Sonia M. Hernandez-Divers, DVM, DACZM, PhD
Avian emergencies are often more challenging than their domestic counterparts because owners are not as aware of their daily condition, birds tend to hide disease, they tend to present in advance stages of disease, they are much smaller and more difficult to manage, have high metabolic rates that, in some cases, can lead to faster disease progression, and in the author's experience, once decompensated, do not appear to have the cardiovascular "reserves" upon which we rely on mammals. In some cases, (such as dyspnea, abdominal distention, and extremely lethargy) practitioners have to walk a fine line between aggressive, life-saving intervention and hastening death through handling. Due to space limitations, this review is limited and should be supplemented with more extensive reviews that utilize references based on avian physiology and research.1-3, 5-6
Prior to Presentation
The reception staff should be well trained on how to respond when an avian emergency calls or presents for treatment. Typically if a bird is showing clinical signs, it needs to be seen. If it has respiratory disease, is "down in the cage", etc. the situation is urgent and the client should be instructed to come in immediately; however, they should understand that transport itself can lead to death.
Obtaining a thorough history will be paramount in solving avian emergencies, as most presentations are related to some aspect of husbandry or care. Questions should include information about length of ownership, any previous illness, exposure to infectious disease or toxins (including cigarette smoke, cleaning agents, recent renovations in household, etc), a complete description of the bird's environment, the patient's reproductive status, a history of recently acquired birds or boarding, quarantine protocols, previous flock illnesses, and diet. Recently obtained domestic birds are more likely to present with acute infectious problems such as chlamydiosis and viral diseases, whereas, birds that are long-term companions are more likely to have diseases such as aspergillosis, chronic nutritional disease or toxicosis. Egg binding and egg-related peritonitis frequently occur in female budgies and cockatiels, while hypocalcaemia is a recognized problem in the African grey parrot. Neonatal birds that are hand-fed commonly suffer from management-related problems such as crop burns and nutritional deficiencies, as well as conditions such as candidosis, Gram-negative ingluvitis and avian polyomavirus.
At the time of presentation, unless the patient requires immediate care, examine the transport cage for discharge, vomit, quantity and quality of feces and urates, nutritional items, or sources of toxins and foreign objects, such as toys. Loose feces and polyuria can indicate enteritis or diarrhea. Voluminous droppings can indicate parasites, avian gastric yeast or digestive tract disorders. Prior to handling the bird, you might obtain important, yet subtle details by observing the bird in its cage for its attitude, stance, respiratory rate, and respiratory effort. For example, a bird closing its eyes indicates lethargy, and a wide base stance typically indicates respiratory difficulty or abdominal distention. Record the respiratory and cardiac rates, as they will serve as a baseline for either monitoring treatment success or in the event the bird is anesthetized later and ventilator frequency has to be set.
The Plan for the Critical Avian Patient
Develop a plan and then follow this plan every time. A plan should include:
1. Triage - Perform a cursory exam (2-5 minutes-which should include obtaining a body weight), and identify and prioritize life-threatening problems. Conditions that need immediate attention include: Airway obstruction, Dyspnea, Cyanosis, Cardiac arrest, Seizures, Uncontrolled/severe hemorrhage, Unconscious patient, Open, full thickness coelomic wounds, Shock. The purpose of the cursory exam is to identify the above conditions and address them quickly. Apply the ABC's of Emergency:
Airway - (stop, look, listen) If bird is unconscious, be certain that the path for air is clear. In my experience, the time from when a bird stops breathing and cardiovascular arrest (followed by brain anoxia and death) is extremely short.
Breathing - If the bird is breathing, note its respiratory rate and quality-it may still need supplemental oxygen. Respiratory problems can be caused by either upper airway obstruction (foreign body, laryngeal edema, laryngeal paralysis, discharges, blood in trachea etc.), or a lower airway obstruction (lung edema, lung lesions, coelomic distention, dystocia, etc.). At this time, it may be necessary to instill an air sac tube (see below), or place the bird in an oxygen-rich environment.
Circulation - (look, feel, listen) If there is no heart beat, cardiac compressions and administration of emergency drugs can be tried, but are typically futile in birds. If the heart rate is irregular or weak, again, emergency drugs may be necessary. Check peripheral pulses (the radial or the ulnar arteries, running parallel to the humerus on the ventral aspect of the wing, or the metatarsal artery on the dorsolateral aspect of the food, are good places to feel peripheral pulses), color of mucous membranes and capillary refill time (ulnar vein) which will indicate peripheral perfusion. If pulses are weak, mucous membranes are pale or dark red, or if capillary refill time is prolonged, assume there is some degree of shock and begin appropriate therapy.
