medical gas systems & vaporizers Flashcards
color coding
oxygen = green nitrous oxide = blue air = yellow nitrogen = black helium = brown
E oxygen cylinders
full at…
2000-2200psi
625-700L
pressure falls proportionally to amt in tank
Air cylinders
full at…
1900-2000psi
625L
pressure falls proportionally to amt in tank
N2O cylinders
full at…
745psi
1590L
stored as liquid, pressure doesn’t indicate amt left in tank
purity of medical gas
specified - united states pharmacopoeia
enforced - FDA
department of transportation (DOT)
establishes requirements for manufacturing, filling, qualification, transportation, storage, handling, maintenance, requalification, and deposition of medical gas cylinders and containers
permanent markings
the DOT regulations require specific marking on each cylinder, etched in
labeling
each cylinder must have a label or decal on side or on shoulder, but may not cover any permanent markings, taped, adhered
tags
full, in use, empty connected by perforations
denotes Amt of cylinder contents and is not used for ID purposes
DISS
diameter index safety system
non-interchangeable connections for medical gas lines
connection consists of a body, nipple, nut combination
only properly mated parts fit together and allow threads to engage
required for every anesthesia machine
safety for handling cylinders
1 - never stand cylinder upright w out support
2 - no empty cylinders on machine
3 - no plastic tape on port when putting on
4 - dont rely on color alone for content info
5 - never oil valves
6 - “crack” valve… particles dust shavings etc cleared, away from everyone else
7 - valve fully open when cylinder inure, marginal opening may result in failure to deliver adequate gas
vaporization dependent on
1 - vapor pressure
2 - temp
3 - amt of carrier gas used
enflurane vapor pressure
172
isoflurane vapor pressure
240
halothane vapor pressure
244
sevoflurane vapor pressure
160
desflurane
669
latent heat of vaporization
number of calories required to change 1 gram liquid into vapor without a temp change
energy for vaporization comes from the liquid itself (or from an outside source)
speficic heat
number of calories required to increase temp of one gram substance by one degree centigrade
liquid, solid, or gas
thermal conductivity
measure of speed with which head flows through a substance
higher the thermal conductivity, the better the substance conducts heat
altitude
increased altitude = decreased barometric pressure
decreased altitude = increased barometric pressure
boiling point
vapor pressure = barometric pressure
temperature
direct relationship
increased temp = increased vaporization
decreased temp = decreased vaporization
variable bypass vaporizer
portion of gas flow pass into vaporizing chamber where it becomes saturated w vapor
vapor-laden portion then rejoins gas flow for dilution to deliverable concentrations