Neuraxial Anesthesia IV Exam I Flashcards
(97 cards)
1
Q
The risk of LAST increases with what 3 things?
A
- **Hypercarbia **(increases cerebral perfusion which increases drug delivery to the brain, decreases protein binding which increases the free fraction of LA available to enter the brain)
- **Hyperkalemia **(neurons are more excitable and more likely to depolarize)
- **Metabolic acidosis **(Lowers seizure threshold and increases brain drug retention by ion trapping)
2
Q
The risk of LAST decreases with what 3 things?
A
- **Hypocarbia **(Decreases cerebral perfusion, reducing drug delivery to the brain)
- Hypokalemia (neurons are less excitable and require larger stimuli to depolarize)
- **CNS depressants **(like benzo’s and barb’s raise the threshold for seizures, providing protection)
3
Q
- Which LA is the most cardiotoxic?
- Why?
A
- Bupivicaine
- Can be lethal
- Because it has a high affinity to the Na channels in the cardiac muscle, and a slower dissociation rate from the receptor during diastole.
4
Q
Rate the difficulty of cardiac resuscitation with LA’s from greatest to least.
A
- Bupivicaine (most difficult)
- levobupivicaine
- ropivicaine
- lidocaine
5
Q
What is the impact of LA’s on heart functions?
A
- Decreases the hearts automaticity, conduction velocity, action potential duration, and the effective refractory period.
- Depresses the myocardium by affecting intracellular calcium regulation.
6
Q
What are the key factors that determine the extent of cardiotoxicity in LAST?
A
- The LA’s affinity to the voltage gated sodium channel in the active and inactive states in the cardiac muscle.
- The rate of dissociation from the receptor during diastole.
7
Q
What is the main reason for using the aspirate and inject method with LA’s?
A
to prevent LAST
8
Q
What is the main purpose of using ultrasound for peripheral nerve blocks?
A
To prevent LAST (accidental LA injection into the vasculature)
9
Q
What are the treatments for LAST? (4)
A
- **Manage airway: **give 100% O2
* Treat seizures: use benzo’s, avoid propofol because it can weaken the heart in large doses and doesn’t replace lipid therapy. - Modified ACLS: use less than 1mcg/kg of epi. Be cautious with epi because it can make LAST resuscitation harder and lower the effectiveness of lipid therapy. Use Amio for ventricular arrythmias.
- Lipid emulsion 20% therapy.
10
Q
How is lipid emulsion therapy given?
A
- Over 70kg: start with 100mL bolus for 2-3 minutes, followed by a 250mL infusion over 15-20 minutes. Repeat or double if unstable.
- Under 70kg: start with a 1.5mL/kg bolus for 2-3 minutes, followed by a 0.25mL/kg/min infusion. Repeat or double if unstable.
11
Q
How long is the lipid emulsion 20% therapy infusion continued for?
A
until 15 minutes after stability is regained.
12
Q
What is the max dose for the lipid emulsion 20% therapy?
A
12mL/kg
13
Q
How does lipid emulsion therapy work in the treatment of LAST? (4)
A
- Lipid sink which sequesters and reduces the LA plasma concentration.
- Metabolic effect: boosts myocardial fatty acid metabolism and increases heart energy use.
- Inotropic: increases heart muscle calcium levels by increasing calcium influx and intracellular calcium concentration.
- Membrane effect: impairs LA binding to voltage gated sodium channels.
14
Q
What should you do next in the treatment of LAST if the patient is unresponsive to modified ACLS and lipid therapy?
A
prepare for cardiopulmonary bypass
15
Q
How quickly will you see LAST symptoms after an LA is administered?
A
almost immediately
16
Q
True or false:
LAST is a frequent event with neuraxial and peripheral anesthesia.
A
False, it is a rare event
17
Q
What are the first 4 steps of the LAST treatment algorithm?
A
- Call for help
- Get LAST rescue kit
- Consider cardiopulmonary bypass team
- Consider administering lipid emulsion early
18
Q
In the LAST treatment algorithm, if the patient is having a seizure, what should you do next?
