3 pH, pK, Henderson-Hasselbalch, Anion Gap, SID Flashcards Preview

AS - N927 Chem/Physics > 3 pH, pK, Henderson-Hasselbalch, Anion Gap, SID > Flashcards

Flashcards in 3 pH, pK, Henderson-Hasselbalch, Anion Gap, SID Deck (16)
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1

Lidocaine Max Doses

7mg/kg w/ Epi
5mg/kg w/out
Total 500mg

2

Mepivacaine

7mg/kg w/ Epi
5mg/kg w/out
Total 500mg

3

Bupivacaine

3mg/kg w/ Epi
2mg/kg w/out
Total 225mg

4

Ropivacaine

3.5mg/kg w/ Epi
3mg/kg w/out
Total 300mg

5

Epi Concentrations

1:1,000 (g/ml) = 1mg/ml = 1,000mcg/ml STOCK
1:10,000 = 0.1mg/ml = 100mcg/ml
1:100,000 = 0.01mg/ml = 10mcg/ml
1:200,000 = 0.005mg/ml = 5mcg/ml
1:400,000 = 0.0025mg/ml = 2.5mcg/ml
1:500,000 = 0.002mg/ml = 2mcg/ml
g/ml x 10^6 = mcg/ml

6

Henderson-Hasselbalch

pH = pK + log(UNprotonated/Protonated)
pK = pH + log(Protonated/UNprotonated)

7

Protonated

Ionized +/-
BH+
A¯ (acid)
H+ donator

8

UNprotonated

Non-ionized (neutral)
B (base)
HA
H+ acceptor

9

Logarithmic

Log(a/b) = Log(a) - Log(b)
Log(a/b) = - Log(b/a)
- Log(a/b) = Log(b/a)
Log(a·b) = Log(a) + Log(b)

Log(1) = 0
1x10^0
Log(100) =2
1x10^2
Log(0.1 or 1/10) = -1
1x10-1
Log(0.01 or 1/100) = -2
1x10-2

10

Plasma Ion Concentration

H+ = 40nmole/L = 4 x 10^-5mEq/L
K+ = 4,000,000nmole/L = 4mEq/L
Ca2+ = 2,500,000nmole/L = 5mEq/L
Mg2+ = 1,000,000nmole/L = 2mEq/L
Na+ = 140,000,000nmole/L = 140mEq/L
nmole/L (1x10^6) / 1,000,000 x charge +/-

11

% Protonated/UNprotonated

pK = pH + log(Protonated/UNprotonated)
BH+/B or A¯/AH

12

Local Anesthetic Onset

↑ non-ionized (unprotonated) = quicker onset time

13

mEq

nmol / 1,000,000 x charge +/- = mEq

14

Local Anesthetic MOA

BH+ ↔ B + H+
Conjugate acid ↔ Base + Proton
Non-polar/neutral/base/UNprotonated form to cross lipophilic membrane
Acidic environment ↑ H+ local anesthetic associates to protonated BH+ active form to act on VGNa+ channels from w/in the cell (intracellular action)
pH or H+ concentration impacts direction (association or dissociation)

15

CO2 Hydration Reaction

CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3¯
Carbonic anhydrase enzyme facilitates reaction

16

CO2/HCO3¯ Formula

pH = 6.1 + log(HCO3¯/H2CO3)
pH = 6.1 + log(HCO3¯/(PaCO2 x 0.03))