Mocha, a 16-year-old, spayed outdoor domestic shorthaired cat, was presented to the local emergency clinic after having been hit by a car. Upon that initial examination, the patient appeared pale and had a right hind-limb non-weight-bearing lameness. Crepitus was detected in the right distal tibia. Stabilization with fluid therapy was initiated, and a soft, padded bandage was place on the right hind limb. Mocha responded well to the initial therapy, and she was referred for further evaluation and fracture repair.

The following day the cat appeared quiet, alert, and responsive. Her mucous membranes remained pale, and she was tachypneic, with respiratory rate 60 breaths per minute, and tachycardic at 260 beats per minute. Crepitus, swelling, and bruising were present in the right hind leg. Moderate flea infestation was noted.

Whole-body and right hind-limb x-rays, complete blood count, serum chemistry profile, total thyroxine level, and urinalysis were preformed. Significant abnormalities included a right comminuted distal tibial fracture; moderate to sever right hind-limb swelling; and anemia, with packed cell volume (PCV) 15 percent (normal 30-45).

Therapeutic Attempts

Recommendations included a major blood compatibility cross-match and blood transfusion followed by external parasite management, then fracture repair. The major blood cross-match procedure was completed for two in-house feline donors, but the cat was incompatible with both. To supply oxygen-carrying support in order both to manage the cat's general condition and allow anesthesia for repair, Oshkosh (polymerized bovine hemoglobin glutamer-200) was administered over three hours at 10 mL/kg/hr.

Oxygen-carrying support in the form of a blood transfusion or use of polymerized bovine hemoglobin glutamer-200 is indicated when anemia leads to compromise of tissue oxygenation. The PCV or hemoglobin level at which transfusion therapy is indicated, or transfusion trigger, is based on several variables, including the measured PCV or hemoglobin value; clinical parameters (heart rate, respiratory rate, general strength, and attitude); rapidity of anemia development (acute or chronic); and the potential for continued blood loss. With clinical parameters and continued potential loss assessment considered, a reasonable transfusion trigger for the feline patient is PCV <18-22 or hemaglobin <6-7.5 for acute anemia and, for chronic anemia, PCV <14-18 and hemoglobin <4.5-6.

Strange Signs of Improvement

Within two hours of initiating this administration, Mocha demonstrated improvement in clinical parameters. Her tachycardia resolved, and her tachypnea and general attitude improved. Following the treatment, the PCV decreased to 10 but total hemoglobin level increased from pretreatment level of 4.8 g/dL (normal: 8-15) to posttreatment level of 6.7.

An oxygen-carrying colloid without cellular components polymerized bovine hemoglobin glutamer-200 is approved for use in dogs, thoughts it use in cats is extralabel. Because of the colloid's vascular expansion qualities and lack of cellular components, the PCV in patients receiving this agent decreases because of dilution effects, even though there is actually more hemoglobin and an improved oxygen-carrying capacity. Thus, monitoring of oxygen-carrying capacity should be done by assessing clinical parameters and measuring total hemoglobin.

Based on Mocha's improvement in clinical parameters and the increased hemoglobin, external parasite control and anesthesia/fracture repair was performed. All procedures were completed without complication, and the patient was discharged two days later. Over the next eight weeks, recheck examinations and client communications revealed improvement and resolution of the anemia, as well as complete fracture healing.

Drs. Crystal Mott and Van Der Veldt practice at
North Florida Veterinary Specialists, PA, in Orange Park.