Evaluation of the effects of time, storage, and anticoagulant on venous blood gas samples in dogs

ABSTRACT To analyze the effects of variables on venous blood specimens from dogs intended for blood gas analysis, four samples were collected from the jugular veins of 30 animals. Two were obtained using a commercial 3mL BD syringe containing lithium heparin (LH) and a 25x7 needle, and two using a conventional 3mL syringe prepared with sodium heparin (HS) and the same needle. Air bubbles were removed, and the samples were sealed. After the initial analysis (within 20 minutes - T0), one LH sample was stored in ice water (0-4 °C) and the other refrigerated; the same procedure was applied to the HS samples. Subsequent analyses were performed at 30, 120, 240, and 360 minutes after the initial test. Time influenced the values of most variables, except chloride, causing changes in bicarbonate and base excess levels. Therefore, immediate analysis is recommended. When it is not possible, storage in ice water is preferable to refrigeration. The use of HS led to variations in ionized potassium and calcium concentrations, which should be considered by the clinician. The commercial syringe resulted in fewer variations and is therefore recommended for preferred use.