Labor Anesthesia & Analgesia Pt. 1 (Exam III) Flashcards by Autumn Walker

What does SROM stand for?

Spontaneous Rupture of Membranes

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What does AROM stand for?

Artificial Rupture of Membranes

Also known as Amniotomy.

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What is occiput anterior (OA)?

the fetus occiput is anterior facing the woman’s anterior abdomen

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What is occiput posterior?

The fetus occiput is facing the woman’s spine

sunny side up = more difficult delivery

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Is OA or OP preferred for delivery?

OA (Occiput Anterior)

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What do the 4 #s after the “P” mean?

Term babies
Preterm babies
Abortions (miscarriage/other loss)
Living children

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Within how many hours after an amniotic sac ruptures does a woman need to give birth?

12 hrs
** to prevent infection **

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How long will the first stage of labor last for a woman having her first baby?

If Primiparous, 8 - 12 hours typically.

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How long will the first stage of labor last for a woman having already had a child before?

If Multiparous, 5 - 8 hours typically.

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What are the two phases of the first stage of labor?

Latent Phase
Active Phase

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What characterizes the Latent phase of labor?

Cervical Effacement (cervix thins)
Minor (2-4cm) cervical dilation
Contractions q5-7 min w/ 30-40 sec duration

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What characterizes the active phase of the first stage of labor?

Cervical dilation up to 10cm
Contractions q2-5min w/ 50-70 sec duration

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How long does the 2ⁿᵈ stage of labor last?

Typically 15 - 120 min

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What characterizes the 2ⁿᵈ stage of labor?

Full (10cm) cervical dilation
Contractions q 1.5-2min w/ 60-90s duration
Fetal Descent
Ends with Delivery

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What event characterizes the end of the 2ⁿᵈ stage of labor?

Fetal Delivery

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The 2ⁿᵈ stage of labor is considered prolonged if it lasts more than….

3 - 4 hours

can be caused by cephalopelvic disproportion

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What are the 6 risks with a prolonged 2nd stage of labor?

fetal trauma
severe umbilical cord compression
maternal trauma (physical & emotional)
increased risk for PP hemorrhage
increased risk for infection
increased admission to NICU

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How long does the 3rd stage of labor last?

15 - 30 min

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When does the 3rd stage of labor begin?

Begins after fetal delivery

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The 3rd stage of labor is prolonged if it lasts more than ….

30 minutes

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What marks the end of the 3rd stage of labor?

Delivery of the placenta

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In what stage of labor is the highest risk of uterine atony and post-partum hemorrhage present?

4th stage

especially w/ a prolonged 2nd stage of labor

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When does the 4th stage of labor occur?

1 hour post-partum

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What causes pain via mechanoreceptor stimulation in the 1st stage of labor?

Stretching and distention of lower uterine segment and cervix

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What causes the visceral pain associated with the 1st stage of labor?

C-fibers entering spinal cord at T10 - L1

In the 1st stage of labor, how is visceral pain transmitted?

By small, unmyelinated C nerve fibers

What spinal levels are primarily affected during the latent phase of the 1st stage of labor?

T10 - T12

What spinal levels are primarily affected during the active phase of the 1st stage of labor?

T12 - L1

What type of pain becomes more predominant in the 2ⁿᵈ stage of labor? What are the characteristics of this pain? What causes this pain?

Somatic Pain - Sharp, easily localized - Caused by stretching & compression of pelvic/perineal structures

What nerve fibers are responsible for the somatic pain characteristic of the 2ⁿᵈ stage of labor?

Aδ fibers of the pudendal nerve

What spinal levels are relevant to the somatic pain associated with the 2ⁿᵈ stage of labor?

T12 - S4

What inhaled anesthetic can a patient use to "self-anesthetize"?

N₂O

What receptors does N₂O work on?

- Inhibits: NMDA glutamate - Stimulates: dopaminergic, opioid, and αlpha 1 & 2

How much does N₂O depress uterine contractility?

Trick question. It does not.

Does N₂O causes neonatal depression?

What nerve block is often used in conjunction with N₂O ?

Pudendal nerve block

What are adverse effects associated with N₂O?

N/V, Dizziness, Paresthesias, Xerostomia

Combination of N₂O and _______ can result in hypoxia, LOC changes, and loss of airway reflexes.

Opioids

Volatile anesthetic agents will cause uterine smooth muscle ________ in a dose-dependent modality.

relaxation

Preeclampsia and hypertension prevent this use of this drug.

