodium depending on the manufacturing process used. Fibres absorb fluid from the wound by capillary action and a gel forms around the fibres. This gel creates the moist warm environment as described by Winter5, which is hydrophilic and allows relatively pain-free dressing changes3.

Alginate dressings have been shown to have properties such as, absorption of fluids up to twenty times the products weight3,4. The alginate fiber uses the principle of ion exchange; penetrated sodium ion replaces a calcium ion. As long as this exchange process works, the fiber swells absorbing exudate, cell debris and microorganisms3,4. Alginate dressings that are high in mannuronic acid readily exchange calcium ions for sodium ions. Fluid uptake by the dressing thus increases, forming a soft gel that can be easily washed away with saline. Fibre dressings, high in guluronic acid, form stronger gels that keep their shape, making removal in one piece possible.

To what extent the released calcium plays a positive role in the wound, is not yet known. In principle it is suggested that calcium alginate dressings play a role in the different biological processes such as, regulation of enzymes, release of hormones and neurotransmitters, muscle contraction and cell proliferation6-8. Alginate dressings facilitate an optimal environment for healing and are useful in the management of exudate9. They have also been shown to be useful for haemostasis10,11 . Controlling of bleeding is suggested to occur when calcium ions are released into the wound, activating platelets and some clotting factors, thereby promoting haemostasis6. Calcium alginate forms a structural formula in which coagulation may occur better and faster and wound exudate is absorbed and bound. Alginates with differing properties may be useful for different wound types6.

When used appropriately, alginates facilitate trauma-free dressing removal and are conformable and easy to use, with high levels of absorbency. The gelling action of alginate dressings creates a warm moist environment that is ideal for wound healing and not painful upon dressing change. Alginates are shown to reduce healing times when compared with other types of dressing10-13. They are not suitable for use in dry ischaemic wounds14.


Fig. 1: Calcium alginate dressings, components, use and comments

Mean Components Use/comments Alginate (alginate dressings, fibers polymer).

Calcium-alginate fibers, respectively Calcium sodium alginate fibers

Composed of parts of brown seaweed Manuronic, glucuronic acid - polysaccharides)

dressings and wound fillers

Indication: Deep - and superficial-, moderately exuding-, bleeding-, infected-, malodorous wounds and cavities (e.g. leg ulcers, pressure ulcers, donor sites). May also be used in combination with wound gels. Application: Fill the wound completely with the alginate and cover with a secondary dressing (gauze, film, hydrocolloid); The dressing may stay in place 1-7 days, depending on exudate production of the wound; in case of infection dressing changes are to take place daily.

Advantages: Haemostatic, high absorbent capacity (up till 20 times its own weight), forms a gel when in contact with exudate or blood (exchange of Ca++/Na+- ions) optimal adaptation (for filling out of deep wounds, respectively pressure ulcers) supports granulation formation; padding effect; easy to apply (in combination with gauze or hydrocolloids films); hypoallergenic; well tolerated by patients; easy to remove the saturated gel masse (with a tweezers or by rinsing) a- traumatic dressing change; also absorbs slough, cell debris and microorganisms in the fiber-, gel structure; regulates moisture and temperature. May be well combined with fluids such as Ringers lactate, polyhexanide solution, etc. If the wound bed is too dry apply 3-5 mm gel underneath the dressing. Important: The product is to be kept within the wound area and covered with a secondary dressing.

Typical calcium alginate products:

- Algosteril - Algisite M - Melgisorb - Sorbsan - Sorbalgon - Suprasorb A - Tegagen,

Typical calcium-sodium alginate product: - Kaltostat,

Typical calcium alginates with adjuvent components:

- Curasorb ( +Zink ) - Sea Sorb soft ( + Cellulose ) - Trionic ( +Chlorophyll +Mangan +Zink ) - Urgosorb ( + Cellulose ),


2. CLINICAL EVIDENCE OF ALGINATES

Attwood15 undertook a randomized controlled trial in patients with split skin graft donor site wounds. In this study alginate dressings (Kaltostat) were found to accelerate wound healing when compared with paraffin gauze. In the first phase of the study 15 patients had half of their wound area dressed with Jelonet and the other half covered with an alginate dressing. It was noted that the area dressed with alginate had healed significantly better than the part that was covered with the paraffin gauze. The second phase of the study examined the standard time of donor site wound healing and patient acceptability of the study dressing used. The dressings were changed at day seven and again a significant improvement on wound healing and patient comfort was noted. Patients reported less pain during wear time and at dressing change in the wound areas, where the alginate dressing was used.

Gupta16 et al. found that dressing changes were much less painful for patients when using alginate dressings when compared with proflavine soaks. This was further supported by Dawson et al17, who compared alginates with saline-soaked swabs. A lower bacterial count was also noted by Gupta16 using alginate dressings in postoperative surgical wounds.

Alginate dressings are often used in the treatment of pressure ulcers and Sayag et al12 undertook a randomized controlled trial in elderly patients comparing the use of Algosteril and Debrisan (dextranomer). Ulcers treated with the alginate dressing showed favourable results when compared with those treated with dextranomer paste dressings12. The endpoint of the study was a 40% reduction in wound surface area. This was achieved in 74% of the alginate group and only 42% of the dextranomer group. The time taken to achieve this reduction in wound surface area was reduced in the alginate group (P=0.000l), suggesting that wounds heal quicker using alginates. This was a useful study in that the control and study groups were well-matched in a large trial.

Foley and Allen19 compared the use of alginate dressings and non-adherent dry dressings postoperatively after toenail surgery. Results showed a reduction in healing time in the alginate group of 22.7 days for total nail avulsion (P


favourably with the hydrofibre and hydrophobic dressings. Bowler and colleagues postulated that although the rate of bacterial sequestration may be dependent on fluid-absorbing tendency, the management of fluid within the dressing is more important.

Foster et al24 conducted a randomized trial of 100 patients comparing the use of Aquacel and Sorbsan in the treatment of a variety of surgical wounds healing by secondary intention. They found that both dressings performed well in relation to minimal pain on removal of the dressing, patient comfort, dressing application and removal, and that there was no statistical difference between the two dressings in their performance.

Smith25explored the treatment of Sorbsan versus polynoxylin and Melolin dressings following toenail removal, with 62 patients randomized to either treatment regime. Those wounds dressed with the alginate dressing had a reduced median healing time and a reduced number of follow up visits were required. The dressing also was easy to remove.

Retention of fluid in the dressing is relevant when the dressing is likely to be challenged by plantar pressure in diabetic foot ulcers. Secondary dressing selection and frequency of dressing changes should be carefully considered when using alginates on diabetic foot ulcers to facilitate removal of contaminated fluid from the wound bed26.

