Exam 1 - Neuraxial Principles (Part 2) Flashcards
What adjunct agents are lipophilic in spinal blocks and rapidly spread to the spinal cord?
- Fentanyl and Sufentanil
- Early respiratory depression
Besides respiratory depression, an overdose of opioids can cause what adverse effects?
- Muscle rigidity
Which opioids are the best adjunct agents for spinal anesthesia in an outpatient setting?
- Fentanyl and sufentanil
- Quicker onset of respiratory depression
What does ERAS stand for?
- Enhance Recovery After Surgery
ERAS attempts to minimize the use of opioids to improve patient outcomes.
What were the three main side effects of neuraxial opioids discussed in the lecture?
- Pruritus
- Respiratory Depression
- PONV
What is the incidence of pruritis from neuraxial opioids?
- 30-100%
What are the treatments for pruritus from neuraxial opioids?
- Benadryl 25-50 mg IV
- Naloxone 0.1 mg IV (best)
- Buprenex (mixed agonist/antagonist)
Although Naloxone is the best treatment for pruritus, it will also reverse the analgesic properties of the opioid resulting in the patient being in pain.
What are prophylactic managements for pruritus from neuraxial opioids? select 2.
A. buprenex 0.3 mg IV
B. zofran 4 mg IV
C. naloxone 0.1 mg IV
D. minimize dose of morphine < 500 mcg
E. nalbuphine 2.5-5.0 mg IV
B. Ondansetron 4 mg IV
E. Nubain 2.5-5.0 mg IV
and Minimize the dose of morphine to < 300 mcg!
____ (hydrophilic or lipophilic) opioids will have delayed respiratory depression and a cephalad spread.
- Hydrophilic (Morphine)
___ (hydrophilic vs lipophilic) neuraxial opioids will have early/ immediate respiratory depression.
- Lipophilic (Fentanyl/Sufentanil)
Neuraxial opioids can be reversed with what medication?
- Naloxone 0.1-0.2 mg
What does this graph show?
- Respiratory depression quickly peaks when the patient receives fentanyl/ sufentanil (1 hour).
- Repression depression peak is delayed when the patient receives morphine (6-7 hours).
PONV from neuraxial opioids is very dose-dependent. What is the recommended neuraxial dose of morphine?
- < 300 mcg
- At less than 100 mcg of morphine, N/V will almost be absent
What is the treatment for PONV from neuraxial opioids?
- Ondansetron (5 HT antagonist) 4-8 mg
- Naloxone 0.1 mg
- Phenergan 12.5- 25 mg IM
What is the incidence rate of urinary retention from neuraxial opioids?
- 30-40%
Since foleys are rarely placed in the OR, it is important to remind PACU nurses to use a bladder scanner/ ultrasound to check for urinary retention.
What is the dose for an “epi wash”?
What is the dose for a “neo wash”?
- Epinephrine 0.2 - 0.3 mg
- Neosynephrine 2-5 mcg
What LA will have a profound effect if vasoconstrictors are added to it?
- Tetracaine
Bupivacaine and Lidocaine will have variable increases.
What is the prophylactic management of hypotension from alpha 2 adrenergic agonst like precedex or clonidine?
- Give fluids (250-500 cc bolus)
If a craniotomy requires a trans-ethmoidal approach, what medication can be given to prevent the Five and Dime (VX) Mechansim?
- Glycopyrrolate (Rubinol) (↑ HR)
α2-adrenergic agonist neuraxial dosage:
Clonidine
Dexmedetomidine
Clonidine 15-45 mcg
Dexmedetomidine 3 mcg
Opioid neuraxial (spinal) dosage:
Morphine
Fentanyl
Sufentanil
Morphine 0.1-0.4 mg
Fentanyl 10-25 mcg
Sufentanil 2.5-10 mcg
Vasoconstrictor neuraxial dosage
Epinephrine
Phenylephrine
Epinephrine 0.2-0.3 mg
Phenylephrine 2-5 mcg
What are the factors affecting the uptake of LA in the neural space?
- Concentration of the LA in the CSF. ( ↑ Concentration, ↑ uptake)
- Surface Area of neural tissue (↑ SA, ↑ uptake)
- Lipid content of the nerve (↑ Lipid content, ↑ uptake)
- Blood flow of the nerve (↑ blood flow, ↑ uptake)
__________ is the clinical phenomenon referring to the temporal blockade of autonomic, sensory, and motor nerve fibers when using neuraxial local anesthetics.
- Differential Block
B fibers are blocked first (sympathectomy), followed by sensory loss (C and A-delta fibers), and lastly motor loss. (motor fibers)
What is the clinical progression of the differential blockade?
When assessing for sensory after performing neuraxial anesthesia. Is it better to assess pain or temperature?
- Be nice and assess temperature with a cold alcohol swap or a cold teaspoon.