Optimal veterinary care for feline trauma patients

September 11, 2019
Laurie Anne Walden, DVM, ELS

Dr. Walden received her doctorate in veterinary medicine from North Carolina State University. She is a practicing veterinarian and a certified editor in the life sciences (ELS). She owns Walden Medical Writing, LLC, and writes and edits materials for healthcare professionals and the general public.

When cats present for emergency care, the veterinary team must consider not only the patients treatment needs but also its stress level. Heres a primer from a veterinary technician specialist.

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The spectrum of injuries that can present in cats is impressive. From chest trauma and head injuries to high-rise syndrome and abdominal bleeding, cats can find themselves in all sorts of predicaments. No matter the cause, fluid therapy, analgesia and nutrition are the basic and necessary elements of care for these patients. Alison Gottlieb, BS, CVT, VTS (ECC), spoke with dvm360 about triage and interventions for feline trauma patients.

Cats that present for emergency care should be assessed promptly. Front desk staff should know the signs of distress in cats (panting, open-mouth breathing, bleeding and lying in lateral recumbency) so they can call for immediate triage, says Gottlieb, an intensive care unit nurse and education coordinator at the Center for Animal Referral and Emergency Services (CARES) in Langhorne, Pennsylvania. 

“If you see a lot of emergencies, make sure you have either a triage person or a senior nurse who is going to be triaging these guys,” she says. Her advice for triaging trauma patients: “Be careful, stay focused, calm the owner and prepare for the worst.” 

Her advice for triaging trauma patients: “Be careful, stay focused, calm the owner and prepare for the worst.” 

Veterinary staff should recognize the needs of cat owners, too, she adds. Injured cats sometimes bite and scratch, so their owners may need medical attention from an appropriate health care provider. She stresses the need for communication and respect for owners' bonds with their pets. Instead of whisking a cat away from its owner without a word, she says, explain to the owner what is happening and keep the lines of communication open during triage and treatment.

Assessing the patient

The most important systems to assess immediately are the respiratory, cardiovascular and neurologic systems, Gottlieb says. She recommends quickly checking at least respiration and basic neurologic status while the cat is still in its carrier. It may also be possible to lift a lip to check mucous membrane color without stressing the cat.

Respiratory system. Observe respiratory rate and effort, Gottlieb says. Increased respiratory rate could indicate either pain or respiratory disease. Lower airway disease (e.g. bronchitis, asthma) is characterized by increased expiratory effort. Upper airway disease (e.g. laryngeal paralysis, obstruction, brachycephalic airway syndrome) causes increased inspiratory effort.1 Patients with pleural effusion may have muffled heart sounds.

Cats can receive supplemental oxygen while other systems are being assessed. Gottlieb recommends having a crash station equipped with a readily available oxygen source. An anesthesia machine is “one of the least ideal ways to provide oxygen to an animal” because of residual anesthetic gas in the machine, she says. In addition, anesthetic machines may not be immediately available for trauma patients and are inconvenient to use for positive-pressure ventilation. She suggests having an oxygen flowmeter connected directly to an oxygen supply at the crash station.

Oxygen can be delivered via face mask, endotracheal tube, nasal cannula or oxygen cage.1 Flow-by oxygen can also be directed into a cat's carrier, especially if removing the cat would cause too much stress. Face masks should be used without the rubber gasket in place to avoid frightening the cat and to allow carbon dioxide to escape. In patients with an airway obstruction that prevents conventional orotracheal intubation, it may still be possible to pass a red rubber catheter into the trachea, Gottlieb says. Patients with head trauma or airway obstruction may require an emergency tracheotomy.

“Always be ready to ventilate, especially in cats,” Gottlieb says. The crash station should be supplied with endotracheal tubes, a laryngoscope, a tie for the tube and a syringe to inflate the cuff. Using a laryngoscope allows assessment of the larynx and may reveal swelling or obstruction. She recommends also keeping at the crash station a self-inflating manual resuscitation bag for patients that need emergency positive-pressure ventilation. These bags can be connected to an endotracheal tube.

Technicians should practice intubating patients in lateral recumbency, she says, because in an emergency, intubating a patient laterally is faster than rolling the patient sternally. Also, lateral intubation does not interfere with chest compressions during cardiopulmonary resuscitation.

In patients with respiratory distress and signs of pleural effusion or pneumothorax, thoracentesis should be performed before extensive imaging is obtained. The stress of being positioned for radiographs can cause a dyspneic cat to decompensate, Gottlieb notes. Pleural effusion also obscures thoracic soft tissues on radiographs, so heart size and lung lesions are easier to see after the effusion has been removed. Rapid imaging techniques such as focused ultrasound assessment of the thorax may be helpful. More advanced diagnostic testing should wait until the patient is stable.1

The most accurate way to assess a patient's oxygenation status is with arterial blood gas analysis, although collecting the sample is invasive and may not be possible in a dyspneic cat.1 Pulse oximetry is noninvasive but may not be accurate in patients with poor perfusion, Gottlieb notes.

