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Principles of Anesthesia I > E4 > Flashcards

E4 Flashcards

1
Q

What is a central line and most common sites of access

A

Access of circulation via large vein

Common sites

  • internal jugular
  • external jugular
  • subclavian
  • femoral
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2
Q

What are advantages or disadvantages of inserting CVC in the external jugular and in the internal jugular

A

External jugular
• Won’t allow CVP monitoring

Internal jugular
•	Readily accessible 
	Won’t disturb surgery or sterile field
•	Allows monitoring of CVP
	Tip at cavoatrial junction
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3
Q

What are advantages or disadvantages of inserting CVC in subclavian and femoral veins

A 
Subclavian 	
•	Allows for CVP monitoring
•	More complicated to insert
	b/c clavicle
	hard to US
•	More likely to cause complications
	PTX risk higher
Femoral
•	Easy in emergency CPR
	Esp if access to head/neck limited
•	Higher risk of infection
	Urine/feces
•	Mobility restrictions
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4
Q

What are indications for CVC and describe why. (7)

A 
1.  Monitoring central venous pressure
•	Indication of fluid status 
2. Infusion of caustic drugs 
•	Vasopressor (long-term)
3. Administration of TPN
•	Not common in OR
4. Aspiration of air emboli
•	Theoretical 
5. Insertion of transcutaneous (shouldn’t this be transvenous??) pacing leads
•	Less likely w/ better external pacing 
6. Venous access for people with poor peripheral veins
•	Last resort
7. Dialysis access
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5
Q

What are 4 contraindications for CVC placement and why

A 
1. Renal cell tumor 
•	extending into right atrium
2. Tricuspid valve vegetation
•	Knocking off veg can cause emboli
3. Site infection
•	May use other site?
4. Site specific
•	CEA misplace normal anatomy
----IJ = less compressible and likely for CVC misplacement
•	Femoral
----Incontinence d/t risk for infection
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6
Q

What are 5 complications r/t CVC insertion

A 
1. Pneumothorax/Hemothorax
•	Especially w/ SC site 
2. Line-related infection 
•	CLABSI
3. Carotid puncture
•	Needles and guidewires can traverse jugulars 
4. Dysrhythmias 
•	PVC/Vtach 
•	w/ wire advancement into ventricle
5. Trauma to nearby nerves
•	Nerves path bundle w/ vessels
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7
Q

What is completed prior to CVC procedure

A

Checklist complete

Time out

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8
Q

What is the landmark for identification of IJ CVC insertion. Describe anatomy

A

Anatomy
 Identification of landmarks for placement
 Apex of triangle
• Where clavicle and sternal heads meet
• Of sternocleidomastoid
• Needle insertion site
• IJ access (lateral/anterior to carotid)

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9
Q

Position of pt for CVC placement and rationale

A

Trendelenburg
• to decrease risk of air embolism
• increases VR
—-Venodilates

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10
Q

Practitioner positioning during CVC placement

A
  • Comfortable height
  • Elbow 90deg for insertion
  • Line of site to US
  • Kit on dominant side
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11
Q

Process of preping CVC site for insertion. Why

A

Process
—-Chin-sternum-shoulder-neck-ear

Because:
• In case of moving from IJ to SC site
 Alternate site already prepared
 Saves time

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12
Q

Describe the drape used for CVC placement

A

•Head to foot
•side to side
•Previously 4 sterile towels “squared off”
–Possibly increased infection rate

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13
Q

Process of visualization w/ US prior to CVC insertion.

A 
•	In Plane vs Out of Plane
•	Identify structures 
•	Right side IJ generally later to CA 
---is IJ collapsable 
---Is CA pulsatile 
•	Identify direction of flow (towards=CA away = IJ)
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14
Q

Difference btwn in-plane vs out-of-plane when inserting CVC. Disadvantage of each

A

Out of plane
 Transducer perpendicular to needle

In plane
 Transducer parallel to needle

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15
Q

What are 3 different types of access processes

A

25g “seeker needle”
Cath over needle (18G)
16G syringe w/ US

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16
Q

Process of accessing vessel w/ 25G vs catheter vs 16g syringe

A

25g “seeker needle”
• Puncture vessel
• Aspirate to confirm vessel

Catheter over needle (18G)
•	Before/after seeker needle
•	Insert in IJ
•	Slide cath into IJ 
•	Connect IV tubing
	Vein=Blood goes up tubing slowly
	Artery=blood “shoots” up tubing

With ultrasound
• 16G access needle w/ central bore to thread J-wire
• Disadvantage
 No visual of arterial puncture vs venous
 Can unscrew syringe to visuals blood

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17
Q

Once guide wire is inserted w/ CVC placement, what should be done and why

A

Use ultrasound identify wire inside vessel
• Picture for chart
 Use out of plane
–identify that you are in the right place

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18
Q

J wire insertion technique

A 
Insert J-wire through needle or catheter
•	 Stabilize needle hand
•	To prevent needle movement inside vessel 
•	So vessel isn’t punctured 
	Or needle removed 
•	J straightens in insertion syringe
•	Returns to J shape once in vessel
•	Rotate J to face left toward sternum
	Guides wire toward heart easier 
	remove needle
•	When identify J wire in place
•	I.e. notice PVC = in RA 
•	Stabilize J-wire so it’s not removed
•	Keep hand on wire!!
	nick skin to enlarge opening
•	For larger CVC access
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19
Q

Once J wire in place, what comes next

A 
remove needle
•	When identify J wire in place
•	I.e. notice PVC = in RA 
•	Stabilize J-wire so it’s not removed
•	Keep hand on wire!!

nick skin to enlarge opening
• For larger CVC access

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20
Q

Process for CVC advancement once J wire in place

A

–Advanced catheter over wire
–never letting go of the J-wire
• HOLD WIRE
• So wire doesn’t fully go in
–in a twisting motion

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21
Q

Importance of catheter distance. Difference in sites.

A

Markings to indicate cath insertion length

Some sites require longer CVCs
 More distance to
• Left IJ
• Left SC

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22
Q

If RIJ isn’t successful why would you not immediately attempt LIJ

A

 Can result in peritracheal hematoma

 Constrict airway

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23
Q

Options for CVC securement

A
  • Suture (not too tight, think removal)

* Securement devices

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24
Q

Basic background of SAB

A 
Injection of local anesthetic (LA)  
•	into the SA space 
•	produces rapid onset anesthesia
	Sole anesthetic 
	in combination
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25
Q

Alternate terms for spinal anesthesia

A 
intrathecal 
subarachnoid block (SAB)
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26
Q

MOA of LA for SAB

A

-Effect oof LA on the nerve root

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27
Q

What does MOA of LA for SAB depend on

A
  • SIZE of nerve fibers
  • MYELIN content of nerve fibers
  • CONCENTRATION of LA
  • DURATION of contact of LA w/ nerve root
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28
Q

Indications for SAB and why

A

Procedures of:

  • lower abdomen
  • perineum
  • LE
  • CS

Why:
reduces morbidity and mortality

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29
Q

What are 4 absolute contraindications for SAB and why

A
  1. Patient’s refusal
  2. Increased ICP
    • Worse w/ puncture
  3. Active coagulopathy
    • Cause hematoma compress SC
  4. Inability to position
    • Moving target = inc risk to stick SC
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30
Q

What are relative contraindications for SAB and why

A
  1. Systemic infection
  2. Hemodynamic profile
    • Pt that would not tolerate
     Results of sympathectomy
     T4-cardioaccelerator nerve block
     decrease in SVR d/t sympathectomy
     Shock
     AS (dependent on afterload/SVR)
    Severe hypovolemia (vasodilation)
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31
Q

Advantages of SAB

A

 Decreased incidence of thromboembolism
 Decreased cardiac morbidity and death
 Reduced risks of bleeding

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32
Q

Landmarks for SAB or epidural needle insertion

A

Iliac crest
• Landmark to locate BODY of L4

Inferior angle of scapula
• Landmark to locate the body of T7
• For epidural anesthetic

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33
Q

What is importance to recall for needle insertion in relation to landmarks

A
  • NEEDLE INSERTION IS NOT AT ILIAC CREST/TUFFIER LINE

* IT IS BETWEEN L4/5 INTERSPACE

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34
Q

Epidural sac begins and ends where

A

Begins=foramen magnum

Caudal Termination=sacral hiatus

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35
Q

Landmark and needle insertion for caudal anesthetic

A

Landmark
• Sacral cornu

Needle insertion
• Sacral hiatus

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36
Q

What type of anesthesia is caudal block and why

A

epidural

B/c SC only extends to L1 in adults and L3 in peds

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37
Q

What is the significance of high/low points of the spinal column

A

Where the LA settles depending on baracity.

