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Describes changes in hematological system during pregnancy.
Plasma volume increases by 40-50%
Red cell volume increases by 15-20%
Blood viscosity decreases by 20%
What are normal H/H values in pregnancy?
12/35
What is autotransfusion after delivery?
Addition of 500 mL of blood into circulation after involution of uterus
Describe changes in clotting factors in pregnancy.
XI and XIII decrease
II and V stay the same
Others increase
How long does it take for blood volume to return to normal postpartum?
8 weeks
How does cardiac output change in pregnancy?
Increases by 30-40%, maximum increase attained by 24 weeks gestation.

Increase in HR first, at end of 1st month, plateaus at 10-15 bpm increase by 28-32 weeks

Stroke volume increases by mid-first trimester and increases progressively through 2nd trimester.
What changes can be seen on echocardiography?
Increase end-diastolic chamber size and total LV thickness. No change in end-systolic volume.
What happens to CVP, PCWP, LVEDP in pregnancy? SVR?
No change in CVP, PCWP, LVEDP

SVR decreases by 20%
What happens to blood pressure in normal pregnancy?
SBP decrease by 8%, DBP decreases by 20%
What mediates the decrease in blood pressure?
Estradiol, progesterone, prostacyclin, nitric oxide
How does cardiac output change in labor? Postpartum?
Labor = increase up to 50% from pre-labor values

Post-partum = increase up to 80% from prelabor (150% from pre-pregnancy) values
What are common EKG findings of parturients?
Sinus tach or benign dysrhythmia
ST depressions, T flattenening
LAD, LVH
How long does it take for cardiac output to return to pre-pregnancy values post-partum?
Decrease to pre-labor values within 24-72 hours

Pre-pregnant values w/in 6-8 weeks
When do respiratory changes occur in pregnancy?
As early as 4th week
What happens to MV in pregnancy?
Increased by 50%

VT increased by 40%
RR increased by 15%
What is normal PCO2 in pregnancy?

What happens to PaCO2-ETCO2 gradient?
32-35 mmHg

Disappears
What happens to oxygen consumption and CO2 production in pregnancy?
Increase by 60%
Which lung volumes are decreased at term?
FRC, ERV, and RV
What happens to IRV, IC, VC, and TLC? CC?
IRV and IC increase

VC, CC are unchanged

TLC slightly reduced
How long does it take for FRC to return to normal postpartum?

Other resp parameters?
1-2 weeks


6-12 weeks
What happens to gastrin during pregnancy?

What happens to total gastric acid production?
Gastrin levels elevated secondary to placental production

Total gastric acid production is decreased
Describe the changes in gastric emptying duing pregnancy and labor.
Pregnancy = no change

Labor = decreased
What does gastric emptying return to normal postpartum?
Day 2
What happens to LFTs in pregnancy?
Slightly increased

Alk phos increased 2-4 fold 2/2 placental production
What happens to serum cholinesterase in pregnancy?
Decrease by 24%. Nadir 33% on postpartum day 3.
How do levels of cholinesterase in pregnancy affect sux dosing?
No change, but monitor with NMB monitor
What happens to GFR in pregnancy? BUN? Cr?
Increased GFR leads to 40-50% reduction in BUN and Cr
What changes occur in tubular reabsoprtion during pregnancy?
Sodium reabs is increased

Glucose and aminoacid reabs decreased, leading to glycosuria and aminoaciduria
When does diuresis occur postpartum? When do renal parameters return to normal?
Diuresis on PP day 3-5

Normalization of renal parameters by 6th week postpartum.
What is the effect of pregnancy on CNS and PNS?
Increased sensitivity to anesthetics

Lower dosing required
Describe changes in thyroid hormones during pregnancy.
TBG increased
Free T3 and T4 are normal
What happens to cortisol in pregnancy?
Increased
What effect does pregnancy have on IOP?
Decreased, leading to potential visual disturbances and/or contact lens intolerance
Which LA, ester or amide, is more likely to give allergic rxn? Why?
Ester, 2/2 metabolism into PABA
What determines the potency of a LA?
Lipophilicity
What determines onset of action of LA?
pKa
What determines duration of action of LA?
Protein binding
Describe the vasoactive properties of local anesthetics.
Lidocaine = vasodilation

Ropivicaine = vasoconstriction
How does temperature affect onset of action?
Increased temperature decreases onset of action
Which LA is most neurotoxic? Least toxic?
Bupivicaine > lidocaine > chloroprocaine
How does levobupivicaine compare to bupivicaine?
S-isomer; less cardiotoxic
How does ropivicaine compare to bupivicaine?
Less toxic but also less potent
What is the equation describing passive diffusion of substances across the placenta?
Q/t = KA(Cm-Cf)/D
How does the route of administration of LA affect maternal plasma concentration?
IV>paracervical>caudal epidural>lumbar epidural>IM>spinal
How does the addition of epi to LA affect action? Should it be added to all LA?
Increases duration of action of lidocaine and mepivicaine

No effect with bupivicaine
How does fetal protein binding compare to maternal protein binding?
50%
How does MW affect placental transfer?
<500 daltons cross freely
500-1000 daltons cross with difficulty
>1000 daltons usually do not cross

(vancomycin is exception)
What is the reason for minute fetal predinisone conc even in the setting of high maternal plasma conc?
Placental metabolism; placenta produces P450 enzymes
What is normal fetal pH?

Maternal pH?
7.32-7.38

7.38-7.42
What effect do antibiotics have on NMB?
Prolong both depol and nondepol

Antagonism by AChEI is unpredictable
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