Introduction
- Good sample collection technique is vital to obtain a blood sample of adequate quality for analysis.
- Peripheral veins, eg cephalic and saphenous, often detrimental → slow blood flow → sample artefacts (hemolysis and microclots.)
Uses
- Collection of blood for analysis.
- Administration of intravenous drugs +/- fluids
.
Advantages
- Simple technique (unless difficult animal).
- Straightforward technique for intravenous drug administration.
Disadvantages
- No real advantages over jugular venipuncture for blood collection.
Requirements
Materials required
Minimum consumables
- Needles: 18-21 gauge/1 in (varies with breed and personal preference).
Either Syringe: 2.5-20 ml.
Or Evacuated tubes: 2-3 ml. - For sample tube preference see
.
Sequelae
Reasons for treatment failure
- Poor technique may preclude venipuncture.
- Repeated attempts at venipuncture may damage vein sufficiently to prevent further sampling.
- Repeated entry into same site with same needle → introduce tissue proteins → abnormal results.
- Use of too fine a needle.
- Failure to remove needle from syringe prior to placing blood in tube.
- Needle pushed directly through evacuated tube top. Fluid flow under pressure inevitably damages the RBCs. Hence remove bung and gently release blood from syringe.
- Excessive back pressure when withdrawing blood.
- Posting samples (time related).
- Minimize by separating serum/plasma from clot or heparinized samples before sending sample.
- Obesity.
- Excess skin folds, eg Shar Pei dogs .
- Vacutainer in small dog → collapsed vein.
- Excess back pressure.
- In chondrodystrophic animals with deformed forelimbs it may be difficult to identify vein.
An ear vein is very useful in these dogs