Cardiovascular system. Mucus membrane color, capillary refill time, heart rate and rhythm, and pulse quality indicate a patient's circulatory status.2 Pale mucus membranes may be a sign of hypotension, hypothermia or anemia. Patients with blue or purple mucus membranes require oxygen supplementation, Gottlieb says.

In cats, shock can cause a clinical triad of bradycardia, hypotension and hypothermia. Animals in shock develop hypotension because of hypovolemia, vasodilation or decreased cardiac output. Unlike dogs, whose heart rate typically increases in response to hypotension, cats with hypotension tend to have normal or low heart rates, probably because of simultaneous stimulation of vagal and sympathetic nerve fibers. A low heart rate does not compensate adequately for low blood pressure, so tissue perfusion decreases. Decreased perfusion leads to hypothermia, which in turn can exacerbate hypotension and bradycardia.3 Therefore, monitoring heart rate, blood pressure and body temperature is crucial for these cats.

Blood pressure can be measured directly (via arterial blood pressure) or indirectly (with Doppler or oscillometric devices). Direct arterial blood pressure monitoring is the most accurate method but may not be available and is associated with risks of arterial catheterization. Doppler blood pressure measurements are more accurate than oscillometric measurements in small animals such as cats. The Doppler device uses a cuff placed around a limb or the tail proximal to a probe located over a peripheral artery. The cuff width should be about 40% of the circumference of the limb or tail. An incorrect cuff size will result in a false blood pressure reading.2

A heart murmur or gallop rhythm may indicate cardiac disease. In cats with heart disease, fluid resuscitation should be cautious, using small volumes of crystalloids.3

Neurologic system. A basic neurologic assessment includes level of consciousness, pupillary light reflexes, pupil size and symmetry, evidence of vision and facial symmetry.2 As noted earlier, some of these parameters can be evaluated while a cat is still in the carrier.

Treatment of head injuries focuses on controlling intracranial pressure. Gottlieb recommends that technicians avoid jugular venipuncture in patients with possible neurologic dysfunction, because pressure on the jugular vein increases intracranial pressure. She also notes that rabies is a possibility in patients with neurologic dysfunction and an unknown or no history of rabies vaccination.

Urinary tract. In hospitalized patients, urine output can be measured or estimated to assess hydration status and kidney function. Urine output normally ranges from 1 to 2 mL/kg/hr in cats and dogs.2 To avoid bladder rupture during palpation, use caution in patients with possible bladder trauma, Gottlieb says.

 

 

Interventions

Intravenous catheterization and fluid administration. For cats presenting for emergency treatment, Gottlieb recommends obtaining the blood sample for initial laboratory tests from the hub of an intravenous (IV) catheter. “There's no reason to stick a cat to get blood and then placing an IV catheter,” she says. This small sample can yield packed cell volume, total solids, blood glucose and blood type.

In cats, IV catheters can be placed in either the cephalic or medial saphenous vein. Medial saphenous catheterization may be less stressful for some cats, Gottlieb says. Placing a peripheral IV catheter can be a challenge in cats with shock, hypothermia or hypotension. For these patients, she suggested warming the leg before catheterization to increase blood distribution to the leg. “Always adhere to the two-stick rule,” she adds. “After two unsuccessful catheterization attempts, have someone else try.”

To avoid swelling of the paw distal to the catheter, use a catheter of appropriate size, Gottlieb advises. Large-bore catheters may be more likely than smaller-bore catheters to cause foot swelling from vascular irritation. She also warns that tape placed around the limb of a dehydrated patient may become too tight after the patient is hydrated. Leave the tape loose or replace it after the patient is hydrated, she recommends.

Cats should not receive an entire shock bolus of IV fluids at one time. “Cats are really sensitive to fluid overload,” she says. The volume of IV crystalloids used to treat shock in cats is about 40 to 50 mL/kg. The safest approach is to give one-fourth of the shock volume intravenously and then reassess the cat's perfusion status.4 Crackles heard on chest auscultation may indicate that the patient has developed pulmonary edema, she says.

IV fluids should be administered judiciously in animals with abdominal bleeding, heart disease, head trauma or pulmonary contusions, Gottlieb says. These patients need appropriate hydration, but increasing their blood pressure with large fluid boluses can be deleterious. Hypertonic saline and colloids can be useful adjuncts or substitutes for isotonic crystalloids, she says.

Pain management. Gottlieb stresses the need for pain relief in trauma patients. “If they are responsive, they need analgesia,” she says. Controlling pain is ethical and prevents pain-related stress and impaired healing.

Pain management for patients with traumatic injuries typically includes opioids and local anesthetics. Some medications can be administered transmucosally via the buccal pouch. Gottlieb says that bupivacaine should never be administered intravenously because it is cardiotoxic.5 Before injecting a local anesthetic agent, always aspirate the syringe to avoid accidental injection into a vein.

Blood transfusion. “There is no universal [blood] donor” for cats, Gottlieb says. As a species, the domestic cat has more than one blood type. Type A is the most common, but cats presenting for emergency treatment may have type B or other rare blood types. Because cats have naturally occurring antibodies against other blood group antigens, transfusion with an incompatible blood type results in red blood cell destruction.6 Therefore, cats must undergo blood typing before transfusion.

