- 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

- patient controlled epidural analgesia - continuous infusion

Ex1 OB2 Flashcards by Rachel Unknown

Pain of labor is mainly d/t

dilation of cervix + lower uterine segment

*common source of bleeding

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Pain of L&D is mediated by

T10-L1
+
S2-S4

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Pain travels via

visceral afferent fibers via sympathetic nerves

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Pain pathway in first stage of labor

visceral* afferent sensory nerve fibers

- uterine plexus, hypogastric plexus, lumbar + lower thoracic sympathetic chains

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Pain in 1st stage of labor - stimuli enter spinal cord at

4 Dermatomes: T10, T11, T12, L1 spinal segments

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mode of pain in first stage of labor occurs where?

non-localized cramping at appropriate dermatome level

- umbilicus to inguinal ligament

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Back labor occurs when?

first stage of labor

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Back Labor

sharp, localized back pain

- d/t referred pain to dermatomes (cutaneous innervation) + sclerotomes (innervation of bone/muscles)

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First Stage of labor is divided into

Latent phase + Active phase

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Pain in Latent phase

confined to T11-T12 dermatomes

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Pain in Active phase

T10 to L1 dermatomes

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Second stage of labor

onset of perineal pain at end of 1st stage of labor signals beginning of fetal descent + start of second stage

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Cause of pain in second stage of labor

Distention of vagina + perineum

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Sensory innervation during second stage of labor

S2-S4

Innervation of perineum is provided via pudendal nerve

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Early vs. late second stage pain

early: low back + perineum
late: originates in perineum

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psychoprophylaxis

“natural childbirth”, focuses on attention

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natural childbirth

Bradley, dick-read, doula, LeBoyer, Lamaze

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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

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PCEA

patient controlled epidural analgesia

- continuous infusion

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epidural analgesia

low doses of LA or opioid combos administered by infusion to provide continuous T10-L1 sensory block during 1st stage of labor

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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