Effects of phlebotomy on haemodynamic characteristics during exercise in standardbred trotters with red cell hypervolaemia

Curriculum vitae paper - Sune G.B. Persson (1931-2009)

Sune Persson was born in Landskrona Sweden in 1931 and grew up on the west coast of Sweden. He graduated from the Royal Veterinary College in Stockholm in 1960 and in 1967 received his PhD entitled ‘On blood volume and working capacity in horses’. Sune pursued an academic career devoted to internal medicine and exercise physiology. He rapidly became Professor of Medicine in 1979 as the veterinary school moved from Stockholm to the Swedish University of Agricultural Sciences in Uppsala.

Changes in central venous pressure and blood lactate concentration in response to acute blood loss in horses

OBJECTIVE

To evaluate selected hemodynamic, blood gas, and biochemical responses to mild to moderate acute blood loss in standing, awake horses.

DESIGN

Prospective study.

ANIMALS

7 healthy mares.

PROCEDURES

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 AND CLINICAL RELEVANCE

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.

The effects of overtraining on blood volumes in standardbred racehorses

Red blood cell hypervolaemia has been used for diagnosis of overtraining in racehorses, and has been suggested as a mechanism of this cause of loss of racing performance. The effects of overload training (OLT) on the plasma, blood and red cell volumes were investigated in a prospective study in 12 Standardbred horses. Measurements of blood volumes were made after eight and 32 weeks of an exercise training study. Horses were randomly allocated to OLT and control groups (n=6) after 16 weeks of training. Training duration and intensity were increased more rapidly for the OLT group from week 16, until overtraining was diagnosed in week 32. There were no significant effects of OLT on plasma, blood or total red cell volumes between weeks eight and 32. These volumes significantly decreased with time. Maximal haematocrit after exercise was lower (P<0.05) in the OT group in week 32 (0.57+/-0.003% L/L) than in week eight (0.59+/-0.004 L/L). It was concluded that red cell hypervolaemia was not a mechanism for the decrease in capacity for exercise that occurs with overtraining.