Mod3: Spinal Anesthesia Part 1

Question 1

Which anesthesia technique involves an injection of a medication into the subarachnoid space which mixes with cerebrospinal fluid (CSF), creating anesthesia in a portion of the body?

Answer 1

Spinal Anesthesia

Question 2

_{SPINAL ANESTHESIA}

Spinal anesthesia is also known as:

Answer 2

Neuraxial anesthesia

Subarachnoid block (SAB)

Intrathecal injection

Question 3

_{SPINAL ANESTHESIA}

How can surgical anesthesia from spinal anesthesia be characterized?

Answer 3

Rapid, Dense, Predictable

Question 4

_{SPINAL ANESTHESIA}

Which regions of the body can be anesthetized w/ spinal anesthesia?

Answer 4

From the upper abdomen to feet

Question 5

_{SPINAL ANESTHESIA}

A catheter can be inserted into the subarachnoid space to extend the duration of the block. This is known as

Answer 5

Continuous spinal

This is usually not done

Question 6

_{SPINAL ANESTHESIA}

T/F: SAB is riskier then GA for the “average patient”

Answer 6

False

SAB is no more or less riskier then GA for the “average patient”

Question 7

_{SPINAL ANESTHESIA - INDICATIONS}

T/F: There are No absolute indications for a spinal

Answer 7

True

Question 8

_{SPINAL ANESTHESIA - INDICATIONS}

Spinal anesthesia is usually indicated for operations usually below which body structure?

Answer 8

The umbilicus

Nipple line dermatome level is T4

Umbilicus dermatome level is T10

Question 9

_{SPINAL ANESTHESIA - INDICATIONS}

Operations below the umbilicus for which spinal anesthesia is indicated include:

Answer 9

Cesarean section

Hernias

TURP (transurethral resection of prostate)

Hip replacements

Lower extremity surgery

Question 10

_{SPINAL ANESTHESIA - INDICATIONS}

Beside being indicated for operations below the umbilicus, spinal anesthesia may be advantageous for which patient populations?

Answer 10

COPD or other respiratory diseases

Cardiac disease (±)

Potential difficult airway (controversial)

Parturients

^{(d/t inc. risk of difficult airway; allows mom baby interactions)}

Question 11

_{SPINAL ANESTHESIA - INDICATIONS}

Why is using spinal anesthesia for potential difficult airway controversial?

Answer 11

?!!!

Question 12

_{SPINAL ANESTHESIA - INDICATIONS}

Why is using spinal anesthesia for Parturients advantageous?

Answer 12

Parturients have an inc. risk of difficult airway

spinal anesthesia allows mom baby interactions

Question 13

_{SPINAL ANESTHESIA - ADVANTAGES}

What are advantages of spinal anesthesia?

Answer 13

Increase Patient satisfaction

^{Rapid recovery - Absence of side effects}

Don’t have to manipulate the airway

Avoid risks of GA in high-risk surgical pts. (COPD, CAD?)

Dec. incidence of DVT, blood loss, and PE’s (in hip replacement)

Decreased stress response (SNS blockade)

Decreased PONV

Decrease exposure to meds

Monitoring mental status

^{(Easier to catch changes in mental status in procedures like TURP that are a/w hyponatremia)}

Question 14

_{SPINAL ANESTHESIA - DISADVANTAGES}

May take longer than induction, why?

Answer 14

Potentially difficult technique

Question 15

_{SPINAL ANESTHESIA - DISADVANTAGES}

Hypotension due to?

Answer 15

Sympathectomy from LA

Question 16

_{SPINAL ANESTHESIA - DISADVANTAGES}

Patient usually awake; why is that a disadvantage?

Answer 16

It may not be suited for the patient to be “awake”

Surgeon uncomfortable with “awake” patient

Question 17

_{SPINAL ANESTHESIA - DISADVANTAGES}

Unknown or extended surgical duration, why?

Answer 17

?…

Question 18

_{SPINAL ANESTHESIA - DISADVANTAGES}

Unexpected surgical delay, why?

Answer 18

Takes time to achieve a good “block”

Is the block successfull?

Is the block holding on, and for how long?

Question 19

_{SPINAL ANESTHESIA - DISADVANTAGES}

Urinary retention, why?

Answer 19

Postoperative urinary retention (POUR) is common after anesthesia and surgery.

Spinal anesthetics bupivacaine and tetracaine delay the return of bladder function beyond the resolution of sensory anesthesia, and may lead to distention of thebladder beyond its normal functioning capacity.