A preferred term, which is more inclusive (borrowed from a critical care colleague), is:
A. C.R.A.S.H. P.L.A.N.: A: Airway; C: Cardiovascular; R: Respiratory; A: Abdomen; S: Spine; H: Head; P: Pelvis; L: Limbs; A: Arteries; N: Nerves
The Neurologic system is often overlooked in avian patients: Assess mentation (alert, depressed, comatose), cranial nerves (pupil position and size, nystagmus, typewriter movements of the head, PLR, menace, palpebral and gag reflexes). Assess the patient for spinal deficits (spinal reflexes, voluntary motor control, muscle tone, pain sensation). When dealing with species with which we are not familiar, it is useful to have something to remind us not to skip any of the systems.
2. Stabilize - At this point you should have outlined the most important problems that need treatment and have begun to do so. When dealing with birds, stabilization may include placing the animal in a warm, dark, quiet enclosure to allow it to settle down while you prepare the equipment needed to treat such as oxygen, fluids, heat sources, emergency drugs etc. Remember: Shock--Definition: The disruption of normal delivery and utilization of oxygen and nutrients to cells and tissues of the body. A disease process in which normal blood flow is impaired and patient experiences cellular hypoxia. This hypoxia causes a shift from the high-energy yielding aerobic glycolysis to low-energy yielding anaerobic glycolysis. If this imbalance is not corrected, cellular injury, dysfunction and eventually death result. Allow your immediate treatment to work for 1-2 hrs, then...
3. Reassess - By this time, if your treatments are working, you should note some degree of improvement. This is the time to consider gathering more biological samples for further diagnostics (if the patient will tolerate it), re-administer treatment, or consider changing your approach.
Malnutrition: a chronic condition that decompensates to a variety of presentations; dystocia; foreign body obstruction (GI or respiratory tract); respiratory disease; vomiting/diarrhea; GI stasis; cloacal prolapse; toxicities; trauma (and associated fractures or blood loss); other household accidents (burning, near-drowning, fans, etc). The reader is referred to complete tables of possible etiologies that tend to present as emergencies in avian patients.
Emergency Treatment Modalities
1. Fluids - Fluid requirements are a function of metabolism. The higher the metabolism of the bird, the higher the fluid requirement. The primary goal in using fluids to treat shock is to increase fluid flow to stabilize blood pressure, to increase O2 delivery to tissues and increase CO2 shuttling as well as improve cardiac performance. Routes for fluid administration in shock: IV or IO. IV or IO may not be realistic for your size of patient and your level of expertise.....SQ fluids are better than nothing, however, this route is not recommended for birds in shock. Birds exhibiting hypovolemic shock should be given colloids, such as hetastarch (Braun Medical Inc. Irvine, CA) at a dose of 10 mL/kg with the dose repeated until the patient shows clinical improvement. Fluid shock doses for birds: 90-100 ml/kg.
Fluids are also used to treat: Dehydration, Toxicity, Hypothermia and to promote dieresis.
Fluid Therapy Requirement=deficit + maintenance + ongoing losses. Deficit=% dehydration X body wt (kg)=L needed to replace deficit. Maintenance for birds: 60-90 ml/kg/24 hr.
Fluid Delivery Routes
Warm subcutaneous (SQ) fluids can be used for mild dehydration or to maintain but not effective during hypovolemic shock because of inadequate absorption secondary to peripheral vasoconstriction. Crystalloids such as lactated Ringer's solution and dextrose solutions up to 2.5% can be delivered subcutaneously. The recommended sites for SQ fluid administration are: inguinal, interscapular, and axillary regions. The inguinal web offers a large potential space for fluids. If administering fluids over the dorsum, avoid placement into the cervico-cephalic air sac by administering caudal to the wings. A small-gauge needle (25-27 ga) should be used to avoid leakage.7 A.E. Rupley, Manual of Avian Practice, Saunders, Philadelphia, PA (1997).
Intravenous (IV) administration of fluids is indicated with moderate to severe dehydration and shock. Fluids can be administered intravenously as a bolus with a syringe or butterfly catheter, or over longer periods with an IV catheter. The superficial ulnar vein, medial metatarsal and right jugular veins can be used for single IV boluses. The right jugular is the preferred site for IV catheterization by many practitioners, but long-term care of this and other IV catheters can be problematic.
The intraosseous (IO) route of administration provides rapid intravascular delivery of fluids. Once placed, IO catheters are more secure than IV catheters and much easier to maintain. A 20- to 25-gauge spinal needle or hypodermic needle (with a 1.5" 25 ga needle as a stylet so they do not become obstructed with cortical bone) can be used. Both the distal and proximal ulna and proximal tibiotarsal have been described, depending on the size and disposition of the bird. The entry site for the distal ulna is ventral to the dorsal condyle.
2. Steroids - Steroids are used for two primary reasons: the treatment of shock--as they are proven to stabilize cell membranes, improve cellular metabolism, improve microcirculation, and promote gluconeogenesis, and to treat neurologic injury because of the aforementioned reasons, and to quickly decrease inflammation and the deleterious effects of the inflammatory pathway on sensitive neuronal tissue. They come with disadvantages such as immunosuppression, delayed healing, negative effects on GI mucosa, typically associated with prolonged and repeated treatment. Judicious use of steroids can be extremely beneficial in the critical patient.4 Shock doses: 2-4 mg/kg dexamethasone IV or IM(frequency will vary); Neurological damage: 2 mg/kg dexamethasone TID for 24-48 hrs; IV or IM or if possible OR methylprednisolone, or prednisolone sodium succinate initially 30 mg/kg IV, then 15 mg/kg TID for 24-48 hrs.
