1
terms and definitions
Travis Seymour
• Acute pain: Pain associated with tissue damage that resolves once the tissue heals
• Allodynia: Pain resulting from nonnoxious stimuli
• Anesthesia: Loss of sensation to the whole or any part of the body
• Chronic pain : Persistent pain that lasts significantly longer than the anticipated resolution time
• General anesthesia: Unconsciousness due to drug-induced, reversible depression of the central nervous system
• Hyperalgesia: Heightened pain intensity from noxious stimuli that normally cause pain
• Neuroleptanalgesia: A combination of opioids and sedatives/tranquilizers that work synergistically; provides effective analgesia and sedation while decreasing the dosing requirements of both types of drugs
• Neuropathic pain: Pain resulting from injury/damage of the peripheral or central nervous system
• Nociception: Transmission of nociceptive information to higher CNS regions
• Nociceptors : Receptors associated with mainly afferent neurons that detect noxious stimuli
• Noxious stimuli: Stimuli causing tissue injury or damage (categorized as mechanical, thermal, chemical, or electrical stimuli)
• Pain: An unpleasant sensation with an emotional component, usually associated with actual or potential tissue damage
• Sedation: Depression of consciousness
• Surgical anesthesia: The plane of anesthesia characterized by unconsciousness, muscle relaxation, and analgesia appropriate for a surgical procedure
• Tranquilization: A behavioral change whereby the patient is relaxed yet cognizant of its surroundings
Pacharinsak, C. and P. Sharp. 2013. Anesthesia in nonhuman primates. In Pocket Handbook of Nonhuman Primate Clinical Medicine, ed. A. Courtney, 1–32. Boca Raton, FL: CRC Press.
Tranquilli, W. J. and K. A. Grimm. 2015. Introduction: Use, definitions, history, concepts, classification, and considerations for anesthesia and analgesia. In Veterinary Anesthesia and Analgesia, the Fifth Edition of Lumb and Jones, eds K. A. Grimm, L. A. Lamont, W. J. Tranquilli, S. A. Greens, and S. A. Robertson. 5th edition, 23–85. Ames, IA: Wiley.
2
understanding anesthetic-related equipment
Daniel Pang
2.1 carrier gas supply
2.1.1 Carrier Gas
2.1.2 Pipeline Oxygen
2.1.3 E Cylinders
2.1.4 Pressure Regulator
2.2 gas safety
2.3 the anesthetic machine
2.4 flowmeters
2.4.1 Safety
2.5 anesthetic vaporizers
2.6 O2 flush valve
2.7 carbon dioxide (CO2) absorber
2.8 breathing systems
2.8.1 Classification
2.8.1.1 Non-rebreathing systems
2.8.1.2 Rebreathing systems: Circle system
2.8.1.3 Open systems
2.9 reservoir bags
2.10 waste anesthetic gas
2.11 atmospheric pollution and occupational exposure
2.11.1 Atmospheric Pollution
2.11.2 Occupational Exposure
2.12 anesthesia machine check out procedure
2.12.1 High-Pressure System
2.12.2 Low-Pressure System
2.12.3 Breathing System
bibliography
Modern anesthetic equipment is reliable when regularly maintained and used appropriately. The provision of general anesthesia to laboratory species is often associated with additional constraints specific to the research setting, including animal positioning and access and drug and equipment restrictions. As a result, the associated anesthetic risk may be increased, emphasizing the role of the anesthetist in providing a successful outcome while safeguarding welfare.
The carrier gas, typically oxygen, is the gas used to carry an inhalational anesthetic agent to the animal. It may be supplied by connecting an anesthetic machine to a pipeline source or directly to a cylinder.
Pipeline oxygen is common in larger units/clinics where it is more convenient to have large, less portable oxygen sources housed together in a secure, remote storage room, from which supplied gas is piped to a large number of suites. The form of oxygen source depends on workplace requirements, ranging from a bank of J cylinders to liquid oxygen containers (Figure 2.1a,b).
• Pipeline oxygen is transported at a pressure of approximately 50–60 psi (345–410 kPa) to the anesthetic machine (Figure 2.2a).
• The final pressure reduction occurs at the flowmeter (see below).
• Oxygen is stored at 1900 psi in both J and E cylinders (Figure 2.2b).
• J cylinders, containing approximately 6800 L of oxygen when full, are approximately 5 feet in height and may be used to supply pipeline oxygen or can be housed in a laboratory for local use (Figure 2.2c).
E cylinders are fitted directly to anesthetic machines and contain approximately 660 L of oxygen when full. In the United States, oxygen cylinders are usually colored green, and in Canada, green with white shoulders.
• To calculate the volume of oxygen remaining in an E cylinder: 0.34 × cylinder pressure (psig); for example, for a half-full c...
