Chem Exam 3 Flashcards
alveolar gas equation
PAO2=FiO2 x (PB-PH2O(alveolar))-(PaCO2/RQ)
or
PAO2=FiO2 x (PB-47mmHg)-(PaCO2/.8)
what parts of the alveolar gas equation come from the ABG
PaCO2 and PaO2
alveolar arterial oxygen gradient
(PAO2-PaO2). normal 5-15mmHg
reasons for normal A-a difference
regional VA/Q mismatch (shunt), anatomic shunt of blood related to thesbian circulation or bronchial circulation
reasons for pathological A-a difference
anatomy shunt of blood related to PFO or intrapulmonary shunt
-alveolar-capillary membrane diffusion block
arterial-alveolar ratio
PaO2/PAO2. used for high FiO2. normal .75 or greater.
P/F ratio
PaO2/FiO2. <200 is ARDS
Henrys Law: for every 1mmHg of pressure applied, there is __________(O2)
.003ml of O2 dissolved in 100ml of blood
Henrys Law: for every 1mmHg of pressure applied, there is ________ (CO2)
.067 of CO2 dissolved in 100ml of blood
Oxygen Content Equation
CaO2=(SaO2 x Hgb x 1.34) + .003(PaO2)
Amount of oxygen delivered to tissue =
O2 content x CO
Daltons Law
total pressure of a gas is equal to the sum of the pressures of the individual gases in the mixture. r/t alveolar equation
Henrys Law
addresses dissolved oxygen. amount of gas dissolved in a liquid is directly proportional to the pressure applied to the gas that overlies the liquid
Henrys Law Equation
Cgas=Pgas/KH where Cgas is the dissolved gas concentration, Pgas is the partial pressure of gas above the liquid (represents gas molecules entering liquid). and KH is the solubility constant for a particular gas in a particular solvent (liquid). represents gas molecules LEAVING liquid.
KH
the higher the KH, the greater the tendency for gas to leave solution. thus, concentration of gas dissolved liquid would be lower and is inversely proportional to Kh
Boyles Law
at a constant temperature, pressure of gas is inversely proportional to volume. P1 x V1 = P2 x V2
Grahams Law
solubility over sq root of MW. CO2 is heavier than O2 and therefore will diffuse slower
Charles’ Law
at a constant pressure, volume of a gas is directly proportional to its absolute temperature. V1/T1=V2/T2
Boyles law PLUS Charles’ Law
dealing with constant number of moles of gas
P1 x V1/T1) = (P2xV2 /T2
Gay Lussacs Law
at a constant volume, the pressure of a gas is directly proportional to its absolute temperature
P1/T1=P2/T2
Ideal Gas Law
Combines Avogadro, Boyle, Charles, Daltons Laws
R=PV/nT where 760 x 22.4/1mole x273 = 62.36
Adiabatic Effect
a gas in a container which is isolated thermally from its environment becomes warmer when it is compressed and cools when it expands. Usually so rapid that heat liberation doesn’t have time to dissipate so you will feel it.
Concentration Effect
accelerating the rate of rise of alveolar concentration of a gas by increasing inspired concentration (FA/Fi=fraction of alveolus/frraction inspired.) optimal ratio =1
Inferior (Apical) Leads
2,3, aVF. RCA artery
Anterior Leads
V1-V4, LAD
Lateral
I, aVL, V5-V6. left circumflex
normal deflection
-30 to 60
left axis deviation deflection
-30 to -90
right axis deviation deflection
90 to 180
reasons for left axis deviation
lying down, LV enlargement, inferior MI, right sided tension pneumo
reasons fo right axis deviation
normal in children, RV enlargement, lateral MI (circumflex), left sided tension pneumo
degrees of the V leads
V1 120 V2 90 V3 75 V4 60 V5 30 V6 0
Beer Lambert Law
amount of energy absorbed or transmitted by a solution is proportional to the solutions molar absorptivity and the concentration in solute. more concentrated solution absorbs more light than a more dilute solution.