Question 20

_{SPINAL ANESTHESIA - DISADVANTAGES}

In which clinical situations is spinal anesthesia not recommended? why not?

Answer 20

Emergency / trauma situations

Will delay surgical procedure

Question 21

_{Spinal Anesthesia: Contraindications}

According to the New York Society of Regional Anesthesia, what are absolute contraindications to spinal anesthesia?

Answer 21

Patient refusal / uncooperative patient

Uncorrected coagulopathies or thrombocytopenia

Infection at site of injection

Hypovolemia

Increased ICP

Indeterminate neurologic disease

Question 22

_{Spinal Anesthesia: Contraindications}

According to the New York Society of Regional Anesthesia, what are relative contraindications to spinal anesthesia?

Answer 22

Septicemia

Shock

Lumbar spine surgery, injury or disease

Unknown duration of surgery

Question 23

_{Spinal Anesthesia: Anatomy Review}

What is the initial landmark that must be palpated before initiation of spinal anesthesia?

Answer 23

The spinous process

Question 24

_{Spinal Anesthesia: Anatomy Review}

How do you know you have access the Epidural space?

Answer 24

After the ligamentum of flavum and before the dura and arachnoide, you will feel the characteristic “poop” that will take you into the Epidural space

Question 25

_{Spinal Anesthesia: Anatomy Review}

What’s the midline spinal neddle path from skin to Subarachnoid space (CSF)?

Answer 25

Skin

SQ fat

Supraspinous ligament

Interspinous ligament

Ligamentum flavum

Epidural space

Dura mater

Subdural space (potential space)

Arachnoid mater

Subarachnoid space (CSF)

Question 26

_{Spinal Anesthesia: Patient preparation}

T/F: Before spinal anesthesia, you must ensure that all other anesthetic options have been discussed with pt

Answer 26

True

Question 27

_{Spinal Anesthesia: Patient preparation}

Complications - inform pt. of:

Answer 27

Potential risks and complications

Question 28

_{Spinal Anesthesia: Patient preparation}

Educate pt. on procedure - Explain which aspects of the procedure?

Answer 28

Positioning

Sensations

Side Effects

Question 29

_{Spinal Anesthesia: Patient preparation}

Educate pt. on procedure - Explain that spinal anesthesia blocks painful sensations, but may not block which sensations?

Answer 29

Pressure & Movement

Question 30

_{Spinal Anesthesia: Patient preparation}

Educate pt. on procedure - Explain to patient that they may experience Odd sensation when legs / lower abdomen become numb

Answer 30

True

Why is that?

Question 31

_{Spinal Anesthesia: Patient preparation}

Answer all pt’s questions and clear up misconceptions

Answer 31

True

Common sense

Question 32

_{Spinal Anesthesia: Patient preparation}

_T/F

Ensure pt. is comfortable and willing to cooperate with anesthetic technique chosen

Answer 32

True

_{<em>Common sense</em>}

Question 33

_{Spinal Anesthesia: Patient preparation}

_T/F

Ensure Informed Consent is signed

Answer 33

True

Standard of Practice

Question 34

_{Spinal Anesthesia: Patient preparation}

Ensure pt has at least how many well functioning IVs?

Answer 34

one

Question 35

_{Spinal Anesthesia: Patient preparation}

Which type of fluid solution should you pre-load the pt w/? How much?

Answer 35

Isotonic crystalloid solution

15 ml/kg

Question 36

_{Spinal Anesthesia: Patient preparation}

Pre-load w/ isotonic crystalloid solution - How much for high block?

Answer 36

1000 ml

Question 37

_{Spinal Anesthesia: Patient preparation}

Pre-load w/ isotonic crystalloid solution - How much for C-sections?

Answer 37

1500 ml

Question 38

_{Spinal Anesthesia: Patient preparation}

Pre-load w/ isotonic crystalloid solution - Be careful if CHF risk, why?

Answer 38

Too much fluid will exacerbate CHF

Question 39

_{Spinal Anesthesia: Patient preparation}

Pre-load w/ isotonic crystalloid solution - Does not prevent hypotension, why not?

Answer 39

?…

Question 40

_{Spinal Anesthesia: Patient preparation}

Place monitors; at a minimum which monitors do you need?

Answer 40

Pulse-ox

ECG

NIBP

O2 _{(if indicated)}

Question 41

_{Spinal Anesthesia: Patient preparation}

Which Pre-medication or alternative could be used for pre-op anxiety?

