chemphys Flashcards
Are fluid compressible?
Minimal to None
Gases and fluid maybe compressible and change volume with change in ?
Temp and pressure
Molecules that have same chemical Formulas but different structures are called?
Isomers
What law states that Matter is made of minute particles called molecules, that exist in various states (solid, liquid, gas, or plasma).
Molecular theory of matter
molecules are in constant motion (random motion) and have a degree of attraction between them called van der waals forces. What law is this?
Kinetic Theory of Matter
The temp at which a gas cannot be liquefied regardless of how much pressure is applied is called?
Critical temp
What are the outermost shell electrons called
Valence electrons
what do are ions
They carry positive and negative charges
What kind of Bond exist in water?
Polar covalent
Will solubility of gas in water increase or decrease with increase temp
Decrease
Will solubility of gas in water increase or decrease with increase pressure.
Increase
Is gas solubility in liquid inversely or directly proportional to temp
Inversely proportional
IS gas solubility in liquid directly or inversely proportional to pressure
Directly proportiona;l
What is the effect of volatile agent general anesthetics on Hypothermic patient
Wakes up slowly.
What law is this? At constant temperature:
The amount of gas dissolved in a liquid is directly proportional to the partial pressure of the gas in contact with the solution
Henry’s Law
Between oxygen and co2 which is most soluble in blood
C02
Name 2 applications of Henry’s Law
- Increasing Fio2
- Increasing the concentration of anesthetic gases by increasing the partial pressure of the gas and hence speeding up delivery into blood and brain.
- Allows calculation of oxygen delivery
- Allows calculation of oxygen and co2 content in blood
State Grahams LAW
A gas diffuses at a rate that is inversely proportional to the square root of its molecular weight.
If a Gas has a higher Molecular weight,would its rate of diffusion increase or decrease
Decrease.
Name 3 contraindications for Nitrous use
- Pneumothorax
2.Middle ear surgery
3.Belly Surgery should be only used in short duration
4.During Nitrous use,cuff should be monitored frequently as it can diffuse into the cuff and increase cuff pressure.causing tracheal necrosis.
Mostly will diffuse into airfilled cavities
State Ficks Law
Diffusion of a gas across a semipermeable membrane is directly proportional to the partial pressure gradient, the membrane solubility of the gas, and the membrane area, and is inversely proportional to the membrane thickness and the molecular weight of the gas.
The diffusion of gas across a biological tissue is explained by what law?
Ficks LaW
Name the clinical applications Ficks law
- Copd
- Diffusion hypoxia
- Placenta drug transfer
- Allows determination of pulmonary Gas exchange
If there is a reduced alveola surface tension will induction be fast of slow
Slow
What is Diffusion hypoxia
During emergence from nitrous oxide anesthetic, rapid elimination of nitrous oxide from the lungs dilutes other alveolar gases, producing alveolar “diffusion hypoxia.”
When Nitrous is in Use,what effect does it have on Air Pocket
Airpocket expansion
N20 is more soluble in blood than Nitrogen.true or false
True
In Ficks Law,Diffusion happens down a concentration gradient true of false
True
What device is used to measure high pressure i Anesthesia
Bourdon gauge
What is the Bourdon gauge Zero referenced to
Zero referenced to the Atmospheric pressure
0 bourdon=760mmhg
How Does the Bourdon gauge Work?
Bourdon gauges contain a coiled tube that expands as pressure is applied.
A linkage connects the coil to a rotating arm that records the pressure.
Gauge pressure is zero referenced at atmospheric pressure and reads zero at 760mm Hg at sea level
What is the Gauge pressure
Absolute pressure-Atmospheric pressure.
state Boyles LAw
Pressure is Inversely Proportional to volume while temp is held constant.As pressure increases vol decreases
Name the Applications of Boyles LAW
Pneumatic Bellows,Squeezing the Reservoir bag,diaphragm on inspiration and expiration during spontaneous breathing
Which gas law states that “the volume of a given gas is directly proportional to the Kelvin Temperature”
Charles Law
___________ remains constant in Charles Law
Pressure
In charles Law, as __________ Increases The volume Increases
Temperature
State Gay Lussacs Law
Pressure of gas is directly proportional to its temperature if the volume remains constant
As Temperature Increases,_____________Increases in Gay Lussacs Law.
Pressure
what is the ideal Gas law?
PV=nRT
Name the Application Of ideal gas law
As a cylinder of compressed Gas empties,pressure falls
The Pressure decreases as The moles Decreases in Ideal Gas laws T/f
T
what is 1mole of a substance
6.02x10 E23. contains 22.4L
Name one Application of Avogadro’s hypothesis
Calibration of Vaporizers
Which Law states that in a mixture of gases, the pressure exerted by each gas is the same as that which it would exert if it alone occupied the container.
