|
|
|
|
|
|
|
|
|
 Introduction Wound healing research did not really begin until the second half of this century. This is perhaps strange given that the skin is the largest and certainly most obvious organ of our bodies. However the belief of Paracelsus1, writing in the early 1500s that "? every Surgeon should know that it is not he but Nature, who heals" has long prevailed. We take healing for granted - until it goes awry or, in the case of the cracked nipples of a new mother, it interferes with the important physiological and emotional process of breastfeeding. Florence Nightingale championed the use of clean cotton - the first gauze - but also bemoaned the dry wound surface that it created, with its problems of adhesion and subsequent secondary trauma. Enter George D. Winter, a pioneer in the area of wound care research who, in 1963, demonstrated that an occlusive polymeric material similar to Saran Wrap® enhanced the healing of partial thickness wounds in pigs2. He chose pig skin because of its similarly to human skin and the experimental wounds involved the removal of all of the epidermis and some of the underlying dermis. This first observation of the beneficial effects of keeping the wound bed moist by preventing evaporation of the exudate sparked an enormous interest. This was both academic with hundreds of new studies being published every year and commercial with the development of a new generation of "moist" wound management products. Opsite®was the first to use this technology. This polyurethane film dressing differed from that first material of Winters in one important aspect. The original film was totally impermeable (or occlusive) to water vapour which caused the tissue surrounding the wound to become macerated. Opsite is a semi-permeable film which allows excess moisture to escape whilst maintaining optimal humidity at the wound bed.
| ||
| ||
|
Moist wound healing The specific mechanisms by which occlusion or maintaining a moist and oxygenated wound environment increases the rate of healing are outlined in Table 1. This general stimulation of cell migration is augmented by a reduction in local wound pain3 and the fact that many of the occlusive dressings are excellent bacterial barriers.4 Dressings that wick away exudate from the wound bed yet maintain the desired level of humidity are the hydrocolloid wafers, polyurethane films and foams, sheet and amorphous hydrogels and alginate fibres. Interestingly, many of these are composed of polysaccharides-a modern day reminder of the Ancient Egyptian use of honey to treat wounds and prevent infection! Figure I is a diagrammatic representation of epidermal cell migration in a dry versus a moist wound environment.
This depicts a partial thickness wound as these are typically those that occur when nipples crack and expose the dermis without much tissue loss. After the initial inflammatory response and provision of a leucocyte-rich exudate, epidermal cells throughout the wound begin to proliferate and migrate across the wound bed. They can only do this over a moist surface and must therefore tunnel down under the dry crust of a wet-to-dry gauze dressed or exposed wound. Macrophages are much more numerous in the moist wound. Any defect in the dermis must be filled with new connective tissue. This granulation phase of healing requires new capillaries which provide the oxygen and nutrients for the synthesis of collagen, fibronectin, elastin, etc. by fibroblasts. Contraction, mediated by myofibroblasts and re-epithelialisation complete the repair process5. Providing the optimal healing environment to sore and cracked nipples Sore and cracked nipples offer a particular challenge,(see Table 2) . How can we prevent nipple and areola soreness and treat any lesions without using materials that would discourage or potentially harm the baby and cause little repeatable trauma to the skin? I have described how there are many types of wound dressings available that maintain humidity and oxygen at the wound bed. Most of these are only available as flat dressings which are difficult, though not impossible, to cut and fit to the nipple area. A second major disadvantage is that most incorporate an adhesive. Repeated removal and reapplication is likely to irritate the nipple and could leave a residue effecting the infant's willingness to suckle. There is some evidence that palliative measures such as warm compresses, tea bags, breast milk and even cabbage leaves can relieve nipple pain6 but these are of little help when the epidermis has been breached. Some of the newer hydrogels are available in an amorphous form from tubes or sachets. These are easier to apply but are likely to spread around the breast, plug bra pads and are not good tasting! In addition, careful reading of the ingredients is advised as potentially sensitising chemicals can be included as anti-oxidants and preservatives7. Is there any other type of material that fulfills the requirements of Table 2? Careful reading of the literature shows that there is growing support for the use of a purified form of the natural wax lanolin. Lanolin in the prevention and treatment of sore and cracked nipples Lanolin is a waxy secretion of the ovine sebaceous gland. It has long been a constituent of hand and nail creams, ever since the centuries’old observation that wool spinners had beautiful soft skin on their hands.
