ALAT ALAT Research Procedures and Techniques Questions and Answers 4 — Questions and Answers
Question 1: When collecting a blood sample from a mouse via the retro-orbital sinus, which anesthetic approach is most commonly recommended to minimize pain and distress?
- No anesthetic is required for this quick procedure
- General anesthesia using isoflurane or injectable agents (Correct answer)
- Local topical anesthetic applied to the eye
- Sedation with ketamine alone at sub-anesthetic doses
Correct answer: General anesthesia using isoflurane or injectable agents
Retro-orbital blood collection requires general anesthesia to prevent pain and minimize the risk of ocular trauma.
Question 2: What is the recommended maximum volume for a single subcutaneous injection in a rat weighing 250 g?
- 0.25 mL
- 0.5 mL
- 2.5 mL (Correct answer)
- 5 mL
Correct answer: 2.5 mL
The recommended maximum subcutaneous injection volume in rats is approximately 1–2 mL per site, with up to 5 mL/kg body weight total, equating to ~2.5 mL for a 250 g rat.
Question 3: A researcher asks you to perform a gavage on a mouse with a compound that has a pH of 2. What is your most important concern?
- The compound may stain the gavage needle
- Acidic compounds can cause severe esophageal and gastric irritation or injury (Correct answer)
- Low pH compounds are always toxic to the liver
- The compound will require refrigeration during administration
Correct answer: Acidic compounds can cause severe esophageal and gastric irritation or injury
Highly acidic compounds can damage the esophageal and gastric mucosa during oral gavage, posing a significant welfare concern.
Question 4: Which of the following correctly describes the preferred site for intraperitoneal (IP) injection in mice to avoid organ damage?
- Upper right quadrant of the abdomen
- Lower left quadrant of the abdomen with the animal's head tilted down (Correct answer)
- Midline of the abdomen at the umbilicus
- Between the shoulder blades on the dorsal surface
Correct answer: Lower left quadrant of the abdomen with the animal's head tilted down
IP injections in mice are given in the lower left quadrant with the head tilted downward to shift organs away and reduce the risk of penetrating the cecum or bladder.
Question 5: When using isoflurane for rodent anesthesia in a research procedure, what equipment is essential to protect personnel from waste anesthetic gas exposure?
- A UV sterilization lamp near the procedure area
- A scavenging system connected to the anesthesia machine (Correct answer)
- Latex gloves and a surgical mask
- A fume hood set to low airflow
Correct answer: A scavenging system connected to the anesthesia machine
A scavenging system captures waste anesthetic gases and vents them away from personnel, reducing occupational exposure to isoflurane.
Question 6: A mouse appears to be recovering from anesthesia but is hypothermic (rectal temperature 34°C). What is the most appropriate immediate action?
- Administer a stimulant drug to speed recovery
- Place the mouse on a warm surface or under a heat lamp and monitor closely (Correct answer)
- Return the mouse to its home cage immediately with extra bedding
- Administer IV fluids to raise body temperature
Correct answer: Place the mouse on a warm surface or under a heat lamp and monitor closely
Providing supplemental heat supports thermoregulation during anesthetic recovery, as hypothermia can delay recovery and cause cardiovascular depression.
Question 7: Which method is considered the gold standard for confirming correct placement of an endotracheal tube in a research animal prior to a procedure?
- Observing chest rise and fall with ventilation
- Detecting CO2 on a capnograph (end-tidal CO2 monitoring) (Correct answer)
- Listening for breath sounds with a stethoscope
- Checking that the tube passed easily without resistance
Correct answer: Detecting CO2 on a capnograph (end-tidal CO2 monitoring)
Capnography (end-tidal CO2 detection) confirms that the tube is in the trachea by detecting exhaled CO2, making it the gold standard for tube placement verification.
ALAT ALAT Research Procedures and Techniques Questions and Answers 4
When collecting a blood sample from a mouse via the retro-orbital sinus, which anesthetic approach is most commonly recommended to minimize pain and distress?