SOP 14.5 - Anesthetic Machine Setup, Surgical Suite

1. Introduction and Definitions:

Anesthetic setup is an important factor before any surgical procedure. The safety of the patient and personnel must be considered. Proper maintenance of the machine and the equipment should be done on a regular basis.

Abbreviations: 

Animal Care Services ACS, Principal Investigator PI, subcutaneous SC, intravenous IV, intraperitoneal IP, intramuscular IM, per os PO, per rectum PR

2. Materials:

• Oxygen (either a stand-alone H-tank or an oxygen system in the facility)
• Anesthetic machine (serviced within the last year)
• Rebreathing tubing system (F or Y circuit)
• Scavenging system (either a system within the facility or f/air canister)

3. Procedures

Set up Oxygen source and Oxygen flow rate for the patient:

• To calculate what the oxygen flow meter should be set to, take the weight of the patient (kg) x 200 mL/kg/min. Change the mL/min to L/min to match the oxygen flow meter unit
• Decide how long the patient will be under anesthetic and determine approximately how much oxygen will be needed for the procedure. (Calculate how many litres are needed per hour and multiply how many hours the surgery is expected to take).
• Turn on the Oxygen tank if there is one in the room or connect directly to the facility Oxygen line. Check the psi on the H-tank, a full tank will contain 2200 psi. To calculate the approximate amount of oxygen in litres contained in the tank you multiply the psi x 3. (eg. If the H-tank reads 1500psi there is approximately 4500L remaining). Ensure there is enough oxygen remaining for the procedure.

Set up the Anesthetic Machine:

• The oxygen tank will have tubing that can connect to the back of the anesthetic machine.
  
• Attach the appropriately sized rebreathing bag to the anesthetic machine. Using the weight of the animal and multiplying it by 60 will give you the size of bag (in mLs) that you need. Ensure to always round up when determining the bag size.
• Connect the metal connection providing fresh Oxygen is attached securely in the machine.
• Connect the F circuit to the anesthetic machine.
• Ensure the scavenge system is hooked up and exhausting either into the facility scavenge system or the f/air canister (ensure to weigh after each use and discard after 50g weight increase).
  
• Ensure CO2 absorbent is not expired. CO2 absorbent should be replaced at a minimum every 3 months, alternatively, it should be changed sooner following manufacturers guidelines or when the granules turn purple, whichever occurs first. Soda lime needs to be changed every 14 hours and (https://www.dispomed.com/detect-soda-lime-exhaustion/) Sodasorb needs to be changed every 8 hours (https://www.midmark.com/animal-health/resource-training-library/blog/sodasorb-lf---the-co2-absorbant-with-safety-you-can-see). Monitoring a patients capnograph during any anesthetic procedure is an important step to ensure the CO2 is being properly absorbed.
• Check Isoflurane levels to ensure that the machine is full.
• Pressure check the machine to ensure that there is no leaking anesthetic gases.
  • Plug the end of the F circuit tubing securely
  • Close the pop-off valve on the machine
  • By turning on the flow meter fill the anesthetic machine with oxygen until the system pressure reads between 15-20 cm/H2O
  • If the system can hold the pressure without dropping, we can be confident there is no leak in the system