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38
Q

What are the high/low points in the spine

A

high = C3 and L3

Low = T6 and S2

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39
Q

Differing baracity in relation to high/low points of spinal column when supine

A

hyperbaric
-settle/extend as high as T6

hypobaric
-can extend as high as C3

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40
Q

Treatment for effects d/t T4 sympatholysis of cardioaccelerator nerve

A

Have ready

  • neosynephrine (alpha 1 agonist)
  • Ephedrin (alph1/beta agonist)
  • –use in case of bradycardia
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41
Q

Significance of the spinous process orientation.

A

Significance
• Determines angle of needle insertion

Thoracic
• Needle angled upward
Lumbar
• straighter

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42
Q

Significance of location of blood vessels

A

Adipose tissue and blood vessels arelocated at lateral aspect of epidural space

Avoid unintentional intravascular injection

Blood w/ needle insertion
• Needle is likely lateral

Vessels may be engorged during pregnancy

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43
Q

Which ligaments will NEVER be punctured when performing SAB.
What would this indicate

A

Anterior and posterior
ligaments

That the needle has gone through the SC

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44
Q

What is the last ligament before the SA space

A

Ligamentum flavum

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45
Q

Significance of the ligaments flavum in SAB

A

The last ligament punctured before reaching the SA space

Variability of depth below skin
• 50% pts avg 4cm
• 80% pts avg 4-6 cm

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46
Q

Significance of the ligaments flavum in SAB

A

The last ligament punctured before reaching the SA space

Variability of depth below skin
• 50% pts avg 4cm
• 80% pts avg 4-6 cm

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47
Q

Where does the SC terminate in adults vs meds?

Why is this significant when performing SAB

A

Termination
• Adult = L1
• Peds = L3

R/t doing SAB
• Th reason insertion is at L4/5 interspace

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48
Q

Slides 17 of SAB lecture identify Spinal cord termination, cons medullaris, caudal equina

A

pic

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49
Q

Slide 18 of SAB lecture identify caudal equina, subdural space, subarachnoid space, LF and epidural space

A

pic

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50
Q

Describe the anatomy of the dura mater

A 
Outer most
Thickest
Starts at the foramen magnum
ends in S2 
•	fuses with filum terminale
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51
Q

Describe the anatomy of the arachnoid mater

A 
Delicate
avascular membrane
Subarachnoid space 
•	 between the arachnoid mater and the pia mater 
•	contains CSF
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52
Q

Describe the anatomy of the Pia mater

A

Adherent to the SC
thin layer of connective tissue cells
• interspersed with collagen

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53
Q

What is the difference when diong spinal and epidural anesthesia

A

the presence of CSF

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54
Q

What are dermatones

A

Sensory level corresponding to spinal nerve

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55
Q

What are dermatones

A

Sensory level corresponding to spinal nerve

–The skin area innervated by a given spinal nerve and its corresponding cord segment

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56
Q 
Corresponding sensory location for following dermatome levels 
•	S1
•	L1
•	T10
•	T6
•	T4
•	T1-2
•	C8
•	C6
A
  • S1—lateral aspect of foot
  • L1—Inguinal ligament
  • T10–Umbilicus
  • T6—Xyphoid process
  • T4—Nipple line
  • T1-2—Inner aspect of FA
  • C8—5th finger
  • C6—Thumb
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57
Q

Concern w/ sensory alteration at C6 and location

A

At thumb

 C3-C5 = phrenic nerve
 Can affect respirations

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58
Q

What should be done if pt feels effects up to C6/5

A

Raise head of bed

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59
Q

What is the Puffier line

A

A line drawn across the superior iliac crest that crosses the body of L4 or the interspace of L4-L5

does not change in the scoliosis pt

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60
Q

How to assess superior iliac crest in the morbidly obese pt

A
  • ask them to show you where their hips are
  • can you feel the bone

-Crease at the top of the buttocks?

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61
Q

General pharmacology and mechanisms principles for SAB

A

Spinal nerves in SA space covered by thin pia layer

LA injected to cauda equina
and spreads to the nerve roots

Spinal nerves are susceptible to injury

Small amount of LA can cause intense blockade

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62
Q

What does LA drug selection depend on for SAB

A

 type of surgery
 length of the surgery
 surgeon

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63
Q

SAB dosing w/ bupicacaine 0.75% to extend to T10 and T4.
How many ml for the dose range?

How many ml if 15 mg bupiv given

A

T10
8-10 mg
1-1.33 ml

T4
12-20 mg
1.6-2.67 ml

15 mg = 2 ml

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64
Q

What are some additives to SAB and purpose of each

A

Vasoconstrictor
• Use to prolong block

Opioid
• Use to intensify the block

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65
Q

What is the MOA, type and purpose of opioid additive to SAB

A

LA and Opioid
 synergistic effect in the intrathecal space

Binds to mu receptors

Selectively modulates nociceptive afferent inputs from A and C fibers

Types
 Hydrophilic
 lipophilic

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66
Q

Mechanism of morphine action in SAB and disadvantages

A

Is hydrophilic

long duration of action due to
• low SC distribution volume
• slow clearance to plasma

Spreads into the intrathecal space

Disadvantage
Rostral spread to the brain
• “Delayed” respiratory depression

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67
Q

Dosing and side effects of morphine additive to SAB

A

Dose
• 0.1 - 0.5 mg
• Increasing dose - increases side effects

Side effects
•	N/V
•	Pruritus
•	MOST COMMON
•	Respiratory depression
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68
Q

MOA of fentanyl/sufentanyl w/ SAB

A
  • Lipophilic agents
  • Rapid spread to the spinal cord
  • Rapid rostral spread
  • early respiratory depression
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69
Q

Advantages of fentanyl use in SAB

A
  • Small doses intensify the block w/o prolonging it
  • Reduces LA dose
  • Faster sensory and motor recovery
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70
Q

Indications and dosing for sufentanyl w/ SAB

A

Same advantages as fentanyl
• Mostly used in labor and C-section
• 2.5 - 7.5 mcg - labor
• 2.5 - 10 mcg for c-section with low concentration bupivacaine

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71
Q

Side effects of intrathecal fentanyl/sufentanyl use w/ SAB.

Most common

A
  • Respiratory depression
  • Pruritus (most common)
  • N/V
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72
Q

MOA of vasoconstrictor use w/ SAB.
Drugs commonly used and dosing
Effects w/ tetracaine, bupiv, lido

A

Prolongs action of the LA
 by reducing blood flow
 Decreases CV absorption

Dosing
 Epi = 0.2 - 0.3 mg/ “epi wash”
 Neo = 2 - 5 mg/ “neo wash”

W/ Tetracaine
 profound increase
With bupivacaine or Lidocaine
 variable increase

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73
Q

What is most important when performing SAB

A

ALWAYS HAVE GETA BACKUP

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74
Q

What alpha 2 agonist adjuncts may be used w/ SAB

A

Clonidine

Dexmeditomidine

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75
Q

MOA of clonidine w/ SAB

Side effects and dosing

A

acts on the substansia gelatinosa
Intensifies AND prolongs sensory and motor block

Side Effects
 Hypotension, bradycardia and sedation

Dose
 15 mcg

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76
Q

Where are alpha 2 receptors located

A

Presynaptic neuron at Lamina II of dorsal horn in SC

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77
Q

Benefit of alpha 2 agonist vs opioid adjuncts w/ SAB

A

alpha2 agonist don’t cause respiratory depression

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78
Q

MOA of dexmeditomidine

Dose

A

 Has similar effect/side effects in prolonging blocks

 Dose=3 mcg

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79
Q

Basic process of uptake and elimination of SAB meds

A

 LA injected into SA space
 Injected to the cauda equina
 Spreads to the spinal nerve roots

