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What three considerations do we have in choosing regional anesthesia?
If you're expecting hemodynamic instability and large blood loss, is regional ok?
Not really suitable for this patient/surgery
What is about the max length of surgery before regional anesthesia becomes uncomfortable for the patient?
TRUE or FALSE. We don't need airway/emergency equipment for regional anesthesia
FALSE. Be prepared for general anesthesia and full resuscitation just in case
The vertebral column has how many vertebrae?
The vertebral colum has ___ cervical,__ thoracic, __ lumbar, __ fused sacral, and __ coccygeal, and has ___ curves.
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 fused sacral
- 4 coccygeal
- 4 curves
Principle site of action for neuraxial blockade is the __________
Which has a more intense block, epidural or spinal?
spinal, always have motor block whereas with epidural you may only have a sensory block
Thoracic curve is convex or concave?
Lumbar is conCAVE
In thoracic, the spinal processes are pointed cephalic or caudal?
- in lumbar they are straight, parallel to the floor
A hyperbaric solution means it's heavier or lighter than CSF?
HEAVIER; usually use hyperbaric for spinal
True or false, hyperbaric solutions follow gravity
TRUE. give spinal in lumbar region and the patient is supine. It will pool in the thoracic and sacral areas
Average sensory level for a spinal is ________
T7 is where?
- At the tip of the scapula
- common landmark for epidural anesthesia
Spinal cord ends at __
After the spinal cord ends, what is there?
Free flowing nerves, CSF all the way down to S2 (cauda equina)
When putting in a spinal, you always want to place it below _______
L1 (don't want to hit the spinal cord)
In kids, the spinal cord can extend to ___
L2 or L3
What landmark is at the top of the illiac crest?
L4 or L3/L4 (interspace)
S2 is the end of???
CSF (end of dural sac)
If you can find the posterior illiac crest (dimples on skinny people), that's the landmark for __________
Is caudal block an epidural?
Yes but specifically it's the most distal, at end of the epidural space
If you only get about 1cm in and hit bone, what are you hitting?
the spinous processes, if it goes 3-4 then hits bone it's likely the lamina
Name the three ligaments in order of which the needle would pass
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum (yellow)
After the epidural space there are three membranes surrounding the spinal cord. Name them in order
- Dura mater
- Arachnoid mater
- Pia mater
True or False, the dura mater and the arachnoid mater are usually adhered to one another
TRUE (that's the one pop you feel as you go through them both at the same time)
Subarachnoid space (spot where we place spinal) can also be called the ___
Can the dura and arachnoid space sometimes not be adhered together well?
Yes, and you may place the needle in the subdural space instead of the subarachnoid space. Not a huge deal but can be reason for failed block
Posterior spinal arteries (there are two) supply the ___________
dorsal or sensory portion of the spinal cord.
There is a single anterior spinal artery that supplies the ________
ventral motor component of the cord
What is the single anterior spinal artery called?
Artery of Adamkiewicz
Where does the anterior spinal artery enter the vertebral column?
- L1, towards the left
- (we're not usually placing a needle near there but good to know)
There are veins in the epidural space, where are they most prominent?
What happens with the veins in the epidural space during pregnancy?
Blood diverts from IVC to the epidural veins and you could puncture a vein. Good news is it seals itself off but it's a bloody tap and you can't inject there
We have a varying amount of catheter space of ___________ for an epidural
2-5cm (push in too far and you could puncture an epidural vein)
What two ways are centralneuraxial anesthestics started?
- Sitting: see spinous processes easily
- Lateral: space is wider so easier to get needle in
There are two kinds of needles: cutting and spreading. What is the advantage of the cutting needle?
You have a better feel for where your needle is going. Cutting will cut the dura fibers that are running longitudinally in that membrane which doesn't cause permanent damage but can cause HA.
What size range are the needles for a spinal?
- 22G to 30G
- The larger gauge = less risk of spinal headache
What is the midline approach?
Go between the spinous processes, don't hit lamina
The effects of local anesthetics on the nerve fibers varies according to what 4 things?
- Size of the fiber
- Myelinated or unmyelinated
- Concentration of local anesthetic
- Duration of contact between the local anesthetic and the nerve fiber
What is differential blockade?
Means that smaller sympathetic nerves (pain and temp) are more easily blocked than the larger motor nerves.
How do you check the level of your spinal?
So when you’re testing a spinal to see how many nerve roots are covered, how high it gets, take a alcohol swab, start high (so pt has baseline) and go lower, the level at which the patient no longer feels the temp difference is the sympathetic level. Two segments down would be the sensory block, so where they couldn’t feel touch and the two segments distal to that would the motor block. (Segment is a dermatome segment)
What happens to the CV system when there is sympathetic blockade from a spinal?
Sudden hypotension and HR tends to go down as well (Bezold-Jarish reflex) Sudden loss of preload, sudden drop in HR and pt passes out
Is the pulmonary system effected by regional anesthesia?
Not much of an effect
What happens to the GI system in regional anesthesia?