A
- Ensure adequate airway
- give benzos
- avoid propofol
19
Q
In the LAST treatment algorithm, if the patient is having an arrythmia or hypotension, what should you do next?
A
- Use modified ACLS
- Use less than 1mcg/kg of epi
- treat arrhythmias with amio
- Avoid LA’s BB’s, CCB’s, and vasopressin
20
Q
In the LAST treatment algorithm, if the patient is stable after administering lipid emulsion, what should you do next?
A
- Continue lipid emulsion infusion for 15 minutes once hemodynamically stable.
- Observe for seizures for 2 hours post event
- Observe for cardiovascular instability for 4-6 hours post event.
21
Q
What is the incidence of a spinal or epidural hematoma?
A
- Low
- 1:200,000
22
Q
What are spinal and epidural hematomas associated with? (3)
A
- pre-existing abnormalities in clotting hemostasis
- traumatic or difficult needle placement
- indwelling catheters and long-term anticoagulation
23
Q
With a spinal or epidural hematoma, cord ischemia is usually reversible if a laminectomy is performed in under how many hours of initial hematoma?
A
less than 8 hours
24
Q
What is a major symptom of an epidural or spinal hematoma?
A
pain
25
What is the biggest risk factor for developing an epidural or spinal hematoma?
Being on long-term anticoagulation
26
What is arachnoiditis?
Inflammation of the meninges associated with:
* Nonapproved administration of a drug into the intrathecal or epidural space (EX: precedex)
* Using non-preservitive free solutions
* Betadine contamination (make sure to wipe it off before you stick the patient)
27
What does arachnoiditis lead to?
extensive sclerosis of arachnoid membranes and constriction of vascular supply.
28
In order for your skin prep to work, what does it have to do?
Dry for at least 30-60 seconds
29
* What antiseptic has to be scraped off the skin before needle puncture for a spinal or epidural?
* Why?
* betadine
* It can cause arachnoiditis
30
Which kit is the spinal kit and which kit is the epidural kit?
31
True or false:
When doing neuraxial blockade, you should always prepare your GETA as a back up
true
32
What are the reasons for prophylactically preparing your GETA set-up when doing neuraxial anesthesia? (6)
* failed block
* high spinal
* LAST
* anyphylaxis
* severe CV collapse
* case exceeds duration of local anesthetic
33
What are the 3 most common reasons for neuraxial blockade failure?
* wrong dose
* wrong location
* wrong position
34
How many times do you prep/scrub the patients back in a spinal or epidural?
3 times
35
Label the spinal kit
1. Betadine
2. sponges
3. gauze
4. sharps
5. spinal needle, 25g, with stylet, pencil point
6. 18g needle attached to 3mL syringe to draw up other meds that dont needle to be filtered
7. 5mL syringe to draw up LA
8. smaller gauge extra needle
9. Epi, if you want to add it to your spinal LA to extend the duration. (not typically used in spinal anesthesia)
10. Smaller gauage extra needle that can also be used for LA infilatration of lidocaine.
11. Introducer needle that the spinal needle goes into.
12. Spinal anesthetic that goes into the subarachnoid space and mixes with CSF. 0.75%, 2mL
13. filter needs to draw up meds from glass viles
14. Lidocaine 1%, 5mL used for local infiltration to numb the patients back.
15. 22-24g infiltration needle for lidocaine
16. Fenestrated drape
36
What are the steps for a spinal anesthesia procedure? (20)
* timeout (ID, consent, allergies, site)
* Place monitors (BP, O2 sat, EKG leads)
* Position patient in "mad cat" position
* Find your landmark and mark the place you are going to stick (tuffiers line beween L4 and L5)
* Don sterile gloves
* scrub the area 3 times with betadine/chloroprep and sponges. Let it dry for 30-60 seconds.
* Whle your prep is drying, draw up your infiltration (epi) and spinal meds.
* If using betadine, use gauze to clean it off patients back.
