OB Flashcards
What causes swelling of the maternal airway?
Increased progesterone, estrogen, and relaxin combined with an increase in ECF.
These tissues also become very friable
Risk of difficult and failed intubation
8x higher than normal
What things make airway edema even worse in parturients?
Pre-eclampsia, tocolytics, and prolonged trendelenburg position
This hormone is a respiratory stimulant
Progesterone
Causes MV to increase by 50%
(40% increase in TV + 10% increase in RR)
Lung volume changes in pregnancy
Increased:
- TV and MV
- RR
Decreased:
- FRC (d/t decreases in ERV and RV)
No changes in other lung volumes! It’s actually pretty easy to think this through.
CV changes in pregnancy
- O2 consumption increased 20%
- CO increased 40% (up to 80% in 3rd stage of labor)
- HR increased 15%
- SV increased 30% (similar to respiratory, with volume increasing more than rate)
- SBP and MAP unchanged (increase in blood volume and decrease in SVR even out)
- DBP decreased 15%
- SVR and PVR both increased d/t NO
- No change in filling pressures (CVP or PAOP)
- Left axis deviation (d/t pushing of diaphragm)
3 Major effects of progesterone
1) Increases RAAS activity
- Increased blood volume and CO
2) Vascular muscle relaxation
- Decreased SVR and increased flow
3) Increased MV
- Rightward shift of dissociation curve
With LUD, the right torso should be elevated ___ degrees
15 degrees
Heme changes in pregnancy
Overall, increasing circulating blood volume and preparing for hemorrhage in labor
- Increase circulating volume and erythrocyte volume (dilution anemia)
- Increased clotting factors
- Decreased natural anticoagulants (C&S)
- Decreased fibrin polymerization and increased fibrin breakdown
Mom makes more clot, but breaks it down faster too
What happens to serum albumin?
Decreases
What happens to pseudocholinesterase?
Decreases (not enough to be clinically relevant though)
Drug characteristics that favor placental transfer
- Low MW
- Non-ionized and non polar
- Lipid soluble
Stages of labor
Stage 1
- Beginning of regular contraction to full dilation
- Divided into latent, and then active phases
- Most cervical dilation occurs during active phase
- Thoracic pain (T10-L1)
Stage 2
- Full dilation to delivery
- Perineal pain begins here (Sacral S2-4)
Stage 3
- Delivery of placenta
2 Major effects of uncontrolled pain in labor
1) Catecholamine release
- Maternal HTN and reduced UBF
2) Hyperventilation (leftward shift and decreased O2 transfer to fetus)
Only LA that decreases efficacy of morphine
2-Chlorprocaine
How is chlorprocaine metabolized?
Pseudocholinesterase (minimal placental transfer)
Presentation of high spinal
Rapid sensory and motor block
Dyspnea
Difficulty phonating
Hypotension (hypotension leads to apnea)
Management of high spinal
Get her BP back up so she will start breathing on her own! (Overall pressers and increase venous return)
- Pressors
- IVF
- LUD
- Leg elevation
If unable to manage her own airway, then INTUBATE
Normal fetal heart rate (FHR)
110-160
Fetal and maternal causes of low FHR (
Fetal:
- Asphyxia
- Acidosis
Maternal:
- Hypoxia
- Drugs that decrease placental perfusion
Fetal and maternal causes of high FHR (>160)
Fetal:
- Hypoxia
- Arrhythmias
Maternal:
- Fever
- Placental infection (chorioamnionitis)
- Meds given to mother (atropine, ephedrine, or terbutaline)
These things decrease FHR variability
- CNS depressants (opioids, sedatives, propofol, barbs, and magnesium)
- Hypoxia
- Fetal sleep
- Acidosis
- Anencephaly
- Cardiac anomalies
Type of decels and what they mean
1) Early
- Occur with uterine contraction
- Compression of fetal head increased vagal tone
- Loss of variability with each deceleration
- NO RISK OF FETAL HYPOXIA (benign)
2) Late
- Deceleration occurs AFTER contraction
- Due to decreased placental perfusion leading to fetal compromise**
- GRADUAL decal that happens with each contraction
- Caused by maternal hypotension, hypovolemia, acidosis, and preeclampsia
3) Variable
- No pattern between contraction and FHR
- RAPID drop in FHR
- Variability is maintained during decel
- Often due to compression of cord (causing baroreceptor mediated reduction in FHR)