Answer 41

Verbal encouragement

Pharmacy

Question 42

_{Spinal Anesthesia: Patient preparation}

Why should pharmacologic agents to relieve anxiety be used with caution in spinal anesthesia?

Answer 42

To maintain patient cooperation

Question 43

_{Spinal Anesthesia: Patient preparation}

T/F: No sedation in L&D w/ spinal anesthesia

Answer 43

True

Mother’s cooperation needed

Question 44

_{Spinal Anesthesia: Patient Positioning}

What is the favorable position for spinal anesthesia? why?

Answer 44

Sitting

Make then arch before they “lean forward”

Back arched (“like a mad cat”) for maximum flexion of lumbar spine

Question 45

_{Spinal Anesthesia: Sitting Positioning}

T/F:

Back arched (“like a mad cat”) for maximum flexion of lumbar spine, NOT LEANING FORWARD

Answer 45

True

Question 46

_{Spinal Anesthesia: Sitting Positioning}

Where would you make them sit?

Answer 46

Usually on side of OR table

Question 47

_{Spinal Anesthesia: Sitting Positioning}

Where are the legs and feet placed?

Answer 47

Legs dangling with feet on stool or chair

Question 48

_{Spinal Anesthesia: Sitting Positioning}

Where are the Forearms placed?

Answer 48

Crossed laying over pillow or on Mayo stand

Question 49

_{Spinal Anesthesia: Lateral Decubitus}

In the Lateral Decubitus position, how are Hips and knees placed? why?

Answer 49

Hips and knees maximally flexed

This Fetal position is used to open vertebral interspace

Question 50

_{Spinal Anesthesia: Lateral Decubitus}

In this position how are the Shoulders and knees placed in reference to the bed?

Answer 50

Shoulders and knees perpendicular to bed

Question 51

_{Spinal Anesthesia: Lateral Decubitus}

Which is more challenging between sitting vs Lateral Decubitus positions?

Answer 51

Lateral Decubitus position is more challenging

Question 52

_{Spinal Anesthesia: Lateral Decubitus}

Since the Lateral Decubitus position is more challenging than the sitting position, why is it used if at all?

Answer 52

It is used when patient can not get into the sitting position

Question 53

_{Spinal Anesthesia: Prone Jack Knife position}

Why would the Prone Jack Knife position be used?

Answer 53

Only if position to be used for surgery

Question 54

_{Spinal Anesthesia: Prone Jack Knife position}

For which type of block, utilizing a LA with which baricity, and for which type of surgery would this position be used?

Answer 54

Sacral block with hypobaric LA for perineal surgery

Question 55

_{Spinal Anesthesia: Prone Jack Knife position}

T/F

Will see free flow of CSF from spinal needle with this position

Answer 55

False

Will not see free flow of CSF from spinal needle

Question 56

_{Spinal Anesthesia: Needles}

The most important characteristics of spinal needles are:

Answer 56

Shape of the tip

Needle diameter

Question 57

_{Spinal Anesthesia: Needles}

Needle tip shapes that cut the dura include:

Answer 57

Pitkin

or

Quincke-Babcock needle

^{Short beveled-cutting edge (Quincke/Greene)}

Question 58

_{Spinal Anesthesia: Needles}

Needle tip shapes with conical or pencil-point tip include:

Answer 58

Whitacre and Sprotte needles

Question 59

_{Spinal Anesthesia: Needles}

Which spinal needle requires more force for insertion?

Answer 59

Pencil point (Whitacre & Sprotte)

Question 60

_{Spinal Anesthesia: Needles}

Why is the Pencil point (Whitacre & Sprotte) easier to ID penetration of the Dura?

Answer 60

Allows for better tactile feel of various tissues encountered

Spreads dural fibers

Aperture distal to tip of needle

Question 61

_{Spinal Anesthesia: Needles}

How do Short beveled-cutting edge (Quincke/Greene) needles enter dural fibers? Where is the needle aperture located?

Answer 61

Cuts dural fibers

Aperture at bevel of needle

Question 62

_{Spinal Anesthesia: Needles}

The use of small needles reduces the incidence of

Answer 62

Post–dural puncture headache (PDPH)

from 40% with a 22-G needle to less than 2% with a 29-G needle

The use of larger needles, however, improves the tactile sense of needle placement, and so although 29-G needles result in a very low rate of post–dural puncture headache, the failure rate is increased

Question 63

_{Spinal Anesthesia: Needles}

Introducer needles (usually 18ga) are inserted into which ligament? what’s their function?

