Obstetric Flashcards
MAC requirements for inhaled anesthetics (2)
- Reduce by 30-40% at peak
2. Returns to normal about 3 days after delivery
Proposed mechanism for reduce MAC requirements?
increased circulating endorphins; 10-20fold increase in progesterone late in pregnancy, have CNS depressant effects
3 examples of reduce in MAC requirements?
- Inspired dose of volatile agent to supplement neuro axial anesthesia for sedation, may cause loss of consciousness
- Increase sensitivity to benzodiazepines and barbiturates
- No change in Propofol or ketamine doses
Blood volume increase or decrease and how does it continue throughout pregnancy?
Increase: starts early, increases rapidly in 2nd trimester and slows in 3rd trimester
Does plasma volume or RBC volume increase and what can that cause?
Plasma volume; dilutional anemia (similar for some drugs)
At term what is a normal Hg?
11.6g/dL
CO and HR increase or decrease and how does it continue throughout pregnancy?
increase: increase at 10 wks, peaks at 30-50% increase at 32 wks
Increase CO and HR leads to what early and then eventually what?
early: SV
later: SV and HR
Is myocardial contractility changed during pregnancy?
NO
HR peaks at what bpm at term?
10-20 bpm
What 3 things decreased with pregnancy?
Systemic resistance, SBP, DBP
Dilutional anemia new “normal” values?
Hgb 9-11 g/dL (depends on iron supplementation)
What would be suggest if Hgb >13 g/dL?
hemoconcentration, need to look for cause (preeclampsia)
Platelet count and function?
No change in count to modest decline of ~10%
Pregnancy is what kind of coagulable state?
hypercoagulable (increase procoagulant factors, decrease fibrinolytic system and natura inhibitors of coagulation)
Why is pregnancy in hypercoagulable state?
minimize intrapartum blood loss
Hypercoagulable state may increase what risk during pregnancy and post parturm?
thromboembolism (6fold)
What does the fibrinolytic system get activated?
postpartum period
Hemoglobin has what kind of estimated change?
decrease 20%
Gastric emptying?
normal throughout gestation but slows with onset of painful contractions and parenteral opioids
What can increase gastric emptying?
clear liquids
When does gastric emptying return to normal?
18-24 hrs
Is gastric emptying impacted by Na channel blocking LA?
NO
Gastric secretions?
reduced (increased pH); but amount of secretions are unchanged
Lower esophageal sphincter (LES) tone?
reduces; increase risk of aspiration and regurgitation
What is LES barrier impacted by? (2)
- Progesterone adn estrogen relax the smooth muscles of LES
- Elevation/rotation of stomach by enlarging uterus
What 2 things can cause changes in liver function?
increased estrogen and progesterone
Hepatic BF?
BF and liver size remain unchanged despite increase CO
Splanchnic, portal and esophageal venous pressure?
increase
Serum albumin concentration?
reduce by 60% due to increase plasma volume; reduced total protein
Gamma globulin pregnancy effect?
no change to slight decrease
Fibrinogen pregnancy effect?
reduction 50%
Bilirubin pregnancy effect?
no change
ALP pregnancy effect?
increase 2-4 fold
GGTP pregnancy effect?
reduced
AST and ALT pregnancy effect?
none
TG and cholesterol pregnancy effect?
increased 2-3 fold
Hb pregnancy effect?
decrease 20%
Platelets pregnancy effect?
no change or decrease about 10%
Clotting factors (7, 8, 10, 12) pregnancy effect?
increase (30-250%)
Fibrinogen pregnancy effect?
increase
Protein S pregnancy effect?
decrease 40-50%
BV pregnancy effect?
increase 35%
Plasma volume pregnancy effect?
increase 55%
CO pregnancy effect?
increase 40-50%
SV pregnancy effect?
increase 25-30%
Pulse pressure pregnancy effect?
increase
HR pregnancy effect?
increase 15-20%
Systemic Resistance pregnancy effect?
decrease 15-20% (trimester specific)
SBP pregnancy effect?
decrease 5%
DBP pregnancy effect?
decrease 15%
Renal BF?
increase 75%
Renal afferent and efferent arterial resistance and when does it return to normal?
reduced; 6 months postpartum
GFR?
increase from 100-150 ml/min by 2nd trimester
BUN and sCr?
reduces; normal and slightly higher values may signal poor renal function
What causes gestational DM?
reduction in renal tubular reabsorption of glucose