Bite wound trauma: Critical information for treating birds (Proceedings)

Bite Wounds

One of the most common avian presentations at our veterinary hospital is the predator attack. These cases often present with severe lacerations, limb amputations and crushing injuries. Apart from stabilization and concern with blood loss, shock and pain rapid treatment with antibiotics are indicated. With our cases we give the owners a 72 hour window for treatment response and at least a week of hospitalization before we consider the patient in good condition. Antibiotic therapy consisting of treatment for both anaerobic and aerobic bacteria is crucial to increasing the chances of a successful case outcome. Listed below are products used to treat wounds sustained in predator attacks.

Products Needed for Wound Management

If one is to treat avian species, especially in potentially critical condition, it is important to have the proper equipment and products to improve the veterinarian's chances for treatment success. Equipment starts out with a digital gram scale (Veterinary Specialty Products, Boca Raton, FL) that can measure up to 6 kg. For smaller birds, a separate digital gram scale (Veterinary Specialty Products, Boca Raton, FL) measures up to 2 kg will be appropriate. The primary difference between the scales is that the 6kg scale will likely weigh in 5 gram increments while the 2kg scale will have measurements in one gram increments. For larger birds, dog and cat scales are used, while ratites need scales manufactured for large animals. It is not only important to weigh the patient upon presentation to determine the proper therapeutic dosages, but to weigh the bird on a daily basis for patient response to treatment. A temperature controlled critical care unit (Lyon Electric, Co, Inc., Chula Vista, CA) is also important . This unit should be fitted for access to supplemental oxygen when needed for patients with respiratory distress. It is desirable to have a unit with humidity control, as dry heat alone may result in dehydration of smaller patients, especially those with extensive wounds that contribute to fluid loss. Many of the newer intensive care units have digital controls that are easy to adjustment for precise environmental parameters.. Isoflurane anesthesia is a must for any avian practice. Sevoflurane (SevoFlo™, Abbott Labs, North Chicago, IL) is an anesthetic agent that has gained popularity in the last few years but the clinical benefit is negligible and the cost significantly more compared to isoflurane.1

A pair of binocular loops (Surgitel®, General Scientific Corp., Ann Arbor, MI) and microsurgical instruments should be part of the avian practice. Binocular loops and microsurgical instruments will be beneficial for any number of animal species undergoing surgical procedures at a veterinary hospital, including all avian patients. The benefits of using binocular loops are numerous and only through their use will one truly appreciate the elevation of their surgical skills, especially with smaller patients. Radiosurgical capabilities will allow the avian practitioner to use this state of the art technology from incision to closure. Pathology is similar to the cold steel of a scalpel, and the dual frequency technology and digital programming of the radiosurgery (Ellman International Inc., Hewlett, NY) unit allows for cutting and coagulation, hemostasis and bi-polar forcep application. There are many applications for the radiosurgery unit in wound management, at a fraction of the cost of LASERs, without compromising surgical quality. Adequate cage space is important for larger birds (e.g., cranes, egrets, ratites and raptors), while hydrotherapy tubs are required for waterfowl.

Therapeutic Agents for Bandaging

Therapeutic agents for the critical patient are often available in most hospitals and include catheters (1½" 22 gauge spinal needle for intraosseous catheters), crystalloid and colloidal fluids , iron dextran (Watson Labs. Inc., Corona, CA), oxygen-carrying hemoglobin solution (Oxyglobin®, Biopure®, Cambridge, MA) and a nutritional critical care formula (Lafeber Co., Cornell, IL). Analgesic compounds have been a beneficial addition to most veterinary hospitals and for the avian patient this has been no exception. Carprofen (Rimadyl®, Pfizer Inc., New York, NY) and butorphenol tartrate (Torbugesic®, Fort Dodge Animal Health, Fort Dodge, IA) are two of the most commonly used analgesic compounds for avian patients. (Do you want to mention Meloxicam here since it is now available in the U.S. and has been used successfully for years in Europe?) The antibiotic, antifungal and antiparasitic agents used to treat both systemic and topical wounds are similar to those found in most veterinary hospitals. Avian patients often tolerate oral fluid medications better than pill or tablet forms. If a veterinary hospital does not have common antibiotic agents formulated in an oral suspension form, then a compounding pharmacy should be contacted. Metronidazole hydrochloride (Watson Laboratories, Inc., Corona, CA) can be difficult to administer orally because of its poor taste. Metronidazole benzoate is considered more palatable than the more common form manufactured in the United States.

