Lower Extremity Nerve Blocks Flashcards
1) Always a good idea to ____ patient prior to performing blocks (pain and anxiety management).
2) _____ - patient still arouseable and able to move.
3) _____ - sedating patient until they are unable to move
4) _____ - perform sedation also so patient will not remember
Give benzodiazepines (valium) to prevent toxic effects of local anesthetic (for example, seizures), reduce stress levels and produce amnestic effect.
1) sedate
2) IV sedation
3) General sedation
4) Amnestic
Regional Anesthesia Advantages:
- Avoid GA, hemodynamic stability, patient participation, earlier discharge, post-op analgesia,
1) ____ = can keep patient awake, still able to breathe on their own
2) Cardiac = ___ & ___ (more stable with regional, less stress on body)
3) Pulmonary Disease = ____, avoid ____ can have synergistic effect on respiratory status. *Narcotics with benzos = resp. depression
4) Avoid use of ____
1) Airway
2) Hypotension and tachycardia
3) COPD, narcotics
4) Opiates
Regional Anesthesia Advantages continued:
1) _____ reduces - postoperative pain, analgesic requirements
* Reduced nausea and vomiting
* Reduces post-op sedation
1) Preemptive analgesia
Regional Anesthesia Contraindications:
1) Absolute contraindication?
2) Mentally disabled, dementia - not a good candidate?
3) Epidural technique should be a contraindication, do not want to cause a hematoma. For regional blocks it depends on how high the INR is and how much risk is associated with procedure?
4) Important to note what the preoperative deficit is - document this and make sure you obtain informed consent?
**skin infection near site of injection, sepsis
1) Patient refusal
2) Inability of patient to cooperate
3) Coagulopathy
4) Pre-existing neurologic deficits
Risks of Peripheral Nerve Blocks:
1) ____ - you can calculate how much you can give your patient to try to prevent this
2) Allergic response
3) ____ - Explain to patient the risks and the benefits. There can be risk of nerve toxicity but usually this will go away with time and occurrence is generally low.
4) Patient c/o uncomfortable positioning during surgery - Ex: ____ - if it gets to be really bad for patient and surgery still going on may need to switch to general anesthesia.
5) Incomplete blocks
1) Local anesthetic toxicity
3) Permanent or transient nerve damage
4) Tourniquet pain
Neuropharmacology of Local Anesthetics:
*2 Classes of LA
1) Metabolized by plasma cholinesterases? *has one “i” in drug names
2) Metabolized by hepatic processes? *has two “i”s
1) Esters (Ex: chloroprocaine)
2) Amides (Ex: Lidocaine, bupivacaine)
This class of LA has a greater potential for producing allergic reactions?
Esters
Neuropharmacology of LA: Toxicity:
1) Systemic absorption can result in ___ & ___ toxicity
2) Depends on site of injection, total dose, the anesthetic itself, and the use of ____
3) Rate of absorption depends on?
* max to min = intercostals, caudal, epidural, brachial plexus, sciatic, lumbar plexus, and femoral
1) CNS & Cardiac toxicity
2) epinephrine
3) Site
These are s/s of ?
*tongue numbness, lightheadedness, dizziness, tinnitus, disorientation, visual disturbances, seizures leading to CNS depression, respiratory depression and arrest, CV instability
CNS Toxicity
Large volumes of local anesthetic can produce these side effects…
*A weird taste in their mouth (metallic taste), this is not a toxicity side effect, more of a general side effect.
Make sure you are in constant communication with patient. Do not stop dialogue need to assess patient’s status constantly.
Do not let surgeon, once you have already given local anesthetic, give general anesthetic.
***Local anesthetic toxicity always starts at the ____ followed by ____, followed by ____, patient will become extremely unstable after this.
***____ - initial increase in BP & HR
(With higher levels of LAs, may result in hypotension, arrhythmias and cardiac arrest)
1) Brain (CNS)
2) Respiratory
3) Cardiac
4) Cardiac toxicity
This readily crosses the BBB?
Local anesthetic
Toxicity Prevention:
- Vigilant monitoring
- Limit dose accordingly
- ____ before each injection
- Inject small volumes (?)
- Aspirate
- 5 mL
Toxicity Prevention:
Patient should always have a ____ on them. Always have an ____.
Always aspirate before injecting (aspirate-inject 5 mL, aspirate-inject 5 mL, aspirate-inject 5 mL and continue this).
*Do this because your needle can move.
*While performing this technique remember to?
- Pulse ox
- IV access
- Talk to patient
*Steps on how to treat?
1) Stop administration of LA
2) Maintain airway, provide oxygen
3) Treat seizure with IV midazolam, propofol or thiopental
4) Treat hypotension with ephedrine, epinephrine, and/or fluids
5) Consider lipids (Ex: intralipid)
6) May require CPR or CPB
Toxicity
1) The addition of ____ prolongs the duration of anesthesia.
2) Use of ____ for local anesthetics permit injection of large volumes for peripheral nerve blocks.
3) Used as an alternative or in conjunction with ____ in selected patients.
1) Epinephrine
2) Low concentrations
3) General Anesthesia
Equipment used in Regional Anesthesia:
This is the gold standard when performing peripheral blocks?
*Other option - peripheral nerve stimulator
Ultrasound
- Anatomic relationship of nerves to muscles, bones or arteries
- Paresthesias
- Nerve stimulator technique
- Ultrasound imaging
All of these are options for?
Nerve localization
Peripheral blockade of the nerves originating from ventral branches of the lumbosacral plexus?
Anatomic location in spinal cord?
- Sciatic Nerve Block
- L4-S3
Provides anesthesia to foot and lower extremity distal to knee and posterior leg?
Sciatic Nerve Block
This is a really good block for patient’s having surgery on Achilles’ tendon?
Sciatic Nerve Block
Sciatic Nerve Block:
- A line is drawn from the ____ to the _____ (this line is bisected and a perpendicular line is drawn over gluteal muscle).
- A second line is drawn from the ______ to the _____.
***Point where latter line intersects the perpendicular line marks the point of needle entry.
- Greater trochanter
- Posterior superior iliac spine
- Greater trochanter
- Sacral hiatus
Sciatic Nerve Block:
1) Dorsiflexion or eversion of the foot indicates?
2) Plantar flexion of the foot and toes indicates stimulation of the?
3) Volume?
1) Common peroneal branch (more lateral)
2) Tibial branch (more medial)
3) 20-30 cc
Sciatic Nerve Block:
*Depends on concentration and depends on patient’s weight (inject less if person is smaller, if person is bigger/muscular inject full 30 mL).
* If getting any ____ we are at the right place.
Aspirate-inject 5 mL, talk, aspirate-inject 5 mL, talk and so on
Foot twitch
Sciatic Nerve Block Complications? (2)
1) Block failure
2) Hematoma