Wounds that are dry or covered with a dry black eschar are not suitable for alginate dressings14, as these dressings require exudate to activate the gelling process. Foster25-27 highlight the importance of using alginates only on moderate to heavily exuding wounds, citing instances of alginates drying out and traumatising adjoining tissues. In addition, Jones and Milton28 point out that moistening an alginate dressing affects the gelling process and limits absorbency; this practice is therefore not recommended.

Following cleansing, the surrounding skin should be dried and the appropriate size of alginate selected. The dressing should not overlap the wound margins1, as there is potential for lateral wicking in alginates, which could lead to maceration29. If rope or ribbon versions are used, these should be packed lightly into the wound; tight packing may cause unnecessary pressure as the fibres swell when absorbing exudate. Several authors have discussed the use of alginates in the treatment of a wound sinus and the potential problems of low levels of exudate causing a plug and limiting drainage in the wound30-34.

Most alginate dressings require a secondary dressing. Selecting a suitable secondary dressing will depend on the level of exudate. If low levels of exudate are expected, then a film dressing may be required to maintain a moist environment. If high levels of exudate are expected, then a more absorbent secondary dressing is required; this may be an absorbent pad or foam3,29,34-37.

If alginates with a high proportion of guluronic acid have been used, these maintain their integrity and can usually be removed intact28. Residual fibres should be irrigated from the wound surface and margins to prevent a build-up of fibres33,34.

Vanstraelen32 also looked into the treatment of split skin graft donor site wounds, but compared an alginate (Kaltostat) with porcine xenograft in 20 patients. It was found that the wounds dressed with the alginate healed three days earlier and also had a good quality regenerated skin. Alginates are often covered with film dressings.33,34


The arrival of Aquacel has prompted studies comparing the use of this hydrofibre dressing and alginate dressings. Armstrong and Ruckley35 undertook a randomized controlled trial of 44 patients with leg ulcers, and found that there was a reduction in the number of dressing changes required in the hydrofibre group, which meant a reduction in treatment costs due to a longer wear time for the dressing. Russell and Carr36 describe a case study of a patient with foot ulcers where Aquacel was used. Although the patient was in a poor condition and died, it had been noted that the number of dressings required were reduced and healing was promoted in the wounds.

Alginates may be may be used for wound cleansing, even for infected wounds, up to the granulation phase36-40. Traditionally, or in case of infection, the alginate is covered with sterile gauze and fixed with surgical tape. The dressing may also be covered with a film, hydrocolloid etc. (e.g. alginate wound filler covered with a hydrocolloid, respectively film), when there is no infection present1. The dressing change interval when a hydrocolloid dressing is used as a secondary dressing is 1-7 days. The dressing is to be changed, when the alginate is changed to a viscous gel, which in itself remains stabile1,3. Normally the gel can be removed with tweezers, without difficulties or the dressing may be gently released from the wound bed using 0,9% NaCl to make it moist1,3. There should be no concerns of leaving remains of the gel behind in the wound, which may cause wound healing delay4.

Fig. 2: Features of Calcium Alginate Dressings1,3:

Advantages Disadvantages Indication Use

Hemostatic properties; high absorbent capacity; regulates moisture and temperature; forms a gel, therefore adaptation for e.g. filling out of deep wounds; supports granulation formation; easy to apply; hypoallergenic; well tolerated by patients; easy to remove providing a-traumatic dressing changes.

Requires a secondary dressing for fixation.

Deep - and superficial-, moderately exuding-, bleeding-, infected-, malodorous wounds and cavities (e.g. leg ulcers, pressure ulcers, donor sites).

Fill the wound completely with the alginate and cover with a secondary dressing (gauze, film, hydrocolloid); The dressing may stay in place 1-7 days, depending on exudate production of the wound; in case of infection dressing changes are to take place daily.


3. CONCLUSIONS ON ALGINATE DRESSINGS

Alginate dressings are positioned for moderate to highly exuding wounds and may be applied to superficial and cavity wounds. A secondary dressing is required to cover the alginate, the choice of secondary dressing is at the discretion of the clinician, depending on the wound condition. Alginates can be used for infected and highly contaminated wounds. These dressings are replacing the conventional gauze dressings for the acute as well as the problem wounds, healing by secondary intention.

There are many dressings available to the clinician for use on wounds healing by secondary intention.

3.1. Clinical Evidence gathered so far includes the following:

q Alginates have been shown to be of benefit in moderate to highly exuding wounds. q The haemostatic properties of alginate dressings high in calcium may be useful in

arresting small bleeding points during sharp debridement. q Alginate dressings high in mannuronic acid, which consequently form only a weak gel

on contact with exudate, may have a place in managing wounds with a sinus as they are less likely to plug and can be flushed easily with saline.

q Alginate dressings are conformable and flexible, and because they also come in small sizes, they are easily used on areas such as the foot, that are difficult to dress.

q Evidence from the literature suggests that alginates are not painful at dressing change, and can reduce healing times.

3. 2. Market Drivers for alginates are: q Favorable reimbursement level, which allows for daily dressing changes. q Ease of use. q Product innovation in the form of hybrid alginates with properties that enhance wound

healing.

3.3. Market Restraints for alginates are:

q The limited use of alginates in wounds with high levels of exudate only. q Price pressure from an increasing number of competing alginate dressings in the

market. q Cost-containment pressures. q Limited innovation possibilities to augment the ease of use and efficacy of alginate

dressings.

3.4. Competitive Analysis: There are over 21 marketers of Alginate dressings of which the top three players represent 78% of the total market share. They are either well-established companies with products within each dressing category or small companies with limited types of wound dressings. Competitive factors include price, contracts and manufacturer reputation.


Alginate Dressing Market: Market Share Trends of Major Market Participants (U.S.) 1998-1999

Company 1999 (%) 98/99 Trend Convatec 39 Down Bertek 24 Down Kendall 15 Up Others 22 Up Total 100

Other companies are: 3M, Bard, B. Braun/McGraw, BSN-Jobst, Carrington, Coloplast, Derma Sciences, DeRoyal, Dumex, Ferris, Hollister, Johnson & Johnson, Medical Resources, Medline, MPM, and Smith & Nephew, Hartmann-Conco Inc., Tycol/Kendall.

