Alginate dressing are highly absorptive, non-occlusive dressings made of soft, non-woven calcium alginate fibers derived from brown seaweed or kelp. Alginate dressing are available as a primary dressing in pad or rope form. These dressings gel on contact with wound exudate, allowing for a moist wound environment and promoting autolytic debridement.
Features of alginate dressing:
• Atraumatic removal
• Can be cut to fit
• Can be layered for more absorption
• Can absorb up to 20 times their weight in exudate
Alginate dressing can absorb up to 12 times its weight of fluid. It can be used in moderately to heavily exuding wound.
Venous/arterial leg ulcer.
Diabetic ulcer, pressure ulcer.
Donor sites, abrasions, lacerations and post-surgical wound.
Alginate rope :dehisced wounds, tunneling wounds, sinus tracts
Alginates that contain silver can be used to manage infected wounds.
Alginate dressings are contraindicated for use on dry eschar, third-degree burns, for surgical implantation, or wounds with heavy bleeding.
Highly absorbent, biodegradable alginate dressings are derived from seaweed. They have been successfully applied to cleanse a wide variety of secreting lesions. The high absorption is achieved via strong hydrophilic gel formation This limits wound secretions and minimizes bacterial contamination. Alginate fibres trapped in a wound are readily biodegraded .
Alginate dressings maintain a physiologically moist microenvironment that promotes healing and the formation of granulation tissue. Alginates can be rinsed away with saline irrigation, so removal of the dressing does not interfere with healing granulation tissue. This makes dressing changes virtually painless. Alginate dressings are very useful for moderate to heavily exudating wounds .
There have been few studies of the effect of alginate dressings on the processes of wound healing.
The healing of cutaneous ulcers requires the development of a vascularized granular tissue bed, filling of large tissue defects by dermal regeneration, and the restoration of a continuous epidermal keratinocyte layer. These processes were modeled in vitro in one study, utilizing human dermal fibroblast, microvascular endothelial cell (HMEC), and keratinocyte cultures to examine the effect of calcium alginate on the proliferation and motility of these cultures, and the formation of capillarylike structures by HMEC.
In the study, the calcium alginate increased the proliferation of fibroblasts but decreased the proliferation of HMEC and keratinocytes. In contrast, the calcium alginate decreased fibroblast motility but had no effect on keratinocyte motility. There was no significant effect of calcium alginate on the formation of capillarylike structures by HMEC. The effects of calcium alginate on cell proliferation and migration may have been mediated by released calcium ions.
These results suggest that the calcium alginate tested may improve some cellular aspects of normal wound healing, but not others.
Reference 1: Doyle JW, Roth TP, Smith RM., et al; Effects of calcium alginate on cellular wound healing processes modeled in vitro. J Biomed Mater Res 1996 Dec;32(4):561-568
The value of alginates in this area has been challenged; a prospective, randomised clinical trial to compare the effectiveness of calcium alginate swabs versus traditional cotton swabs in the control of blood loss after extraction of deciduous teeth included 101 healthy children, aged 3-5 years. Teeth were extracted under general anaesthesia and blood collected for measurement in order to compare blood loss using the two systems. The number of teeth extracted ranged from 1-14; total blood loss ranged from 0.53-78.13 ml with a median of 12.9 ml. Calcium alginate swabs, used in 51 subjects, were not found to produce any clinical or statistical advantage over traditional cotton swabs .
Reference 1: Henderson NJ, Crawford PJ, Reeves BC., A randomised trial of calcium alginate swabs to control blood loss in 3-5-year-old children. Br Dent J 1998 Feb 28;184(4):187-190
A prospective double blind controlled trial examined the differences in post-operative split skin graft donor site pain between sites dressed with three differently treated types of dressing; a dry calcium alginate dressing, a saline moistened calcium alginate dressing and a bupivacaine hydrochloride (0.5%) moistened calcium alginate dressing.
There was a significant reduction in post-operative pain in the calcium alginate and bupivacaine group (group 3) at 24 and 48h when compared to the other two groups (p < 0.04). There was no difference in ease of removal of dressings or the quality of wound healing on day 10 between the three groups.
This study suggested a significant reduction in post-operative pain in bupivacaine soaked calcium alginate, without reducing the beneficial effects of the calcium alginate on donor site healing .
Reference 1: Butler PE, Eadie PA, Lawlor D, et al. Bupivacaine and Kaltostat reduces post-operative donor site pain; Br J Plast Surg 1993 Sep;46(6):523-524
A controlled trial set out to compare calcium alginate with the more traditional saline-soaked gauze for packing abscess cavities, following incision and drainage. Patients were randomized to receive either calcium alginate (16 patients) or gauze dressing (18 patients). At the first dressing change the patient marked on a linear analogue scale the pain experienced; the nurse noted similarly the ease of removal of the dressing.
Calcium alginate was significantly less painful to remove after operation (P less than 0.01), and also easier to remove (P less than 0.01) than gauze dressings. If abscess cavities are packed after incision and drainage, calcium alginate appears to be an improvement on conventional dressings .
Reference 1: Dawson C, Armstrong MW, Fulford SC, et al., Use of calcium alginate to pack abscess cavities: a controlled clinical trial; R Coll Surg Edinb 1992 Jun;37(3):177-179
Alginate dressings have been employed in footcare for many years, for sinus drainage and in the treatment of fissures, hypergranulation tissue, interdigital maceration, heloma molle and other lesions. Alginates have been used effectively in the treatment of diabetic and trophic foot ulcers.
Reference 1: Fraser R, Gilchrist T., Sorbsan calcium alginate fibre dressings in footcare; Biomaterials 1983 Jul;4(3):222-224