Medical Gases Flashcards
2 Sources For Gas
Inlet gas or E-cylinder
Gas Colors:
- O2
- N2O
- Air.
- N
- H
- Green
- Blue
- Yellow
- Black
- Brown
Regulatory Agency for:
- Gas purity/contents
- Manufacturing and everything else
- FDA
2. DOT
Vapor Pressure: Enflurane
172 mmHg
Vapor Pressure: Isoflurane
240 mmHg
Vapor Pressure: Halothane
244 mmHg
Vapor Pressure: Sevoflourane
160 mmHg
Vapor Pressure: Desflurane
669 mmHg
Latent Heat of Vaporization
Calories required to change 1g of liquid to vapor (without temp change)
Specific Heat
Calories required to increase temperature of 1 gram of substance by 1 degree C
Altitude effects on:
- Variable Bypass
- Tec 6
- At high altitude/lower barometric pressure, deliver higher concentration of anesthetic; at low altitude/high barometric pressure, delivering lower concentration of gas
- At high altitude/lower barometric pressure, you deliver lower concentration of anesthetic; at lower altitude/higher barometric pressure, delivering higher concentration of gas.
* Vaporizers must be calibrated based on the altitude
TEC 6:
- Flow and control of gas
- Internal pressure
- 2 paths; diluent flow, gaseous Des that meet at outflow; Des concentration controlled by differential pressure transducer and dial controlled by anesthetist
- 1500 mmHg (twice atmosphere) of Desflourane
Minimal Carrier Gas flow for Sevo
2 L/min
Cylinder Permanent Markings:
- DOT3AAA
- 2015 psig
- Next line #
- sign
- sign
- DOT specification #
- Maximum pressure in PSI
- Manufacture serial number
- Can fill up to 10% more than max pressure
- Can be serviced every 10 years instead of 5
Nitrous Oxide Pressure/Volume/Weights at:
- Full
- Half Full
- No Liquid N20
- Nearly Empty
- 745 psi, 1590 L, 20.7 lbs
- 745 psi, 795 L, 17.3 lbs
- 745 psi, 250 L, 14.2 lbs
- 350 psi, 125 L, 14.1 lbs
Cylinder Labels:
- White Panel
- Diamond Shape
- Signal Words
- First label on left; denotes the name of the contained gas
- Denotes hazard class of contained gas
- Words like CAUTION or WARNING that elaborate on hazards and prevention measures
Cylinder Tags
Denote amounts only, do not identify; will have FULL, IN USE, or EMPTY connected by perforations
DISS system components
Diameter Index Safety System, provides non-interchangeable connections; consists of nipple and nut on pipeline and body on machine
Cylinder Safe Handling (7 items)
- Never stand upright without support
- Never leave empty cylinder on machine
- Never leave plastic on ports while installing
- Never rely only on cylinder COLOR
- Never oil valves
- Always crack slowly away from other personal to expel debris
- Valve should always be fully open when in use.
Vaporization Definition
Molecules of a liquid constantly convert to a gas; evaporation is a surface phenomenon that occurs naturally; vaporization depends on vapor pressure, temperature, and type of carrier gas
Vapor Pressure Definition
Pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid’s evaporation rate.
Thermal Conductivity
Measure of speed with which heat flows through a substance; higher thermal conductivity, better substance conducts heat
Boiling Point
Occurs when vapor pressure=atmospheric pressure
3 characteristics of vaporizers
Agent Specific, Temperature compensated, variable bypass
Flow of gas in vaporizer (6 items)
- Inlet port
- Pressure compensator
- Vaporizing chamber
- Over anesthetic agent
- Past control cone
- Through outlet port
Vaporizer control components (4)
- Concentration dial
- Temperature compensating bypass
- Control cone
- Internal on/off switch