Note all figures are rounded; the base year is 1999 Source: Frost & Sullivan


4. REFERENCES

1) Gensheimer D A review of calcium alginates. Ostomy/Wound Management 39(l):34-43:1993

2) Morgan D Alginate dressings. Journal of Tissue Viability 7(l): 4-14:1996 3) Andriessen, A, Huid en wondverzorging in: Leerboek intensive-care-verpleegkunde. Van

den Brink GTWJ, Lindsen F, Uffink Th (eds).Lemma BV Utrecht: 2003; 4th edition, Part 2, 25-105

4) Kammerlander G, Lokaltherapeutische Standards fr chronische Hautwunden. Wien; New York: Springer, 1998 198 202

5) Winter GD Formation of scab and rate of epithelialisation of superficial wounds in the skin of the young domestic pig. Nature 193: 293-4:1962

6) Thomas S Alginate dressings in surgery and wound management part I. Journal of Wound Care 9(2): 56-60:2000

7) Oliver LC, Blaine G Haemostasis with absorbable alginates in neurosurgical practice. British Journal of Surgery 37: 307-10:1950

8) Shotaro Harada et al. Clinical evaluation on Sorbsan (Calcium Alginate Dressing) for the treatment of skin ulcers. J O Medicine and Pharmaceutical Science 10(2):473-495:1994

9) Pudner R Alginate and hydrofibre dressings in wound management. Journal of Community Nursing 15(5): 38-42:2001

10) Kneafsey B, O'Shaughnessy, Condon KC The use of calcium alginate dressings in deep hand burns. Burns 22(l): 40-3:1996

11) Harding KG, Jones V. Price P Topical treatment: which dressing to choose. Diabetes/Metabolism Research and Reviews 16(Suppl I): S47-50:2000

12) Sayag MD, Meume S, Bohbot S Healing properties of calcium alginate dressings. Journal of Wound Care 5(8): 357-62:1996

13) Belmin J, Meaume S, Rabus M, Bohbot S Sequential treatment with calcium alginate dressings and hydrocolloid dressings accelerates pressure ulcer healing in older subjects: a multicentre randomised trial of sequential versus non-sequential treatment with hydrocolloid dressings alone. Journal of the American Geriatric Society 50 (February): 269-74:2002

14) Pudner R Alginate dressings. Practical Nursing 9(12): 18-20:1998 15) Attwood Al Calcium alginate dressing accelerates split skin graft donor site healing. British

journal of Plastic Surgery 42: 374-9:1989 16) Gupta R, Foster ME, Miller E. Calcium alginate in the management of acute surgical

wounds and abscesses. Journal of Tissue Viability 1(4): 115-16:1991 17) Dawson C, Armstrong M, Fulford S, Faruqi RM, Galland RB. Use of calcium alginate to

pack abscess cavities: a controlled clinical trial. Journal of the Royal College of Surgery of Edinburgh 37(3): 177-9:1992

18) Royal Pharmaceutical Society British Pharmacopeia. Appendix: Wound dressings. Royal Pharmaceutical Society, London, 1994

19) Foley GB, Allen J. Wound healing after toenail avulsion. A comparison of Kaltostat and Melolin as postoperative dressings. The Foot 4: 88-91:1994

20) Bale S. Baker N, Crook H et al. Exploring the use of an alginate dressing for diabetic foot ulcers. Journal of Wound Core 10(3): 81-4:2001

21) Cullum N, Najid M, O'Meara S, Sheldon T.Use of dressings: is there an evidence base? In: Boulton AJM, Connor H, Cavanagh PR (Eds). The Foot In Diabetes. 3rd edn. Wiley, Chichester: 153:2000


22) Doyle JW, Roth TP, Smith RM, Yi YQ, Dunn RM. Effects of calcium alginate on cellular wound healing processes modeled in vitro. Journal of Biomedical Materials Research 32: 561-8:1996

23) Bowler PG, Jones SA, Davies BJ, Coyle E. Infection control properties of some wound dressings. Journal of Wound Care 8(10): 499-502:1999

24) Foster, L., Moore, P., Clark, S. A comparison of hydrofibre and alginate dressings on open acute surgical wounds, Journal of Wound Care 9; 9: 442-445:2000.

25) Smith, J. Comparing Sorbsan and polynoxylin/Melolin dressings after toenail removal., Journal of Wound Care 1; 3: 17-18:1992

26) Foster AVM, Greenhill MT, Edmonds ME. Comparing two dressings in the treatment of diabetic foot ulcers. Journal of Wound Care 3(5): 224-8:1994

27) Foster, L., Moore, P. Acute surgical wound care 3: fitting the dressing to the wound, British Journal of Nursing. 8; 4: 200- 210:1999.

28) Jones V, Milton T When and how to use alginates. Nursing Times 96(29): 2-3:2000 29) Moody M Calcium alginate: a dressing trial. Nursing Standard 13(Suppl): 3-6:1991 30) Butcher M Management of wound sinuses. Journal of Wound Care 8(9): 451-4:1999 31) Stansfield G Managing wound exudate in the diabetic foot ulcer. The Diabetic Foot 3(3):

93-8:2000 32) Vanstraelen, P.Comparison of calcium sodium alginate (Kaltostat) and porcine xenograft

(E-Z Derm) in the healing of split-thickness skin graft donor sites, Burns 18; 2: 145-148:1992

33) Thomas S Alginate dressings in surgery and wound management: part 3. Journal of Wound Care 9(4): 163-66:2000

34) Andriessen J, Wondbehandeling methodieken en middelen, Pharmaceutisch Weekblad 1991; 126 (3)

35) Armstrong, S., Ruckley, C. Use of a fibrous dressing in exuding leg ulcers, Journal of Wound Care 6; 7: 322-324:1997

36) Russell, L., Carr, J. New hydrofibre and hydrocolloid dressings for chronic wounds, Journal of Wound Care. 9; 4: 169-172:2000

37) Thomas, S. Alginate dressings in surgery and wound management-part 2, Journal of Wound Care 9; 3: 115-119:2000

38) Timmons, J. Alginates and hydrofibre dressings, Professional Nurse 14; 7: 496-503:1999 39) Williams, C.Algosteril calcium alginate dressing for moderate/high exudate, British

Journal of Nursing 8; 5: 313-317:1999 40) Williams, C. An investigation of the benefits of Aquacel Hydrofibre wound dressing,

British Journal of Nursing 8; 10: 676- 680:1999


5. SUPRASORB H

Hydrocolloid (HCD) dressings consist of hydrophilic colloid particles (e.g. carboxymethylcellulose) placed in a hydrophobic polymer matrix, with a semipermeable polyurethane surface, not permeable to fluids and microorganisms,1-15.

Hydrocolloids have been around since early 1980. They are widely used for a variety of wound types in different settings. Their limited absorbent capacity1 is the reason why other absorbent dressings, such as foams are increasing. Also hydrocolloids are occlusive adhesive dressings, which make them less suitable for wounds at risk for infection, such as diabetic foot ulcers and arterial wounds1,6,9,11. Most hydrocolloids disintegrate (form a gel) leading to malodor and require more time upon dressing changes, as the wound needs to be cleansed. The gel they form on the wound is sometimes wrongly identified as pus1,2,6,11-39. In the beginning of the sixties in-vitro research was started on the application of HCD s. The first known products were Varihesive (Duoderm) (Convatec) and later Comfeel (Coloplast). Fig.1: Shows features of HCD s.

