Abstract

All veterinarians will at some point encounter the wildlife casualty patient. It is important to obtain as much history as possible, identify the species, safely restrain the animal and clinically assess the patient so that an appropriate disposition can be determined. Should it be decided that treatment is warranted then life-threatening conditions will need to be addressed first. The principles of first aid also apply to wildlife including establishment of a patent airway, as well as ensuring adequate ventilation, cardiac function, and peripheral circulation. Control of any hemorrhage and treatment for shock are also important considerations. Once the animal has been stabilized a more thorough physical examination can be performed. Further therapeutic considerations include fluid therapy, thermal regulation, nutritional support, antibiotic and anti-inflammatory therapy as well as pain relief.

Trauma is the most common cause of morbidity of wildlife presented to wildlife centers, wildlife rehabilitators and clinical veterinarians. Consequently, the veterinarian is often presented with soft tissue wounds and orthopedic injuries that require management. The principles of wound management and bandaging, with some modification, can also be applied. Unique avian bandaging techniques include the figure-of-eight bandage, interdigitating and ball bandages for digit and foot injuries, and the tape splint bandage for leg fractures of small birds.

Triage

There are many factors to consider when accepting and treating wildlife patients including the financial resources that are available. Standard triage protocols should be followed. An assessment of the likelihood of the animal returning to full function is essential to conserve resources and prevent unnecessary suffering of the patient. In many cases euthanasia is the preferred option including cases with severe injuries and poor prognosis for recovery, if treatment would be unnecessarily prolonged or painful, if intervention would interfere with natural selection, if the animal is a non-native or nuisance species, and if rehabilitation and release could result in the introduction of infectious diseases. Animals intended for release should be able to function within the natural habitat, including reproduce, and in many cases the injuries may not be life-threatening but would prevent return to normal function. Euthanasia should also be considered for these cases. It should be remembered that nothing done in the interests of an individual animal should unnaturally jeopardize healthy wild populations. Consultation with local wildlife rehabilitators as well as state and federal wildlife personnel can be helpful in determining an appropriate disposition for the animal. Knowledge of state and federal regulations governing wildlife rehabilitation in the area of operation is also important.

First Aid

Initial Assessment

It is important to obtain as much history as possible although the opportunity to obtain a thorough history is often limited. However, minimal information should include, species (if known), location of where the animal was found, date and time of recovery, information on the circumstances or conditions under which the animal was found, and if the animal has received any treatment. Once the history has been obtained the animals should be observed from a distance to determine the severity of the problem, as well as whether to proceed with the physical examination or delay until after stabilization. Visually examining the animal will assist in assessing the animal's behavior, neurologic, respiratory and gastrointestinal function, posture, and gait. During this initial assessment it is also important to identify and prioritize the injuries, and the examination may need to be performed in stages or delayed to avoid stress and death.

ABCs

Most wildlife cases that are presented to veterinary hospitals should be considered emergencies. Many animals will have injuries that are several days old and will be dehydrated, cachetic, and hypo or hyperthermic. It is important that these life-threatening problems be addressed prior to performing a more thorough physical examination and other diagnostic tests. The first step is to ensure that the airway is patent. For most birds and reptiles the glottis is easily visualized at the base of the tongue and can be easily intubated. For small species, intravenous catheters may be used as endotracheal tubes. Non-cuffed tubes should be used in birds, crocodilians, and chelonians due to complete tracheal rings. In cases where intubation is difficult, the animal can be masked with oxygen. In cases where handling of the animal would be very stressful then placing the animal into an oxygen cage may help to stabilize it.

The veterinarian should also check for a heart beat or pulse. Cardiac compressions can be performed using the same techniques described for domestic animals; however, cardiopulmonary resuscitation is rarely successful or warranted in wild animals.

