Abstract
The effect of 4 sampling routines-venipuncture, intravenous cannula, intravenous cannula following the administration of a tranquiliser (xylidino dihydrothiazine hydrochloride), intravenous cannula following exercise-were compared. Blood pH and base excess values were similar after venipuncture and cannula sampling, but higher (P<0·05) after the administration of the tranquiliser and lower (P<0·05) following exercise. Blood haemoglobin, haematocrit and lactate levels followed this pattern, while plasma protein levels were similar for all treatments except after exercise, where they were higher (P<0·05). The recovery of various blood parameters to normal values after a period of exercise was also studied: acidbase balance had returned to near normal within 60 min, while haemoglobin and haematocrit levels had returned to normal within 10 min.