Fig. 1: Features of hydrocolloid dressings

Advantages

Disadvantages

Indication

Use/comments

Adhesive; absorption (depending on thickness and product), easy to apply, flexible and easy to mold, water resistant (showering and a short time bath are allowed) stays in place for a prolonged period of time (up to 7 days, depending on the product and exudate production), high wear comfort, efficient wound cleansing, granulation and epithelialization, protects the newly formed skin, additional support as pressure ulcer prophylaxis.

Not transparent (except extra thin version); malodor may occur; the dressing disintegrates when in contact with the wound. The adhesive dressing is not to be used on sensitive skin, such as in venous leg ulcer patients.

Superficial and deep, exuding wounds and cavities (deep wounds should be filled with wound gel, alginates or hydrofibers) for wound cleansing, granulation and epithelialization as well as protection of epithelium with thin skin. (Should not be left in situ for longer > 5-7 days).

The dressing is applied 3-5 cm overlapping the wound edge; underneath the HCD, wound gels may be applied for dry-, sloughy wounds, or alginates, respectively hydrofibers for heavily exuding wounds, deep wounds, as a wound filler; during dressing changes, wound cleansing, using a rinsing fluid, such as saline.


6. CLINICAL EVIDENCE ON HYDROCOLLOIDS

HCD may be used for skin protection, such as for heels or other areas where friction may occur. HDC may also be used under surgical tape, used for the approximation of wound edges for delayed primary closure6. According to Barnes hydrocolloids may provide some protection from shearing stress56. However, they do not substantially reduce pressure to the wound area56. Consequently HCD should be viewed as only one component of a total treatment protocol.

The beneficial healing effects of hydrocolloid dressings depend upon the interaction between the dressing and exudate to create a moist healing environment6. Use of hydrocolloids in dry wounds will not produce the healing effects outlined above and more cost-effective options such as wound gels are available in these circumstances.

The risk of denuding new epithelium is more difficult to reduce than for alginate dressings as the outer layer of hydrocolloids is resistant to soaking with sterile saline. Use of hydrocolloids is therefore indicated for most moderately exuding wounds. However, hydrocolloids are absorbent to a certain extent, the dressings do not cope well with heavily exuding wounds and excessive exudate may tend to saturate the dressing. In wet wounds exudate may spread beyond the wound edges and lead to maceration of the surrounding skin57. Moreover the interaction between the dressing and exudate creates a yellow, foul smelling and (occasionally) bloody discharge56,58. Saturation of dressings in heavily exuding wounds and leakage of this discharge may significantly reduce patient tolerance56.

As for all moist wound dressings, use of hydrocolloids is contraindicated for clinically infected wounds. However, the presence of an unpleasant exudate should not be confused with clinical infection58. Hydrocolloid dressings are opaque and should be changed infrequently. Consequently, use is precluded in wounds with bone and tendon involvement due to the need for close monitoring of such wounds56.

Use in diabetic patients59 and in patients with ischemic ulcers is generally ill-advised21. Allergic reactions have been observed for specific products; sensitivity to a dressing may be due to the specific formulation of the inner layer of hydrocolloid material rather than to the class of dressings. Hydrocolloid dressings are highly conformable to irregular wound surfaces and are marketed as sheets, granules, pastes and powders58. The outer layer of these dressings forms an effective barrier against water so that the patient may bathe normally and without additional restriction21,58.

Dressing changes should be limited to facilitate the beneficial effects of the moist wound environment and prevent undue disruption of granulation tissue and epidermal cell growth58. However, care should be taken to prevent maceration. At a minimum, dressing changes should occur once every 7 days but may be as frequent as every day for heavily exuding wounds58.

HCD as early moist wound healing products had to go against prejudices that under occlusion an infection may develop. Hundreds of international studies and clinical case reports have contributed that HCDs show marked progress in moist wound healing7-55. Studies have shown that infection rates in wounds treated with occlusion are on average 2,6%, versus 7,1% for conventional dressings, gauze, ointment or paraffin gauze7.


During an international forum for wound microbiology in Barcelona 1989, Hutchinson7,19,20 presented the results of 103 studies performed on more than 7200 wounds, where 2,1% of the wounds covered with an occlusive dressing were infected, versus 5,3% of the wounds covered with conventional dressings2. Of the 103 studies in 52 studies wounds were covered only with a HCD. When looking only at the HCD group, the infection rate was 1,02% vs 4,01% infections in the group covered with conventional dressings1,2,19,20.

Autolytic debridement uses the body s own enzymes to dissolve necrotic tissue within the wound. A moist environment accelerates the autolytic process6,15. Occlusive and semi-occlusive dressings allow better contact between the necrotic debris and lysosomal enzymes in the wound. Hydrocolloids, hydrogels, transparent films, and alginates are moist interactive dressings that can be used for autolytic debridement6,42. This method is selective and causes little or no pain. However, autolytic debridement may be slow6.

Wikblad & Anderson33 compared the effectiveness of three types of wound dressings in Swedish patients undergoing elective coronary bypass or valve replacement surgery. Seventy-seven of the patients were randomized to an occlusive hydrocolloid dressing (DuoDerm) and 92 patients to a conventional absorbent dressing and 81 patients to a semi-occlusive dressing. In the patients reported on (n=216) the incidence of wound infections requiring antibiotics was 5% (n=11). Of these infections, only 8 were found in sternum incisions; 5 of the 8 were in the group of patients with absorbent dressings.

A study by Michie & Hugill32 evaluated occlusive wound dressings (DuoDerm) in elective plastic surgery. In this study the 40 wounds of 28 patients were randomized to one half the incision covered with an occlusive dressing and the other half covered with an impregnated gauze dressing.

A study comparing occlusive (Comfeel) with non-occlusive dressings by Holm et al 199831 was conducted in Denmark for which patients were selected with clean abdominal wounds after surgical intervention. If patients developed a wound infection after surgery they were withdrawn from the trial. These withdrawn patients' results were analyzed to provide infection rates for the study. The outcome was beneficial for the study dressing.

Lansdown30 evaluated silver coated HCD and reported some benefits, however there are still a lot of unanswered questions as to the resorption and resistance of silver applied in this fashion.


7. EXAMPLES OF HCD IN MORE DETAIL

Duoderm CGF / Granuflex / Varihesive

Manufacturer: ConvaTec

Description: Improved formulation hydrocolloid dressing

Key Indications: Leg ulcers and pressure ulcers. As a primary dressing for burns, donor sites and traumatic wounds.

Key Claims: Minimal leakage, long wear time, accelerated healing, and improved comfort and convenience, cost effective, efficient control of wound exudate.

Size Range: 10 x 10cm, 15 x 15cm, 15 x 20cm, 20 x 20cm, 20 x 30cm.

Related Dressings: Granuflex Bordered, Granuflex Extra thin

Comments: Granuflex (improved formulation) is a sterile hydrocolloid dressing containing gelatin, pectin and sodium carboxymethylcellulose40. The hydrocolloid has a top-film on its outer surface, coated with a thin layer of foam. To date, Granuflex is one of the most widely used dressings for chronic wounds. It is waterproof and provides effective exudate management.

