1. What is saturated Vapor Pressure?
2. Therefore, volatile gases have high saturation vapor pressures because?
1. It is the amount of pressure exerted by vaporized gas in a fixed container that creates an equilibrium between the liquid and gas.
2. It take a higher pressure to force gas back into the liquid.
1. What is vapor pressure?
2. volatile gases have high vapor pressures
1. It is the amount of pressure (collisions) exerted between the molecules in a container.
2. because a lot of molecule have vaporized and are colliding more.
1. Vapor pressure is directly or inversely related to temperature?
1. directly proportional
1. what is boiling point?
2. what is another way of describing boiling point?
1. the number of molecules leaving the liquid is greater than ones returning
2. the vapor pressure at which the liquid equals the ambient or atmospheric pressure - therefore it will become a gas.
- At sea level, the vapor pressure will equal 1 atmosphere.
1. What is boiling point dependent upon?
2. What is vapor pressure dependent upon?
1. High altitude will take longer or shorter cooking time?
2. what does High altitudes do to boiling point and vapor pressure?
3. pressure cookers do the opposite?
1. longer bc the boiling point is lower.
2. lower boiling point with a lower vapor pressure.
1. What is STP?
2. Volatile agents have a greater propensity to become gases at STP?
3. Therefore, Volatile agents have a Higher or lower VP?
1. Standard temperature and pressure
- 0o C
- 1 atm 760 mmHg
3. High VP bc the gases will exert a stronger force, overcoming atmospheric pressure and will become a vapor.
1. What 3 things does vaporization depend upon?
1. ambient temp
2. vapor pressure of a substance
3. amnt of carrier gas flow.
1. When a molecule leaves liquid what happens to the temp of the liquid?
2. What effect does this have on anesthesia?
1. It cools
2. As temp cools, vaporization decreases bc it is temp dependent. Therefore, vaporizers must be constructed to have high thermal conduction to liquid to stablize evaporation rate. copper bronze, aluminum, stainless steel.
What are the Vapor pressures (STP) and boiling points of
Sevoflurane - 160 - 58.6
Isoflurane - 238 - 48.5
Halothane - 243 - 50.2
Desflurane - 660 - 22.8
What 2 things are saturated vapor pressure dependent upon?
1. Agents VP
2. ambient Temp
1. Vapor pressure = Ambient Pressure
1. The more volatile the agent, bp? SVP?
1. Low boiling point
2. High Saturated Vapor Pressure
What is Volumes percent?
1. Volumes of vapor per 100 volumes of gas
What are the vaporizer types?
- Tech 4 and Tech 5
- Uses flow over
- automatic temperature compensation
- Agent specific
2. Tec 6
- electrically heated
- Uses gas blender that injects into FGF
- calibrated agent specific
Variable bypass used what method to deliver anesthesia vapors to pt?
What happens to vapor pressure and temperature when gas flows over liquid agent?
1. Vapor pressure decreases and then more gas may escape the liquid.
2. Temp decreases which further decreasing vapor pressure.
1. What is Latent heat of vaporization?
2. What is the latent heat of vaporization for
1. the amnt of heat required to vaporize 1ml of liquid.
2. Sevoflurane - not specified
Isoflurane - 25
Halothane - 20
Desflurane - 39
1. What is evaportation?
2. What is evaporative cooling
1. conversion of liquid to gas below it's boiling point
2. loss of heat d/t evaporization
The greater the VP, the greater the latent heat of vaporization?
1. What is the only agent that requires a heat supply?
2. Why must desflurance be heated if it has a high Vapor pressure.
3. Do Desflurane use a a carrier gas?
2. Because it would cool off the liquid VERY quickly (bc it removes a lot of heat per 1ml vaporized = high latent heat of vaporization) and thus alter the delivery concentration. Therefore, Des is fully vaporized by heating to 39C / VP of 1550mmHg and injected into FGF.
3. NO - uses electricity to inject.
What are the two control points of the tech 6 to control release of Gas?
1. concentration control dial - Anesthetist
2. pressure transducer - increase or decrease with Gas flow to maintain accurate percentage delivery
1. HLH vs LHL
2. Halothane added to sevo vaporizor = ?
3. Sevo added to Halothane Vaporizor =?
4. Isoflurane into Halothane vaporizor =?
1. High vapor pressure agent added to Low pressure vaporizor = High delivery to pt
2. High delivery to pt.
3. Low delivery to pt.
4. about normal delivery d/t similar VP.
1. How many mls of gas are created by 1ml of Isoflurane?
2. How many mls of gas are created by 1ml of Halothane?
2. Halothane 240cc/1ml
1. What is the bimetallic strip on a variable bypass vaporizor.
1. as temp rises, it is the valve that preferentially diverts air to bypass instead of through the vaporizer.