Answer 63

Inserted into interspinous ligament

An introducer needle can assist with guidance of smaller-gauge spinal needles in particular

Prevents bending or deflection of thinner spinal needle

Question 64

_{Spinal Anesthesia: Needles}

What’s the advantage of using the fitted stylet?

Answer 64

To prevent bending and clogging of spinal needle with CSF

especially the smaller guage needles

Question 65

_{Spinal Anesthesia: Needles}

If used, why must the fitted stylet be removed?

Answer 65

To assess for CSF flow or inject LA

Question 66

_{Spinal Anesthesia: Needles}

Which spinal needle is represented in the picture?

Answer 66

Whitacre

Question 67

_{Spinal Anesthesia: Needles}

Which spinal needle is represented in the picture?

Answer 67

Sprotte

Question 68

_{Spinal Anesthesia: Needles}

Which spinal needle is represented in the picture?

Answer 68

Quincke

Question 69

_{Spinal Anesthesia: Needles}

What is Orifice Diameter (OD) used for? What’s the relationship between OD and needle gauge?

Answer 69

OD is used to determine gauge

The smaller the OD/ the larger gauge

Question 70

_{Spinal Anesthesia: Needles}

What’s the typical Spinal needle gauge?

Answer 70

22-29ga

Question 71

_{Spinal Anesthesia: Needles}

Needles of what gauge require introducer?

Answer 71

<22ga

Question 72

_{Spinal Anesthesia: Local anesthetics most commonly used}

Which LA provides the most profound sensory block?

Answer 72

Bupivacaine

Question 73

_{Spinal Anesthesia: Local anesthetics most commonly used}

How long will a Bupivacaine block last?

Answer 73

2-4 hours

Depending on dose

Question 74

_{Spinal Anesthesia: Local anesthetics most commonly used}

Which LA is short acting (1 hr), and is a/w controversial use at high concentrations, d/t transient rediculopathies?

Answer 74

Lidocaine

Question 75

_{Spinal Anesthesia: Local anesthetics most commonly used}

Which LA provides the most profound motor block in spinal anesthesia?

Answer 75

Tetracaine

Question 76

_{Spinal Anesthesia: Local anesthetics most commonly used}

Which LA is the Longest acting in spinal anesthesia?

Answer 76

Tetracaine

Longest acting (~ 4 hrs depending on dose)

Aslo provides the most profound motor block

Question 77

_{Spinal Anesthesia: Local anesthetics most commonly used}

Which LA has the fastest onset, but also the shortest duration?

Answer 77

Chloroprocaine

Question 78

_{Spinal Anesthesia:​ Common Spinal LA}

Lidocaine

• Dose (mg):*
• Regression 2 Derm (min):*
• Resolution (min):*
• Prolongation (%):*

Answer 78

Lidocaine

• Dose (mg):* 25 -100
• Regression 2 Derm (min):* 40-100

Resolution (min): 140-240

Prolongation (%): 20-50

Question 79

_{Spinal Anesthesia:​ Common Spinal LA​}

Marcaine (Bupivicaine) 0.75%

Dose (mg):

Regression 2 Derm (min):

Resolution (min):

Prolongation (%):

Answer 79

Marcaine (Bupivicaine) 0.75%

Dose (mg): 5-20 (15)

Regression 2 Derm (min): 90-140

Resolution (min): 240-380

Prolongation (%): 20-50

Question 80

_{Spinal Anesthesia:​ Common Spinal LA​​}

Tetracaine 0.5%

Dose (mg):

Regression 2 Derm (min):

Resolution (min):

Prolongation (%):

Answer 80

Tetracaine 0.5%

Dose (mg): 5-20

Regression 2 Derm (min): 90-140

Resolution (min): 240-380

Prolongation (%): 50-100

Question 81

_{Spinal Anesthesia:​ Common Spinal LA​​​}

Chloroprocaine

Dose (mg):

Regression 2 Derm (min):

Resolution (min):

Prolongation (%):

Answer 81

Chloroprocaine

Dose (mg): 30-100

Regression 2 Derm (min): 30-50

Resolution (min): 70-150

Prolongation (%): NR

Question 82

_{Spinal Anesthesia:​}

What are the Determinants of local anesthesia spread?