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80
Q

What are factors affecting uptake of LA w/ SAB (4)

Rationale for each

A

Concentration of LA in the CSF
 Faster uptake w/ higher concentration
 2% > 0.75%

Surface area of the neural tissue
 Inc area = more uptake

Lipid content of the nerve
 Higher content = more uptake

Blood flow of the nerve
 More flow = more uptake

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81
Q

How to assess level of SAB

A

Use something cold to determine dermatome level

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82
Q

Explanation for pt movement following SAB

A

Pt may have adequate sensory block

Motor block occurs after sensory b/c order of fibers

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83
Q

What are the principles of differential block w/ SAB

A

Nerve fibers differ in their sensitivity to LA
Gradual and segmental block
• different nerve fibers when exposed to LA

Smaller diameter axons = more sensitive

Myelinated fibers = more susceptible than non-myelinated

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84
Q

Order of loss w/ block

A

autonomic
sensory (pain/temp)
motor

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85
Q

Describe the arrangement of nerves in a bundle and how does this relate to SAB

A

B-Fibers = outer nerves
C-Fibers = 2nd nerve
A-delta fiber = 3rd level
A-alpha/beta/gamma = central

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86
Q 
What are each of the following nerves responsible for
B fiber
C fiber
A-Delta fibers
A-alpha 
A-beta
A-gamma
A 
B fiber = autonomic (physiologic)
C fiber=pain/temp (sensory)
A-Delta fibers=pain/temp (sensory)
A-alpha = motor tone
A-beta= touch/pressure
A-gamma = motor function
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87
Q

What are sensory fibers

Physiologic

Motor

A

Sensory:
C fiber
A-delta fiber
A-beta fiber

Autonomic/physiologic:
B fiber

Motor:
A-gamma
A-alpha

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88
Q

Function, myelination and SAB order of A type fibers

alpha, beta, delta, gama

A

alpha = proprioception, motor; heavy; last

beta = touch, pressure; heavy; intermediate

gamma = muscle tone; heavy; intermediate

delta= pain, temp, touch; heavy; intermediate

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89
Q

Function, myelination and SAB order of B fibers

A

Preganglionic autonomic vasomotor

Light

Early

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90
Q

Function, myelination and SAB order of C fibers

A

Postganglion vasomotor
Pain, temp, touch

None

Early

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91
Q

How are the levels of sympathetic, sensory and motor level block related w/ SAB

A 
Zones of Differential Block r/t sensory level 
-Sympathetic level 
	2-6 levels higher 
Sensory
-Motor level
	2 levels below
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92
Q

Describe recovery from SAB

A
  • Reverse sequence

* Motor recovers first

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93
Q

Process of elimination of LA following SAB

A

Elimination of LA from CSF
Vascular absorption
• via SA and epidural blood vessels

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94
Q

General factors that affect intrathecal spread

A

 We need to decide which LA to use for planned surgery
 Take into consideration the dose and the length of surgery
 Surgeon

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95
Q

As we age, what physiologic aspects affect SAB (4)

A
  1. With advanced age=neural nerves are vulnerable to LA
  2. Number of myelinated nerves decreased
  3. Conduction velocity in motor nerves decreased
  4. CSF volume decreases and specific gravity increases
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96
Q

What effects does age have on SAB intrathecal spread

A

 Faster onset
 Higher level of blockade
 Longer lasting anesthesia

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97
Q

How does height affect LA spread w/ SAB

A

Normal-sized adult
 height does not play a role in LA spread

In extreme cases
 length of the spinal column may affect the spread

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98
Q

How does weight affect LA spread w/ SAB

A
  • The LA spread is influenced by high BMI

* The abdominal mass of obese patient decreases CSF volume

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99
Q

What is the difference between spread and uptake of LA w/ SAB

A

Spread = from site of LA injection to the top of where it extends

uptake = absorption

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100
Q

How does CSF volume affect spread of LA w/ SAB

Normal CSF

A

Small CSF volume
• Correlates to extensive spread of LA in intrathecal space
• Maximum spread of anesthetic is higher

100 to 160 mL in adult humans

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101
Q

Which pressure-volume loop would be most likely to correlate to increased spread

A

The restrictive loop (small)

associated w/ morbid obesity

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102
Q

How does site of injection affect spread of LA w/ SAB

Site note recommended and why?

A

Higher site of injection spreads higher than lower injection
• L2-L3 = spread is higher compared to L4-L5

Not recommended
• Spinal injection site higher than L3
• L3 and higher injection site caused neural damage

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103
Q

What is barbotage and How does it affect LA spread w/ SAB

A
  • Aspirating CSF before injecting LA
  • Mixing the LA and CSF in syringe
  • Found not effective
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104
Q

How do you know CSF is present with barbotage

A

CSF is warm…

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105
Q

How does the dose of LA affect the spread during SAB

A

larger dose increases
• the spread of LA
• the level of anesthesia
• the block duration

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106
Q

What is density

A

Density is a physical characteristic
• weight in gram of 1 mL of a solution
• at a specified room temperature

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107
Q

What is baracity

Correlate to LA/CSF

A
  • Relationship of density btwn LA and CSF
  • LA density > CSF = HYPERBARIC
  • LA density < CSF = HYPOBARIC
  • LA density = CSF = ISOBARIC
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108
Q

Should baracity of LA be taken into consideration for epidural anesthesia

A

NO b/c no CSF

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109
Q

How can you determine the baracity of LA

A

NS = isobaric

Sterile water = hypobaric

dextrose = hyperbaric

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110
Q

Describe the activity of iso, hypo and hyperbaric LA and their relation to CSF

A

Isobaric – “Stays where you put it”
 LA density or specific gravity = CSF

Hypobaric – “Floats” up
 Lighter than CSF
 LA has a density or specific gravity < CSF

Hyperbaric – Settles to Dependent aspect of the SA space
 Heavier than CSF
 LA has a density or specific gravity > CSF

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111
Q

label each picture of slide 56 and 57. Which is iso, hypo or hyperbaric

A

pics

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112
Q

What factors affect spread of LA w/ SAB (8)

A
  1. Age
  2. Height
  3. Weight
  4. CSF properties
  5. Site of injection
  6. Barbotage?
  7. Dose of LA
  8. Baracity
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113
Q

Cardiac effects r/t the heart d/t SAB

A
  • Dec SVR
  • Dec preload
  • Dec RH pressures
  • Dec CO
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114
Q

Why do CV effects occur w/ SAB

A

loss of sympathetic activity
• accompanies a spinal anesthetic
• results in vasodilation below the level of blockade

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115
Q

Peripheral CV effects d/t SAB

A

Arterial and venous dilation
• Venodilation > Arterial dilation
• Veins contain 75% CV volume

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116
Q

Rationale for hypotension d/t SAB

A 
Sympathectomy (T1-T4) 
•	causes arterial and venous dilation
High block 
•	can cause unopposed bradycardia
Bradycardia + hypotension = not so good
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117
Q

What are HR risk factors r/t SAB

A

BRADYCARDIA
• Baseline HR < 60 beats/min
• Use of β-adrenergic receptor blocking agents
• Prolonged PR interval
• Sensory level above T6 (sympathetic 2-6 levels above**)

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118
Q

What is preloading and co-loading in r/t SAB management

A

preloading = volume before SAB

co-loading = volume WITH SAB

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119
Q

What is the management of CV effects of SAB

A
  • NOT normovolemic=Give IV fluids if

* Normovolemic = give ephedrine (more effective)

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120
Q

Volume management principles for CV effects of SAB

A

Volume for initial treatment of hypotension
• from balanced salt solutions
• do not contain glucose

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121
Q

Are glucose solutions indicated for CV effect management w/ SAB? Why or why not

A

No

b/c “we don’t want them to pee”
Can lead to hypovolemia

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122
Q

Pharmacologic management of CV effects w/ SAB and rationale

A

Phenylephrine:
• alpha agonist
 If HR is normal or elevated
• causes an increased SVR w/o HR

Ephedrine:
 mixed alpha and beta agonist
 if bradycardia
 will increase HR and increase PVR

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123
Q

50 mg of ephedrine in 1 ml vial
Mix to get 5 mg/ml
How much NS?