Ketamine

What is the obstetric dose of ketamine?

0.2 - 0.5 mg/kg

What is the IV onset & duration of ketamine?

Onset: 30 seconds Duration: 5-10 min

What is the IM onset & duration of ketamine?

Onset: 2-8 min Duration: 10 - 20 min

What is the ketamine infusion loading dose and rate?

Loading: 0.2 mg/kg (over 30 min) Infusion: 0.2 mg/kg/hr

What are the neonatal consequences of benzodiazepines?

- Neonatal respiratory depression - Neonatal hypotonicity - Neonatal impaired thermoregulation

What is the IM dose of meperidine?

50 - 100mg IM q4hours

What is the IV dose of Meperidine?

25 mg IV q2-4 hours

What is the weight based dose of IV morphine?

0.05 - 0.1 mg/kg IV

What is the weight based dosing of IM morphine?

0.1 - 0.2 mg/kg IM

What is the active metabolite of morphine than can accumulate in the neonate?

Morphine-6-glucuronide

What is the PCA dosing of remifentanil?

20 - 40mcg (lockout of 2-3 min)

What is the IV/IM dose of butorphanol?

1-2mg IV/IM q3-4 hours

What is the dose of nalbuphine?

5 - 20 mg IV/IM/SQ

What opioid can result in significant fetal bradycardia?

Nalbuphine

Why is toradol typically not used in labor?

- Suppresses uterine contractions - Premature constriction of DA - Inhibits PLT aggregation

What nerve block is typically provided by the OBGYN during the 1st stage of labor? How does it work?

Paracervical Block ## Footnote Blocks transmission through paracervical ganglion

What are the 2 maternal complications that can happen w/ a paracervical block?

1. LAST 2. syncope

What are the two fetal complications that can occur with paracervical block?

Fetal LAST (more severe) Fetal Bradycardia (more common)

Who is the paracervical block contraindicated in?

Pts w/ uteroplacental insufficiency or non-reassuring FHR

What nerve block is an alternative to pharmacologic pain management in the 2ⁿᵈ stage of labor?

Pudendal nerve block

What is a *drawback* to the pudendal nerve block?

Minimizes the urge to push

What are the **risks** associated w/ the **pudendal NB**?

* injection into pudendal artery - LAST * fetal trauma or injection of LA

What form of anesthesia covers both 1st and 2ⁿᵈ stage of labor?

Neuraxial

What 7 things must we have prepped before neuraxial placement?

1. Vasopressors (ephedrine, phenylephrine) 2. emergency meds (atropine, epi, narcan, calcium, sodium bicarb) 3. induction agents 4. intralipids 5. Oxygen 6. suction 7. airway equipment

What must we monitor during neuraxial placement?

1. BP - q1-5 min initially (then every 15min) 2. pulse-ox 3. FHR - continous during & after placement (document)

Epidural veins are decompressed in what position?

Lateral lying ## Footnote *harder to place, less risk of intravascular catheter*

Why is there an increased risk for cephalad spread of neuraxial LA in pregnant patients?

Due to apex of thoracic curvature shifting from T8 to T6.

Why is there an increased risk of venous cannulation with an epidural in pregnancy?

* they have epidural vein engorgement & a smaller epidural space

Why is there a **decreased intervertebral gap** in pregnancy?

* the gravid uterus makes the curvature of the lower spine tighter

What alteration happens w/ **Touffier's line** in pregnancy?

* it is elevated d/t forward rotation of the pelvis

What are absolute contraindications to neuraxial anesthesia? **(UUBEAR)**

- Refusal - Uncooperative patient - Uncontrolled hemorrhage w/ ↓volume - Epidural site infection - Bleeding issues/disorder - Anticoagulated

What are the *relative* contraindications to Neuraxial? **(ELLSSAPUSH)**

1. Elevated ICP 2. LA allergy 3. language barrier 4. severe fetal depression 5. severe maternal cardiac dz 6. active coagulopathy 7. Untreated systemic infection 8. pre-existing neuro deficit 9. skeletal anomalies 10. hardware in spine

What are the risks associated with epidural placement that is too early in labor?

- ↑ risk for instrumented delivery - Prolonged 2ⁿᵈ stage of labor - Risk of ineffective epidural and need for replacement

What happens if an epidural is placed too late?

1. patient can't get into a good position for placement 2. patient can't stay still