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- Initial analgesia provided by intrathecal administration of an analgesic (or mixture)
- Labor analgesia is maintained using analgesic(s) delivered via an epidural catheter
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See Chapters 121, 122, 123, and 124 for Figures.
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- Epidural space accessed using an epidural needle
- A long spinal needle is passed through the epidural needle into the intrathecal compartment
- The spinal analgesic is administered and the spinal needle is withdrawn:
- Most common intrathecal doses are: 2–2.5 mg isobaric 0.25% bupivacaine or 0.2% ropivacaine with 10–20 μg fentanyl or 2–2.5 mg sufentanil
- An epidural catheter is passed via the epidural needle, aspirated, and secured as usual
- An epidural infusion is started as usual:
- Testing of the epidural catheter is not common:
- Careful aspiration for blood and CSF usually reveals intravascular or intrathecal catheter placement in multiorifice catheters
- Spinal effects are hard to differentiate from the original spinal dose
- Intravascular catheter placement testing with diluted epinephrine is notoriously poor in obstetrical patients:
- Heart rate variability at baseline is considerable due to periods of pain
- There is no EKG monitoring to assess T-wave amplitude
- Response to epidural infusion often reveals concealed intrathecal or inadvertent intravascular catheter position:
- Currently used dilute concentrations of epidural infusions are unlikely to produce rapid, dangerous cephalad spread of neuraxial blockade
- Do not bolus an “untested” catheter with a full bolus dose immediately after a CSE dose (i.e., without an infusion running for 15–20 minutes) without testing for intrathecal and intravascular placement first as it may produce inadvertent high blocks or local anesthetic toxicity
- Starting an epidural infusion straightaway allows onset of epidural analgesia by the time the spinal dose wears off
- Adjust inadequate level of initial analgesia by bolusing the epidural catheter:
- Initial doses may need to be reduced by about half
- After about 30–45 minutes, usual “top-up” boluses should have the same effect as with a routine labor epidural
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