* drape the patient
* numb patients back with infiltration LA (epi)
* Place introducer needle at your landmark between L4 and L5.
* Place spinal needle into the introducer needle.
* pull stylet out and look for steady/free slowing CSF drips.
* attach your syringe with your spinal LA.
* aspirate a small amount of CSF into syringe before pushing LA to prevent LAST.
* When your are done giving med, pull everything out including introducer and spinal needle.
* lay patient flat
* BP and HR evaluation
* Dermatome assessment
* reposition patient to prevent high spinal (1st 5 minutes)
37
How do you know your bevel is up on your spinal needle?
the little notch on the cap of the stylet is also pointing up.
38
When doing a spinal block, why do we keep our stylet in the spinal needle until we are ready to give our spinal meds?
to keep the tip of the needle from clotting off until we are ready to give our meds.
39
Label the 4 spinal needles
40
What are the 2 "cutting" spinal needles?
* Quincke
* Pitkin
41
What are the 5 "non-cutting/pencil point" spinal needles?
* Sprotte
* Whitacre
* Pencan
* Greene
* Gertie Marx
42
* What is the preferred type of needle for spinal anesthesia?
* Why?
* Non-cutting/pencil point
* They are better at preventing post dural puncture headache.
43
What 2 pieces of information on the spinal and epidural kit will you have to chart?
* Lot number
* Expiration date
44
What is your patient at risk of if you use an expired spinal or epidural kit?
infection
45
What are the 4 advantages of using a non-cutting/pencil point needle for a spinal block?
* Pencil point needles drag fewer contaminants into subnormal tissue
* A click or pop can easily be sensed with a pencil point needle
* Pencil point needles carry significantly less risk of post dural puncture headache.
* Pencil point needles are associated with less than a 1% risk of post dural puncture headache and a failure rate of about 5%.
46
What are common problems encountered with spinal anesthesia blocks? (8)
* Lack of free flowing CSF (rotate your needle 360 degrees to make sure you aren't up against a wall).
* No swirl (if using a hyperbaric solution. Won't see swirl in hypobaric or isobaric solution)
* Resistance with injection (not in the correct spot, may need to readjust needle)
* Paresthesia (can happen during insertion of spinal needle. stop procedure and pull the needle a little and then redirect the needle)
* Checking swirl halfway/end? (check swirl multiple times during med administration t make sure you didn't accidently migrate to a vessel)
* Blood instead of CSF (LAST, not in the right place)
* No block (check lot number and expiration date on kit. May be expired)
* Partial block (May need to consider converting to GETA at this point. Could try repositiong patient)
47
Label the epidural kit
1. Betadine
2. Sponges
3. Gauze
4. Sharps
5. Plastic loss of resistance syringe
6. Tuohy needle 17-19g
7. Epidural needle with stylet
8. filter needle
9. Small gauge 22-25g LA infiltration needle
10. 18g needle to draw up other meds that don't need to be filtered.
11. Cap to lock the catheter in place/place to administer meds.
12. Filter to place on the end of epidural catheter to filter all drugs.
13. Syringe to draw up meds.
14. Meds
15. Meds
16. Meds
17. Meds
18. Glass loss of resistance syringe to check if you are in the epidural space.
19. normal saline
20. there will also be an epidural catheter.
48
What are the steps for an epidural? (20)
* Time out
* Place monitors
* position patient
* Mark your landmark
* don sterile gloves
* do your 3 sterile preps with either betadine or chlorahexadine and let dry for 30-60 seconds.
* While prep is drying draw up your meds
* If betadine was used, use gauze to scrape it off patients skin.
* drape patient
* infiltrate area with LA lidocaine
* point epidural needle cephalad and place in the interspinous ligament
* with draw stylet and attach LOR syringe
* continue advancing needle until you get LOR
* Note depth of touhy needle at this point and remove LOR syringe
* thread catheter to 3-5cm into the epidural space.
* withdraw needle while advancing catheter
* place catheter to the correct skin marking cm.