Answer 82

Baricity and patient position

Dose/volume/concentration

Site of injection

Patient characteristics

Question 83

_{Determinants of local anesthesia spread}

What are the two most important/predominant influencers of local anesthesia spread?

Answer 83

Baricity

Patient position

Question 84

_{Determinants of local anesthesia spread}

We know that Dose = Volume × Concentration. Which of those three is the most reliable determinant of local anesthetic spread (and thus block height)?

Answer 84

Dose

This is true for isobaric (smaller role) and hypobaric local anesthetic solutions

This is relatively unimportant with hyperbaric solutions

Also, Higher concentration = higher level block

Question 85

_{Determinants of local anesthesia spread}

The spread of Hyperbaric local anesthetic injections are primarily influenced by:

Answer 85

Baricity

Question 86

_{Determinants of local anesthesia spread}

Site of injection is a determinant of local anesthesia spread for LA with which baricity?

Answer 86

Isobaric LA

_{<em>not hyperbaric</em>}

_{This also uncertain}

Question 87

_{Determinants of local anesthesia spread}

How do Pregnancy and Obesity affect the spread of local anesthetic and block height?

Answer 87

In theory, the increased abdominal mass in obese and pregnant patients, and possible increased epidural fat, may decrease the CSF volume and therefore increase the spread of local anesthetic and block height.

This has indeed been demonstrated using hypobaric solutions which are characterized by more variable spread anyway, but not hyperbaric solutions

Question 88

_{Effect of Baricity and position on LA spread}

The ratio of the density of a local anesthetic solution to the density of CSF is also known as?

Answer 88

Baricity

Defined as the mass per unit volume of solution (g/mL) at a specific temperature

Baricity of a local anesthetic solution is conventionally defined at 37° C

The density of CSF is 1.00059 g/L (Miller)

The density of CSF is 1.0003 + 0.0003 g/ml (PPT)

Question 89

_{Effect of Baricity and position on LA spread}

Local anesthetic solutions that have a higher density than CSF are termed

Answer 89

Hyperbaric

Ratio of the density >1

Question 90

_{Effect of Baricity and position on LA spread}

T/F

The spread of hyperbaric solutions is more predictable, with less interpatient variability

Answer 90

True

Question 91

_{Effect of Baricity and position on LA spread}

Which substances are commonly added to render local anesthetic solutions either hyperbaric or hypobaric?

Answer 91

Dextrose (5%-8%) or sterile water, respectively

Question 92

_{Effect of Baricity and position on LA spread}

Why do Hyperbaric solutions will preferentially spread to the dependent regions of the spinal canal

Answer 92

Gravity

It causes solutions to flow downward in CSF to most dependent region in spinal column

Question 93

_{Effect of Baricity and position on LA spread}

Local anesthetic solutions that have the same density as CSF are termed

Answer 93

Isobaric solutions

LA solutions with density = CSF

Baricity = (1.0)

Question 94

_{Effect of Baricity and position on LA spread}

LA without additives

Answer 94

Isobaric solutions

Question 95

_{Effect of Baricity and position on LA spread}

To obtain an isobaric solution, Lyophilized (powdered) LA* must be reconstituted with:

Answer 95

NS

Question 96

_{Effect of Baricity and position on LA spread}

T/F:

Isobaric solutions tend not to be influenced by gravitational forces

Answer 96

True

Gravity has little to no effect on distribution

Question 97

_{Effect of Baricity and position on LA spread}

T/F:

Isobaric solutions tend to create a “belt” of anesthesia

Answer 97

True

What does “belt” of anesthesia mean?

Question 98

_{Effect of Baricity and position on LA spread}

What does “belt” of anesthesia mean?

Answer 98

…

Question 99

_{Effect of Baricity and position on LA spread}

Local anesthetic solutions that have a lower density than CSF are termed:

Answer 99

Hypobaric solutions

LA solutions with density < CSF

Baricity = (<0.9990)

Question 100

_{Effect of Baricity and position on LA spread}

To obtain an hypobaric solution, Lyophilized (powdered) LA* must be reconstituted with:

Answer 100

Sterile water

Question 101

_{Effect of Baricity and position on LA spread}

Due to gravitational forces, how do Hypobaric solutions move in CSF?

Answer 101

Rise in CSF

Question 102

_{Effect of Baricity and position on LA spread}

What’s the only commonly used lyophilized LA?