Product Weaknesses:

q The dressing has very limited absorbency and fluid retention, even when compared to other hydrocolloids1,2,15,29-31.

q Granuflex is relatively impermeable to vapor transpiration and as a result wound exudate is simply trapped between the dressing and the skin.

q Un-retained fluid is prone to leakage, necessitating frequent dressing changes that increase nursing time required and the number of dressings required per wound1,2,15.

q Odor, mess, patient discomfort and risk of bacterial penetration are significant clinical issues16-26. This makes HCD less suitable for diabetic foot ulcers and other wounds at risk for infection26.

q Creates a build up of back pressure caused by trapped fluid. This is particularly undesirable on pressure ulcers where additional pressure on the wound should be avoided35.


Comfeel Ulcer

Manufacturer: Coloplast

Description: Hydrocolloid dressing

Key Indications: Pressure ulcers, leg ulcers, burns, donor sites and minor injuries.

Key Claims: High flexibility and conformability, high cohesion, balanced adhesion, water permeable, impermeable to bacteria, odor proofing.

Size Range: 4 x 6cm, 10 x 10cm, 15 x 15cm, 20 x 20cm

Related Dressings: Comfeel Systems Plus, Plus Clear and Transparent

Comments: Comfeel consists of sodium carboxymethylcellulose particles embedded into an adhesive elastic mass. A semi-permeable polyurethane film covers the dressing.

Comfeel has strong adherence, pliability and clinical efficacy.

Product Weaknesses:

q Data1 indicates that Comfeel is far less absorbent than foam dressings. This HCD was tested against a standard - and an adhesive foam dressing (Smith & Nephew). The fluid handling data indicates a failure for Comfeel to handle 23% of the delivered fluid. The poor fluid handling ability of Comfeel, when compared with foam dressings, occurs as a result of the dressings inadequate absorbency and permeability1.

q Risk of leakage due to poor fluid handling ability.

q Risk of maceration of surrounding skin due to the above weaknesses41-49.

8. CLINICAL POSITIONING

HCD are positioned for wound cleansing debridement support as well as for the support of epithelialization. They may be classified as follows:

q type A only classical hydrocolloid (e.g. Hydrocoll, Suprasorb H, Tegasorb, Varihesive, )

q type B mixed hydrocolloids (with alginate Comfeel plus) (with silver ions Contreet H)

q type C combined hydrocolloids (with polyacrylate pad Combiderm)


Fig. 2: Hydrocolloids, composition, use and comments

Mean composition Use/comments

Hydrocolloid Hydrocolloid dressings

hydrophilic, colloidal particles (e.g. Guar, Karaya, Carboxy methylcellulose, Gelatin, pektin) inserted into a hydrophobes polymer stand (e.g. Polysobutylen matrix) plus more or less semipermeable PU surface, not permeable for liquids and germs

Advantages: Adhesive (partly reinforced with an adhesive border), high absorbent capacity (depending upon thickness and product), easy to apply, flexible and easy to mould, water resistant (shower and a short bath is possible), prolonged time in situ (up to 7 days - depending on the product and amount of exudate), comfortable, effective cleansing, Granulation and epithelium stimulation, protection of newly formed skin, additional aid to the pressure ulcer prophylaxis Disadvantages: Not transparent (except specially-thin and/or transparent), it must be applied correctly

INDICATION: Superficial and deep, not to moderately exuding wounds and wound cavities (fill deep wounds with hydrofiber, gel or alginate), for wound cleansing, granulation and epithelialization as well as for epithelium protection in case of thin skin; leg ulcers, pressure ulcers, all type of wounds (in case of infection treatment with the hydrocolloid is to be discontinued, the wound is to be treated with an antiseptic for a few days; with a timely start of topical antiseptic therapy, systemic antibiotic therapy is often not necessary - Exception Diabetes patients), Split thickness skin grafts, abrasions, small burns...

APPLICATION: Apply the dressing with a 3 - 5 cm overlap to the wound edges; underneath the hydrocolloid a gel, alginate or hydrofiber may be used for highly exuding, deep wounds as a filler - the effect of the hydrocolloids is thus supported; with each dressing change particularly here accurate cleansing is to be performed with wraps, rinsing or bathing as well as the dry phase which follows after cleansing;

IMPORTANT: Extensive and deep, partly wet necroses should be removed surgically (faster, shorter therapy duration and it is possible to observe the depth of the necrosis and condition of the wound bed). Thick hydrocolloids as well as the special forms over the past years are replaced by foam dressings. The thin, transparent and/or film-like hydrocolloids are still strongly represented (easy handling, moldable , to be combined with wound fillers..)

Classical hydrocolloids

Algoplaque, Algoplaque HP, Askina Biofilm S, Askina Biofilm Transparent, Hydrocoll, Metoderm, NuDerm, Restore, Sure Skin, Suprasorb H, Tegasorb, Traumasive, Varihesive - E, Varihesive extra thin, Varihesive E Border,...

hydrocolloid plus alginate combination

Comfeel Plus,

hydrocolloid plus silver combination

Contreet H,


9. CONCLUSION ON HCD

Within the Exudate Management Market, the hydrocolloid sector is mature. The market is still in a state of slow growth and has not yet reached a plateau, i.e. growth estimated at 4%. The reason why they are still growing is because, as home healthcare or alternative care markets get on the moist wound healing band wagon they are being introduced to moist wound healing with hydrocolloids, just like the hospitals were over 10 years. It has to be remembered, that moist wound healing stated in the hospitals and that most of the KOLs come from the hospital setting and alternative care is lagging far behind still.

Moreover hydrocolloids are still the most widely used dressing, in spite of its drawbacks. Also, probably clinicians are starting with hydrocolloids because of cost. Absorbent dressings are still more costly for the cash poor alternate market.

There are many competitor hydrocolloid products and profit margins are declining through increased competition. There are over 17 marketers of Hydrocolloid dressings world-wide of which the top three represent a 70% market share. This is a mature market where companies are either well established with products within each dressing category or small with limited types of wound dressings. Competitive factors include price, contracts and manufacturer reputation.

Fig. 3: Hydrocolloid Dressing Market: Market Share Trends of Major Market Participants (U.S.) 1998-1999

Company 1999 (%) 98/99 Trend Convatec 60 Down Smith & Nephew 7 Down Coloplast 3 Up Others 30 Up Total 100

Note all figures are rounded; the base year is 1999 Source: Frost & Sullivan


10. REFERENCES

1) Shutler, S., Stock, J., Bales, S., Harding KG., A multi-centre comparison of a Hydrocellular adhesive dressing and a Hydrocolloid dressing in the management of stage 2 & 3 pressure sores, Poster, 5th EWMA Conference 1995. CT89/16.