* Test dose catheter with 1.5% lido with epi, 3mL to make sure you aren't intrathecal or intravascular.
* Secure with dressing and note skin marking cm
* Establish segmental blockade with the epidural dosing
49
What is the biggest difference between a spinal and epidural kit?
The epidural kit has an indwelling catheter that stays in the patient for continuous infusion of medication.
50
What does each marking on the tuohy needle indicate?
1cm or 0.1mm
51
What is the most common type of epidural needle?
tuohy needle
52
What are the characteristics of the tuohy needle?
* 30 degree curved (most curved of all the epidural needles)
* blunt tip so it is less likely to puncture the subarachnoid space.
53
Besides the tuohy needle, what are the 3 other epidural needles called?
* Hustead
* Crawford
* Weiss
54
Describe the hustead epidural needle
Most similar to the tuohy but with a 15 degree curve instead of 30 degrees
55
Describe the crawford epidural needle
* preferred when catheter placement is difficult or the angle is steep like for a thoracic epidural
* 0 degree curvature
56
Describe the weiss epidural needle
* 15 degree curvature
* has wings which make it easier to hold onto when placing epidural.
57
What is the typical gauge of an epidural needle?
17-18g
58
What is the length of the touhy needle from tip to hub?
9cm
59
What is the length of the tuohy needle from tip to window?
10cm
60
What is the purpose of a multiport epidural catheter versus a single port catheter?
The multiport gives you a more even distribution of your LA in the epidural space.
61
What is the optimal epidural space lenght/depth of your tuohy needle?
* 3-5cm
* This is the amount of catheter you have to have inside the epidural space.
62
Describes the measurements/ markings on the epidural tubing.
* 1 dark line = 5cm
* 2 dark lines = 10 cm
* 2 dark lines + thick bolded line = 11 cm
* 3 dark lines = 15 cm
* 4 dark lines = 20 cm
63
What is a flexitip epidural catheter?
* An epidural catheter that is easier to thread, stiffer, and less expensive.
* However, can cause inadvertent SAB puncture.
64
How do you determine the distance of epidural catheter?
* Measure the skin to epidural space.
* After reaching the epidural space with your tuohy needle, subtract the visible needle length from the total length of the needle. EX: total length = 9cm - 4cm of visible length outside of patient = 5cm of tuohy needle inside of patient.
* skin to epidural space = 5cm.
* skin marking
* the optimal epidural catheter depth = 3-5cm in the epidural space.
* Therefore, the catheter should be secured at 10cm at the skin. EX: depth of epidural space = 5cm + 5cm of catheter depth in epidural space = 10cm at the skin.
65
If your skin to epidural space is 6 (because you see 3cm of needle outside of skin), what is your skin marking for your epidural catheter at if you insert 5cm of catheter?
11cm
66
How old should a tattoo be before you can place a spinal or epidural in the area?
at least 5 months old
67
What is the concern for placing an epidural or spinal on a patient with a lumbar tattoo?
There is a risk that tattoo ink could be carried into the spine, potentially leading to inflammation and chemical arachnoiditis
68
What did the 2002 report about lumbar tattoos and neuraxial anesthesia prove?
That most cases showed that epidurals with lumbar tattoos do not cause neurological problems.
69
What are the 3 recommendations for placing an epidural in the area of a lumbar tattoo?
* Try to avoid placing the needle directly through the tattooed skin
* If needed, avoid nicking the skin
* Best to perform procedure after 5 months of tattoo application for safety.
70
What are the 3 most important numbers to record with your epidural catheter?
* Depth to epidural space (distance from skin to epidural space)
* Catheter marking at the skin
* Catheter depth/length in the epidural space (# of cm in the epidural space, typically 3-5cm)
71
True or false:
You can use air, saline, or a combination of both in your LOR syringe to inject into the epidural space
True
72
How do you know you are in the epidural space?
* You lose resistance
* the epidural space (because it is a potential space) will suck in the air or saline from your LOR syringe.
