Labor Anesthesia & Analgesia pt2 Flashcards
Preeclampsia and hypertension prevent the use of this drug.
Ketamine: causes increases in HR and BP
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: 6 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?
Cross placenta easily
- 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: can accumulate and lead to respiratory depression
What is the PCA dosing of remifentanil?
20 - 40mcg (lockout of 2-3 min)
What is the IV/IM dose of butorphanol (stadol)?
1-2mg IV/IM q3-4 hours
half life 4.6 hours
What is the dose of nalbuphine (nubain)?
5 - 20 mg IV/IM/SQ
half life 5 hours
What opioid can result in significant fetal bradycardia?
Nalbuphine (nubain)
Why is toradol typically not used in labor?
- Suppresses uterine contractions
- Premature constriction of DA
- Inhibits PLT aggregation => bleeding
What nerve block is typically provided by the OBGYN during the 1st stage of labor to provide short term pain relief with cervical dilation?
Paracervical Block
What are the two fetal complications that can occur with paracervical block?
- Fetal LAST (more severe)
- Fetal Bradycardia (more common)
risk of injection into fetal scalp
What nerve block is an alternative to pharmacologic pain management in the 2ⁿᵈ stage of labor?
Pudendal nerve block
What form of anesthesia completely covers both 1st and 2ⁿᵈ stage of labor?
Neuraxial techniques
Epidural veins are decompressed in what position?
Lateral lying
Harder to place.
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.
Also from epidural vein engorgement.
What are absolute contraindications to neuraxial anesthesia?
- Refusal
- Uncooperative patient
- Uncontrolled hemorrhage w/ ↓volume
- Epidural site infection
- Bleeding issues/disorder
- Anticoagulated
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
Does meperidine cross the placenta?
lipid soluble - crosses placenta readily
What metabolite issues may arise with meperidine administration
Normeperidine active metabolite: can cause seizures
What is notable about the lipid solubility of morphine?
hydrophilic, slower onset
What is the obstetric infusion dose of fentanyl?
50-100mcg/hr
What is notable of the lipid solubility of fentanyl?
Lipophilic, crosses placenta readily, but works quickly
Remifentanil is metabolized by?
plasma esterases, and is ultra short acting
What are the primary downsides of a pudendal nerve block?
- minimizes urge to push
- risk for LAST (injection into pudendal artery)
- risk for fetal injection
What preanesthetic checks should be made prior to neuraxial anesthesia?
- NPO status
- informed consent
- IV access
- Intralipids and vasopressors/emergency meds
- Labs (plt)
Studies have typically shown which to be better: coloading or preloading with fluids prior to neuraxial anesthesia?
Co-loading with fluids
Blood pressure monitoring should be adjusted to what with the administration of neuraxial anesthesia?
- cycle 1-5 minutes during intial stage of dosing
- change to 15 minutes after initial 20-30 min
EKG typically not required
What are risks associated with epidural placement that is too late?
- Pt no longer able to get in good position
- pt no longer able to sit still
somewhat uncooperative