CO2 will absorb light at how many nm?
4300
end products of neutralization rx
CaCO3 (calcium carbonate), water, and heat. this is an exothermic rx.
when does indicator dye turn ethyl violet and what does it respond to
when pH is <10.3, responds to hydration not alkalinization
prevention of absorbent desiccation and CO2 formation
use low gas flows, change absorbent at least weekly, shut off all flow meters when not in use
how is CO2 measured
infrared light absorption (4300nm)
deoxyhemoglobin
absorbs light at 660nm.
oxyhemoglobin
absorbs infrared light at 940nm
methemoglobin definition
HGB in which iron heme group is in ferric state, which means it cannot bind oxygen and carry oxygen to tissues
reasons for methemoglobin
aniline dyes, nitrates or nitrites, many meds like local anesthetics
Osmol
one mole (GMW) of solute particles dissolved in a solution. indicator of osmotic activity, so it refers to osmotically active particles in a solution
Osmolarity
osmotic concentration of a solution expressed as osmoles of solute per liter of solution. 1osmole/L=1osM
Osmolality
osmotic concentration of a solution expressed as osmoles of solute per kg of solution. 1kgH2O=1L solution
normal adults: 285-295mOsm/kg
normal children: 275-290mOsm/kg
Osmotic Equillibrium between intra and extracellular fluids
- large osmotic pressures can develop across the cell membrane with a relatively small change in solute concentration of ECF
- for each 1mOsm concentration gradient of an impermeable solute about 19.3mmHg of osmotic pressure is generated across the cell membrane
- if the cell membrane is exposed to pure water and the osmolarity of the intracellular fluid is 300mOsm/L then the osmotic pressure that develops across a membrane is 5790mmHg
- demonstrates the large force that can act to move water across the cell membrane when the intracellular and extracellular fluids are not in osmotic equilibrium
Van Hoffs Law:
π=CRT
C= solute (osmoles/L)
R= 62.36
T=temperature (in kelvins, 310 = 273 + 37)
Spectrophotometry
method to measure how much a chemical substance absorbs light by measuring the intensity of light that has passed through a sample solution. “how to measure concentration”
Soda Lime Equation
- CO2 + H2O -> H2CO3
- H2CO3 + Na(OH) -> Na2CO3 + H2O + Heat
- Na2CO3 + Ca(OH)2 -> CaCO3 + Na(OH)
Calcium Hydroxide
Ca(OH)2 + CO2 -> CaCO3 + H2O
E Cylinder
oxygen tank at 20C with pressure of 1900 psi (129 atm) and has 660 liters of gas
Joule Thompson Effect
is the decrease in temperature as a result of the loss of heat when a gas expands freely into space
Expansion requires work which requires heat. The heat is taken from the environment. Endothermic process.
Think of a compressor with air conditioning – must work to allow gas to cool when released
If a gas is being compressed, it also takes work. Gas molecules must have less energy. Energy given off is exothermic. Heats up.
Adiabatic Change
a volume change in a gas during which heat is neither gained nor lost to the environment
Adiabatic Effect
a gas in a container which is isolated thermally from its environment becomes warmer when it is compressed and cools when it expands
what makes the most CO
desfluorane
Colloid Osmotic Pressure
takes into consideration of the weight of a substance because we consider how many moles we have (the weight itself is not what we are looking at). This is most often related to the effect of large proteins that stay in the vasculature that influence water molecules (they have an osmotic effect)
Net filtration pressure (NFP)
= (Pc – Pif) – (πp – πif)
Where Pc = capillary hydrostatic pressure (outward)
Pif = interstitial fluid hydrostatic pressure (inward) (is usually -3mmHg)
Πp = osmotic force due to plasma protein concentration (inward)
Πif = osmotic force due to interstitial fluid protein concentration (outward)
