title: Changes in central venous pressure and blood lactate concentration in response to acute blood loss in horses.
abstract: OBJECTIVE
  To evaluate selected hemodynamic, blood gas, and biochemical responses to mild to moderate acute blood loss in standing, awake horses.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  7 healthy mares.
  
  
  METHODS
  Each horse was restrained in standing stocks, and its head was maintained in a neutral position; sedatives and tranquilizers were not administered. During a 1-hour period, blood was collected into collection bags by use of a suction pump. The rate of blood collection was approximately 16 mL/kg/h (7.3 mL/lb/h). Thirty minutes after blood collection, the blood was readministered at the same rate. Central venous pressure (CVP), central venous blood gas, blood lactate concentration, and heart rate were measured at baseline (after placement of catheters), after removal of blood, and after readministration of blood.
  
  
  RESULTS
  In response to blood loss, CVP decreased and blood lactate concentration increased significantly, compared with baseline values; heart rate and results of central venous blood gas analysis did not change significantly. After readministration of blood, CVP returned to baseline value and blood lactate concentration approached baseline value.
  
  
  CONCLUSIONS
  Changes in CVP and blood lactate concentration appear to be early indicators of hypovolemia in horses, which may represent acute blood loss in trauma patients; these variables should be monitored to assess the potential need for blood transfusions. These variables can be used to monitor responses of horses to blood transfusions when whole blood is administered as the replacement fluid.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
authors.forename: K Gary
authors.initials: KG
authors.lastname: Magdesian
authors.forename: C Langdon
authors.initials: CL
authors.lastname: Fielding
authors.forename: Diane M
authors.initials: DM
authors.lastname: Rhodes
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Ruby
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006470:Hemorrhage / Q000503:physiopathology / Q000662:veterinary; D006487:Hemostasis / Q000502:physiology; D006734:Horse Diseases / Q000503:physiopathology*; D006736:Horses / Q000502:physiology*; D020896:Hypovolemia / Q000175:diagnosis / Q000662:veterinary*; D007773:Lactates / Q000097:blood*; D011446:Prospective Studies
chemical_list: D007773:Lactates