A

Mix w/ 9 ml NS to get 5 mg/ml

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124
Q

What can affect mortality r/t CV effects of SAB

A

Increase mortality

• Can be d/t Failure to treat or delay treatment

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125
Q

What should be done if HTN results from ephedrine or neo use when pt has SAB

A

• it must be managed with vasodilators, narcotics, and anxioloytics

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126
Q

What is the decreased of bleeding/DVT due to when a spinal is in place

A

The vasodilation effect of the epidural causes slower bleeding (he says in his second lecture)
Intentionally lowering BP to decrease the chance of bleeding

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127
Q

At what point does a SAB affect respirations and why. How can this affect the healthy vs chronic dx adult

A

Cephalad mov’t of block paralyzes
• the abdominal muscles
• intercostal muscles

Pulmonary alterations
• in healthy adult are of little clinical significance

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128
Q

What potential pulmonary complications may occur as SAB moves cephalad

A

Increase the potential for hypoxia when loss of:
• Phrenic nerve paralysis (C3-C5)
• loss of accessory muscles of ventilation

High Spinal
• Decreased FRC d/t paralysis of abdominal muscles
• as the sensory block reaches the level of T2-T4 (sympathetic fibers that supply lungs)
• Loss of perception of intercostal and abdominal wall movement May cause the patient to feel dyspneic

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129
Q

What can happen to pt w/ lung disease that experiences high spinal

A

Dec FRC

Dyspnea

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130
Q

What are causes and alterations w/ high spinal

A

Cause:

  1. Sensory and sympathetic nerve block that supply the lung at the T2-T4 level
    - —— loss of perception of intercostal and and wall muscles causing dyspnea
  2. Paralysis of abdominal muscles
    - —–Decreased FRC
131
Q

Tips to prevent or negate high spinal

A

Raise head of bed
–esp w/ hyperbaric LA, will settle w/ gravity

Prevention, intervene before symptoms start

132
Q

Mechanism and effects of altered thermoregulation d/t SAB

A
  • -SAB impairs central thermoregulation
  • -Hypothermia that is d/t peripheral redistribution of blood flow and heat d/t vasodilation
  • -Leads to shivering
133
Q

Options to address thermoregulation alterations w/ SAB

A

Bair hugger (careful, not too hot)

Ondansetron (also prevent HoTN and low HR)

134
Q

What are your general preparations prior to SAB (3)

A

 Preparation and monitoring patient
 Prepare drugs and equipment
 Always have a general anesthesia set up

135
Q

Considerations when preparing pt for SAB preoperatively

A

Assess patient
• What is the surgery?

Review history
• Anticoagulants and Antiplatelets

Informed consent
• Tell pt complications/risks—spinal HA, hematoma

136
Q

When preparing pt for SAB, what considerations for sensory level block should be considered.

A

–What is the surgery

137
Q

What are the corresponding surgeries for each dermatome level

S2-S5--
S3--
S2--
L2--
L1-- 
T10--
T8--
T6--
T4--
A

S2-S5–Peri-anal/anal surgery (saddle block)
S3–Scrotum
S2–Penis
L2–Foot/ankle surgery
L1–Thigh/lower leg/knee
T10–Vag delivery/uterine/hip/tourniquet
T8–Testicular procedures (embryonically derived from T10-L1 like kidneys)
T6–Uro/Gyn/lower abd
T4–Upper abd/C-section

138
Q
  • Peri-anal/anal surgery (saddle block)
  • -Scrotum
  • -Penis
  • -Foot/ankle surgery
  • -Thigh/lower leg/knee
  • -Vag delivery/uterine/hip/tourniquet
  • -Testicular procedures (embryonically derived from T10-L1 like kidneys)
  • -Uro/Gyn/lower abd
  • -Upper abd/C-section
A

S2-S5–Peri-anal/anal surgery (saddle block)
S3–Scrotum
S2–Penis
L2–Foot/ankle surgery
L1–Thigh/lower leg/knee
T10–Vag delivery/uterine/hip/tourniquet
T8–Testicular procedures (embryonically derived from T10-L1 like kidneys)
T6–Uro/Gyn/lower abd
T4–Upper abd/C-section

139
Q
  • -Scrotum
  • -Penis
  • -Foot/ankle surgery
  • -Uro/Gyn/lower abd
  • -Upper abd/C-section
  • -Thigh/lower leg/knee
  • -Vag delivery/uterine/hip/tourniquet
  • Peri-anal/anal surgery (saddle block)
  • -Testicular procedures (embryonically derived from T10-L1 like kidneys)
  • -Upper abd/C-section
A

S3–Scrotum
S2–Penis
L2–Foot/ankle surgery
T6–Uro/Gyn/lower abd
T4–Upper abd/C-section
L1–Thigh/lower leg/knee
T10–Vag delivery/uterine/hip/tourniquet
S2-S5–Peri-anal/anal surgery (saddle block)
T8–Testicular procedures (embryonically derived from T10-L1 like kidneys)

140
Q

What type of needle is common for SAB insertion.

Why is this needle used. How should it be inserted

A

Connical aka pencil tip
WHITAKER

Beveled end
Very small gauge (25, 27)

Insert bevel up to direct meds cephalad

141
Q

Beveled needle orientation w/ insertion for blocks

A

bevel facing cephalad to direct medication up

142
Q

What type of LA solution would be best for foot/ankle or thigh/knee surgery when doing a SAB

A

Isotonic solution

“because you’re already there”

143
Q

What is the most important aspect of preparing a pt for SAB

A

positioning
positioning
positioning

144
Q

Describe the sitting position for SAB placement

A
  • With Legs hanging over side of bed
  • Patient hug a pillow
  • Put Feet up on a Stool (no wheels)
  • Assistant MUST keep the patient from Swaying
  • Curve her back like a “C”
  • Up in the Bed (quicker but not optimal)
145
Q

When would the lateral position be appropriate for SAB insertion

Describe the position

A

Hip surgery, poor spine flexion

  • Needs to be Parallel to the Edge of the Bed
  • Legs Flexed up to Abdomen
  • Forehead Flexed down towards Knees
146
Q

What is the order of layers traversed by the needle w/ the median approach for SAB

A
  • Skin
  • Subcutaneous fat
  • Supraspinous ligament
  • Interspinous ligament
  • Ligamentum flavum
  • Dura Mater
  • Subdural space
  • Arachnoid Mater
  • Subarachnoid space
147
Q

Which layers are not traversed with the paramedic approach vs the median approach for SAB insertion

A

Supraspinous ligament

Interspinous ligament

148
Q

What layers are traversed fly the needle for SAB via paramedic approach

A
  • Skin
  • Subcutaneous fat
  • Ligamentum flavum
  • Dura Mater
  • Subdural space
  • Arachnoid Mater
  • Subarachnoid space
149
Q

What spinal cord ligaments will never be touched by the spinal needle

A

Anterior ligament

Posterior ligament

150
Q

Why is introducer used for SAB

A

because the spinal needle is so small it would not make it through all the layers

151
Q

What is the fist ligament past via the median approach of the SAB

A

Interspinous ligament

152
Q

What is the last ligament passed before epidural space

A

Ligamentum flavum

153
Q

Sign that needle has passed through ligaments flavum

A

Pop

154
Q

Sign that needle is in SA space

A

CSF drip (when stylet is removed)

155
Q

Why is a stylet in the spinal needle

A

Prevent clotting of needle

Remove when in SA space

156
Q

When CSF is mixed w/ LA for SAB…

Describe

A

Barbotage
Hyperbaric = swirl
iso/hypotonic = inc volume

157
Q

Describe the parmesan approach for SAB

A

Same process except more lateral approach

Spinal needle will be inserted further than w/ midline

158
Q

Difference in spinal and local infiltration syringe

A

Spinal syringe is smaller

159
Q

Once needle is in w/ SAB what should your hands do

A

stabilize the needle by anchoring a hand/finger on the pt

160
Q

Why are the spinal needle and introducer removed together

A

to prevent debris from microscopic “shredding”

