Types of Regional/Conduction Anesthesia Flashcards
T/F: Post op mortality and morbidity is increased with neuraxial blockade?
False
Into what space is LA injected for spinal anesthesia?
Into the subarachnoid/intrathecal space.
What are three indications for spinal?
- Surgery of lower abdomen.
- Surgery of lower extremities.
- Surgery on perineum.
What must be done prior to considering spinal anesthesia?
Preoperative assessment:
- Note baseline neuro deficits.
- Bacteremia/abcess/infection.
- Check for anticoagulant use.
- Cardiac disease (specifically AS).
What is the only true absolute contraindications to spinal?
Patient refusal.
What are “relative” contraindications to spinal?
- Lack of cooperation (ex: MRDD).
- Increased ICP.
- Significant coagulopathies.
- Skin infection at site.
- Hypovolemia.
- Fixed cardiac state
- Difficult airway.
- Existing neuropathy.
How long should plavix be discontinued prior to spinal anesthesia?
7 days prior
T/F: Aspirin must be stopped 7 days prior to spinal anesthesia?
False: no contraindication
What are a couple examples of herbal supplements that are potential contraindications for spinal anesthesia?
Ginko.
Ginseng.
Fish oil.
How long should spinal anesthesia typically last?
1-4hours.
If spinal anesthesia is lasting longer than expected, what could potentially be a risk?
Spinal or epidural hematoma.
What are signs of spinal or epidural hematoma?
Prolonged spinal effect.
New onset weakness.
New onset back pain.
New onset bowel/bladder dysfunction.
Spinal or epidural hematomas must be surgically decompressed within how many hours?
8 hours
What are risks of permanent neurologic injury with spinal anesthesia?
Epidural anesthesia?
Spinal 1-4.2:10,000
Epidural 0-7.6:10,000
The anatomy of the vertebral column is broken down into categories, what are they?
7 Cervical vertebra. 12 Thoracic 5 Lumbar. 5 Sacral. 4 Coccygeal.
What are the three intralaminar ligaments in order?
- Surpaspinous ligament
- Interspinous ligament.
- Ligamentum flavum.
Which intralaminar ligament connects the apices of spinous processes?
Supraspinous ligaments
Which intralaminar ligament connects the caudal edge of the vertebra above to the cephalad edge of the lamina below?
Ligamentum flavum.
While advancing a spinal needle, which intralaminar ligament would your needle first pass through?
Supraspinous ligament.
(Skin, subcutaneous, supraspinous, interspinous, ligamentum flavum).
The spinal cord ends at what position in a new born (under 2 years)? In an adult?
Under 2 yrs: L3.
Adult: L1.
Where are spinal needles placed to ensure spinal cord is not damaged?
Below L2
What are the 3 meninges covering the spinal cord?
- Dura mater.
- Arachnoid.
- Pia mater
What meninge is closest to the spinal cord?
Pia Mater
What meninge is in between the pia mater and the dura mater?
Arachnoid
What is the anatomically proper word that spinal needles are placed into below the spinal cord?
Cauda equina.
What is the conus medullaris?
The spinal cord begins to taper into a cone shape between T12 and L1.
Where is the CSF located?
Subarachnoid space
What is the volume of total CSF? CSF in spinal canal?
Total=140ml
Spinal canal 30-80ml
How much CSF is produced daily?
500ml/day
What is the specific gravity of CSF at 37C?
1.004-1.009
What are the 6 things that affect level of spinal blockade?
- Drug dose.
- Drug volume.
- Turbulence of CSF.
- Increased IAP.
- Spinal curvatures.
- Baricity of LA
Does IAP increase or decrease the level of the spinal?
Can increase because the pressure creates a thinner vessel for the volume to spread over.
T/F: While laying supine, the LA will settle away from the lumbar region?
False: Laying supine, the LA settles in lumbar region.
If laying prone, the LA will settle away from lumbar region.
What are examples of things that increase the turbulence of the CSF?
- Coughing.
- Barbotage.
- Rapid injection.
- Patient movement
What is the most common LA solution for spinal anesthesia, isobaric, hypobaric, or hyperbaric?
Hyperbaric
How can the baricity of a LA be increased?
By added dextrose
How can a LA be made into a hypobaric solution?
By adding sterile water.
What is the purpose of a pencil point spinal needle?
Trying not to cut fibers.
trying to just spread the fibers apart without causing damage.
