Labor Anesthesia & Analgesia pt4 Flashcards
Why is lidocaine not routinely used for labor analgesia?
- Poor differential block
- Tachyphylaxis risk
- ↑ placental transfer / ion trapping
What is neuraxial lidocaine useful for?
- Identification of non-functional catheter
- Need for rapid sacral analgesia
- Instrumented vaginal delivery/perineal repair
- Emergent operative delivery
What dose of neuraxial lidocaine is used for emergent operative delivery?
2% Lidocaine 10 - 20 mls w/ 2mls of Bicarb to speed onset
Bicarb (2mls) w/ 18mls of 2% Lido
What will bicarbonate do when paired with lidocaine in neuraxial anesthesia?
Speed up onset
Good for emergent operative delivery.
What dose of lidocaine is used for identification of a non-functional catheter?
5 - 10mls of 2% Lidocaine (100-200mg)
What dose of Lidocaine is used for rapid sacral analgesia?
5-10mls 0.5 - 1% Lidocaine
What dose of Lidocaine is used for an instrumented vaginal delivery or for perineal repair?
5-10mls Lidocaine 1.5 - 2% +/- epinephrine
What are the advantages and disadvantages of Chloroprocaine?
Advantages:
- Rapid onset
Disadvantages:
- Short duration
- Poor differential blockade
- interferes with actions of bupivacaine/opioids
When is neuraxial chloroprocaine useful?
Emergent instrumented or operative delivery and/or perineal repair (very rapid onset and short duration)
What dose of chloroprocaine is used for emergent instrumented delivery?
10mls of 2-3% chloroprocaine
What are the benefits of neuraxial opioids?
- ↓ LA dosage (20 - 30% reduction)
- ↓ latency (faster onset)
- ↑ analgesia quality
- ↑ duration of analgesia
Which opioids will have a faster onset?
Lipophillic (fentanil, sufentanil, etc)
Which neuraxial opioids will have a later onset (but provide postoperative pain relief) ?
Hydrophillic
Morphine.
What is the dose of epidural additive clonidine?
75 - 100 mcg
What are the advantages of neuraxial clonidine?
- Analgesic effect
- ↓ LA requirement
- ↑ block quality/duration
- No motor blockade
What are the disadvantages of neuraxial clonidine?
- Maternal HoTN & bradycardia
- Maternal sedation
What is the typical dose of neuraxial/epidural dexmedetomidine?
0.25 - 0.5 mcg/mL
What is precedex used for in neuraxial anesthesia?
- ↓ latency (Faster onset)
- ↑ duration of block
- ↓ LA requirement
What adverse effects can occur with higher concentration of neuraxial dexmedetomidine?
- Maternal sedation
- HoTN & bradycardia
What is the MOA of neuraxial Precedex?
- Suppressed C-fiber transmission
- Hyperpolarization of postsynaptic dorsal horn neurons.
What is the typical dose (concentration and rate) of bupivacaine in a continuous epidural infusion?
0.05 - 0.125% Bupivacaine
8 - 15 mL/hr
What is typical dose (concentration and rate) of ropivacaine in a continuous epidural infusion?
- 0.08 - 0.2%
- 8 - 15 mL/hr
What is a PCEA?
Patient controlled epidural anesthetic: +/- background infusion or PCEA only
- Less bolus dosing needed by provider
What is the main factor in determination of LA dosing for a spinal?
Patient height & level of anesthesia desired.