161
Q

What are complications of SAB (7)

A
  1. Backache
  2. Postdural puncture HA
  3. Systemic toxicity
  4. Total spinal anesthesia
  5. Transient neurologic symptoms
  6. Cauda equina syndrome
  7. Spinal hematoma
162
Q

What leads to backache following SAB

A
  • Repeated needle insertion by provider (needle trauma)
  • Local anesthetic irritation
  • Ligamentous strain d/t muscle relaxation
163
Q

What needs to be included when performing the informed consent

A

The risks/complications

esp, backache, postural HA, spinal hematoma

164
Q

59 minutes

A

pg 16

postural HA

165
Q

Why is surgical positioning of a pt important to the CRNA

A
  • It’s our respondsibilty
  • Joints should be in natural alignment or padded to prevent injury
  • There are paths changes that can occur
  • Safety belts must be used
  • Nerve injury can happen quickly and may be irreversible
166
Q

What should the anesthetist consider prior to positioning pts

A

 The PROCESS FROM HEAD TO TOE
 PROPER POSITIONING DEVICES
 HOW MUCH HELP IS NEEDED

167
Q

Which position is the most common surgical position

A

Supine

168
Q

Requirements for armboards

A

Armboards

They must be secure if in use

169
Q

What are pathophysiologic alterations to CV and pulm systems in supine position

A
  • ↑ VR, preload, SV, and CO

* ↓Vt, ↓ FRC

170
Q

Describe the guidelines for arm abduction positioning

A

Out to the side
• < 90 degrees
Padded armboards
• secured to the table and patient at the axilla

The arms should be supine (palms up)
Elbows padded
Arm is secured with a Velcro strap

171
Q

Describe guidelines for arm adduction positioning

A

Tucked alongside the body
Arms held along the side of body
• via draw sheet under the body and over the arm

Hand and forearm
• supine (palms up)
• neutral position (palms toward body)

Elbows are padded
• may also tuck one arm
• if surgeon must stand on side of patient

172
Q

Complications from supine malpositioning

A

Back ache
Pressure alopecia
Nerve injuries
Stretch injuries

173
Q

What are specific nerve injuries and stretch injuries that can occur d/t supine positioning

A 
Nerve injuries 
• Arms abducted >90°
	Brachial plexus 
	axillary nerve injury 
• hand/arm is pronated
	Ulnar nerve injury

Stretch injury
• when neck is extended
• head turned away (C5-T1)

174
Q

Guidelines for trendelenburg positioning

A

Similar to supine (padding and alignment) but tilt the head of the patient ↓

Use a non-sliding mattress To prevent patient from sliding

Securement/sliding prevention
• Taped or used shoulder braces

Monitor for pt sliding (use of tape or mark on sheet at head)

175
Q

Edema considerations and CV alterations d/t trendelenburg positioning

A

Edema
• face, conjunctiva, larynx, and tongue
• d/t time or volume

  • ↑ MAP, SVR, and ICP
  • ↑ VR from blood in the lower extremities
176
Q

What are some pulmonary alterations d/t trendelenburg positioning and how are those treated

A 
↓ lung volumes 
↓ pulmonary compliance 
↓ FRC
	B/c diaphragm shifted superiorly
•	Risk of endobronchial intubation from abdomen pushing carina cephalad

Treat:
 Higher pressures in ventilated patients
 To maintain volumes

177
Q

In addition to CV and pulm alterations what is an important consideration/complication w/ trendelenburg positioning.
Recommendation for prevention of this issue

A

• Possibility of postoperative visual loss (POVL)
• Prevention
 decreasing the amount of tilt
 periodically placing the patient level for a specified period of time

178
Q

Important guidelines for reverse trendelenburg positioning

A

 Same as supine (alignment and padding)
with tilt the head of the patient ↑

Slide prevention
• Use a foot rest
• something under the feet

179
Q

CV effects of reverse trendelenburg positioning

A

↓ preload and CO

 d/t venous pooling in the LE

180
Q

Pulm effects of reverse trendelenburg positioning

A

Downward displacement of abdominal contents and diaphragm =
 ↓mean thoracic pressure
 ↓work of breathing
 ↑FRC

181
Q

Cerebral considerations with reverse trendelenburg positioning and why

A

↓ perfusion to brain

• Concern w/ long case or hypotensive pt

182
Q

Which procedures may utilize the sitting position

A

shoulder
neuro
some ortho

183
Q

Guidelines for body placement when pt is in sitting position

A 
Head = cradle or pins
Knees = slightly flexed for balance and prevent sciatic stretch
Feet = supported to prevent sliding
184
Q

What additional requirements are needed for the pt in sitting position

A

Compression stockings to maintain VR

At least 2 fingers distance btwn chin and sternum (to prevent spine issues?)

185
Q

Describe the modification option for the sitting position

A

BEACH CHAIR position
• used frequently in shoulder cases
• less severe hip flexion
• slight leg flexion

186
Q

Nerve complications of sitting position

A
  • Sciatic nerve injury

* Neurologic and cervical spine injuries

187
Q

Pathophysiologic considerations for pts in sitting positions

A
  • Improved ventilation in non-obese patients
  • ↓ VR, CO, and CPP
  • Hypotension risk
188
Q

What procedures may utilizes the prone position

A

Spine
Rectal fissures
Achilles

189
Q

Proper initial positioning of pt in prone

A

Patient lying on stomach in “superman” position
 Don’t completely stretch out arms
 should be < 90 degrees

190
Q

Guidelines for body placement w/ prone position

A
  • Superman
  • Arms outishand <90 dg
  • head supported
  • legs padded, slightly flexed at knees/hips
191
Q

Guidelines for head placement with prone position

A 
Head supported face down
•	using a prone pillow 
•	neutral position 
•	No pressure on eyes, face, and ears
	Commercially made ProneView 
	other prone pillow

• Do not turn the patient’s head
 Risk occlusion of jugular or carotid

192
Q

Risks if pt head turned during prone case

A

Risk of jugular or carotid occlusion

193
Q

Patient equipment for prone position

A
  • EKGk leads on their back
  • Intubate while supine then turn prone
  • Prevent ETT dislodgment by reconfirming position after turning prone
194
Q

Guidelines for airway w/ prone position

A
  • Intubate the patient
  • supine on the bed
  • then turn into prone position
  • ETT dislodgement–reconfirm position once prone
195
Q

Complications to consider for pts in prone position

A

Nerve injureis
Post-op visual loss
Eye injuries from head positioning
ETT dislodgment

196
Q

What nerve complications can occur d/t prone positioning

A

Ulnar nerve injury
 if elbows are not padded

Brachial plexus injury
 if arms are abducted > 90 degrees

197
Q

Cause of post-op visual loss following prone positioning

A

• d/t decreased perfusion/ischemia

198
Q

what can poor head positioning in prone position lead to

A
  • -eye injuries
  • -Pressure injury to eyes, face, ears
  • -occlusion to jugular or carotid
199
Q

Pathophysiologic considerations for pts in prone position

A
  • May reduce amount of fluid in the lungs
  • -BUT extra fluid could overload heart
  • Shift of ventilation/perfusion to dependent areas
  • -V/Q mismatch
  • Skin breakdown or blisters
  • -from friction; pad
200
Q

Procedures that may use the lithotomy position

A

GU
Hemorrhoid
Rectal

201
Q

Guidelines for body placement in lithotomy position

A

–Pt supine
–Legs in stirrups
–Arms tucked on armboard
–may use Tburg or reverse Tburg
LE placement
–Hip flexed 80-100 deg
–legs abducted 30-45 deg from midline
–knees flexed

202
Q

What supports are used in lithotomy position and for what

A

Leg = padded or candy cane stirrups

Arms = armboard

203
Q

Describe leg positioning guidelines for lithotomy position.

Very important consideration to remember during LE positioning.

A
  • Hips flexed 80-100 degrees
  • legs abducted 30-45 degrees from midline
  • knees flexed

Lower extremities MUST be raised/lowered in synchrony
 To prevent pressure/stress on LE

204
Q

What precautions should the CRNA take when the foot of the bed is lowered for a pt in lithotomy position

A

• Protect the hands and fingers from crush injury

205
Q

Guidelines for pt care in lithotomy position during long cases.