Describe a Touhy needle?
Typically used to epidurals, Bevel is very flat with slight curve in it.
Also, typically very large needles (17gauge).
While laying lateral, would the affected side be placed up while using a hypobaric LA? Hyperbaric LA?
Affected side up with hypobaric.
Affected side down with hyperbaric
Is the sitting or lateral position preferred for obese patients?
Sitting to assist in identification of midline.
Describe needle technique with midline approach?
Right in the middle, straight with the needle, maybe 10degree cephalad angle.
Describe needle technique with paramedian approach?
Needle placed 1-1.5cm lateral to midline. Aimed medially and slightly cephalad. Passed lateral to the supraspinous ligament.
In what situation would the paramedian needle approach be warranted?
Useful in patient who cannot be maximally flexed or whose intrapspinous ligaments are ossified.
What lumbar vertebra does the iliac crests intersect?
L4 or the L3-L4 interspace.
Why is contamination of spinal kit with antiseptic solution specifically avoided?
It is potentially neurotoxic (arachatinitis).
What direction should the bevel be facing upon insertion of the spinal needle?
Bevel should be parallel to the fibers that run longitudinal.
Which ligament creates a sudden “pop” once entered?
Ligamentum flavum.
How is correct placement of spinal needle confirmed?
Free flow of CSF into the hub of the needle.
Describe the steps of administering the spinal anesthetic into the subarachnoid space:
- Syringe with appropriate dose is filled.
- CSF confirmed free flow.
- Aspiration
- Slow injection of drug.
- Re-aspiration at end of injection.
- Needle gently removed
- Patient placed in desired position.
What will happen upon aspiration with a hyperbaric solution? Isobaric solution?
Hyperbaric solution: will see swirl.
Isobaric: will only see volume change.
How long does fixation of LA take?
Approx 20 minutes
How is any ascending anesthetic level assessed?
Pinprick or alcohol swab.
How should vital signs be monitored followed after spinal anesthesia?
BP/HR/RR at least once every minute until deemed stable.
If sensory blockade is confirmed at the T7 level, at what level would sympathetic and motor be blocked?
Sympathetic is 2 above (T5).
Motor is 2 below (T9).
Do younger or older patients have more profound hypotension from spinal anesthesia?
Younger because the vessels are very elastic and not athersclerosed.
T/F: Heart rate is effected significantly in most patients following a spinal?
False:
only 10-15% have significant bradycardia.
What is treatment for CV response to spinal anesthesia?
Fluid load (can preload). Oxygen mask. Vasopressors. Atropine. Epi/NE. CPR.
Should CV effects be anticipated with spinal?
Yes; and steps should be taken to minimize the degree of hypotension and bradycardia via preload of fluids and pretreatment of vasopressors.
T/F: The diaphragm is typically the effected muscle following spinal anesthesia?
False. Diaphragm involvement would be rare.
What two things are effected in relation to breathing following a spinal?
- Blocked ability to use accessory muscles (no effective cough, forced exhale.
- No sensation of breathing.
What are the complications of spinal anesthesia?
- Failure of block.
- Spinal headache.
- High spinal (treat all symptoms).
- Nausea.
- Urinary retention.
- Hypoventilation.
- Backache.
Which vertebral region has a wider epidural space?
Lumbar region 5-6mm wide.
Mid-thoracic region 3-5mm wide.
T/F: Spinal anesthesia develops in a segmental manner and selective blockade can be achieved?
False; Epidural blockade can .
Is the site of action for an epidural different than a spinal anesthetic?
No; works on the same place, but we just don’t put it in the same place.
Which anesthetic approach has a slower onset and lower intensity, epidural or spinal?
Epidural
Which way will an epidural spread in the thoracic region? Lumbar region?
Thoracic region= both up and down.
Lumbar region= Only up (no where to go down).
What is the technique that should be used to locate the epidural space for lumbar epidural placement?
Loss of resistance technique
What technique should be used to locate the epidural space for thoracic epidural placement?
Hanging drop technique.
Which ligament must be punctured in order to enter the “potential” epidural space?
Ligamentum Flavum
If correctly placed in the epidural space, a test dose of epi/LA should have what effect on HR?
No effect; however, if injected into an epidural vein, a 20-30% increase in HR will be seen.
Does position have an effect on epidural level?
No; because it is not “floating” in the CSF