Wound Management for the General Practitioner

It starts with a statement that every veterinarian has heard some derivative of – “Dr. Hilton, we have a dog coming in this afternoon that had a mass removed from his carpus last week, and the owner says the dog got the stitches out so they put a bandage on it and now they are worried because it is open and might be infected.”

Without even making eye contact with the surgery technician who is standing there for the conversation, she knows the questions that are running through your mind:

• Did the owner take the E-collar off and the dog simply licked the stitches out?
• Was the closure too tight and the dog was not properly exercise restricted and the incision dehisced because of its location?
• Is the biopsy still pending and it was an incompletely excised tumor, hopefully not mast cell, that is having problems healing?
• How infected is this incision going to be from the bandage, and what am I going to do about it?

The afternoon rolls around, and the dog is brought to the treatment area with a white athletic sock on its foot and covered in athletic tape to prevent it from falling. You know the dog is there because you can smell it without even turning around. As the tape and athletic sock are removed, you see a wide-open incision with unraveled suture material along the skin margins, what appears to be past-date hamburger meat in the middle, with fetid purulent discharge just oozing out the center.

Now, this is where one of two paths can be taken. You can casually call the local emergency clinic and inform them that a transfer is on the way, or you can use the basic principles of wound management we discuss to set your patient and owner up for success while you set yourself apart as a veterinarian. I hope after reading this, you’ll feel comfortable choosing option 2.

Knowing that to solve any major problem, you must break the problem into small manageable pieces, let us look at the small manageable pieces of wound management:

1. Where is this wound coming from?
2. What should I do to this wound to help it heal?
3. What medications and treatments should I be using?
4. How often should I look at this wound and does the owner understand the plan?

Where is this wound coming from?

Wound management is a delicate balance between the world of surgery and dermatology. With every surgical procedure a veterinarian performs, there is an iatrogenic wound that is usually readily managed with primary closure after the procedure is completed, and the list of differentials for wounds associated with underlying dermatologic conditions can be pretty extensive. For this brief discussion, we will narrow our focus to managing wounds that are not primary closure candidates, in difficult locations, or are obviously infected, such as the picture below.

What Should I Do To This Wound To Help It Heal?

It may seem like the obvious answer, but before we can start treating a wound, we need to actually see it. And by see, I do not mean the dried scabs and purulent discharge over the surface of the wound or the rock-hard matted fur along the periphery. It is time to put on a pair of gloves and shave the entire area that is affected, with an additional 2-3cm of normal, healthy skin along the periphery. After the fur has been shaved, any dried scabs and crusts on the central portion of the lesion should also be removed. They may require soaking with sterile saline or chlorhexidine to aid in their removal.

Unless the wound is small and you are dealing with a highly tolerant patient, these are generally ulcerated and painful patients. Sedation is an extremely useful tool to make this procedure easier on your staff and the patient. Suppose the patient is an otherwise young, healthy animal. In that case, I have found a combination of dexmedetomidine 5mcg/kg mixed with butorphanol 0.2mg/kg administered intravenously gives rapid sedation to allow adequate shaving and cleaning to be performed and equal volume of atipamezole administered intramuscularly for reversal once complete.

Suddenly, the patient in the picture above, now appears as below and leads to the next question…

What Medications And Treatments Should I Be Using?

As veterinarians, when we see the above case, we feel very comfortable in our treatment plan because the wound is entirely superficial.  Ensure an E-Collar is placed to prevent the patient from licking at the area. We start the patient on our favorite topical and oral antibiotic therapy, with oral cephalexin 22mg/kg twice daily or cefpodoxime 5-10mg/kg once daily as my first choice in combination with topical medicated therapy such as Douxo S3 Pyo wipes for small areas or Douxo S3 Pyo Mousse for larger areas, both of which contain chlorhexidine 3%.  With the systemic side effects of glucocorticoid therapy, I recommend using oclacitinib (Apoquel) to help reduce inflammation and generalized pruritis.  As a rule of thumb, I always recommend antibiotic therapy for 1 week past clinical resolution, meaning if the superficial wound heals in 2 weeks, there should be 3 weeks of therapy employed.  Also, just by looking at the wound it is easy to appreciate how uncomfortable the patient must be, so we must not forget to give appropriate pain control.  With superficial wounds, a nonsteroidal anti-inflammatory, is my first option after ensuring that renal and hepatic function is adequate on laboratory analysis.  I generally start with carprofen 2.2mg/kg twice daily for a minimum of 7 days.  For those patients with impaired metabolic function or are currently receiving medications that are contraindicated with NSAID usage, I will use gabapentin 10mg/kg every 8-12 hours also for a minimum of 7 days.

