Physics Final Flashcards
Human tissue heat capacity is ____ that of water
0.85
Define specific heat capacity
amount of heat required to raise temperature of 1 kg of a substance 1 K
Define heat capacity
amount of heat required to raise the temperature of a given object by 1 K
What is the specific heat capacity of water?
4.18 kJ kg-1
1 kcal kg-1
1 Cal/g
What is the SI unit of heat capacity?
J/K
1 calorie = ? Joules
4.18
1 Calorie = ? calories
1000 calories
What is the specific heat of blood?
0.86 cal/ (gm x *C)
You administer 4 L of IV fluids @ 21*C for a 70 kg patient. What effect will this have on the patient’s temperature?
lower it by approx. 1*C
Vapor pressure is dependent on what?
temperature and substance
Do you lose energy or gain energy when vaporizing water?
Lose energy
What is HME?
Heat moisture exchanger
Why do we need humidification?
- maintain function of cilia
- maintain surfactant properties
- reduce drying of secretions
What type of humidifier is the most efficient?
ultrasonic nebulizer
What is the difference between absolute and relative humidity?
Absolute: mass of water vapor in a given volume of air
Relative: Absolute vs. amt required to saturate that given vol. (ex. weather - usually %)
What is difference between hydrophobic and hygroscopic?
Hydrophobic hates water (pore membranes)
Hygroscopic loves water (wool and foam coated membranes)
What does HMEF stand for?
Heat Moisture Excange Filter
What does the S beside the number on HME mean?
Means a sample port available on filter
What does the number on the side of the HME represent?
How much tidal volume can accurately be put through humidifier
What are some hazards of HME’s?
Excessive breathing circuit resistance which could limit spont breathing
Weight could cause kinking of ETT which causes airway obstruction
Can aspirate HME material
Increased dead space rebreathing
Another site for airway disconnection
What effect do HME’s have on dead space and airway pressure?
A. None
B. Increase, Decrease
C. Decrease, Increase
D. Increase Both
E. Decrease Both
D. Increase both ANNA DID YOU MEAN D INCREASE BOTH???????
YES!!!!!!! FORGOT TO CHANGE THE ANSWER AFTER I ADDED A 2ND PART TO THE QUESTION
Maximum deposition occurs in the alveoli for particles with what diameter?
3 micrometers
What is the relative humidity of the trachea and the HME?
- 77 trachea (77%)
- 57 HME (57%)
What is Henry’s Law?
At a particular temperature the amount of a given gas dissolved in a given liquid is DIRECTLY proportional to the PARTIAL PRESSURE of the gas in equilibrium with the liquid.
Gases are (more/less) soluble at higher temperatures?
LESS!!!
ANNA I HAVE THAT GASES ARE LESS SOLUBLE IN MY NOTES???
I SHOULDN’T TRY TO STUDY WHILE FALLING ASLEEP
What is the Otswald solubility coefficient?
the volume of gas which dissolves in one unit of the liquid at the temperature concerned (is independent of pressure)
What is the Main difference between Otswald solubility coefficient and Bunsen solubility coefficient?
Otswald is used more in Anesthesia and does not have to correct for temp. and pressure
What is the standard temperature used when determining Ostwald coefficients?
37* C
Define partition coefficient
Ratio of the amt of substance present in one phase compared with another, the two phases being of equal volume and in equilibrium
What is the blood-gas partition coefficient for N2O?
0.47
What is the blood-oil partition coefficient for N2O?
0.34
What is the oil-blood partition coefficient for N2O?
2.98
When determining partition coefficients, what must be accounted for?
The order of the phases you wish to determine.
EX gas-blood partition coefficient (1L / 0.47L) much different than blood-gas coefficient (0.47L / 1L)
List the path/order a gas takes to enter body.
Machine –> lungs
Lungs –> blood
blood –> fat (brains most important for us)
The Oxygen content equation is
CaO2 = 1.36 x (SaO2/100) x 0.0031 x PaO2
What is the normal range for CaO2?
16-22 ml O2 / dL
What is the formula for uptake of inhalational agents?
Uptake = Solubility x CO x (Pa-Pv)
What is a MAC?
Minimum Alveolar Concentration in
Percent at equilibrium, at 1atm, at which 50% of test subjects will not respond to noxious stimuli
What is the determining factor of whether the patient has reached a proper MAC value and anesthesia has been produced?
Partial pressure of anesthetic agent in the brain
What is the partial pressure in the brain for an agent @ MAC of 2%?
What is partial pressure that produces anesthesia for an agent at MAC of 1%?
(0. 02 x 760mmHg) = 15.2mmHg
7. 6 mmHG
What is the MAC of Sevo for a 24 year old?
How does it change per decade?
2.6%
Decreases 0.2%
Gases with a (lower/higher) solubility will reach pressures faster
lower
Anesthesia is produced by what?
the partial pressures of the anesthetic agents in the brain tissue
Concentration has what effect on induction?
Greater concentration = faster induction