Health Assessment in Pregnancy and Anesthesia Quiz

Study Notes

Pregnancy affects almost every organ system, with changes starting in the first trimester
Maternal changes during pregnancy are critical to understand, with the number one goal being to take care of the mother
Good maternal care is essential for good fetal care

Cardiovascular changes:
- Increased intravascular volume (35-45%)
- 45-55% increase in plasma volume
- 20-30% increase in erythrocyte volume
- Increase in cardiac output (40-50%)
- 25-35% increase in stroke volume (SV)
- 15-25% increase in cardiac output (CO)
- Decrease in systemic vascular resistance (SVR) by 20%
- Decrease in pulmonary vascular resistance (PVR) by 35%
Respiratory changes:
- Increased minute ventilation (MV) by 45-50%
- Increased tidal volume (TV) by 40-45%
- Respiratory rate (RR) increases by 0-15%
- Total lung capacity (TLC) decreases by 0-5%
- Vital capacity (VC) remains unchanged
- Functional residual capacity (FRC) decreases by 20%
- Oxygen consumption increases by 20%
Hepatic and biliary changes:
- Increased AST, ALT, and bilirubin levels to upper limits of normal
- Decreased plasma protein concentrations
- Decreased plasma cholinesterase levels by 30%
- Placenta production of alkaline phosphate levels results in double the normal value, leading to gallbladder issues
Renal changes:
- Increased renal blood flow by 60%
- Increased clearance of creatinine, urea, and uric acid
- Upper limits of BUN and Cr in pregnancy are 50% lower

Uterine blood flow increases from 100 ml/min to 700 ml/min (10% of CO)
80% of uterine blood flow perfuses the intervillous space (placenta) and the rest perfuses the myometrium (muscle)
Uterine blood flow has minimal autoregulation

Mostly limited to non-elective surgery
Common reasons for surgery include cholecystectomy, appendectomy, maternal trauma, cancer, and fetal procedures (EXIT)
Maternal hemorrhage is the number one cause of maternal death worldwide
Up to 2% of pregnant patients will require surgery

All general anesthetic drugs cross the placenta
No studies found an increase in birth defects in women undergoing anesthesia while pregnant
Small increase in risk for miscarriage or preterm delivery
In general, the second trimester is the safest for anesthesia
Regional anesthesia is always preferred

Fetal heart rate (FHT) should be monitored after 18 weeks
At 25 weeks, FHT variability is a sign of fetal wellbeing
Decision to monitor FHTs during surgery needs to be a three-way discussion between OB provider, surgeon, and anesthesiologist