The Anesthetic Machine Flashcards
What are the two types of anesthetic systems
Bain and circle
List some components of the anesthetic machine
Compressed carrier gas supply, oxygen flow meter and anesthetic vaporizer, breathing circuit, scavenging system
Describe the oxygen flow meter and anaesthetic vaporizer
Flowmeter allows oxygen carrier gas to flow at a rate of liters per minute. The oxygen gas picks up gas and anesthetic from the vaporizer.
Describe the breathing circuit
Conveys carrier gases and inhalant anesthetic to the patient and removes exhaled carbon dioxide.
What are the two types of breathing circuits
Re-breathing circuits a non-rebreathing circuits
Describe the gas scavenging system
Disposes of excess and waste anesthetic gases
What are the two types of anesthetic vaporizers
Percision and non Percision vaporizers
How much oxygen does a healthy conscious animal receive in the air
21%
How much oxygen does an animal received in the anesthetic system
Up to 100%
Why is the oxygen percentage so high in the anesthetic system
Due to the fact that anesthetized patients have a decrease respiratory rate and tidal volume which causes a risk of hypoxia with normal air.
Describe the compressed gas cylinders
Contain a large volume of courier gases in the highly pressurized compressed state.
What are the two types of compressed gas cylinders
The E cylinder and the K cylinder
Describe the E cylinder
Small and directly attached to a machine by the yoke
Describe the K cylinder
Large and freestanding. Connected to the machine via the gas line
What is the function of the anesthetic machine
To deliver oxygen and volatile anesthetic gas to and from patient and to deliver oxygen gas to critical patients. The carrier gas oxygen transport vaporized anesthetic gas to patient at a controlled flow rate.
What happens if a cylinder is dropped
It will cause it to fly at a high velocity in the opposite direction of released gas.
How do you calculate the liters of oxygen by the psi for the E cylinder
Times by .3
How do you calculate the liters of oxygen by the psi
Times by 3.1
When should oxygen tanks be changed
When pressure drops below 100 or 200 psi
When should Oxymed be called
When pressure drops below 500
Describe the pressure reducing valve
Reduces the pressure of the gas to a constant and safe operating pressure of 40 to 50 psi
What is the flowmeter
Dial attached to a graduated glass cylinder and a moving indicator that indicates gas flow rate in liters per minute
How do you read the ball indicator in the flowmeter
At the center of the ball
How do you read the rotor indicator in a flowmeter
At the top of the rotor
What happens if the flowmeters opened
Allows oxygen gas to flow through the machine if the dial is open and sets the gas flow in liters per minute
What does the flowmeter reduce oxygen pressure to
15 psi
What is the oxygen flush valve used for
Used to rapidly deliver a large volume of pure oxygen gas. Delivers oxygen gas directly into the circuit on bypasses oxygen flow meter and anesthetic vaporizer
What is the uses for the oxygen flush valve
Rapidly delivers oxygen to critically ill patient. Rapidly fills depleted reservoir bag. Dilutes anesthetic gas remaining in the circuit
What is the vaporizer used for
Convert liquid anesthetic to vapor anesthetic
How do you know when to refill the vaporizer
If over half of the anesthetic has evaporated
What is a Percision vaporizer
Delivers exact concentrations of anesthetic.
What are some components to the circle rebreathing system
Fresh gas inlet, Unidirectional valve, pop off valve, reservoir bag, carbon dioxide absorber, pressure manometer, breathing tubes
What is the fresh gas inlet
The point at which the carrier gas on the anesthetic gas enter the system
How is the fresh gas inlet connected to the circle system
By the vaporizer outlet port
What is a Uni directional valve
Located inside a clear housing that allows the anesthetist to observe the action of the valves. Can be used to monitor respiratory rate
What happens when a patient enhales in the Uni directional valve
Inspiratory Uni directional valve will open to allow passage of fresh gas to the patient
What happens to the Uni directional valve when the patient exhales
Carbon dioxide and anesthetic gas is released from the bloodstream and exhaled.
