Anesthesia machine functions
- Receives gases from central supply system or pressurized cylinders
- Controls the flow of desired gases & reduces their pressure
- Measures a precise amount of gases & loads them with anesthetic vapors
- Provides gas to patient for breathing
- Provides monitoring & safety features
First anesthesia performed:
- Done by Dr Crawford Long
- March 30, 1842
Oxygen E-cylinder volume and pressure
- 660 Liters
- 2200 psig
Nitrogen E-cylinder volume and pressure
1590 liters
745 psig
Air E-cylinder volume and pressure
- 625 Liters
- 2000 psig
The O2 knob is larger & textured differently than the other gases as an added safety measure as well. True or false?
True
FiO2
O2 (L/min) + Air (L/min) (0.21)
Total Gas Flow (L/min)
Only 1 vaporizer can be used at a time for safety. There is a locking mechanism, called a ______ ______that disengages the other vaporizers once 1 is selected.
vaporizer interlock
MAC of des, sevo, iso respectively
6.0, 2.0, 1.2
Vaporizers have a ____ ____ system or a ___ ___ system.
funnel fill
key fill
Circle System Components
- Fresh Gas Inlet– where anesthetic agents enter circuit
- Unidirectional Valves
- Inspiratory Limb
- Expiratory Limb
- Gas reservoir bag
- APL
- CO2 absorber
Basic Ventilation Modes (3)
- Spontaneous–Patient is breathing on their own without assistance
- Assisted–Augmentation of tidal volume with patient making some respiratory effort
- Controlled–Total control of respiration with patient making no respiratory effort
When to change absorbent
- CO2 in inspired gases
- Color change
- Heat in canisters
In VCV at 500mL, what happens to the peak pressure & plateau pressure when you increase the respiratory rate from 10 to 20 while leaving tidal volume constant & I:E 1:2?
Increase both peak pressure and plateau pressure
What happens to the I:E ratio when you increase respiratory rate?
decreases
What happens to the I:E ratio when you increase tidal volume?
- decreases
- longer inspiration, shorter expiration
In volume control mode, waveform is _____ shaped.
triangular
In pressure control ventilation, waveform is ______ shaped.
rectangular
Who enforces medical gas purity?
FDA
As far as regulation goes, who does pretty much everything other than testing for gas purity?
DOT
The cylinder gases go through:
- A cylinder yoke
- An inlet filter
- A pressure gauge
- A check valve
- A high pressure regulator
_________ was designed as a safety feature to help ensure that cylinders are not installed on the wrong cylinder yoke.
Pin Index Safety System
Only used on cylinder sizes A-E
Pressure regulators are found ____________.
directly behind the yoke
If the pressure in the gas supply module is too high, above ________psig, the pressure relief valve opens and vents the gas to atmosphere. .
approximately 75