However, wound management causes our stress and anxiety to rise when we see patients such as the two cases below.

Knowing that extensive surgical dehiscence wounds, degloving wounds, and contaminated wounds cannot have a primary closure because of contamination or sheer lack of tissue mobility, rather than immediately calling the local emergency/referral hospital to refer, we can use simple techniques in our own hospitals to manage these daunting cases.

Before initiating any oral therapy in these patients, obtaining an aerobic culture from the wound bed is vital to ensure that we are truly treating the underlying bacterial infection with the appropriate antibiotic therapy. Commonly, I will send home only five days of presumptive antibiotics, once again usually cephalosporins, and have a frank discussion with the owner that we will either be extending that therapy or changing once culture and susceptibility results have been returned. Unlike superficial wounds, these are much more extensive, and pain management should concurrently be more encompassing. At the time of presentation and initial treatment, I prefer to administer hydromorphone 0.1mg/kg or methadone 0.2mg/kg intramuscularly or subcutaneously if intravenous injection is not possible, otherwise hydromorphone 0.05mg/kg or methadone 0.1mg/kg if given intravenously. It is common during the initial treatment phase to use fentanyl patches for prolonged opioid analgesia while employing both non-steroidal anti-inflammatory therapy and gabapentin therapy if otherwise medically appropriate.

Debridement of necrotic tissue is key in these cases to stimulate healthy granulation tissue formation and wound contracture, but realize that the full extent of diseased tissue may not declare itself until 3-5 days after the initial insult, resulting in more than a single episode of debridement being required. Although surgical debridement is always an option, wet-to-dry bandage placement or nonadherent hydrophilic pad placement (calcium alginate, polyurethane foam, hydrocolloid, hydrogel) followed by bandaging is our best friend. As seen in the cases above, simple bandaging is not always possible. Suture loops placed circumferentially along the wound margin in healthy tissue allow tie-over bandage placement to perform atraumatic and reduced stress bandage changes for the patient while providing tension to bring the wound edges closer together gradually. However, depending on the patient’s comfort level and extent of injury, sedation may still be required for the first several bandage changes.

Before placing the banding material, consider other treatments to accelerate the healing process if available to you, such as therapeutic laser therapy or topical collagen application. Therapeutic laser has been shown to reduce pain by enhancing oxygen delivery and improving nerve cell regeneration, reducing inflammation through accelerating leukocyte activity, and promoting healing through increased macrophage activity. Topical collagen application, such as Collastate (PRN Pharmacal), can help promote granulation tissue formation and serve as an additional bacterial barrier.

Now that you have a plan for bandaging the wound…

How Often Should I Look At This Wound And Does The Owner Understand The Plan?

Wound management is an exercise in patience, and this must be thoroughly communicated to the owner for the best possible outcome. Sure, minor superficial wounds can commonly be rechecked in 2 weeks to ensure that everything is healing appropriately, but for larger wounds requiring second-intention healing with wet-to-dry bandages, tie-over bandage placement, and therapeutic laser therapy, it is vital to monitor the healing process much more frequently. After the initial wound debridement and bandage placement, the owner should be prepared to have bandage changes ideally every 24 hours but not to exceed every 48 hours. The purpose of changing the bandages with this frequency is to remove all necrotic tissue and exudate that becomes attached to the contact layer of bandage material, thereby increasing blood supply to healthy tissue, preparing the area for healthy granulation tissue formation, and minimizing the risk for opportunistic infection.

It is only once the bandage is removed and no evidence of necrotic tissue exudate is present that the duration between bandage changing can be extended to every 3-4 days, and once the entire wound has evidence of healthy granulation tissue, the decision to leave the bandage off for topical therapy alone, such as Collasate as previously mentioned or Medihoney Gel for a protective barrier, can be made, as long as communication with the owner has established continued compliance with wearing an E-Collar. Examples of healthy granulation tissue from the previous two cases, as well as a third, are shown below:

Although large wounds can be daunting at initial presentation, breaking the treatment plan into smaller pieces as described and communicating the process to the owner along the way will not only allow you to expand the services that you can provide without the necessity of referral but will increase your rapport with clients and overall confidence as a veterinarian.

Sources

Moist Wound Healing in Dogs and Cats: Using MRDs to Improve Care.  Todays Veterinary Practice.  Issue July/August 2015

Use of therapeutic laser in the veterinary field.  The Veterinary Nurse.  Volume 12.  Issue 8