What is the use of the pop off valve
Allows excess gas to exit the system and enter the scavenger. Prevents build up of excessive pressure within the circuit
What position should the pop off valve always been when connected to the animal
Open
Describe the reservoir bag
Rubber bag that gradually inflates as gases enter the circuit or patient exhales. Deflates one patient inhales.
What are some uses of the reservoir bag
Flexible storage reservoir.
Respiratory monitoring tool
. Aids in confirming proper ET tube placement,
allows delivery of oxygen and anesthetic gases to patient
Why is bagging beneficial
Helps reinflate collapsed alveoli. can normalize respiratory rate
How do you calculate which of reservoir bag you need
Minimum of 60 mL per kilogram
What happens if your reservoir bag is too small
Reservoir may not be large enough for patient to breathe easily. May over inflate during expiration increasing the pressure in the patient’s airways
What is the optimum size for reservoir bug
Three quarters full at peak inspiration
What is the use of the carbon dioxide absorber
Absorb carbon dioxide
How do you know when you need to change the carbon dioxide absorbing soda lime
The pH indicator causes granules to change color when saturated
After how many hours of use is it recommended to change soda lime granules
14 to 18 hours of use
What is the function of the pressure manometer
Indicates the pressure of gases within the breathing system
What is the negative pressure relief valve used for
Admits room air into the breathing circuit if negative pressure is detected
What are the breathing tubes used for
Carries anesthetic gas to and from the patient
What are the three types of breathing systems
Total rebreathing (closed) Partial rebreathing (semi closed) Non rebreathing
Describe the total rebreathing system
Closed Pop off valve
All gasses are recirculated
Slow turnover of gases
Only for animals over 7-10kg
What are three concerns with total rebreathing
Co2 accumulation
Difficult to exhale
O2 depletion
Describe a semi closed system
Pop off left open
All exhale gases escape to scavenger, requires high oxygen flow rate.
For animals less than 10kg
Describe the brain system
Tubing allows incoming gases to be warmed by the surrounding exhaled gases. Lighter and less cumbersome system. No CO2 canister
Describe the induction flowrate
High oxygen flow rate to saturate circuit with carrier gas and static
Describe maintence flowrate
Oxygen flow rate reduced
Describe the recovery flow rate
Hi oxygen flow rate
What is the unit for waste anesthetic gas concentration
Ppm
What are the two categories of health hazards induced by long-term effects of anesthetic gas
Short-term problems and long-term problems
What are some short-term problems of anesthetic gas
Fatigue, headache, drowsiness, depression, irritability
What are some long-term effects of anesthetic gas
Reproductive disorders, liver and kidney damage, bone marrow abnormalities
What is the list of gas toxicity in order
Isoflurane
Sevoflurane
Halotane
Methoxyflurane
What are two types of scavenging systems
Active system
Passive system
What does the active system do
Suction created by vacuum pump draws gas in the scavenger
Describe passive systems
Positive pressure of gas in the machine pushes gas in the scavenger
What is a risk in active and passive scavenging systems
Obstruction
What are the two types of leak test
High pressure leak test at 50 psi
low pressure leak test at 15 psi
Why do you do a high pressure leak test
To check for leaks between gas tanks and flowmeters
Why do you do low-pressure leak test
To test for leaks from anesthetic machine to breathing circuit
How do you do a high-pressure system leak test
Turn the tank on.
Note tank pressure reading.
Turn tank off.
Recheck tank pressure gauge one hour later
Describe doing a low-pressure system leak test
Close pop off valve and occlude patient port.
Set flowmeter to 2 L per minute.
Turn off flowmeter when bag fully inflated
When is a high pressure leak test done
Every week
When is a low pressure leak test done
Every time machine is assembled for you
What are seven ways to minimize gas release
Minimize use of anesthetic chambers. Avoid using masks to induce or maintain anesthesia.
Used cuffed eT tubes for adequate size when possible.
Ensure reservoir bag is synchronized with patients respiration.
Avoid turning vaporizer and flowmeter on until machine is connected to ET tube.
Do not release contents of reservoir bike into room area.
Leave patient attached until extubation to allow expired gasses to enter the scavenging system