2) Solfest et al, A model to compare wear time of hydrocolloid dressings. Poster reprint. 16th Annual Clinnical Symposium on Advances in Skin and Wound Care. Orlando, Fla;September 2001.

3) Aysan E, Ayar E, Baskent A, Eren Z, Tutuncu H. Outcomes of using transparent hydrocolloid dressings versus dru gauze on surgical wounds. Advances in Skin & Wound Care. 2001;March/April.

4) Xakellis GC, Chrischilles EA. Hydrocolloid versus saline-gauze dressing in treating prussure ulcers: a cost-effectiveness analysis. Arch Phys Med rehabil. 1992;73(5);463.

5) ISO 14155. International Standard for Clinical Investigation of Medical Devices. International Organisation for Standardization,1996.

6) Andriessen, A, Huid en wondverzorging in: Leerboek intensive-care-verpleegkunde. Van den Brink GTWJ, Lindsen F, Uffink Th (eds).Lemma BV Utrecht: 2003; 4th edition, Part 2, 25-105

7) Huchon D. Comparison between granuflex and paraffin-impregnated medical gauze in the treatment of pressure sores. Going into the 90s: The Pharmacist and Wound Care. Eurosciences Communication: 1992; France. 23-26.

8) Van der Cammen TJ, OCallaghan U and Whitefield M. Prevention of pressure sores. A comparison of new and old pressure sore treatments. British Journal of Clinical Practice 1987;41:1009-11. 9) Bishop JB, Phillips LG, Mustoe TA, Van der Zee AJ, Wiersema L, Roach D, et al. A

prospective randomised evaluator-blinded trial of two potential wound healing agents for the treatment of venous stasis ulcers. Journal of Vascular Surgery 1992;16:251-7.

10) Blair S, Backhouse C, Wright D, Riddle E and McCollum C. Do dressings influence the healing of chronic venous ulcers? Phlebology 1988;3:129-34.

11) Gilchrist B and Reed C. The bacteriology of chronic venous ulcers treated with occlusive hydrocolloid dressings. British Journal of Dermatology 1989;121:337-344.

12) Hermans MHE. Air exposure versus occlusion: merits and disadvantages of different dressings.Journal of Wound Care 1993;2:362-5.

13) Gotzsche P, Liberati A, Torri V and Rossetti L. Beware of surrogate outcome measures.

14) International Journal of Technology Assessment in Health Care 1996;12:238-246. Prescription Cost Analysis data, England 1997. Department of Health, Government Statistical Service Branch SD1E

15) Bradley M, Nelson A, et al. Dressings and topical agents used in the healing of chronic wounds: a systematic review. NHS Centre for Reviews and Dissemination Report, 1998.

16) Lock PM. The effects of temperature on mitotic activity at the edge of experimental wounds. In: Symposium on wound healing (Plastic, surgical & dermatological aspects) Espoo, Finland A. Lingren & Sner A/B, Moiridat 1979: 103-108:1979.

17) Hofman D. The use of hydrocolloids, Nursing Times, 92(29), 64, 66, 68:1996 18) Hulten LDressings for surgical wounds, American Journal of Surgery,167(1A), 42S-

44S; discussion 44S-45S:1994 19) Hutchinson JJ McGuckin M. Occlusive dressings: a microbiologic and clinical review,

American Journal of Infection Control, 18(4), 257-68:1990


20) Hutchinson JJ Lawrence JC. Wound infection under occlusive dressings, J HospInfect, 17(2), 83-94:1991.

21) Kannon GA Garrett AB. Moist wound healing with occlusive dressings. A clinical review, Dermatologic Surgery, 21(7), 583-90:1995.

22) Lawrence JC. Dressings and wound infection, Rn, 54(7), 10:1991 23) Lawrence JCDressings and wound infection, Am J Surg, 167(1A), 21S-24S:1994 24) Lotti T, Gasperini S Rodofili C. Should we use occlusive dressings in the treatment of

acute wounds?, International Journal of Dermatology, 36(2), 97-9:1997 25) Mertz PM, Marshall DA Eaglstein WH. Occlusive wound dressings to prevent bacterial

invasion and wound infection, Prof Nurse, 14(7), 496-9, 501, 503:1999 26) Schmitt M, Vergnes P, Canarelli JP, Gaillard S, Daoud S, Dodat H, Lascombes P,

Melin Y, Morisson-Lacombe G Revillon Y. Evaluation of a hydrocolloid dressing, Journal of Wound Care, 5(9), 396-9:1996

27) Rasmussen H, Larsen MJ Skeie E. Surgical wound dressing in outpatient paediatric surgery. A randomised study, Dan Med Bull, 40(2), 252-4:1993

28) Ryan TJ. Wound dressing, Dermatol Clin, 11(1), 207-13:1993 29) Pudner R. Hydrocolloid dressings. Practice Nursing 1998; 9: 17-19 30) Lansdown AB, Jensen K, Jensen MQ. Contreet Foam and Contreet Hydrocolloid: an

insight into two new silver-containing dressings. J Wound Care 2003; 12(6): 205-10. 31) Holm C, Petersen JS, Gronboek F Gottrup F. Effects of occlusive and conventional

gauze dressings on incisional healing after abdominal operations, European Journal of Surgery, 164(3), 179-83:1998

32) Michie DD Hugill JV. Influence of occlusive and impregnated gauze dressings on incisional healing: a prospective, randomized, controlled study, Annals of Plastic Surgery, 32(1), 57-64:1994

33) Wikblad K Anderson B. A comparison of three wound dressings in patients undergoing heart surgery, Nursing Research, 44(5), 312-6:1995.

34) Helfman T, Ovington L Falanga V. Occlusive dressings and wound healing, Clinics in Dermatology, 12(1), 121-7:1994

35) Dealey C. Role of hydrocolloids in wound management, British Journal of Nursing, 2(7), 358, 360, 362 passim.1993

36) Eaglstein WH. Occlusive dressings, J Dermatol Surg Oncol, 19(8), 716-20:1993. 37) Field FK Kerstein MD. Overview of wound healing in a moist environment, American

Journal of Surgery, 167(1A), 2S-6S:1994. 38) Findlay D. Modern dressings: what to use, Aust Fam Physician, 23(5), 824-5, 828-9,

832-9:1994 39) Foster L Moore P. The application of a cellulose-based fibre dressing in surgical

wounds, J Wound Care, 6(10), 469-73:1997. 40) Heffernan A Martin AJ. A comparison of a modified form of Granuflex (Granuflex

Extra Thin) and a conventional dressing in the management of lacerations, abrasions and minor operation wounds in an accident and emergency department, Journal of Accident & Emergency Medicine, 11(4), 227-30:1994.