- Get the sympathetic blockade so parasympathetic is unopposed!
- Increased salivation, increased peristalsis, decreased sphincter tone
What happens to the urinary tract w/regional anesthesia?
Remember the curves of the spine effect where the local anesthetic will pool. Get prolonged sacral blockade so loss of bladder control and urinary retention until the block wears off completely (why our patients will need foley)
How does regional blockade effect the metabolic and endocrine system?
Blocks surgical stress
What dermatome is at the nipple line?
Where is the T10 dermatome?
If our laboring patient had an epidural and suddenly needed a C section, what could we do?
Increase the volume of local anesthetic (to achieve the same type of block as a spinal at the nerve root)
What are some indications for spinal anesthetics?
- Patient preference in the absence of contraindications
- Type of operation ---TURP, TURB
- Consider in patients with aspiration risk and difficult airways
Name a cutting needle and two spreading needles
- Cutting: Quinckie
- Spreading: Whitacre & Sprotte
What are the MOST important factors affecting the level of spinal anesthesia? (there are 3)
- Baricity of the anesthetic solution
- Position of the Patient (during & immediately after injection)
- Drug dosage
What are some other factors affecting the level of spinal anesthesia?
- Site of injection
- Curve of spine
- Drug volume
- Intra-abdominal pressure & pregnancy
- Needle direction
- Height (of pt)
How big are epidural needles?
17-18G; need to be able to fit catheter through them
What two ways can we ID the epidural space?
- Loss of resistance (most common): push fluid into a syringe and when no longer feel resistance you're in
- Hanging drop technique: Leave a drop of water on the needle hanging and as you push in the needle, the drop will get sucked in when you're in
Should your patient be awake for spinal and epidural placement?
- YES for spinal
- Prefer for epidural (if pt has pain or parathesia you don't want to inject)
What are the ABSOLUTE contraindications to neuraxial blockade?
- Infection at the site of injection
- Patient refusal
- Severe hypovolemia
- Increased ICP
- Severe AS
- Severe MS
What are the relative contraindications to neuraxial blockade?
- Uncooperative patient
- Pre-exisiting neurological deficits
- Stenotic valve heart lesions
- Severe spinal deformity
What are the controversial contraindications to neuraxial blockade?
- Prior back surgery at the site of injection
- Inability to communicate w/the patient
- Complicated surgery (prolonged operation, major blood loss, or maneuvers that compromise respiration)
Is there a contraindication for neuraxial blockade w/NSAIDS or ASA?
Is there a contraindication to neuraxial blockade with Ticlopidine or Tirofiban?
YES, d/c 14 days pre-op
Is there a contraindication to neuraxial blockade with Clopidogrel or Abciximab?
YES, d/c 7 days pre-op
Is there a contraindication to neuraxial blockade with Eptifibatide?
Yes, d/c 4-8 days pre-op
If the patient is getting subQ heparin, is this a contraindication for neuraxial blockade?
No but measure platelet count if on it for more than 4 days
And when removing catheter, if the patient has been on it for more than 4 days check the platelet count
If your patient needs IV heparin and just got a neuraxial blockade, how long do you wait?
- To remove catheter, wait 2-4hrs after IV heparin dose and make sure normal PTT and ACT
If you need neuraxial blockade, what are the concerns w/warfarin?
- Stop 4-5 days pre-op & document normal INR pre-insertion
- Remove catheter when INR <1.5
What are your concerns with LMWH and neuraxial blockade?
- Delay insertion 10-12 hrs after last dose
- Delay 24 hrs after blood tap
- For removal w/ once daily dosing: wait 10-12hrs after last dose and restart next dose 2 hr later
- For removal w/ twice daily dosing: remove 2 hrs before next dose
Should you avoid neuraxial anesthesia in patients on Fibrinolytic or Thrombolytic Therapy?
TRUE or FALSE? The removal of the epidural catheter is nearly as great a risk for spinal hematoma as it’s insertion, so the timing of it’s removal and anticoagulation should be coordinated.
List the complications of neuraxial blockade
- Urinary Retention
- Transient Neurologic Symptoms
- High or Total Spinal Anesthesia
- Subdural Injection
- Cardiac Arrest During Spinal Anesthesia
- Systemic Toxicity
- Cauda Equina Syndrome and Other Neurologic Deficits
- Meningitis and Arachnoiditis
- Epidural Abcess
- Spinal or Epidural Hematoma
Do younger or older patients have a higher risk of PDPH?
Younger more frequently
Do females or males have a higher risk of PDPH?
Do larger or smaller needles have a higher risk of PDPH?
What does the needle bevel have to do w/the risk of PDPH?
- Higher risk when dural fibers are cut tranversely
- Splitting needle is better than cutting
Does pregnancy increase the risk of PDPH?
Does the # of dural punctures increase the risk of PDPH?
YES, more risk w/multiple punctures
What are two factors that DON'T increase the risk of PDPH?
- continuous spinals
- timing of ambulation