Hemostasis

An animal can lose no more than 1% of its body weight in blood volume making hemostasis a priority, especially for small animals. Direct pressure to the area, bandages, styptic powders especially for broken nails and beaks, tissue glue, sutures, and radiosurgery can all be used. Broken blood feathers will need to be removed if actively bleeding. If a large volume of blood has been lost then an appropriate volume of replacement fluid should be provided.

Shock

Shock is a clinical syndrome of poor tissue perfusion with lack of oxygen to tissues resulting in cell death. It is a life-threatening problem and can be caused by trauma, blood loss, and septicemia. Clinical signs include cold extremities, pale mucous membranes and rapid heart rate. Treatment should include fluid therapy, steroids and supplemental heat.

Thermoregulation

Measuring the body temperature with a thermometer is ideal; however, the lack of baseline physiologic data for most wildlife species is an impediment to diagnosing thermoregulatory issues. Most birds have a body temperature between 104°F and 108°F whereas most mammals maintain body temperature between 100°F and 104°F. The exception is the Virginia opossum (Didelphis virginianus) which has a body temperature between 92°F and 96°F. Hyperthermia can result from overexertion, excitement and environmental factors. The animal may pant, have open-mouth breathing, red mucous membranes and appear dehydrated. Treatment consists of minimizing stress and handling, placing in a cool environment, parenteral administration of fluids, and spraying the feet and mouth (if the animal can swallow) with water. Care must be taken to avoid rebound hypothermia. For this reason use of alcohol on feet is usually avoided. Some sick and injured animals, especially birds and neonates, are particularly susceptible to hypothermia or excessive energy expenditure associated with heat conservation. In addition, wet animals will lose heat rapidly. Hypothermic animals will be cold to the touch and appear depressed. Wet animals should be dried with towels if necessary. All cases of hypothermia should be warmed up slowly. Sources of heat include temperature-controlled incubators, heating pads, hot water bottles, heat lamps, etc. Care must be taken to avoid overheating or thermal burns. Low settings for heating pads should be used and animals should never have direct contact with a heat source.

Fluid Therapy

It is safe to assume that the majority of wildlife patients have some degree of dehydration. Most cases present with isotonic dehydration so balanced fluids such as 0.9% saline or lactated Ringer's solution that are warmed to the patients temperature are most useful. Fluids can be delivered to wildlife using the same basic techniques described for domestic animals. For animals with a functioning gastrointestinal tract and mild dehydration fluids may be given per os. Subcutaneous fluid administration is an excellent route for many wildlife species in which maintaining intravenous access is problematic. Sterile isotonic solutions should be used and no more than 5% of body weight of fluids as a single dose (and no more than 10% of body weight per day) should be given. Intraperitoneal or intra-coelomic administration can be useful for mammals and reptiles, but should be avoided in birds due to the presence of large air sacs. Intraosseous administration of fluids via the ulna or tibiotarsal bone (the pneumatic bones should be avoided) is an excellent method to deliver fluids in severely dehydrated birds. These catheters are much easier to maintain and have fewer complications than intravenous catheters. The range of daily maintenance fluid rates for birds and mammals is 75-100 ml/kg/day and for reptiles the range is 20-30 ml/kg/day.

Physical Examination

Prior to physical examination it is important to properly and safely restrain the animal. This requires the proper equipment, use of the correct technique and properly trained staff. Safety of the handler is paramount. Appropriate protective gear such as gloves, surgical masks, and goggles should be worn as necessary. Physical restraint can be very stressful for wild animals and the handling should be minimized and discontinued if the restraint is too stressful or detrimental to the animal's health. Placing an animal in a darkened (ventilated) cardboard box can help decrease stress. For these reasons sedation or general anesthesia is often preferred and considered less stressful in many circumstances.