A

Rest Periods in long cases
• to level the patient
• lower the lower extremities
• Maybe not during robotic surgeries

206
Q

Complications that may result from lithotomy position

A

lower back pain
nerve injuries
compartment syndrome

207
Q

what nerve injuries may occur as a result of lithotomy position

A
  • Brachial plexus injury
  • Ulnar nerve injury
  • Common perineal injury (foot drop)
  • Lateral femoral cutaneous injury
208
Q

Pathophysiologic considerations for pts in lithotomy position
CV, pulm, and Tburg/reverse considerations

A

CV
• ↑ VR, preload, SV, CO, AND ICP

Pulm
• ↓Vt, ↓ FRC
• Exacerbated by obese abdominal body habitus

Cardiovascular and pulmonary changes
• May occur with further positioning in Trendelenburg or reverse Trendelenburg

209
Q

What vascular assessment should be performed in prone, lithotomy and lateral decubitus positions

A

Check pedal pulses preoperative

and once placed in position to ensure there isn’t decreased perfusion

210
Q

Examples of procedures that would utilize lateral decubitus positioning

A

thoracotomy
nephrectomy
hip replacement

211
Q

Which side is down in a right lateral decubitus position

A

right side is down

212
Q

Guidelines for body placement during lateral decubitus positioning

A
  • Lying on side w/ anterior or posterior support
  • Head support w/o pressure to ears and eyes
  • -check dependent ear
  • Dependent leg slightly flexed
  • arms are in from and supported, abducted 90deg
  • Axillary roll
  • Pillow between knees
213
Q

What positioning aids may be needed for lateral decubitus positioning

A
  • Anterior/posterior roll or bean bag
  • Head support
  • Axillary roll
  • Pillow between knees
214
Q

Describe the axillary roll used in lateral decubitus positioning. Purpose and placement.

A

Axillary roll
 to prevent brachial plexus compression
 placed between chest wall near nipple line and bed
 should NOT be placed in the axilla despite the name

215
Q

Possible complications of the lateral decubitus position

A

Inferior vena cava compression

Nerve injuries

Eye or ear injuries

ETT dislodgement

216
Q

Cause of inferior vena cava compression in lateral decubitus position

A

Kidney rest

Bed flexed

217
Q

What nerve injuries may occur from lateral decubitus positioning

A

Ulnar nerve injury
 if elbows are not padded

Brachial plexus injury
 if arms are abducted > 90 degrees

218
Q

What should be assessed after the pt has been positioned in the lateral decubitus position

A

Assess airway

Make sure ETT has not dislodged

219
Q

Pathophysiologic considerations for pts in the lateral decubitus position

A

CV
• ↑ VR, preload, SV, and CO

Pulm
• ↓Vt, ↓ FRC
• V/Q mismatch d/t
 inadequate ventilation to dependent lung
 decreased blood flow to the nondependent lung

220
Q

What are the most common peripheral nerve injuries r/t positioning

A
  • Ulnar nerver

- Brachial nerve

221
Q

Why do peripheral nerve injuries occur

A

stretch
pressure
ischemia
unknown

Can occur in as little as 30 minutes

222
Q

Incidence of HA w/ SAB vs epidural blocks.

What is the cause in this difference.

A

HA incidence is LESS frequent in spinal anesthesia vs epidural anesthesia

B/c of needle size difference. Epidural is much larger than SAB (25g or 27g)
–Likelihood of dura closing is less w/ larger needle

223
Q

What leads to post-dural HA s/p epidural

A
  • -Result of accidental dural puncture (“wet-tap”)

- -Use of larger needles w/ epidural

224
Q

What symptoms can a “wet-tap” lead to

A

HA
Pain that radiates in neck
N/V

225
Q

What symptoms are characteristically associated w/ post-dural puncture HAs

A
  • HA:
  • -Mild or absent when supine
  • -w/ elevation = severe fronto-occipital HA
  • Neck pain:
  • -Pain radiates to neck causing stiff neck feeling

-N/V

  • Double vision
  • Tinnitus
  • Seizures if severe
226
Q

What is the mechanism leading to the post-dural HA

A

-Low CSF leading to CN traction

227
Q

What causes visual changes w/ post-dural HA

A

Traction causes failure of the affected eye to ABDuct leading to diplopia

CN VII (abducens)

228
Q

What CN are affect by “wet-tap”

A

CN VI (abducens)

CN VIII

229
Q

What can a wet-tap lead to

A

Low CSF volume
Diploplia
Tinnitus
Seizure

230
Q

In rare cases wet-tap can lead to seizures. Why

A

Caused by cerebral hypotension from dural puncture that leads to cerebral vasospasm

231
Q

What are most common d/dx of post-dural complications

A 
Nausea = 60%
Vomiting = 24%
Neck stiffness = 43%
Ocular = 13%
Auditory = 12%
232
Q

Etiology of pst-dural puncture HA

A
  • Loss of CSF volume
  • CSF leak > production
  • Cerebral vasodilation as CSF vol decreases
  • vasodilation causes pain
233
Q

what are risk factors for pts prone to post-dural HA

A
  1. Age (young > old)
  2. Gender (female > male)
  3. H/o previous post-dural HA
  4. Needle design/size (large > small)
  5. Multiple dural punctures
234
Q

Why is post-dural puncture HA more common in young pts

A

b/c older pts have more inelastic dura so it is less likely to “break”

235
Q

Treatment options for post-dural puncture HA

A
  • Position = supine
  • Meds = NSAIDS, Narcotics
  • Caffeine
  • Blood patch
236
Q

Precautions w/ use of caffeine for post-dural puncture HA

How much caffeine and examples of dosing

A

Caution for elderly and those who can’t tolerate CNS/cardiac stimulation

300-500 mg of oral/IV caffeine once or BID

1 cup coffee = 50-100 mg caffeine
Black tea= 60-90 mg
Soft drink = 30-50 mg

237
Q

What is a blood patch?

How is this performed?

A

Pts blood is used occlude puncture
-Blood will clot and occlude the perforation preventing further CSF leak

Patient in the lateral position
 the epidural space is located
 with a Tuohy needle at the level of the dural puncture
 or an intervertebral space LOWER so blood will go up to perf
• 20 ml blood is then taken from the patient’s arm

238
Q

What leads to systemic toxicity w/ epidural anesthesia

Preventative measures

A
  • Very rare w/ spinal b/c drug dosages are low
  • More common w/ epidural anesthesia b/c
  • -higher dosage
  • -epidural veins inc risk of intravascular injection

Prevention:
Reason why test dose and incremental injections

239
Q

Where is blood injected for blood patch

A

Epidural space

240
Q

Complications of total spinal anesthesia

A

-Profound hypotension and bradycardia are common secondary to complete sympathetic blockad

 Respiratory arrest

241
Q

What is transient neurologic symptoms and etiology

A

 Pain, in the legs or buttocks after spinal anesthesia
 Greater with lidocaine
 The mechanism responsible is unknown

242
Q

What is caudal equina syndrome, symptoms and etiology

A

Etiology
Pooling of toxic concentrations of undiluted lidocaine
• around dependent cauda equina nerve roots

Symptoms
•	Low back pain
•	weakness 
•	sensory deficits
•	Bowel and bladder dysfunction
243
Q

Cause of spinal hematoma

How can it be prevented

A

Cause:
coagulopathy, r/t medications or history

Can lead to paralysis

Prevention:
thorough history and assessment. Are they on anticoags or have altered labs

244
Q

Chose which..Epidural or SAB
1. Which would you use for a 5 hr case

  1. Which is fast in onset
  2. Which has more risk for systemic toxicity
  3. Which has greater risk for post-dural puncture HA
  4. Which takes longer to perform
A
  1. Epidural
  2. Spinal
  3. Epidural
  4. Epidural
  5. Epidural
245
Q

Advantages of epidural vs spinal anesthesia

A
  • Can do at almost any level of the spine to target specific dermatomes
  • Allows titration of the block d/t Cath insertion in epidermal space
  • Continuous postop analgesia
246
Q