73
When placing an epidural, why should you not test dose with the tuohy needle?
Because you still have to insert your epidural catheter which has the potential of going to a vein.
74
What is the composition of a test dose for an epidural?
lidocaine 1.5% with epi 1:200,000 for a total of 3mL.
75
What is the purpose of the test dose of lidocaine 1.5% with epi when placing an epidural?
* To test if you are in the intrathecal space or intravascular.
* If you are intrathecal you will see a decrease in heart rate and BP, as well as dense motor blockade within 5 minutes with your test dose from the lidocaine
* If you are intravascular you will see an increase in heart rate and BP by 20% or more with your test dose from the epi.
76
* What signs will you see if your have accidental intravascular placement with your epidural?
* What should you do?
* an increase in HR by 20% or more
* ringing in ears (tinnitus)
* metallic taste in mouth
* numbness around mouth
* replace the catheter.
77
What are the 2 special considerations when giving a test dose?
* For pregnant women: give the test dose after a contraction ends for clearer results.
* Patients on heart medications you will see a big increase in blood pressure (greater than 20mmHg), however, this could also mean the needle is intravascular.
78
True or false:
a good test dose for an epidural is positive
* false
* A good test dose is negatove because that means you aren't intrathecal or intravascular
79
When is the best time to tape and secure your epidural catheter?
once you have done your test done and it is negative
80
What are the 2 ways to identify you are in the epidural space?
* LOR syringe
* Hanging drop method (outdated method)
81
What is the hanging drop method for identifying epidural space?
* A saline drop is placed at the hub of the needleand the needle without a syringe is advanced.
* The epidural space is identified when the saline drop is sucked into the needle by the negative pressure.
* This methos is less precise than the LOR syringe.
82
What are the 2 different types of LOR syringes?
* glass
* plastic (cheaper)
83
If you are accidentally in the subarachnoid space with an epidural, should you pull it or keep it?
Depends on hospital policy. Some hospitals allow you to keep it to give a bolus dose for a spinal.
84
What are the 2 dosing regimens for an epidural?
* bolus dose
* continuous infusion
85
* What is the initial dose for your epidural?
* What increments is it given in?
* 1-2mL per segment of the spine to be anesthetized
* Given in 5mL increments
86
When do you give the top up dose for an epidural?
before 2 segment regression has occurred
87
When 2 segment regression has occurred, how much of the initial loading dose can safely be administered to maintain the block?
1/2 to 3/4 of the initial loading dose
88
What is the best practice for dosing regimen for an epidural? (4)
* accurate dermatome assessment
* aspirate for blood or CSF
* inject slowly in 5mL increments
* Monitor closely for 30 minutes for hypotension and unexpected dermatome spread
89
* If a lumbar epidural started at L4-L5, how many mL of LA are needed to block T10 for surgery?
* What would the top op dose be?
* 14mL for your initial dose
* Top up dose is 7mL
90
True or false:
Every time you give an incremental dose for an epidural you need to aspirate?
true, just to be sure your catheter hasn't migrated to a vessel
91
What is the recommended top up time from initial dose for 2-chloroprocaine?
45 minutes
92
What is the recommended top up time from initial dose for lidocaine and mepivicaine?
60 minutes
93
What is the recommended top up time from initial dose for bupivicaine and ropivicaine?
120 minutes
94
What are common problems encountered with epidurals? (6)
* CSF, wet tap
* paresthesia
* can't thread the catheter
* aspirate blood
* positive test dose
* "false" positive test dose
95
In CSE anesthesia which comes first the spinal or the epidural?
The spinal is done first before the epidural
96
What are the steps for CSE anesthesia?
* Use your tuohy needle first as your guide to get the epidural space.
* Put your spinal needle inside your tuohy needle and advance until you reach the subarachnoid space.
* Administer spinal LA
* pull spinal needle out
* Then thread your catheter for your epidural.
* Then you can administer your epidural LA.
97
What type of hospitals is CSE anesthesia typically done in?
teaching hospitals with surgical residents