Topical therapeutic products, including antibiotic ointment may be applied depending on the nature of the injury and advantages of using the product for that particular case. When prescribing a topical ointment for avian use caution must always be taken into account. Owners need to be educated on the application process, using only a small amount to treat the lesion to reduce the possibility of feather matting. Topical ointments containing corticosteroids are not recommended for avian species due the high potential for severe side effects. Preparation-H® (Wyeth Laboratories, Marietta PA) has been advocated for dermal wounds to decrease the healing time. An active ingredient in the Preparation-H® ointment is live yeast cell derivative that increases the respiratory component of the epithelium surrounding the wound thereby increasing the healing capacity of the tissue. There has been a recent advance in wound management with the advent of Tricide® (Molecular Therapeutics, LLC, Athens, GA). This product is an antimicrobial potentiator used to flush the wound bed and control infection. Some topical antibiotic preparations that have been used with success by the authors are triple antibiotic ointments (e.g., Neosporin®, Pfizer Inc, New York, NY) and silver sulfadiazine cream (SSD) (Smith & Nephew Heath Care, London).

Bandage Materials

Appropriate bandage material is extremely important in wound management. Nonstick surface bandaging material (Adaptic®, Ethicon Inc., Arlington, TX) will protect the tissue bed and prevent leakage of serum into the contact layer and thereby prevent adhesion of the bandage to the wound. Semiocclusive dressings (Tegaderm®) also aid in the healing of skin lesions but may be difficult to apply because of poor adhesive qualities. Tissue glue (Nexaband®, Veterinary Products Laboratories, Phoenix, AZ) or cyanoacrylic bandages have been used to repair minor skin lacerations or incision sites. Although tissue glue is convenient to use for the appropriate injury, it can be expensive and the shelf life has been disappointingly short. Cyanoacrylic bandages have been advocated to cover larger tissue defects in the past, but there is a newer product that is more tissue friendly allowing for reepithelization and tissue respiration. VET BIOSIST™ (VBS) (Cook Veterinary Products, Spencer, IN) is an extracellular matrix derived from the submucosal layer of the porcine small intestine. The protein matrix bandage, which consists of mainly of Type I collagen with some Type III and V present, is freeze dried to preserve the structural integrity of the product. VET BIOSIST™ can be used on large skin wounds that cannot be closed by primary intension. The affected area should be prepared for bandaging using standard techniques prior to the application of VBS. Aseptic handling techniques should be employed when preparing the protein matrix bandage for tissue application. The VBS sheet should be cut to overlap the affected area by approximately 3 mm. This allows for tissue overlap when the bandage is placed over the wound for suture placement. The VBS bandage should be rehydrated in a sterile dish containing 50 ml of sterile saline or water. This process takes approximately 3 minutes. Once applied to the wound, the VBS should be sutured in place using 4.0 or smaller diameter monofilament resorbable suture material. It is very important to remember that VBS needs to have an aqueous dermal gel applied, so the matrix sheet remains moist during the healing process. If the bandage is maintained properly and not rejected by the patient then the protein matrix should serve as an epithelial framework in which the bandage material is incorporated into the host tissue. Nonadhesive bandage material should cover the VBS prior to applying an appropriate outer dressing. The outer dressing should be changed daily when reapplying the aqueous dermal gel to maintain the VBS hydration status. CARRASORB™ (Veterinary Products Laboratories, Phoenix, AZ) is another product that protects dermal lesions and speeds the healing process. CARRASORB™ is a freeze dried gel that is manufactured for application on medium exudating wounds. It contains the ingredient acemannen, which is a complex carbohydrate product derived from the aloe vera plant, and can be applied topically to a dermal lesion that has been prepared similar to the manner described for VBS. If the lesion is dry, then the freeze dried gel product may be moistened with a wound cleanser to provide a moist wound environment.

Items needed to complete bandages include cast padding, gauze sponges, VetWrap® (3M Company Animal Care Products, St. Paul, MN), Elasticon® (Johnson & Johnson Medical Inc., Arlington, TX) (and white cloth tape (waterproof and nonwaterproof. Fiberglas cast material, temperature sensitive cast material (Vet-lite™, Runlite S.A., Micheroux, Belgium) and UV light sensitive dental acrylic (Triad™, Henry Schein, Port Arthur, NY) are used to make splints and wound bandages for the nonpsitticine avian species. Ethylcyanoacrylates (ECA) (Cyanovanear™, Ellman International Inc., Hewlett, NY) using a catalyst is available for beak repair and UV light sensitive dental acrylic may be used for the same purpose. Pins, wire and aluminum rods are used for beak structure foundations prior to the application of prosthesis and for foot braces respectively.

*The material contained in this proceedings article was previously published: Riggs SM, Tully TN: Wound management in nonpsittacine birds. Vet Clin N Am (Exotic Anim Pract) 7:19-34, 2004.

References

1. Greenacre CB: Comparison of sevoflurane to isoflurane in psittaciformes. Proc Assoc Avian Vet, Reno, NV, 1997, pp 123-124