Originally published in the February 2015 issue of Veterinary Practice News Pictures courtesy of Dr. Karol Mathews Medical grade honey can be poured directly into an open wound. There is something satisfying about treating an open wound successfully. As with many veterinary endeavors, there are multiple ways to do so. Some are clearly better than others. Most hospitals have their “goo” of choice: silver sulfadiazine, antibiotic ointment, sugar Betadine (a.k.a. “sugardine”), steroid cream, zinc oxide, trypsin ointment. Some of these products have some research behind them, while many others are supported by mere belief—sometimes surprisingly strong—as sole scientific evidence. Meanwhile, sugar and honey have been widely used in human medicine for centuries. Both are safe, effective, readily available and cost-effective. Karol Mathews, DVM, a board-certified criticalist and professor emerita at the Ontario Veterinary College in Guelph, Ontario, Canada, has written extensively about their use in veterinary medicine.*“It is interesting how we seem to rediscover ancient remedies that actually work,” she says Pictures courtesy of Dr. Karol Mathews: Sugar is poured onto a lap sponge that will be wrapped around a wound on the distal limb. Back to the Future There are accounts of using honey for open wound management as early as 2000 B.C. Honey is a widely recognized treatment in human medicine, but has arguably not been used to its fullest potential in veterinary medicine. Honey has a high glucose content, which bacteria use instead of amino acids, resulting in lactic acid production, in place of malodorous compounds from amino acids. This action deodorizes the wound—typically overnight. Honey also decreases edema, accelerates sloughing of necrotic tissues, promotes granulation and provides a protective protein layer over the wound. But it doesn’t stop there. Honey also has antibacterial properties through four mechanisms: it lowers the wound’s water content (i.e. it increases its osmolarity); it is highly acidic (pH 3.6-4.5); it attracts macrophages; and it is a substrate for ongoing production of a very low concentration of hydrogen peroxide (H202), which kills bacteria. The concentration of H2O2 that accumulates in one hour is approximately 1,000 times less than in the 3 percent H2O2 that is commonly used in practices. It is therefore harmless for tissues. “Interestingly, despite centuries of use, there is no reported resistance to the antimicrobial effects of honey,” says Dr. Mathews. In vitro and in vivo studies** of Ontario honey performed at the Ontario Veterinary College have shown efficacy against common bacterial pathogens, multi-drug resistant E.coli and Enterococcus, and even methicillin-resistant staphylococcus aureus (MRSA). Because of its high osmolarity, honey draws lymph into the wound, providing necessary nutrients for tissue regeneration. Honey also provides amino acids, vitamins, enzymes and minerals, which increase the speed of granulation. Sugar has been used for medicinal purposes since 1679. Granulated sugar creates a very low water concentration environment in wounds, which increases osmolarity. It shares similarities with honey by drawing lymph into the wound, providing the nutrients needed for regeneration. Because sugar draws moisture from the wound’s bacterial environment, it inhibits bacterial growth. However, as sugar becomes diluted, less water is removed from the wound, potentially enhancing bacterial growth. This is the reason “sugar bandages” have to be changed twice daily initially, or more frequently if strike-through is noted. Like honey, sugar deodorizes the wound, decreases edema, attracts macrophages, speeds up debridement and forms a protective layer. Pictures courtesy of Dr. Karol Mathews Sugar is copiously applied to an open flank wound. Caring for the Wound Appropriate analgesia should be administered while assessing and cleaning the wound. Before application of sugar or honey, the wound should be copiously lavaged with body temperature tap water or sterile fluids. Then the wound should be blotted dry. Surgical debridement of avulsed and devitalized skin may be performed at this point. However, where viability is questionable, allow the debridement action of honey or sugar to remove and allow the viable tissue to thrive. In most cases the honey/sugar chemical debridement reduces the need for surgery. Approximately 30 ml of honey (see "Which Honey Should You Use?" below) should be used for every 10 by 10 cm area. You can use commercial honey dressings, pour honey directly into the wound, or soak gauze squares or laparotomy sponges in liquid honey prior to application. Interestingly, honey-soaked dressings will not decrease the absorptive properties of the gauze. The bandage should be changed one to three times daily, depending on the amount of exudate and strike-through, i.e. if drainage reaches the external layer of the bandage (see box, left). “The lack of honey at bandage change indicates the need for more frequent changes or more honey applied, whereas the presence of a good covering of honey indicates that the change interval can be lengthened,” explains Dr. Mathews. At bandage change, note when the necrotic tissue separates easily from the wound bed. This tissue may be removed with hemostats, with no pain experienced. You should notice deodorization and improved tissue health after only 24 hours, early granulation tissue after 48 hours and a granulation bed forming after 72 hours. Frequently, wounds become sterile within 48 hours. In a human study, wounds were sterile within one week of starting honey dressings, including wounds that had failed to respond to systemic antibiotics. When you use granulated sugar, a large quantity is required to reach all areas of the wound and fill all pockets. Sugar becomes diluted rather quickly, so the more, the better. Bandages may require replacement at least twice daily. That frequency can be decreased based on the response. As with traditional bandages, they should be changed if strike-through occurs. Depending on the severity of infection, wounds can become sterile in as little as two days. Healthier tissue can be noted within 48 hours and granulation tissue appears around day five. With both honey and sugar applications, the patient’s hydration status and protein level should be monitored regularly during periods of heavy exudation. The beauty of sugar and honey is that these cheap and simple compounds can help with multiple steps of wound management: antisepsis, debridement, granulation and epithelialization. So next time you are cooking up a treatment for an open wound, consider adding honey or sugar to your menu. Which honey should you use? Sadly you can’t just use any honey off the shelf at your local supermarket. Honey used in wound management should be raw, unpasteurized (mild heat is applied, which may alter activity) or not pasteurized (pasteurization denatures enzymes). Honey used in wounds should come from an apiary. The hives and the flowers should be located away from fields where herbicides and insecticides are used. Your patient’s wounds deserve medical grade honey. It might be a good idea to buy a jar of the good stuff before you need it. Alternatively, you can use commercial dressings. Strict Aseptic Technique Needed in Wound Therapy Open wounds should be taken seriously Open wounds are often treated casually, with no protection of the “operator” and no concern for contamination of the wound. Yet hospital bacteria are a major concern for nosocomial (a.k.a. hospital-acquired) multi-drug resistant infection. Multiple issues are at stake: protection of the doctor or technician treating the wound (skin and clothes); protection of the wound from further contamination; and protection of the environment (floor, cage, cage door, wet sink, shower head, scissors, etc.). Therefore, strict aseptic technique must be used during all steps of wound therapy: Before wound treatment, surface areas, scissors and shower head should be cleaned with an antiseptic. During wound treatment, staff members should wear caps, masks, gloves and gowns (not sterile, a clean one is all your need to protect yourself and your clothes). Only sterile instruments should be used. After wound treatment, “hard” surfaces and scissors should be cleaned with an antiseptic again. References * K Mathews and A Binnington. “Management of wounds using sugar.” Compendium Cont Edu for Pract Vet 2002, 24 (1), p. 41-50. * K Mathews and A Binnington. “Management of wounds using honey.” Compendium Cont Edu for Pract Vet 2002, 24 (1), p. 53-60. ** J Pask et al. “Antibacterial Efficacy of Honeys from Southwestern Ontario.” 2013 MSc Thesis presented to the Faculty of Graduate Studies, University of Guelph, Ontario, Canada. A.J. Debiasse, a technician in Stroudsburg, Pa., contributed to this column.