Daltons Law of partial pressure
Ptotal=p1+p2+p3
The concentration of the vapor (measured as a percentage at 1 atmosphere, i.e the partial pressure) that prevents the reaction to a standard surgical stimulus in 50% of subjects is called
MAC(Minimum Alveoli Concentration)
Minimum alveolar concentration or MAC is the concentration of a vapour in the alveoli of the lungs that is needed to prevent movement in 50% of subjects in response to surgical stimulus
What would be the reason why a Gas cannot be Liquefied?
Because it Ambient temperature is above the critical point.
When can a gas be liquefied?
This can happen when enough pressure is applied to a gas that its ambient temp is below critical point.
Why cant oxygen Be Liquified?
Its ambient temp is above critical point
WHy does Nitrous have to be weighed
Its part liquid and part gas.
What is the Critical Temp of oxygen
-119 deg celcius
Can Oxygen Be liquefied at room temp?
No
The main oxygen storage per hospital supply is in what form? liquid/Gas
Liquid
GAses are stored at what temp in the hospital supply
-160 deg celcius
Nitrous oxide Crit temp is?
36.5 deg celcius
What form is Nitrous oxide stored
Liquid
what pressure is nitrous oxide stored
745mmhg
What is Adiabatic
A change in temperature of the matter without gain or loss of heat
Expansion of A Gas Causing cooling effect is called
Joule-Thompson effect
State Poiseuille’s Law
Describes the relationship between rate of flow and:
1) pressure gradient across length of tube – direct
2) radius4 of the tube – direct
3) length of the tube – inverse
4) viscosity of the fluid – inverse
Q= pi r^4/\P
8 nL
Name the Applications of Poiseuille’s Law
IV Flow
Airways
Vascular flow – Polycythemia vs. Anemia
Thorpe Tubes – at low flows
Poiseuille’s Law is Apllied in what kind of Flow?
Lamina or Turbulent?
Lamina
Density flow(Turbulent) is used in which can of flow meters
Variable orifice(Heliox) Flow meters
Density flow is determinant of flow when flow is?
Turbulent and high flow
Viscocity Flow is determinant of flow when flow is
Lamina and low flow
At what point is Laminar flow converted to turbulent flow
when Reynolds number is >2000
what is Reynolds number?
=Velocityxdenstiyxdiameter/viscosity
Name the Factors that Change Flow from Laminar to Turbulent
- Increased velocity
- Bend >20 degrees
- Irregularity in the tube
State the Bernoullis principle
The lateral wall pressure is LEAST at the point of greatest constriction and the speed is the GREATEST
Thus, flow will be faster through the constricted portions and slower at the wider portions of a tube
Narrow Diameter = ↓ Lateral wall pressure = ↑ Speed
Wider Diameter = ↑ Lateral wall pressure = ↓ Speed
Name 3 applications of the Bernoullis principle
Nebulizers
Venturi Oxygen Masks (24-40% O2)
Jet Ventilation
State the Law of Laplace
The pressure gradient across the wall of a sphere or tube is directly proportional to the wall tension and inversely proportional to the radius of the vessel
What happens to Wall tension if the Vessel Increases?
Wall Tension Increases
Effects of Laplace law can be found in
ALveolus,Capillaries walls,arterial walls,Aneurysm,Emphysema,Baby’s First Breath
Clinical Applications of Laplace
1.Normal Alveoli and the need for surfactant during expiration
2.Vascular Pathology- Aneurysm rupture due to increased wall tension
3.Ventricular volume and work of the heart- a dilated
ventricle has greater tension in its wall (end diastolic
pressure rises)
what law states :
That resistance which will allow one ampere of current to flow under the influence of a potential of one volt
v=IR
R=V/I
ohms law
Name 2 clinical Applications in Ohms law
Thermistors
strain gauges in pressure transducers
Sources Of Electricity in the OR
Metal is a good conductor, your patient is lying on a metal bed, surgery causes bleeding, blood is wet, the room is full of electrical equipment RISK TO THE PATIENT = BURNS
Macroshock: Current distributed through the body, culprit: faulty wiring, improper grounding
Microshock: Current applied in or near the heart, culprit pacing wires, fault equipment during cardiac cath
Electrocautery
Microshock power level to cause VFib
50-100 microamps
Macroshock power level for Vfib and complete physiologic damage
100-300 milliamps -V-Fib, resp intact
6000 milliamps -complete physiologic damage
