730 Flashcards
Zwitterion
Molecule with positive and negative charge
MAP calculation
Metric chart
Henrys law-gas/liquids
At constant temperature the amount of gas dissolved in a liquid is directly proportional to the partial pressure of the gas at equilibrium above the gas-liquid interface
Grahams Law
The rate of effusion (gas diffusion through an orifice) of a gas is inversely proportional to the square root of its molecular weight….
i.e. small molecules diffuse faster…
Diffusion vs osmosis
Diffusion is the movement of particles from high to low concentration
Osmosis is the movement of water (or the solvent) from a less concentrated solution to a more concentrated solution in an attempt to reach equilibrium
Osmotic pressure
The pressure required to prevent osmosis
Ideal body weight calc men and women
Women: 100 + (5lbs/inch over 5ft)
Men: 105 + (6lbs/inch over 5 ft)
Fahrenheit from C
F= (5/9*C)+32
C to f : double it and add 30
F to C: subtract 30 an halve it
C from Fahrenheit
C=5/9(F-32)
Acceptable Blood Loss calculation
(ABL)
Based on EBV (estimated blood volume)
EBV*0.20=ABL
EBV for Men: 75mL/kg an Women: 65mL/kg
You have ephedrine 50 mg in 1 mL. You want to prepare a syringe with 10 mg/mL. What size syringe should you use? In the second step, you set up a proportion to answer the question, If the final concentration is to be 10 mg/mL, how much diluent do you add to 1 mL of ephedrine (50 mg/mL)?
5mL syringe,
1mL to 4mL lol
example 4: Epinephrine is available, marked “1/1,000” and “1 mg/mL.” You are asked to “double-dilute” it, so you take 1 mL of the epinephrine 1:1,000 and add 9 mL diluent. Then you discard all but one mL of the new mixture, and add 9 mL diluent. What is the resulting concentration of epinephrine in micrograms/mL?
• Epi 1:1,000 contains 1 mg/mL (= 1,000 mcg/mL). Taking 1 mL and adding 9 mL diluent yields a syringe with 1,000 mcg/10 mL (100 mcg/1 mL).
• Taking 1 mL of this mixture (containing 100 mcg/mL) and adding 9 mL diluent to it yields a syringe containing 100 mcg/10 mL. Each mL of the “double-diluted” new mixture contains 10 mcg/mL.
What is 0.0625% Bupivicaine in mg/ml?
0.625 mg/ml
% is g/100ml so it is 62.5mg/100ml or
0.625mg/ml
Give me mcg/ml from bag of 400mg in 250ml using the trick thingy
In each 0.25 mL (1/1,000th of the volume), there is 1/1,000th of the drug mass the entire bag holds.
• 400 mg x 0.001 = 0.4 mg = 400 mcg
• 250 mL x 0.001 = 0.25 mL
Epi 1:100,000
Give me micrograms/ml
Ratios are grams/ml
10mcg/ml
Epi 1:200,000
5mcg/ml
Epi 1:1,000,000
1mcg/ml
Epi 1:1,000,000
1mcg/ml
Impact of hypokalemia on cell membranes
Hyperpolarizes
Impact of hyperkalemia on cell membranes
Depolarizes
Potassium redistribution
(shift intracellularly)
-insulin+D50
-hyperventilation
-bicarbonate
-Beta-2 agonist (Albuterol)
Elimination
-potassium wasting diuretics
-kayexalate
-dialysis
EKG response to hypokalemia
Long PR and QT
Flat T wave
U wave
EKG response to hyperkalemia
5.5-6.5 Peaked Twaves
6.5-7.5 Pwave flattening
7-8. QRS prolongation
>8.5 QRS-Sine wave- VF
Calcium gluconate in Hyperkalemia
The role of calcium gluconate in treating hyperkalemia is to stabilize cardiac cell membranes. Calcium should promptly be administered to any patient with hyperkalemia and EKG changes indicating a hyperkalemic emergency.
Elevated potassium levels destabilize cardiac membranes by increasing the threshold potential of cardiac myocytes.
Calcium supplementation decreases the threshold to restore the transmembrane voltage gradient.
Tidal volume
Amount of gas inhaled and exhaled during breath
6-8 ml/kg
Minute ventilation
Vs
Alveolar ventilation
Tidal volume x respiratory rate
(Tv-dead space)x resp rate
What does increased dead space (Vd) lead to?
Widens paCO2-EtCO2 gradient- causes co2 retention
A-a Gradient
Difference between alveolar oxygen and arterial oxygen
Normal when breathing room air is <15mmHg
Causes of increased gradient:
-aging
-vasodilators- decreased HPV
-R to L shunt-defect or bronchial intub
-diffusion limitation
Estimation of % shunt based on A-a gradient
Shunt increases by 1% for every 20mmHg
Why is acidosis associated with hyperkalemia?
When H+ is transported into cells K+ is transported out
Normal HCO3-
22-26mEq/L
ABG
How do we know if it is a respiratory disorder?
pH and PaCO2 move in opposite directions
ABG
How do we know it’s a metabolic disorder?
Bicarbonate and ph move in same direction
Normal anion gap
8-12 mEq/L
Causes of Metabolic Acidosis
Elevated Anion Gap
M ethanol
U remia
D iabetic ketoacids
P araldehyde
I soniazid
L actate (sepsis/cyanide)
E thanol, ethylene glycol
S alicylates (inhibits Kreb cycle)
Metabolic acidosis
Normal Anion Gap
HARDUP
H ypoaldosteronism
A cetazolamide
R enal tubular acidosis
D iarrhea
U retosigmoid fistula
P ancreatic fistula
Hypercarbia in PULMONARY blood vessels vs peripheral circulation
CO2 is a vasoconstrictor in the lungs and can cause pulmonary hypertension and increase right heart workload
What metabolic disturbance can an MTP cause?
Metabolic alkalosis
-liver converts citrate to bicarbonate
Key difference between gap and non-gap acidosis
Accumulation of acid=gap acidosis. NO BICARBONATE
Loss of bicarbonate or ECF dilution= non-gap acidosis. GIVE BICARBONATE
How does pulse oximeter work
Based on beer-lambert- relates light passed through solution and the concentration of solute
Two wavelengths
660- absorbed by deoxyhemoglobin
940- absorbed by oxyhemoglobin
Spo2 is the ratio- (oxy/(oxy+deoxy)) *100
Explain left shift on oxygen/hemoglobin curve
Increased affinity for O2 (binding at lower partial pressure of Oxygen)
Left=Love
In Lungs:
Decreased H+, Lower CO2, Lower temp
Explain right shift of Oxy/hemoglobin curve
Decreased affinity for O2-
Right=Release
Occurs near metabolically active tissue
Higher temp, increased CO2 and H+
