Determining reservoir bag size
If a reservoir bag is too small a patient...
- Cant inflate lungs enough
- Over inflates during expiration and increases thoracic pressures
If a reservoir bag is to big a patient...
- Difficult to breathe
- Difficult to see breaths
How to determine ET tube size
Measure from most rostral aspect of the mouth to the thoracic inlet
What is the risks if ET tube is too long?
- Only one lung will be infused with oxygen and anesthetic gas
- Mechanical dead space will be increased leading to hypoxemia
Parts of the compressed gas supply
- Compressed gas cylinder
- Tank pressure gauge
- Pressure-reducing valve
- Line pressure gauge
- Flow meters
- Oxygen flush valve
Parts of the anesthetic vaporizer
- Vaporizer inlet port
- Vaporizer outlet port and common gas outlet
Parts of the breathing circuit (rebreathing R or non-rebreathing NR)
- Fresh gas inlet ( R and NR)
- Unidirectional valves (R)
- Pop-off valve (R and NR)
- Reservoir bag (R and NR)
- Carbon dioxide absorber canister (R)
- Pressure manometer (R)
- Air intake valve (R)
- Breathing tubes (R)
- Y-piece (R)
Parts of the scavenging system
- Discharge hose (passive or active system)
- Pressure regulator (active system)
- Outflow pipe (Passive and active system)
- Pump (active system)
Check both ___ and ___ oxygen supplies at the beginning of the day to be sure they are turned on
When handling compressed gas cylinders:
- Avoid contact with flames, sparks or sources of ignition
- Turn tank on only when its attached to a yoke or pressure regulator
- Store tanks only attached to a yoke secured in a cart of chained to the wall
- Never attempt to attach a tank to a yoke that doesnt fit and never tamper with the safety on a tank
Volume in L of oxygen present in a compressed gas cylinder can be calculated by..
Multiplying the pressure in an E tank by 0.3 or by multiplying the pressure in an H tank by 3
When turning off a flow meter turn ___ just until the ball or rotor drops to ____
Helps explain why a change in vaporizer setting takes time t be reflected in the circuit and gives the anesthetist a rough idea as to how long a change in anesthetic concentration will occur
To calculate the time constant..
Divide total volume of the breathing circuit in L by the carrier gas flow rate in L/min
When the vaporizer setting is changed it takes __ times the constants to effect a __ change in the circuit concentration
Vaporizers must be checked before each procedure to make sure the liquid anesthetic level is between the ___ and ___ lines of the window. Should be kept at least ___ at all times
What to do if a bottle of liquid inhalant anesthetic breaks?
Vacate the room ASAP and allow room to air out until anesthetic agent is completely evaporated and evacuated from the room
After use of the non-rebreathing circuit the connector of the rebreathing circuit must be reattached to outlet port before next patient, failure to do so can result in...
- Inability to keep patient anesthetized
- Exposure of personnel to anesthetic gas
When manual ventilation is provided the __ must be close before the bag is pressed. Between each breath the pop-off valve must be ___ again to allow the escape of gas.
During any procedure the reservoir bag must be __ full at peak expiration
Signs that CO2 granules must be changed
- Hard brittle
- Slightly off white color
- Color change of 1/2-1/3
- CO2 level grater than 0 during peak inspiration as measured with a capnograph
- Always change after 6-8 hours of use
Maximum safe pressure manometer readings when chest is closed
- 0-2 cm H20 when patient breathing spontaneously
- 20 cm H20 in small animals when PPV provided
- 40 cm H20 in large animals when PPV provided
Small animal tubes are used on small anesthetic machine for patients over ___ and pediatric tubes for patients weighing __ to reduce mechanical dead space
Choice of machine, reservoir bag, breathing tubes, oxygen flow rate, and breathing circuit type are all based on patients...
When the oxygen tank is half full the tank pressure gauge will read
Nitrous oxide is present in the tank as a...
Liquid and a gas
Amount of oxygen an animal is receiving is indicated by
Flow meters that have a ball for reading the gauge should be read from the ___ of the ball
Most commonly recommended ratio for nitrous oxide and oxygen flow rates is
33% oxygen and 67% nitrous oxide
Minimum size for the reservoir bag can be calculated as
Flutter valves on an anesthetic machine help...
Control the direction of movement of gases
Pop-off valve is part of the anesthetic machine and helps...
Prevent excess gas pressure from building up within the breathing circuit
In small animal anesthesia when the patient is bagged the pressure manometer reading should not exceed
20 cm H20
Rebreathing is determined by...
Fresh gas flow
Non-rebreathing systems should have maintenance flow rates that are
Very high at least 200 mL/kg/min
Negative pressure relief valve is important when..
There is a failure of oxygen flow through the system
Tidal volume of an anesthetized animal is considered to be..
10 mL/kg of body weight
Scavenging system is generally attached to..
Reservoir bag that is not moving well may indicate that...
ET tube is not in trachea, animal has decreased tidal volume, and leak around ET tube
Increase in depth of anesthesia can be achieved quickly by...
Having high oxygen flow rates and high vaporizer settings
Concentration of anesthetic delivered from a nonprecision vaporizer may depend on...
Temperature of liquid anesthetic, flow of carrier gas through the vaporizer, back pressure and type of anesthetic in the vaporizer
When an anesthetic machine is operating correctly, the pressures in the machine are...
40-50 psi between the pressure-reducing valve and the flow meters, 15 psi between the flow meters and the breathing circuit, and 15 psi entering a VOC vaporizer