Ex1 OB2 Flashcards
Pain of labor is mainly d/t
dilation of cervix + lower uterine segment
*common source of bleeding
Pain of L&D is mediated by
T10-L1
+
S2-S4
Pain travels via
visceral afferent fibers via sympathetic nerves
Pain pathway in first stage of labor
- visceral* afferent sensory nerve fibers
- uterine plexus, hypogastric plexus, lumbar + lower thoracic sympathetic chains
Pain in 1st stage of labor - stimuli enter spinal cord at
4 Dermatomes: T10, T11, T12, L1 spinal segments
mode of pain in first stage of labor occurs where?
- non-localized cramping at appropriate dermatome level
- umbilicus to inguinal ligament
Back labor occurs when?
first stage of labor
Back Labor
- sharp, localized back pain
- d/t referred pain to dermatomes (cutaneous innervation) + sclerotomes (innervation of bone/muscles)
First Stage of labor is divided into
Latent phase + Active phase
Pain in Latent phase
confined to T11-T12 dermatomes
Pain in Active phase
T10 to L1 dermatomes
Second stage of labor
onset of perineal pain at end of 1st stage of labor signals beginning of fetal descent + start of second stage
Cause of pain in second stage of labor
Distention of vagina + perineum
Sensory innervation during second stage of labor
S2-S4
Innervation of perineum is provided via pudendal nerve
Early vs. late second stage pain
early: low back + perineum
late: originates in perineum
psychoprophylaxis
“natural childbirth”, focuses on attention
natural childbirth
Bradley, dick-read, doula, LeBoyer, Lamaze
TENS
- nociceptive inhibition of presynaptic level of nerve in dorsal horn by limiting transmission
- placement of electrodes over low back (T10-L1)
- early labor, not proven in studies
PCEA
- patient controlled epidural analgesia
- continuous infusion
epidural analgesia
low doses of LA or opioid combos administered by infusion to provide continuous T10-L1 sensory block during 1st stage of labor
Advantages of epidural
- sensory block (not motor)
- decreased catecholamines
- access if emergent C/S
How to administer 0.125% bupivicaine when only 0.25% available?
10mL 0.25% bupivicaine + 10mL saline
Which is better for an epidural:
10mL 0.125% or 5mL 0.25%
10mL 0.125%
Mom is complaining of pain in lower abdomen, but legs from upper thighs down are very heavy. She feels contractions. The attending asks for you to make her level higher (she already has epidural running). How do you achieve this?
VOLUME.
Give 10mL 0.125% (brings level up to ~ umbilicus)
Giving 5mL 0.25% would only make the block more dense, not more coverage.
Commonly accepted criteria to proceed with epidural analgesia include
No fetal distress
Good regular contractions 3-4 minutes apart lasting 1 minute
Adequate cervical dilation (3-4 cm)
Engagement of fetal head
**acceptable as long as the parturient requests it, and the obstetrician approves it.
epidurals and length of labor
regardless of when you get it, whether it’s very early on before you’re even getting induced or much later in the delivery, there is no statistically significant change in the length of labor
PIEB
programmed intermittent epidural bolus
Normal medication + dose for initial epidural bolus
10mL 0.125% Bupivicaine
Epidural - ACOG standard
Nurse must stay in room for at least 15-20 minutes after placement
Tx for HOTN d/t epidural
- IV fluid bolus
- vasopressors
- supplemental O2
- Left uterine displacement
Vasopressors used if mom becomes HOTN after epidural
-ephedrine 5-15mg
or
-phenylephrine 25-50 mcg
What may occur if moms bp drops d/t epidural?
Decels (baby heart rate drops)
Should the epidural be maintained while in second stage of labor?
- If patient has good motor function, epidural can be maintained
- if motor block too strong for pt to push, or unable to sense contractions: turn off or titrate down
During rounds, pt claims she is uncomfortable despite epidural. What are your next steps?
- determine how dilated + where uncomfortable*
- 5cm, first baby, severe pain: okay to top off
- 5cm 3h ago, needs to be rechecked
How to determine where moms block is when epidural is infusing?
Ice Test
How does the ice test work
Fill glove with ice. Place on arm, ask if she feels. If yes - go to ankle and progressively move upward to hip, asking if she feels cold.
Normally: feels cold at ankles, knees, thighs, but not at hip.
Hip: if she feels–> top off with volume. Goal is to be numb up to umbilicus
“topping off” depends on
VOLUME
Top off options
\+ 10mL of infusing gtt \+10mL 1.5% Lido (quick on) \+10mL .25% Bupi (careful, long) OR 100mcg Fentanyl for dense analgesia if mom in severe pain/not close to delivery
Spinal analgesia is used for
-Mostly C/S
-laboring if early on, can give lower concentrations; or if placing epidural + need immediate relief (CSE)
OR forcep delivery w/o epidural
Spinal dose for C/S
1.5mL 0.75% Bupi
Spinal dose for labor
1mL 0.25% Bupi
What should all opioids be in spinals?
preservative free
Intrathecal dose: Morphine
0.25-0.5mg
Intrathecal dose: meperidine
10-15mg
Intrathecal dose: fentanyl
12.5-25mcg
Intrathecal dose: Sufentanil
3-10mcg
When would 0.25% 1-2mL of Bupi be given as a spinal?
mom comes from home, 9cm, needs quick, short term relief
0.25% 1-2mL of Bupi in spinal provides relief when/for how long?
5minutes onset
1.5-2h DOA
CSE effect on baby
Fetal bradycardia for ~ 5-8min
(d/t acute reduction in catecholamines or imbalance of norepi on uterine tone)
*may need pressors for a few minutes
Which blocks (performed by OB) are alternative options to neuraxial anesthesia?
Paracervical (Stage 1 labor) block
Pudendal (Stage 2 labor) block
Where is a paracervical block injected?
LA injected into fornix of vagina (lateral to cervix) - blocks nerve transmission thru paracervical ganglia (posterior to junction of cervix/uterus)
When is a pudendal block used?
Vaginal delivery w/o epidural
Outlet Forceps delivery