41) Hermans MH. Clinical benefit of a hydrocolloid dressing in closed surgical wounds, Journal of et Nursing, 20(2), 68-72:1993.

42) Hermans MHE. An overview of physiological aspects of occlusive and nonocclusive dressings... reprinted from Primary Intention, May 1995, New Zealand Practice Nurse:1995

43) Hickerson WL, Kealey GP, Smith DJ, Jr. Thomson PD. A prospective comparison of a new, synthetic donor site dressing versus an impregnated gauze dressing, J Burn Care Rehabil, 15(4), 359-63: 1994


44) Bowler PG, Jones SA, Davies BJ Coyle E. Infection control properties of some wound dressings, J Wound Care, 8(10), 499-502:1999

45) Kiernan M. Nurse prescriber. Wet, sloughy and necrotic wound management. Community Nurs 1999;5(Pt 3):512.

46) Varghese MC, Balin AK, Carter DM, Caldwell D. Local environment of chronic wounds under synthetic dressings. Arch Dermatol 1986;122:527.

47) Timmons J. (1994) Occlusive dressings reduce wound infection rates. Alginates and hydrofibre dressings, Nurs RSA, 9(1), 12-3.

48) Wipke-Tevis DD Stotts NA. (1998) Effect of dressings on saphenous vein harvest incision pain, distress and cosmetic result, Prog Cardiovasc Nurs, 13(3), 3-13.

49) Alsbjorn BF, Ovesen H Walther-Larsen S. Occlusive dressing versus petroleum gauze on drainage wounds, Acta Chir Scand, 156(3), 211-3:1990.

50) Briggs M. Surgical wound pain: a trial of two treatments, J Wound Care,5(10), 456-60:1996

51) Cannavo M, Fairbrother G, Owen D, Ingle J Lumley T. A comparison of dressings in the management of surgical abdominal wounds, J Wound Care, 7(2), 57-62:1998

52) Chang H, Wind S Kerstein MD. Moist wound healing, Dermatology Nursing,8(3), 174-6, 204:1996

53) Cho CY Lo JS. Dressing the part, Dermatologic Clinics, 16(1), 25-47:1998. 54) Dale J. Wound dressings, Prof Nurse, 12(12 Suppl), S12-4: (1997 55) Siegel DM, Sun DK Artman N. Surgical Pearl: a novel cost-effective approach to

wound closure and dressings, Journal of the American Academy of Dermatology, 34(4), 673-5:1996

56) Barnes HR 1993, Wound care: fact and fiction about hydrocolloid dressings , J Gerontol Nurs, 19(6), 23-6.

57) Hansson C 1997, Interactive wound dressings: A practical guide to their use in older patients , Drugs & Aging, 11(4): 271-284.

58) Choate CS 1994, Wound dressings. A comparison of classes and their principles of use , J Am Podiatr Med Assoc, 84(9), 463-9.

59) Apelqvist J, Larsson J & Stenstrom A 1990, Topical treatment of necrotic foot ulcers in diabetic patients: a comparative trial of DuoDerm and MeZinc , Br J Dermatol, 123(6): 787-92.


11. SUPRASORB G

The main components of the hydrogel dressing are sodium carboxymethylcellulose and propylene glycol. The Suprasorb gel sheet has a polyurethane film carrier. Hydrogels develop through expansion of macromolecular organic structures with water, which are classified in the group of fluid rich hetero-gels. These wound gels are saturated with fluid up to 92% and is therefore suitable for use in dry and black necrotic wounds1-4,. Gels are used as donators of water and therefore are called watery polymer gels. A good quality gel can bind the same amount of exudate, as the amount of gel put into the wound1-3,5. Hydrogels may have a cooling and soothing effect and are therefore used in radiation wounds and superficial burns1. A modified Duhring Chamber test demonstrated Suprasorb G, amorphous and gel sheet to be non-irritating for the skin6.

Features of hydrogel

Advantages Disadvantages Indication Use Suitable for cleansing and granulation phase, especially if the wound produces small amounts of exudate; the gel primarily donates moisture to the wound, but is also able to absorb some cell debris and wound exudate1-3,5.

A secondary dressing is required (e.g. foam dressings, films, or hydrocolloids) 1,2

.

Moisturizing of dry slightly exuding wounds, in order to stimulate autolysis and cellular mechanisms. Absorption and binding of broken down cell debris and wound exudate1-3,5.

Apply the gel in a layer of 3-5 mm into the wound, in case of deep wounds the rest of the wound is to be filled out with foam or alginate; if possible it is advised to apply an occlusive dressing, films, hydrocolloids etc., which enhances the activity1,2,5. The dressing can stay in place for 1-7 days; in case of infected wounds dressing changes should take place daily1,2,5.

12. CLINICAL EVIDENCE ON HYDROGELS Hydrogels are reported to have benefits in providing selective, non-surgical debridement, facilitating autolysis7. The formulation of different wound gels results in a varying ability to donate water and absorb fluid from the wound8. The clinical experience of many individuals has suggested that such materials are useful in clearing slough from wounds9, as well as providing/maintaining a beneficial moist wound healing environment10,11. Hydrogels exist both as sheet forms (e.g. Vigilon) and in amorphous forms (e.g. Intrasite, Sterigel, etc. ). The amorphous hydrogels are reported to be more practical in terms of their clinical application1,2. They may be applied for cavity wounds as a wound filler12, providing a MWH environment and facilitating drainage of wound exudate, pus and debris1,2,12.


Amorphous Hydrogels use and comments1,2

Mean composition Use/comments

Classical hydro-gels, amorphous wound gels

Hydro-gel Wound gel

Hydrophilic material (e.g. modified starch, carboxymethylcellulose, propylen glygol, calcium alginate) in specific format

Advantages: Effective for cleansing11-13 and granulation phase1,2, especially if the wound produces small amounts of exudate; the gel primary donates moisture to the wound, but is also able to absorb cell debris and wound exudate1,2,11-13. Disadvantages: A secondary dressing is required (e.g. foam dressing, films, and hydrocolloid).

Application: Apply the gel in a layer of 3-5 mm onto the wound, in case of deep wounds the rest of the wound is to be filled with foam, alginate or hydrofiber; if possible additionally it is advised to apply an occlusive dressing, films, hydrocolloids etc., enhancing the activity. The dressing can stay in place for 1-7 days; in case of infected wounds dressing changes should take place daily. Important: extensive and deep, partly moist necrotic areas should be surgically removed.

Typical cellulose gels

Intrasitgel, Normlgel, Suprasorb G, Tegagel, Varihesive Hydrogel,

Single use!

Cellulose gels with adjuvant alginate

NuGel Purilon Gel

Single use!

Hydro-gels/-Wound gels with anti-infection components

Cellulose gel with polihexanide

Prontosan W Gel with 0,1% polihexanide

After opening the packaging, the product may be kept for 6 weeks and is to be used for one patient only.