Answer 102

Tetracaine

Tetracaine is an ester local anesthetic

It is packaged either as niphanoid crystals (20 mg) or as an isobaric 1% solution (2 mL, 20 mg). When niphanoid crystals are used, a 1% solution is obtained by adding 2 mL of preservative-free sterile water to the crystals. Mixing 1% solution with 10% dextrose produces a 0.5% hyperbaric preparation that may be used for perineal and abdominal surgery in doses of 5 and 15 mg, respectively

Question 103

_{Effect of Baricity and position on LA spread}

What’s a lyophilized LA?

Answer 103

LA supplied as a lyophilized powder that can be reconstituted with dextrose, NS, or sterile water prior to injection

Question 104

_{Effect of Baricity and position on LA spread}

Supine position and influence of normal spinal curvature

Answer 104

A thoughtful understanding of the natural curvatures of the vertebral column can help predict local anesthetic spread in patients placed in the horizontal supine position immediately after intrathecal administration

Question 105

_{Effect of Baricity and position on LA spread}

Supine position and influence of normal spinal curvature. What’s the injection site of LA (Hyperbaric solutions) in the supine position

Answer 105

Lumbar lordosis

Question 106

_{Effect of Baricity and position on LA spread}

Supine position and influence of normal spinal curvature. How do Hyperbaric solutions flow when injected in the supine position?

Answer 106

Both cephalad and caudad

Question 107

_{Effect of Baricity and position on LA spread}

For Unilateral procedures in supine position using Hyperbaric solutions, how is the operative site positionned during injection?

Answer 107

Dependent

Question 108

_{Effect of Baricity and position on LA spread}

For Unilateral procedures in supine position using Hyperbaric solutions, operative site dependent during injection. What could this cause?

Answer 108

Pain

(broken hip)

Question 109

_{Effect of Baricity and position on LA spread}

For Unilateral procedures in supine position using Hyperbaric solutions, how long are pts left in lateral position?

Answer 109

Pt left in lateral position for 3-5 mins

Question 110

_{Effect of Baricity and position on LA spread}

For perineal procedures using Hyperbaric solutions, how long is pt left in sitting position for “Saddle Block”?

Answer 110

Pt left in sitting position 5 – 10 min

Question 111

_{Effect of Baricity and position on LA spread}

What’s a “Saddle Block”?

Answer 111

Low spinal anesthesia technique that provides segmental block for those parts of the perineum, buttocks and inner thighs that would touch a saddle at the time of riding a horse

Question 112

_{Effect of Baricity and position on LA spread}

For Mid-high abdominal procedures using Hyperbaric solutions, how is the pt positionned?

Answer 112

Pt positioned supine with slight trendelenburg

Be careful – not the best option!!!??

Question 113

_{Effect of Baricity and position on LA spread}

For Mid-high abdominal procedures using Hyperbaric solutions, Pt positioned supine with slight trendelenburg. Why is this not the best option?

Answer 113

???

Question 114

_{Effect of Baricity and position on LA spread}

For Perineal procedures using Hypobaric solutions, how is the pt positionned?

Answer 114

Jackknife-prone position

Again, not the best option!!!

Question 115

_{Effect of Baricity and position on LA spread}

For Perineal procedures using Hypobaric solutions, pt positionned in Jackknife-prone position. Why is this not the best option?

Answer 115

???

Question 116

_{Effect of Baricity and position on LA spread}

T/F:

Isobaric solutions are Not influenced by patient position or gravity

Answer 116

True

Question 117

_{Factors influencing onset and duration of block}

Onset of most LA:

Answer 117

Within a few seconds

Regardless of local anesthetic used

Question 118

_{Factors influencing onset and duration of block}

Time to reach peak block - Lidocaine

Answer 118

10 min

Question 119

_{Factors influencing onset and duration of block}

Time to reach peak block - bupivacaine/tetracaine

Answer 119

20 min

Question 120

_{Factors influencing onset and duration of block}

What’s the Principal determinant of duration of action (DOA) of a LA?

Answer 120

The Drug itself

_{The DOA is drug-specific}

Question 121

_{Factors influencing onset and duration of block}

LA ranked from shortest duration to longest duration:

Answer 121

Chloroprocaine < Lido < Bupivacaine < Tetracaine

CLBT

Question 122

_{Factors influencing onset and duration of block}

How does increasing dose of LA affect level and duration of the block?