Point-of-care rapid blood-typing cards are available for clinic use. Crossmatching, a method of directly testing the compatibility of donor and recipient cat blood, can also be performed to ensure safety. Transfusions can consist of packed red blood cells, plasma, platelets or whole blood. Blood substitutes may be available for patients for whom no compatible donor can be found.6

Transfusions of blood products should always begin at a slow rate, Gottlieb says, and patients must be monitored closely for evidence of adverse reactions.

Nutrition. Gottlieb emphasizes the importance of nutritional support for hospitalized cats. Cats presenting with traumatic injuries may have been missing for days before they were found and may already be malnourished when they arrive at the hospital. Malnutrition delays wound healing, contributes to muscle loss and increases morbidity. Anorexia puts obese cats at risk for hepatic lipidosis.7

“Anticipate anorexia,” Gottlieb says. Hospitalized cats may refuse food for a number of reasons, including stress, pain, unfamiliar food, unfamiliar surroundings, presence of dogs, proximity of the litter box to the food bowl in the cage, effects of medications and injuries to the mouth or jaw. She recommends keeping accurate records of the amount and type of food patients eat and beginning nutritional support if voluntary intake does not meet their energy requirements.

Potential routes of assisted feeding are enteral (by mouth or feeding tube) and parenteral (IV). Enteral feeding is preferred because it maintains the intestinal barrier7 and is less expensive. Oral syringe feeding is not recommended because it can cause food aversion and increase the risk for aspiration.7 Gottlieb suggests several methods to encourage cats to eat on their own (see sidebar "Tips for getting hospitalized cats to eat").

Tips for getting hospitalized cats to eat

Getting hospitalized cats to eat can be tough, Gottlieb says, for a number of reasons. Before resorting to assisted feeding, try these tactics for enticing cats to eat:

Offer dry food if the cat refuses canned food.

Offer favorite foods from home.

Warm the food.

Remove uneaten food from the cage.

Add freeze-dried liver, gravy or tuna juice to the food.

Have the owners feed the cat in a quiet room in the hospital.

Remove protective collars for meals.

Use a flat dish; some cats don't like having their whiskers touch the dish.

If a cat's nose is crusty, clean it.

Give cats attention or privacy when eating, whichever they prefer.

Give private eaters a cardboard box to hide in.

Be sure pain and nausea are treated adequately.

Try feline synthetic pheromone products in the cat's environment to reduce stress.

Try appetite-stimulating medications.

Feeding tubes are useful for cats with anorexia or injuries that make eating difficult. Tube feeding should begin within a few days of the onset of anorexia, bearing in mind that the cat may not have eaten for some time before arriving at the hospital. Feeding tubes should be placed sooner in cats that are very young or old, debilitated, at risk of developing hepatic lipidosis or likely to be unable to eat for an extended time.7

The choice of feeding tube (nasoesophageal, nasogastric, esophagostomy, gastrostomy or jejunostomy) depends on the cat's medical condition, expected duration of assisted feeding and ability to undergo anesthesia and surgical tube placement. Nasoesophageal and nasogastric tubes are generally placed with local (intranasal) anesthesia; the other types require general anesthesia.7

The amount of food delivered through a feeding tube depends on the patient's calculated resting energy requirement. Feeding can be either continuous or by bolus, beginning with a small amount administered slowly, then gradually building up to the full amount. Flushing the tube with water after a feeding helps prevent clogs, Gottlieb says.

Parenteral nutrition is used in the short term for patients that cannot receive enteral nutrition. It requires a dedicated venous catheter, and patients must be monitored carefully for signs of sepsis and other complications.

Conclusion

Cats are not like dogs, Gottlieb says, especially regarding their level of anxiety in the clinic. Veterinary technicians must balance cats' treatment needs with the need to minimize their stress to achieve the best outcomes for these patients.

References

1.   Sumner C, Rozanski E. Management of respiratory emergencies in small animals. Vet Clin North Am Small Anim Pract 2013;43(4):799-815.

2.   Pachtinger G. Monitoring of the emergent small animal patient. Vet Clin North Am Small Anim Pract 2013;43(4):705-720.

3.   Kirby R. Feline shock and resuscitation, in Proceedings. 30th World Small Animal Veterinary Association World Congress 2005.

4.   Mazzaferro E, Powell LL. Fluid therapy for the emergent small animal patient: crystalloids, colloids, and albumin products. Vet Clin North Am Small Anim Pract 2013;43(4):721-734.

5.   Allweiler S. Local and regional analgesic techniques. Merck Veterinary Manual website. merckvetmanual.com/management-and-nutrition/pain-assessment-and-management/local-and-regional-analgesic-techniques. Accessed September 4, 2019.

6.   Cotter SM. Overview of blood groups and blood transfusions. Merck Veterinary Manual website. https://www.merckvetmanual.com/circulatory-system/blood-groups-and-blood-transfusions/overview-of-blood-groups-and-blood-transfusions. Accessed September 4, 2019.

7.   Kathrani A. Nutritional support in the intensive care unit. In Pract 2016;38(suppl 4):18-24.