Clase 12. Administración de sustancias Parte 2

Blood Sample Collection in Mice

Considerations for Blood Sampling

• The second part of blood sampling methods discusses the effects of different collection techniques on mice, emphasizing the need for proper training to minimize pain and stress.

• Various methods require immobilization or anesthesia depending on the blood extraction site; venous blood from the lateral tail vein is often collected without anesthesia but requires special equipment.

Blood Volume and Extraction Guidelines

• Guidelines indicate that only a small amount of blood can be extracted from mice, with preferences for certain veins like the submandibular vein for larger samples.

• It is crucial not to exceed 10% of total blood volume during extraction to avoid physiological changes due to hypovolemia; this equates to about 55-70 mL per kg body weight.

Safe Practices in Blood Collection

• Maximum safe extraction limits are set at 1% of an animal's body weight per occasion, with a recommendation for recovery time between extractions (3 weeks).

• If more than 10% is extracted, fluid replacement may be necessary via subcutaneous or intraperitoneal injection.

Techniques and Procedures

• Detailed procedures include warming the mouse under heat sources, cleaning the tail with ethanol, and making careful incisions to prevent coagulation issues.

• Simple hemostasis can be achieved by applying pressure with gauze; if bleeding persists, silver nitrate may be used as a cauterizing agent.

Alternative Blood Collection Methods

• Other sites such as the saphenous vein or pedal vein are discussed; however, these methods carry risks of trauma and hemorrhage.

• The retro-orbital plexus can yield larger volumes but requires monitoring post-extraction due to potential visual complications.

Advanced Techniques

• Jugular puncture and cardiac exanguination are mentioned as terminal procedures requiring deep anesthesia; they should only be performed when absolutely necessary.

Anesthesia Techniques in Veterinary Medicine

General Anesthesia and Blood Collection Techniques

• General anesthesia is always employed for procedures involving blood collection, ensuring the animal's comfort and safety during the process.

• The technique involves a rotational movement to insert a capillary tube through the sinus membrane, carefully avoiding damage to surrounding eye structures.

• Jugular puncture is highlighted as an effective method for serial blood collection, allowing for large volumes of high-quality samples while maintaining animal welfare under anesthesia.

• Cardiac puncture is described as a terminal procedure performed under deep anesthesia, enabling maximum blood collection immediately before euthanasia.