3. Air sac cannulation and oxygen support - If a bird displaying respiratory difficulty does not improve in an oxygen chamber, is making "squeaky or whistling" sounds, appears to gasp, etc a presumptive diagnosis of upper airway obstruction can be made which will necessitate air sac cannulation. Most birds will require general anesthesia and rapid placement of the cannula. The area caudal to the last rib and cranial to the thigh musculature is surgically prepped. A small skin incision is made. Blunt dissection with straight hemostats can facilitate penetrating the musculature, aiming cranio-dorsally. The air sac cannula is gently but firmly inserted through the body wall and into the caudal abdominal air sac, often producing a "popping" sound. The air sac cannula end-piece is attached to the oxygen source or ambulance bag for manual ventilation. If needed, deliver intermittent positive pressure ventilation (IPPV) at the normal resting respiratory rate for the species at hand, while the pressure should mimic normal coelomic cavity expansion. It is important to understand that air sac cannulation omits the valuable, normal physical and physiologic mechanisms normally in place in the upper airway to prevent foreign material and pathogens from invading the lower respiratory tract; therefore, the longer an air sac cannula is in place, the higher the probability the avian patient will develop secondary infections introduced through the cannula. Endoscopic examination of the air sac cannula and caudal abdominal air sac is useful for monitoring. If lower respiratory disease is suspected, air sac cannulation is contraindicated. Introduce the bird into an incubator enriched with oxygen. Oxygen concentrations should be limited to 40% to 50%, as higher oxygen levels have been shown to cause lethargy, respiratory distress and death in some species. The incubator air should be humidified to avoid further evaporative fluid losses.
Other treatment modalities and factors typically considered to maximize success:
1. Therapeutics - Glucose (hypoglycemic animals); Potassium (severely cachectic, anorectic); Vitamin B (cachectic, anorectic); -Vit E, Se (neuromusculoskeletal dz); -Vit A, D (cachectic, anorectic); Iron Dextran (anemic); NSAID's (inflammation, analgesia; Antibiotics.
2. Collect biological samples for Quick Assessment Tests (QAT's) for further information, consider more extensive lab work in the future.
3. Supplemental heat (circulating warm air, fluids, or incubators). An initial cloacal temperature is useful for monitoring treatment success.
4. Wound Care and fracture stabilization - Try to minimize the contamination of the wound. Preventing an infection by dealing with the wound directly will be more efficacious than ignoring the wound and attempting to treat it with antimicrobials later. Flush wound with disinfecting agents that will not cause further cellular damage. Rinse with physiologic saline. Apply a sterile dressing to protect from further contamination.
5. A stress-free environment away from the busy clinic, away from barking dogs and hissing cats. Time to rest and sleep.
6. Nutrition - Birds have high metabolic rates and disease, injuries, etc place high caloric demands on birds. A plan for nutritional support should be made immediately; however, the functional status of the GI tract should be evaluated and hydration corrected before feeding a bird. Utilize the following formula to determine how many calories are needed: BMR (kcal/day) = K(body wt in kg)0.75 ; where K=78 in non-passerines, 129 in passerines. MER (kcal/day) = 1.5 X BMR; If bird is septic, has head trauma or neoplasia: MER X 1.5=kcal/day needed. Birds can be gavaged with LRS first until normal urates are noted, then changed to easily digestible recovery formulas that provide only simple carbohydrates and calories, and later changed to more balanced formulas.
Back to Basics
While the bird is resting in a quiet, dark area (approx 2 hrs before re-evaluation), it is important to once again, calmly, review the history with the owner, repeat a more thorough physical exam, revamp the list of differential diagnosis, and make a diagnostic plan for the future.
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2. Cousquer, G. First aid and emergency care for the avian casualty. 2005. In Practice 27:190-203.
3. Graham, J. E. 2004. Approach to the dyspneic avian patient. Seminar in Avian and Exotic Pet Medicine 13 (3): 154-159.
4. Hess, L. 2002. Corticosteroid synthesis and metabolism in birds. Seminar in Avian and Exotic Pet Medicine 11 (2): 65-70.
5. Jones, M. P. and C. G. Pollock. 2000. Supportive care and shock. In: Olsen, G. H. and S. E. Orosz (eds.) Manual of Avian Medicine. Mosby, St Louis, Pp 17-46.
6. Quesenberry, K.E. and E. V. Hillyer. 1994. Supportive care and emergency therapy.
7. In: Ritchie, B. W., G. J. Harrison and L. R. Harrison. Avian Medicine: Principles and Application (eds.) Wingers Publishing, Lake Worth, Florida. Pp 382-416.