| ||
| ||
|
Occlusion, whether in the form of a film dressing or an oil-based barrier cream, hydrates or moisturises the skin by preventing the insensible loss of water vapour. This must be monitored however, otherwise waterlogging or maceration could occur. It is for this reason that all the "moist" wound dressings allow some water vapour to escape. Lanolin shares this ability to permit a two-way exchange of water and gases with with the best of the polymer-based wound dressings. When lanolin is mixed with water in vitro it naturally hydrates to form an emulsion with a minimum droplet size of 50nm8. More recent research by the Westbrook Lanolin Company in the UK9 has shown that when lanolin is absorbed into the upper layers of the epidermis it spontaneously absorbs local water, forming a reservoir with similar droplet sizes. This is one of the mechanisms by which lanolin smoothes and hydrates the skin. Allowing evaporation from the emusion on the surface of the skin prevents maceration. Lanolin must also meet the other criteria for "moist" wound covers, especially those pertaining to lack of toxicity. In the summer of 1988 a Texas nurse first drew attention to the use of lanolin on the cracked nipples of nursing mothers. Sheep are frequently dipped in pesticide solutions and the world was becoming increasingly aware of the persistence of these toxic chemicals in the environment. Thus the FDA called for new limits to pesticide residues in lanolin especially when incorporated into products where "ingestion or absorption" is likely. These would include nipple creams, lipsticks and lip balms. A USP Monograph for Modified Lanolin came into force on May 15 199210 which stipulated a total pesticide limit of 3ppm (down from the 40ppm limit allowed for unmodified lanolin). At the same time the much debated issue of lanolin’s allergenicity was addressed. Many publications had indicated that the allergenic fraction was free alcohols and that when these are reduced to less then 3%w/w even patients with eczema fail to exhibit an allergic response11. The Modified Lanolin Monograph sets the free alcohol limit to 6%w/w but some manufacturers provide material with <3%. Clinical experience with lanolin Lanolin has been widely used to treat nipple pain and lesions during breastfeeding for many years. This was confirmed by a mere hour surfing the Web. I stopped counting after 100 anecdotal accounts of its effectiveness! Turning to the published literature6,12, only a few studies have attempted to statistically compare lanolin to other treatments. This is not surprising, nor should the lack of fully randomized clinical trial data discourage new mothers from using it. I have been associated with the wound care industry for 12 years and we have still not decided upon the most predictive measures of wound healing nor developed a protocol that can accommodate all patients. Summary This article has described the importance of maintaining moistness in an acute cracked nipple. I encourage all mothers, nurses and lactation consultants to acquaint themselves with this method of treatment, which has been the subject of 30 years of clinical research. Simple, low cost, easy to apply products such as purified lanolin can lessen soreness by preventing the areola and nipple from drying out. They also provide the essential moist environment that will allow the cracked skin to heal efficiently coupled with a proven safety record. Dr. Allison Wren, BSc, MSc, PhD, MBIRA, studied central nervous system Pharmacology at Manchester University (UK) and researched the neurobiology of the disease depression for her PhD thesis. In 1985 she began a UK based company that manufactured and sold a range of wound management products. In 1989 the company was acquired by Merck and Co and merged with Calgon Vestal Labs subsidiary, based in St. Louis. Dr. Wren moved to St. Louis as VP R & D for Calgon. She has lectured widely on the subject of wound management and is known for her commitment to the education of all in this field. When Merck sold Calgon Vestal, Dr. Wren moved to the Kelco unit of Monsanto, where she was responsible for the development of new Biomedical business. She now writes and consults to the general Medical Device industry from her home in La Jolla.
| ||
| ||
| ||
| ||
|
Bibliography Paracelsus (1493-1541). "Warily must the Surgeon take heed not to remove or interfere with Nature’s balsam which healeth wounds. Nature has her own Doctor in every limb; wherefore every Surgeon should know that it is not he, but Nature, who heals" Winter, G.D. (1962) Formation of scab and the rate of epithelialisation of superficial wounds in the skin of the domestic pig. Nature, 200,377-378. Eaglestein, W.H. (1985) Experiences with biosynthetic dressings. J. Amer. Acad. Derm., 12, 434-440. Mertz, P.M. et al (1985) Occlusive wound dressings to prevent bacterial invasion and wound infection. J. Amer. Acad. Derm.,12, 662-668. Doughty, D.B. (1992) Principles of wound healing and wound management. In Acute and Chronic Wounds:Nursing Management, ed. R.A.Bryant. Mosby-Year Book Inc., 31-68. Pugh L. et al (1996) A comparison of topical agents to relieve nipple pain and enhance breastfeeding. Birth, 23, 88-93. Ziemer, M.M. et al (1995) Evaluation of a dressing to reduce nipple pain and improve nipple skin condition in breastfeeding women. Nursing Research, 44, 347-351. Clark, E.W. (1990) New concepts of lanolin. Presentation at In-Cosmetics Seminar, Birmingham, UK, March. Clark, E.W. and Steel, I. (1993) Investigations into biomechanisms of the moisturising function of lanolin. J. Soc. Cosmet. Chem. 44, 181-195. United States Pharmacopia XXXIII-NF XVIII, pages 871-872. Edman, B. and Moeller, H. (1989) Testing a purified lanolin preparation by a randomised procedure. Contact Dermatitis, 20, 287-290. Spangler, A and Hildebrandt, H. (1993) The effect of Modified Lanolin on nipple pain/damage during the first 10 days of breastfeeding. Intl. J. Childbirth Education, 8, 15-18. Posted With the Permission of Medela, Inc.
|
|