Polyacrylate gel with Hydrosomes, Phospholipides, PVP

Repithel Gel with 3% PVP-iodine incorporated in Phospholipid/ hydrosomes

After opening the packaging, the product may be kept for 6 weeks and is to be used for one patient only. Specific action on fungi and bacteria reparative characteristics at body cells


Hydro-gel/-Wound gel sheets use and comments1,2 Mean composition Use/comments

Hydrogel Hydrogel sheets

Hydrophile polymere (e.g gelatin, polyacrylamid polymere, methacryl acid, polyurethane, polyethylenoid) + water (water content depending on the product is between 35%-96%), semi-permeable polyurethane surface, (most products)

Advantages: Semitransparent surface, soft, comfortable, refreshing, flexible (not as supple as hydrocolloid sheets, hydro - polymer sheets, film dressings); add moisture (for dry wounds)

Disadvantages: A secondary dressing for fixation is necessary (most products are without adhesive), moderate absorbent capacity (depending upon water content), Maceration of the peri-wound skin in case of high levels of exudate, dries out (exception: Products with semipermeable surface); nowadays replaced by hydrocolloids, foam sheets, films with e,g, gels as wound filler

Indication: Dry wounds, superficial injuries, split thickness skin grafts; wound surfaces with little exudate production, Epithelialization phase;

Application: Directly on the wound and peri-wound skin; additionally fix with secondary dressing; In situ on the average days;

IMPORTANT: Extensive necrotic surfaces, partly moist necroses should best be removed surgically (much faster, shorter therapy duration and the removal of necrosis can be observed as well as the condition of the wound underneath the necroses).

Gel sheets with alcohol

Hydrosorb, Hydrosorb plus, Opragel, Primamed, Suprasorb G Gel sheet, Spenco,...

Mostly replaced by hydrogels from the tube

Gel sheets without alcohol

Geliperm, Interesting for eyelids (coma patients) or for inflamed nipples for cooling and protection

13. CONCLUSIONS ON AMORPHOUS GELS There are over 24 companies marketing amorphous gels. These companies are either well-established companies with products within each dressing category or small companies with limited types of wound dressings. Competitive factors include price, contract, and manufacturer reputation.


Amorphous Hydrogel Dressing Market: Market Share Trends of Major Market Participants (U.S.), 1998-1999

Company 1999 (%) 98/99 Trend Carrrington 30 Stable ConvaTec 20 Stable Smith & Nephew 18 Up Bard 12 Down Others 20 Up Total 100

Others include 3M, B.Braun/McGaw, Beiersdorf-Jobst, Brennen Medical, Coloplast, Derma Sciences, Dumex Medical, Gentrell, Geritrex, Healthpoint, Hollister, Hyperion, Johnson & Johnson, Kendall, Medi-Tech International, Medline, Molnlycke, MPM, Sage, Southwest Technologies, and Swiss-American.

Note: all figures are rounded; the base year is 1999 Source: Frost & Sullivan

The Debridement Market: If we look at the previous estimated 2002 market size in revenues for Gel Sheets, Amorphous Gels and Enzymatic debriders, in the US market represents:

q $ 89.9 Million for Enzymatics (source: Kalorama) q $ 32.2 Million for Hydrogel Sheets (source: Frost & Sullivan) q $ 17.7 Million for Amorphous Gels (source: Frost & Sullivan)

Convatec, 20%

Bard, 12%

Smith & Nephew, 18%

Carrington, 30%

Others, 20%

Amorphous Hydrogel Dressing Market


Depending on their positioning hydrogels may be seen as a debriding agent. Therefore it is applicable to look at debriding agents as well as MWH dressings.

Data from Kalorama on the debridement market in general and enzymatic debriders in particular seems not as specific as would be required. IMS data on Enzymatic Debriding Agents (EDA s) seems more accurate. It offers global sales of the top four EDA s:

Active Enzyme Brand Company Global Market Share

Sales U.S. $ Millions

CAGR 1995-1999

Clostrideopeptidase A (Collagenase)

Santy/Iruxol Smith & Nephew

54% 58 1%

Deoxyribonuclease/ fibrinolysin

Elase/Fibrolan Warner Lambert

27% 30 -16%

Papain Urea Accuzyme Healthpoint 14% 15 72% Streptodornase Varidas Wyeth

Lederle 5% 6 -4%

EDA Total 109 -4%

Source: IMS Health 1999

This market, started to experience noticeable growth in 2000 with the transfer of Santyl from Knoll to Smith and Nephew, who has now withdrawn with this product from the US market, due to regulatory issues. In addition, Healthpoint s product continues to grow steadily. Both Santyl and Elase are available globally, Accuzyme is only in the U.S. and the U.K. and Varidase is only in Europe.

In terms of potential wounds that require debridement it is estimated that:

Proportion of cases requiring debridement1

Pressure Ulcers 20% Venous Leg Ulcers 27% Diabetic Ulcers 53%


14. REFERENCES

1) Andriessen, A, Huid en wondverzorging in: Leerboek intensive-care-verpleegkunde. Van den Brink GTWJ, Lindsen F, Uffink Th (eds).Lemma BV Utrecht: 2003; 4th edition, Part 2, 25-105

2) Kammerlander G, Lokaltherapeutische Standards fr chronische Hautwunden. Wien; New York: Springer, 1998 198 202 3) Ovington L, Pierce B. Wound dressings; Form, function, feasibility and facts. In: Krasner

DL, Rodeheaver GT, Sibbald RG (eds). Chronic Wound Care: A clinical source book for healthcare professionals. Third edition, Wayne, PA; HMP Communications, 2001:311-9

4) Royal Pharmaceutical Society (1994) British Pharmacopeia. Appendix: Wound dressings. Royal Pharmaceutical Society, London

5) Sprung P, Hou Z, Ladin D. Hydrogels and hydrocolloids; an objective comparison, Ostomy/Wound Management 1998;44(1).

6) Prieur H, Nissen HP, Examination to determine skin irritation in human subjects using a modified Duhring Chamber test, 2001, report data on file at L&R.

7) Mulder G. Cost effective management care. Gel vs wet to dry debridement. Ostomy Wound Manage 1995; 41: 896900.

8) Thomas S, Hay NP. Assessing the hydroafnity of hydrogel dressings. J Wound Care 1995; 3: 8991.

9) Flanagan M. The efficacy of a hydrogel in the treatment of wounds with non viable tissue. J Wound Care 1995; 4: 264267.

10) Winter GD. Formation of the scab and the rate of epithelialization of superficial wounds in the skin of the young domestic pig. Nature 1962; 193: 293294.

11) Choucair M, Phillips T. A review of wound healing and dressings. Skin Ageing 1998; 6 (Suppl.): 3743.

12) Berry DP, Bale S, Harding KG. Dressings for cavity wounds. J Wound Care 1996; 5: 1013.

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