Answer 122

Increasing dose => increased level => increased duration

Question 123

_{Factors influencing onset and duration of block}

T/F:

Higher the block the longer it will last

Answer 123

True

Question 124

_{Factors influencing onset and duration of block}

Higher block regresses faster than lower block, why?

Answer 124

Because Block is “less dense” d/t dilution in the CSF

Question 125

_{Factors influencing onset and duration of block}

T/F:

Cephalad spread results in lower drug concentration in CSF

Answer 125

True

Question 126

_{Factors influencing onset and duration of block}

How does Addition of adrenergic agonists affect duration of block?

Answer 126

Prolongs duration of block

Question 127

_{Factors influencing onset and duration of block}

How does Addition of adrenergic agonists prolong duration of block?

Answer 127

Result of vasoconstriction of spinal cord vessels

Leading to decreased vascular uptake of LA

Question 128

_{Factors influencing onset and duration of block}

How does Addition of adrenergic agonists causes analgesia?

Answer 128

Stimulates alpha2 receptors in spinal cord

This inhibits antinociceptive afferents

→ analgesia

Question 129

_{Factors influencing onset and duration of block}

Addition of adrenergic agonists has the greatest effects with which LA?

Answer 129

Tetracaine

Duration increased by 40-100%

Be aware of extended recovery time

Question 130

_{Factors influencing onset and duration of block}

Compared with Tetracaine, how does addition of adrenergic agonists affect Bupivacaine?

Answer 130

Effects are somewhat less

Duration increased by 20-50%

^{vs. 40-100% with Tetracaine}

Question 131

_{Factors influencing onset and duration of block}

How are effects of adding adrenergic agonists to Lidocaine?

Answer 131

Controversial

Question 132

_{Factors influencing onset and duration of block}

Which dose of Epinephrine is added to LA for spinal anesthesia?

Answer 132

0.2-0.3mg of Epi

Question 133

_{Factors influencing onset and duration of block}

Which dose of Phenylephrine is added to LA for spinal anesthesia

Answer 133

2-5mg of Phenylephrine

Question 134

_{Factors influencing onset and duration of block}

Which dose of Clonidine is added to LA for spinal anesthesia?

Answer 134

75-150mg of Clonidine

Question 135

_{Factors influencing onset and duration of block}

What’s a benefit of adding Clonidine to LA for spinal anesthesia?

Answer 135

Increased analgesic properties

Question 136

_{Factors influencing onset and duration of block}

Adding Clonidine to LA for spinal anesthesia must be avoided in CAD and HTN, why?

Answer 136

….

Question 137

_{Intrathecal opioids}

T/F:

Intrathecal opioids may be administered with or without LA

Answer 137

True

Question 138

_{Intrathecal opioids}

What are major benefits of Intrathecal opioids?

Answer 138

Provides intense analgesia

Motor or sympathetic function unaffected

Better block, better analgesia!!!

Question 139

_{Intrathecal opioids}

What are side effects of Intrathecal opioids?

Answer 139

Resp. depression

N/V

Pruritus

Urinary retention

Question 140

_{Intrathecal opioids}

What are the most common opioids added to spinal anesthesia?

Answer 140

Fentanyl

Duramorph

Sufentanil

Question 141

_{Intrathecal opioids}

What are dose, onset, and DOA of Fentanyl when added to spinal anesthesia?

Answer 141

Dose: 10-25 mcg of Fentanyl

Onset: Rapid

DOA: 2-8 hrs

Question 142

_{Intrathecal opioids}

What are dose, onset, and DOA of Duramorph (PF Morphine) when added to spinal anesthesia?

Answer 142

Dose: 0.1-0.25 mg of Duramorph (PF Morphine)

Onset: slower

DOA: 6-24 hrs

Question 143

_{Intrathecal opioids}

T/F

All drugs given Intrathecal must be Preservative Free (PF)

Answer 143

True

Duramorph if Preservative Free (PF) Morphine

Question 144

_{Intrathecal opioids}

What are disadvantages of Duramorph (PF Morphine) when added to spinal anesthesia?

Answer 144

Delayed respiratory depression

May require overnight stay

Question 145

_{Intrathecal opioids}

What are dose, onset, and DOA of Sufentanil when added to spinal anesthesia?

Answer 145

Dose: 10 mcg of Sufentanil

Onset: Rapid

DOA: 2-8 hrs

Question 146

_{Intrathecal opioids}

What’s a major side effect a/w Sufentanil when added to spinal anesthesia?

Answer 146

Itching