Development of anemia, phlebotomy practices, and blood transfusion requirements in 45 critically ill cats (2009-2011).

OBJECTIVE: To describe the incidence of the development of anemia, the number of phlebotomies performed daily, the approximate volume of blood withdrawn, the transfusion requirements and their association with duration of hospitalization and survival to discharge in critically ill cats.

DESIGN: Retrospective study from January 2009 to January 2011.

SETTING: University teaching hospital.

ANIMALS: Cats hospitalized in the intensive care unit (ICU) for >48 hours.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Medical records of cats hospitalized for >48 hours in the ICU were examined. Of the 45 cats included, 60% (27/45) were not anemic upon admission to the ICU. Of these, 74.1% (20/27) developed anemia during their ICU stay. Development of anemia was associated with a longer duration of hospitalization (P = 0.002) but not with survival (P = 0.46). Fourteen cats (31.1%; 14/45) received one or more packed red blood cell transfusions and had significantly longer ICU stays (P < 0.001). Transfusion requirements were not associated with survival (P = 0.66). The median number of phlebotomies per day for all cats in the ICU was 3 (range 1-6). This was significantly associated with the development of anemia (P = 0.0011) and higher transfusion requirements (P = 0.16) in the 14 cats that received a transfusion. The estimated volume phlebotomized was significantly (P < 0.001) greater in cats that required a transfusion (median volume 3.32 mL/kg/ICU stay) compared to cats that did not require a transfusion (median volume 1.11 mL/kg/ICU stay) but was not associated with survival to discharge (P = 0.84).

CONCLUSIONS: Development of anemia necessitating blood transfusions is common in critically ill cats and leads to significantly longer duration of ICU hospitalization. Iatrogenic anemia from frequent phlebotomies is an important cause for increased transfusion requirement. Fewer phlebotomies and other blood conserving strategies in these patients may help reduce the incidence of anemia and decrease transfusion requirements, as well as result in shorter hospital stays.