Veterinary Technician National Exam (VTNE) Practice Exam

Which choice correctly lists the order in which gases pass through a typical circular anesthetic circuit?

1. Pressure regulator, vaporizer, patient, CO2 canister, flowmeter

2. Vaporizer, pressure regulator, flowmeter, CO2 canister, patient

3. Pressure regulator, flowmeter, vaporizer, patient, CO2 canister

4. Flowmeter, pressure regulator, vaporizer, patient, CO2 canister

The correct answer is: Pressure regulator, flowmeter, vaporizer, patient, CO2 canister

The correct sequence of gases passing through a typical circular anesthetic circuit begins with the pressure regulator, which reduces the pressure of the gas coming from the tank to a safer level for use. Following this, the flowmeter is employed to quantify the flow rate of the gas mixture. After the flow has been set, the gas enters the vaporizer, where the anesthetic agent is added to the carrier gas, allowing for delivery of the anesthetic in a controlled manner. The gas then flows to the patient, where it is inhaled. Finally, any exhaled carbon dioxide from the patient is captured in the CO2 canister to prevent rebreathing of exhaled gases. This order is essential for ensuring the safe and effective administration of anesthetics during procedures, as each component serves a specific purpose in controlling the flow and concentration of anesthetic drugs being delivered to the patient.