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Medical Gases
Kevin's Medical Gases Lecture (SIUE Nurse Anesthesia)
Question | Answer |
---|---|
What is absolute pressure? | Absolute pressure is the sum of all pressure. It is zero referenced against a perfect vacuum. Pabsolute = Pgauge + Patm |
What is gauge pressure? | Gauge pressure is the pressure relative to the local atmospheric or ambient pressure. It is zero referenced against ambient air pressure. Pgauge = Pabsolute - Patm |
What is the absolute pressure of a full E cylinder of O2? | 2200 psi + 14.696 = 2214.696 |
What is vapor pressure? | Vapor pressure is the pressure exerted by the vapor of a substance in contact with its liquid or solid phase in a sealed container. |
What is vapor pressure a function of? | Temperature |
What is saturated vapor pressure? | Saturated vapor pressure is when the substance is in dynamic equilibrium with its gaseous and liquid state at a given temperature. |
Which law predicts partial pressures? | Dalton's Law |
What is STP? | STP = Standard temperature and pressure. Standard temperature is 0°C. Standard pressure is 100 kPa. |
What is the working pressure of an E cylinder of O2? What is the service pressure of an E cylinder of O2? How much of an overfill is included in the working pressure? | 2200 psi 1900 psi 10% |
Name some oxidizing gases | O2, air, volatile agents, N2O |
Name some non-oxidizing agents | N2, CO2 |
What is boiling point? | Temperature at which the vapor pressure is equal to the atmospheric pressure. |
What is the boiling point a function of? | heat and pressure |
What is a cryogenic liquid? | A liquid which has a normal boiling point below -150 C at 1 atm. |
1 atm is equal to? | 1 barr 760 torr 760 mmHg 14.696 psi 101.325 kPa |
1 psi is equal to? | 54 mmHg |
1 mmHg is equal to? | 1.36 cmH2O |
What is the formula to convert between F and C and K? | 0°C = 273.15 K = 32°F [°C] = ([°F] − 32) × 5⁄9 [°F] = ([°C] × 9⁄5) + 32 [°C] = [K] − 273.15 |
What is the definition of a compressed gas? | A gas that, in a cont., will have an abs. press. > 40 psi at 70°F or 21.1°C. A gas having, in a cont., an abs. press. > 104 psi at 130°F or 54.4°C, regardless of press. at 70°F. A liquid having a vapor press. exceeding 40 psi at 100°F or 37.8°C. |
What color is Oxygen tank? | Green |
What color is N2O tank? | Blue |
What color is Helium tank? | Brown |
What color is CO2 tank? | Grey |
What color is N2 tank? | Black |
What color is Air tank? | Yellow |
Which dept. is responsible for the design, construction, testing, marking, labeling, filling, storage, handling, maintenance, and transportation of high pressure cylinders? | DOT |
What are the NIOSH exposure limits for HA? | 2 ppm/hr |
What are the NIOSH exposure limits for N2O? | 25 ppm/hr for OR; 50 ppm/hr for dental office; 0.5 ppm/hr when combined with HA. |
What is the maximum exposure to N2O for 8 hours? | 200 ppm |
Name 3 safety features of a compressed gas cylinder. | 1. Cylinder markings. 2. Color coding. 3. Pin Indexed Safety System(PISS). |
What are the requirements for hydrostatic testing? | 1. Interior hydrostatic pressure testing every 5 or 10 years. 2. Cylinders are pressure tested to 1.66 times their service pressure. |
What are the requirements for tensile strength? | Cylinders must have up to 10% tensile strength. |
Who performs tensile strength and hydrostatic test? | Underwriters Laboratory |
Name 8 rules for compressed gas safety. | 1. Full cyl. stored away from empties. 2. Sml cyl. placed in racks. 3. Lg cylinders chained to the wall. 4. Should be secured in upright position. 5. Never transfill. 6. Buy from licensed supplier. 7. "Crack" cylinder. 8. Must have regulator. |
What must a cylinder be marked with? | Neck ring identification Retest markings Format is: month – facility – year – + rating – * stamp + = 10% overfill. * = 10-year retest. identifying symbol manual specifications serial number Owner symbol Date manufactured |
What is the critical temperature? | The critical temperature is the temperature below at which a gas boils under pressure. The critical temperature of oxygen is -119°C The critical temperature of N2O is 39.5°C |
What happens when gas boils? | It turns into a liquid |
Will N2O be a liquid or a gas at room temp in a cylinder? | liquid |
Will O2 be a liquid or a gas at room temp in a cylinder? | gas |
To what % is an E cylinder of N2O filled? | 90-95% |
Name 2 ways to determine how full N2O cylinder is? | 1. Tare weight 2. Frost line |
Name 2 terms which describes the cooling of liquids as they vaporize. | 1. Latent Heat of Vaporization 2. Joules-Thompson Effect |
What happens to the pressure in the tank as the liquid cools due to LHV and what law explains it? | The pressure will decrese slightly. Guy-Lussac's Law (pressure and temp relationship) |
What is the type of gauge which measures high pressures? | Bourdon Gauge |
What is the type of gauge which measues lower pressures and at which pressure does it work? | Thorpe tube. 16 psi. |
What is the American National Standards Institute (ANSI) responsible for? | basic performance and safety requirements for anesthesia machine components, endotracheal tubes and connections, pressure and vacuum, and gas pressure regulators. |
What are the percentages for the components of atmospheric air? | N2 = 78.08% O2 = 20.95% Argon = 0.93% CO2 = 0.03% |