Induction Meds: Neuraxial Flashcards
Where are receptors targeted with opioid neuraxial anesthesia?
Opioid receptors of the substantia gelatinosa.
S28*
What is general rule of dosing for epidural opioids?
- Dose = 5 - 10 x normal
S29*
Diffusion of opioids across the _____ ______ results in systemic absorption.
dura mater
S30*
Where can opioids be injected during an epidural that results in systemic absorption?
What should be done if this occurs?
- Epidural venous plexus
- Add epi to the infusion.
S30*
What is Cephalad movement (in regards to epidurals)?
Cephalad Movement = the movement of drug/injectate up the spinal cord towards the brain.
S31*
What drug attribute decreases cephalad movement?
Lipid solubility
S31
This drug exhibits much more cephalad movement than __________.
Why is this?
Morphine > Fentanyl & Sufentanil
- Fentanyl and it’s derivatives are much more lipid soluble and thus exhibit less cephalad movement.
-More in spinal cord < remains in CSF and migrate cephalad
S31
What can cause cephalad movement? (besides characteristics of drugs themselves)
Coughing and/or straining
S31
When would epidural admin/ CSF levels peak for the following drugs:
- Fentanyl
- Sufentanil
- Morphine
- Fentanyl - 20min
- Sufentanil - 6min
- Morphine - 1-4 hours
S32*
When would epidural admin/ plasma levels peak for the following drugs:
- Fentanyl
- Sufentanil
- Morphine
- Fentanyl - 5-10 min
- Sufentanil - 5 min or less
- Morphine - 10 - 15 min
S32*
When would intrathecal/cervical/CSF levels peak for the following drugs:
- Fentanyl
- Sufentanil
- Morphine
- Fentanyl - N/A
- Sufentanil - N/A
- Morphine - 1 - 5 hours (due to cephalad movement)
S32
What is the most common side effect from neuraxial opioid administration?
Why does this occur?
- Pruritis
- Cephalad migration to trigeminal nucleus
most common in OB
S33
What are the treatments for pruritis induced by neuraxial opioids?
- 10mg Propofol
- Naloxone
- Antihistamines
- Gabapentin
S33
Name the list (its a lot) of side effects that can occur with neuraxial opioid administration.
- Pruritis
- N/V
- Urinary retention
- Respiratory depression
- Sedation
- Skeletal muscle rigidity
- Herpes virus reactivation
- Neonatal effects.
S33 to S35
If neuraxial opioids induced a reemergence of a herpes virus, how long would this occur after opioid administration?
- 2 - 5 days
S35