Anesthesia Lab Final Flashcards
What would delivering anesthetic gas in air (21%O2) lead to in the patient? Why?
Hypoxemia due to hypoventilation & V/Q mismatch induced by anesthetics themselves
What is the minimum acceptable % of O2 delivered for people & small animals?
30-35% (FiO2 = 0.30-0.35)
what is the metabolic requirement for oxygen?
What is the minimum O2 flow required?
5-10mL/kg/min
This would be the minimum O2 flow required!
how are E cylinders usually attached to anesthesia machine?
directly via a yoke
How is cylinder pressure usually measured
PSI (pounds per square inch)
How is breathing system pressure measured?
cmH2O (centimeters water)
Where is the low pressure in an anesthetic machine system?
between flowmeter output & common gas outlet
What is considered the breathing system pressure
the pressure in patients’ lungs
What is the capacity of E cylinder?
660 L
What is the capacity of H cylinder?
6600 L
What are both the E & H cylinder filled to a pressure of?
2200 psi
How to calculate remaining O2 in a tank?
Minutes remaining?
What is DISS
Diameter index safety system
Non-interchangeable gas-specific threaded connection system
What is a regulator
AKA prssure-reducing valve
decreases tank pressure to a safe working pressure (approx. 50 psi) which is supplied to flowmeter
Where do you read the flow in a flowmeter
MIddle of ball
Top of bobbin
Where should O2 flowmeter be when there are multiple flowmeters?
On far right (downstream of all other gases) to prevent delivery of a hypoxic gas mixture
At what rate does the quick flush deliver gas when used?
Between 35-75 L/min directly to patient circuit
When is it appropriate to use the quick flush?
What type of gas mix will be flushed?
What precaution must be taken if quick flush is to be used?
To quickly decrease anesthetic gas % in the circuit
No mix! this is pure O2 that has bypassed the vaporizer
Patient should be disconnected from the circuit temporarily before the O2 flush valve is utilized
What is a possible complication of use of the quick flush?
Barotrauma = PNEUMOTHORAX
What do anesthetic vaporizers do
Deliver selected % of anesthetic vapor to fresh (common) gas outlet
“volumes percent”
What is vapor pressure
pressure exerted by vapor molecules when liquid & vapor phases are in equilibrium
What is saturated vapor pressure
maximum administration percentage of a vapor
How do vaporizers work
a specific concentration is created by variable-bypass system, where fresh gas flows over a reservoir of liqui anesthetic & mixes with carrier gas
What is a common feature of all modern vaporizers?
What type is it if the anesthetic % is known?
They are out-of-circuit (VOC)
precision vaporizer
What were vaporizers in the past considered?
VIC - vaporizers in circuit
Non-precision
cannot produce a known anesthetic %
NOT RECOMMENDED CURRENTLY
What must you not do before transporting a vaporizer
Cannot be tipped - must be emptied before transporting
What is the common gas outlet?
Where is it
where gas exits the vaporizer
connected by a hose to the fresh gas inlet
What are the 2 types of pt breathing systems & examples of each type?
Re-breathing system
- circle
- Universal F
Non-rebreathing system
- Bain (modified Mapleson D)
- Mapleson F
Advantages of rebreathing system?
Disadvantages?
Advantages: Lower fresh gas flow rate required
- pt breathes warm, humidified gases
- saves $
- decr environmental pollution
Disadvantages:
- higher resistance to breathing due to valves
- changes in anes gac conc occur slowly d/t lower fresh gas flow
- more components→more leak potential
Advantages of non-rebreathing system?
Disadvantages?
Advantages:
- Light, minimal dead space, minimal resistance to ventilation (use for small pts <3kg)
- Anes gas conc changes rapidly d/t high fresh gas flow & sm circuit volume
- fewer components→less potential for leaks
Disadvantages:
- pt breathes cold, dry gas
- more $
- incr envionmental pollution
How to calculate tidal volume (TV) & reservoir bag size for rebreathing system
Tidal volume = 15mL/kg
Bag size = TV x 6 round up to nearest L
For horses usually 30 L bag or 20 L ventilator capacity
