Medical Gas Systems and Vaporizers Objectives Flashcards
What are 2 sources for gases?
piped in and cylinders ( E size)
Name the colors associated with each of the following gases: Oxygen; Nitrous oxide; air; nitrogen; helium
O2: green N2O: blue air: yellow N: black He: brown
When are E size O2 cylinders considered full? How does the pressure reading change as the tank empties?
2000-2200psi & ~625-700L
as O2 is used; pressure falls PROPORTIONALLY
When is an air tank considered full? How does pressure reading change as the tank empties?
1900-2000psi w/ ~625L
Like O2: pressure falls in proportion to the amount left in the tank
When is an E tank of N2O considered full? Does the pressure reading indicate the amount left in the tank?
745psi w/ ~1590L
NO! N2O is stored as liquid; therefore pressure reading does not indicate amount left in the tank
When does the psi reading on a tank of N2O drop?
only when all of the liquid is evaporated, at which time the pressure will drop in direct proportion to the rate at which gas is used
At this point the tank is nearly empty
How do you figure out if your N2O tank is full?
weigh it
What agency specifies the purity of medical gases? Who regulates this?
United States Pharmacopeia; regulated by FDA
What agency dictates the requirements for manufacturing, filling, qualification, transportation, storage, handling, maintenance, re-qualification, and disposition of medical gas cylinders and containers?
DOT
What 3 things must be on each cylinder per the DOT?
Permanent markings: specific to each cylinder
Labeling: label or decal on side or shoulder; may not cover the permanent marking
Tags: Full, in use, empty
For the PISS system, there are 7 pin positions. What is the order of the #ed pin positions on the radius of the yoke?
left to right: 6; 5; 4; 7; 3; 2; 1
How big are the pins?
4mm in diameter and 6mm long except for pin 7, which is slightly thicker
Safe handling procedures for cylinders dictate that you should never leave a cylinder upright without ___________ and should never leave an __________cylinder on the machine
support; empty
What are some other safety handling procedures for cylinders?
Never leave the plastic tape on the port while installing the cylinder.
Never rely on the cylinder’s color for id of its contents
Never oil valves
How do you clear particles of dust, metal shavings and other foreign matter from the cylinder valve before applying any fitting?
slowly and briefly “crack” the valve away from you and others
Why should the valve always be fully open when a cylinder is in use?
marginal opening may result in failure to deliver adequate gas
What is vaporization? Why does it matter?
conversion of liquid to gas
the inhalation agents we use today are liquid that must be converted to vapor to be inhaled
What is vaporization dependent on?
vapor pressure
temperature
amount of carrier gas used
How are molecules of a volatile agent distributed in a closed container?
btw liquid and gas phases
What creates vapor pressure of a gas within a closed container?
the gas molecules inside the container bombard the surface of the liquid and the walls
What is vapor pressure contingent on?
temperature and physical characteristics of the liquid, i.e. boiling point?
What happens to vapor pressure as temperature increases?
it increases because more molecules enter vapor phase
What are the vapor pressures of the following gases at 20 degrees Celsius: Enflurane, Isoflurane, Halothane, Sevofluane, Desflurane?
Enflurane: 172mmHg Isoflurane: 240mmHg Halothane: 244mmHg Sevoflurane: 160mmHg Desflurane: 669mmHg
What does passing a carrier gas over the liquid anesthetic do?
shifts the equilibrium of gaseous and liquid phases toward the vapor phase;