Disadvantages of epidural vs spinal anesthesia

A
  • Longer time to perform epidural
  • Slower onset
  • Less dense block
247
Q

Contraindications for epidural block

A
  • Similar to SAB
  • PT REFUSAL = ABSOLUTE
  • Tattp (<6 mo = NO!)
248
Q

Where does the epidural space begin and end

A

Begin = Base of skull @ foramen magnum

End = Sacral hiatus (S2)

249
Q

When inserting needle from posterior, which comes first subarachnoid or epidural space

A

epidural space (dura mater–arachnoid mater–subarachnoid space)

250
Q

What are the contents in the epidural space

A 
Fat
Areolar tissue
Lymphatics
Veins
Nerve roots 
Blood vessels
251
Q

What population is more likely to be prone to blood vessel puncture w/ epidural block and why

A
  • common in pregnant patient
  • d/t engorgement of the epidural veins
  • from caval compression
252
Q

What approach is more likely to result in blood vessel puncture

A

The off-midline paramedic approach

253
Q

What is the last ligament before the epidural space

A

Ligamentum flavum

254
Q

How does spinous process orientation differ btwn cervical vs lumbar vertebrae

What does this mean for needle insertion

A

Cervical AND lumbar = horizontally directed
–Needle entry = direct horizontally

Thoracic SP = Sharp caudal angulation
–Needle entry = point cephalad and use paramedic approach

255
Q

What is the safest point of entry when performing Epidural Block

Difference in adults/peds

A

BELOW THE LEVEL OF THE
SC

Adults = lower L1 border
Peds= Lower L3 border
256
Q

General physiologic effects of an epidural block

A

Sensory and motor block

Central and peripheral sympathetic block

257
Q

What nerve fibers are associated w/ central vs peripheral sympathetic block

A

Central = T1-T4

Peripheral = T5 - L4

258
Q

Chronotropic, inotropic and dromotropic differences

A

chronotrop = rate

inotropic = contractility

dromotropic = speed of conduction

259
Q

What are CV effects r/t epidural block

A
  • Loss of motor tone DECREASES blood flow to organs
  • Effects depend on level of block
  • -HIGH thoracic= thoracic myocardial effects
  • —-loss of chronotropic and inotropic drive
  • -LOW thoracic = Vascular dilation
  • —-Dilation of pelvis and lower limbs (BELOW block) can affect organ perfusion?
260
Q

What CV effects are r/t high thoracic block and at which levels

A

Level = T1-T4

Effects on CARDIAC sympathetic activity

  • -block segments of CARDIAC REFLEXES
  • -blocks outflow from VASOMOTOR center to CARDIAC sympathetic fibers
261
Q

CV effects on vasculature with an epidural block

A
  • Veno/arterial vasodilation
  • -DEC SVR
  • -Venous > arterial dilation
  • Venous pooling
  • -DEC VR, RA pressure, CO
262
Q

What does venous pooling lead to

A

–DEC VR, RA pressure, and CO

263
Q

When using a thoracic approach for epidural block decrease HR and hypotension are noted.

What are the physiologic effects and how should it be treated

A

Effects:
DEC VR, RA pressure, CO

Tx:
O2, fluid, ephedrine (b/c HR is low)

264
Q

What are preemptive interventions when noting gradual decline in HR and BP w/ epidural block above T4

A

O2, fluids and leg elevation

Have ephedrine ready

265
Q

Sudden decrease in HR can cause what? How is this treated? Why does it occur?

A

Causes:

  • Profound dec in VR
  • can lead to cardiac arrest

Tx:
O2, fluids, elevate legs, Atropine and/or ephedrine

D/T:
B fiber sympathectomy

266
Q

What are the determinants of epidural block spread

A
  • Site of injection

- Volume/dose of LA

267
Q

Injection consideration when performing a thoracic epidural block

A
  • Produces symmetrical spread of solution
  • Use less volume b/c potential for higher block and resultant hemodynamic instability
  • Needle inserted at cephalad angle (d/t SP angle)
268
Q

Injection considerations when performing lumbar epidural block

A

-There is preferential cephalad spread d/t narrowing of epidural space at lumbosacral joint

  • Delay onset may be d/t larger diameter of the L5-S1 nerve roots
  • -Can cause patchy anesthesia

-Direct catheter cephalad

269
Q

How does LA volume relate to epidural block

A

larger LA volume = more segments blocked

270
Q

LA volume considerations w/ lumbar vs thoracic epidural block injections

A

Lumbar injection:

  • Recommended bolus vol = 10-15 ml (incremental)
  • -Will cause mid-thoracic block (T6@xyphoid)

Thoracic injection:

  • Recommended bolus vol = 5 ml to start
  • -Need less volume to achieve higher block
271
Q

Principles and rule for dose injection w/ epidural blocks

A

• Dosing is incremental for all epidural blocks
 Only after a negative aspiration for CSF and blood

Rule
	1–2 mL per segment to be blocked
	i.e. to achieve a T4 (nipple) sensory level from an L4-5 injection
	L4 to T4 = 12 segments 
	~ 12–24 mL of LA given 
	incremental dosing
272
Q

How much LA would be given to achieve a block at nipple line (which level is this) from L4-L5 injection

A

 i.e. to achieve a T4 (nipple) sensory level from an L4-5 injection
 L4 to T4 = 12 segments
 ~ 12–24 mL of LA given

273
Q

What are purposes of adding adjunctive meds w/ LA for epidural blocks

A
  • Prolong epidural block (Vasoconstrictor)
  • Improve quality of blockade (Opioids)
  • Accelerate onset of blockade (alkalization)
274
Q

What medications can be added to prolong an epidural block.

What specific effects to these meds have w/ LA

A
  • Epi increases duration
  • -GREATEST w/ lido, mepiv, 2-chloro
  • -some w/ bupiv, levobu, etido
  • -Ltd w/ ropiv

Phenylephrine

  • less used
  • not as effective
275
Q

What medication addition can accelerate LA onset w/ epidural block.
What is the MOA

A

Alkalinization w/ NaHCO3 (1 mEq/10 ml LA)

Effects INCREASE:

  • pH (lower H+)
  • Nonionized concentration
  • Diffusion rate b/c more nonionized
  • Onset speed
276
Q

Which LA would alkalinization not be useful

A

When using Ropivacaine

B/c of Ropiv structure

277
Q

Why does 3% 2-Chloro have a faster onset

A

because concentration is higher

278
Q

Onset AND duration (plain) in min:

3% 2-chloro
2% Lido
2% Mepiv
0.5-0.75% Bupiv
1% Etido 
0.75-1% Ropiv
0.5-0.75 Levo
A

3% 2-chloro—10-15//45-60

2% Lido—15//80-120

2% Mepiv—15//90-140

0.5-0.75% Bupiv—20//165-225

1% Etido—15//120-200

  1. 75-1% Ropiv—15-20//140-180
  2. 5-0.75 Levo—15-20//150-225
279
Q

When 1:200,000 epi is added to the following, what is the duration in minutes:

3% 2-chloro
2% Lido
2% Mepiv
0.5-0.75% Bupiv
1% Etido 
0.75-1% Ropiv
0.5-0.75 Levo
A

3% 2-chloro—60-90

2% Lido—120-180

2% Mepiv—140-200

0.5-0.75% Bupiv—180-240

1% Etido—150-225

  1. 75-1% Ropiv—150-200
  2. 5-0.75 Levo—150-240
280
Q

3 ml test dose totals for following LA w/ 1:200,000 epi in mg:

3% 2-chloro
2% Lido
2% Mepiv
0.5-0.75% Bupiv
1% Etido 
0.75-1% Ropiv
0.5-0.75 Levo
A

3% 2-chloro–90//0.015

2% Lido—60//0.015

2% Mepiv–60//0.015

0.5-0.75% Bupiv–15-22.5//0.015

1% Etido–30/0.015

  1. 75-1% Ropiv–22.5-30//0.015
  2. 5-0.75 Levo–15-22.5//0.015
281
Q

Which LA are shortest, intermediate, longest duration

A

Shortest:
2-chloro

Intermediate:
Lido, Mepiv

Long:
Ropiv
Bupiv

282
Q

Which LA has the fastest and slowest onset

A

Fastest onset = 2-chloro

Longest onset = Bupiv**, Ropiv, Levo

283
Q

If the sensory block target is T6 what is the reference level and where should you initially block

A

T6 = xyphoid process

You should block higher than T6 so that the block lasts b/c level drops with time

284
Q

Which LA would be best for an emergency C-section, why and what is it’s structure

A

2-chloro – b/c of the 3% 2-chloro has the highest concentration of LA
ESTER
More rapid onset d/t higher pKa??