One of the first steps is to correctly identify the species and age class. Maintaining local wildlife field guides to assist with species identification can be useful. It is important to perform a full and systematic physical examination so that no clinical problems are missed. Overall body condition should be assessed and a body weight obtained. Thin or emaciated state would indicate a chronic or prolonged problem. Hydration status should be evaluated. In mammals, dehydration will manifest as sunken eyes, tacky mucous membranes and skin "tenting." Birds can be much harder to assess for dehydration but stringy oral mucous is often a good indicator. The hydration status of reptiles can also be assessed using skin turgor, quality of oral cavity saliva, and sunken eyes. In snakes, an opaque, wrinkled spectacle is a sign of dehydration. Particular areas to examine in birds include palpation of the pectoral area to assess body condition as well as palpation of the abdomen to detect ascites, neoplasia, egg-binding, etc. Both wings and legs should be fully extended and examined for muscle loss, swellings, wounds, fractures and luxations. Reptiles in the process of shedding should be handled gently. A crocodilian's mouth should be taped closed to minimize the likelihood of injury to the handler.

Wound Management

The goals of wound management, i.e., the establishment of a healthy vascular wound bed which is free of foreign debris, necrotic tissue and infection, applies to all species. Most wounds in wildlife patients are dirty infected wounds and the first step in wound management is the removal of necrotic tissue. Fur or feathers should be removed from the wound and from the wound edge. Clippers should not be used on rabbits due to the fragility of their skin. Sharp dissection, or surgical debridement, of the wound can be performed and the wound lavaged with irrigation solutions such as 0.9% saline, or dilute chlorhexidine or Povidone iodine solutions. Surgical scrub, hydrogen peroxide and alcohol should be avoided as they are tissue damaging. The wet-to-dry bandage is a very useful technique to further débride wounds. Gauze pads should be soaked in 0.9% saline or dilute chlorhexidine solution and wrung out before being applied to the wound. Additional dry gauze should be placed on top of the moistened pads and all of the gauze secured to the wound using Vet-wrap. The bandage should be changed daily and is typically used for 4-5 days, after which it may result in tissue desiccation. Topical antibiotic ointments can be very useful to prevent tissue desiccation, inhibit infection, and stimulate granulation and epithelial tissue production. Products to avoid include gentamicin sulfate cream, nitrofurazone and petroleum-based products as they all slow down healing. Good products to use include 1% silver sulfadiazine, neomycin-polymixin-bacitracin, and zinc bacitracin.

Bandaging Techniques

Bandages are important to provide support, protect wounds from desiccation and infection, absorb exudate, reduce swelling, stabilize fractures and provide comfort. The principles of bandaging also apply to wild animals. Fractures should be stabilized to minimize the risk of further injury and to control pain. Wing fractures can be immobilized with a figure-of-eight bandage or body wrap. The figure-of-eight bandage is appropriate for fractures distal to the elbow, and a body wrap (with or without the figure-of-eight bandage) is used for fractures/luxations of the humerus and elbow and shoulder joints. Vet-wrap is an ideal material to use. For small birds, placing the wings in a normal body position and taping the primaries where they cross can provide adequate support. Bandages should be changed every 3-4 days and the wing monitored for contraction of the patagial tendon and muscle atrophy. In birds, fractures of the legs can be immobilized with modified syringe case splints, and tape splints can be used to stabilize the toes or distal limb of passerines, or other similar sized birds. White, porous tape is an ideal material to use. Ball bandages can be useful for toe fractures, soft tissue injuries to the feet, or covering bumblefoot lesions. This type of bandaging should not be used for waterfowl. Fractures of the reptile limb can be immobilized by taping the limb to the animal's body or tail. In chelonians, the limb can be reduced into a normal position within the shell and taped into place. Shell fractures should be carefully debrided, irrigated, and covered with non-adherent bandage material until a full repair can be made. For mammals, limbs can be splinted using standard techniques described for domestic mammals such as Robert Jones bandages. When splinting any limb, the joint above and below the fracture should be stabilized, and the bandage and splint monitored for any complications.

Suggested Reading

1.  Mullineaux E, Best R, Cooper JE (editors). BSAVA manual of wildlife casualties. British Small Animal Veterinary Association, Gloucester, UK 2003; 1-295.