285
Q

What is the reason that 2-chloro duration is so short

A

B/c it is an ester and is metabolized by plasma cholinesterase’s NOT the liver

286
Q

What are draw backs w/ the use of 2-chloro and why

A
  1. Short duration d/t plasma cholinesterase metabolization
  2. decreased efficacy of subsequent epidural opioids d/t 2-chloro repeated dosing and binding to mu receptors
  3. Metabolite is PABA which can have greater incidence of allergic response
287
Q

Describe the motor function effects from epidural block. How does it r/t SAB. Which medications are more or less effective?

A

-Takes longer to achieve motor blockade than w/ SAB

  • Lido = GREATEST motor fan depression
  • Ropiv = LEAST motor depression
288
Q

Which LA would be best suited for a working epidural and WHY.

Which La would be best suited for complete motor block

A

Working epidural:
Ropivacaine
B/c it has the LEAST motor depression

Complete:
Lido

289
Q

What are some techniques that can be used for better motor blockade

A
  • Choose appropriate LA (lido)
  • Increase dose of drug
  • Repeat or Top-Up dose
  • Use epinephrine
290
Q

Surgeon performing knee surgery does not want the pt to move. Pt has epidural, what techniques can you use to ensure motor blockade is adequate

A
  • Use appropriate LA (Lido is best)
  • Increase the DOSE of the drug
  • Repeat or top-up dose
  • Use epinephrine
291
Q

Difference in Touhy and Crawford needle for epidural insertion

A

Touhy = disposable 19 g

  • wings at hub to help stabilize/insert
  • Plastic stylet inside

Crawford = 19g reusable
-Metal stylet inside

Stylet = prevents clotting inside insertion needle

292
Q

Anatomy of the Touhy needle

A

19 g
Wings
9 cm length
w/ 1cm Marks from tip to hub

293
Q

What is the purpose of markings on touhy

A

So anesthetist can determine how deep the epidural space is once inside
helps gauge length of catheter for insertion

294
Q

What is the average distance from skin to epidural space
What is the possible min to max distance between skin and E space
How is depth affected by habitus

A

4-6 cm

Min = ~3 cm
Max= ~ 8 cm

Can be less w/ thin and more w/ obese

295
Q

Describe the epidural catheter anatomy

A 
Has markings to determine insertion distance 
1 mark = 5 cm
2 marks = 10 cm
1 BOLD mark = 11 cm
3 marks = 15 cm
4 marks = 20 cm
296
Q

How far should an epidural catheter be inserted into the epidural space.

If a pts epidural space depth his 5 cm, how much catheter will be inserted total

A

2-6 cm INTO space

7-11 cm TOTAL for catheter insertion (should be at bold 11 cm mark?)

297
Q

Guidelines and principles for epidural catheter insertion

A

2-6 cm into epidural space

MIN distance increases risk of DISLODGMENT
MAX distance increases risk of UNILAT block or catheter kinking

298
Q

Once epidural catheter is placed, what precautions should be taken

A

Remove touhy very carefully so that catheter does not come out also

299
Q

What is the purpose of the LOR syringe

A

Since the epidural space is a potential space, it has negative pressure

Thus, when a syringe w/ air or saline is inserted to the epidural space level, the air or saline should lose resistance

Loss of resistance indicates epidural space

300
Q

2 methods of identifying epidural space

A

LOR

Drop method

301
Q

What is the drop method for identifying epidural space

A

Place drop of saline at the hub of the needle w/o syringe and advance

The epidural space should “suck” in the drop d/t negative Patm

Not widely used

302
Q

Complications of using air w/ LOR syringe

A

Pneumocephalus

303
Q

Which pts would be most appropriate for a paramedic approach for epidural block

A

Pts that can’t be positioned easily or cannot flex the spine d/t trauma or arthritis, for example

Pts w/ spine deformities such as kyphosis or prior lumbar surgery

304
Q

What is a major difference. btwn spinal and epidural anesthesia

A

Needle size
Access point
TEST dose for epidural blocks

305
Q

Why are test doses required w/ epidural blocks

A

To ensure:

  • No unintentional intravascular injection
  • No intrathecal LA injection
306
Q

What are s/sx of intravascular injection of LA when doing epidural block.
What should be done

A

A change of HR by >/=20%
Tinnitus
Metallic taste
Circumoral numbness

307
Q

How much is a test dose for epidural block

A

3 ml

Maybe w/ 1.5% lido w/ epi 1:200,000

308
Q

What does a positive test dose indicate

A

That the LA is in the vein
OR
That the LA is intrathecal

309
Q

Using 1.5% lido w/ 1:200,000 epi a CRNA notes a HR from 90 to 110. What could explain this

A

Intravascular injection of the LA w/ epi

310
Q

Inadvertant intrathecal injection of lido when giving test dose for epi block would result in…

A
  • Immediate, significant motor block (c/w SAB)

- Dense motor block w/in 5 min MAY lead to suspicion of SAB

311
Q

If test dose is positive, what should the CRNA do

A

Remove needle and replace catheter

312
Q

Complications associated w/ test doses for epidural blocks in peds, pregnancy, or pts taking B-blockers

A

Peds:
Peaked P waves
Changes in the T wave

Pregnancy:
Give after contraction is over b/c HR inc w/ pain

Beta-blocker pt
HR change may not indicate intravascular injection
Change in SBP >20 mmHg may be more indicative of IV injection

313
Q

What is the appropriate loading dose for epidural block

A

Between 10-15 ml given in 3-5 ml increments

Waiting 3-5 min between each increment to assess response

314
Q

What actions are taken if an epidural block is not complete.

A

Replace the catheter

Dont waste time trying to reposition

315
Q

What measures can enhance sensory and block and improve quality/duration

A

Enhance sensory block:
Give 1/4 to 1/3 initial dose 15 min post initial bolus

Enhance quality/duration
Epi or HCO3 will speed onset and enhance block
Fentanyl will improve the quality

316
Q

What changes is dosing may occur w/ continuous infusion

A

Lower concentration of LA

Opioids may be added

317
Q

When is top-up dosing indicated

A
  • Before “two-segment regression”
  • -Given before the block REGRESSES
  • -i.e. goal is T4 but sensory regression to T6
318
Q

Once two-segment regression has occurred, how should the CRNA address this

A

Top-Up dose of 1/3 to 1/2 the initial loading dose to maintain the block

319
Q

Initial bolus dose totaled 10 ml for an epidural block. Pt sensory block has regressed from nipple line to xyphoid, how much LA should the CRNA give

A

5 ml (1/3 -1/2 initial bolus)

320
Q 
Recommended top up time (in min) for 
lido
2-chloro
mepiv
bupiv/ropiv
A

lido–60
2-chloro–45
mepiv–60
bupiv/ropiv–120

321
Q

What are advantages of continuous infusion epidural anesthesia

A
  • -Hemodynamic stability

- -can be continued post for analgesia

322
Q

Technique for assessing sensory and motor block

A

sensory:

  • pin-prick (avoid)
  • Alcohol swab (TEMP loss w/ pain)
Motor block:
Bromage scale
0 = moves hip, knee, ankle
1 = no hip, moves knee/hip
2 = no hip/knee, ankle
3 = no hip/knee/ankle
323
Q

How is CSE performed

A
  • Perform spinal w/ Tuohy
  • Once at epidural space insert spinal needle through touhy into SA space
  • After barbotage give LA for SAB
  • Pull spinal needle BUT keep touhy
  • Insert epidural cath

Principles of Anesthesia I (4 decks)

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