Mod3: Spinal Anesthesia Part 2

Question 1

_{Spinal Anesthesia: Assessment of Block}

The skin area innervated by a given spinal nerve and its corresponding cord segment is also know as:

Answer 1

Dermatome

Corresponds to a portion of the spinal cord that gives rise to all nerve rootlets of a single spinal nerve

Question 2

_{Required Block Levels}

What’s the Dermatomal block Level for Upper Abd/C-Section procedures?

Answer 2

T4 = nipple line

^{[Dermatomal block Level]}

“Upper Abd/C-Section procedures”

Question 3

_{Required Block Levels}

What’s the Dermatomal block Level for GYN/Urological procedures?

Answer 3

T6: Xiphoid level

“GYN/Urological procedures”

XX

Question 4

_{Required Block Levels}

What’s the Dermatomal block Level for Hip Surgery?

Answer 4

T10 = Umbilicus

“Hip Surgery”

Question 5

_{Required Block Levels}

What’s the Dermatomal block Level for Upper Leg procedures?

Answer 5

L1 = Upper Anterior Thigh

“Upper Leg procedures”

Question 6

_{Required Block Levels}

What’s the Dermatomal block Level for Foot & Ankle procedures?

Answer 6

L2 = Mid Anterior Thigh

“Foot & Ankle procedures”

Question 7

_{Required Block Levels}

What’s the Dermatomal block Level for Perineal procedures?

Answer 7

L1-L2 or

S2 w/saddle block

“Perineal procedures”

Sacral nerves are larger and harder to block

Question 8

_{Spinal Anesthesia: Assessment of block}

How do we assess that our blocks are working?

Answer 8

Assess progress of block level q 2-3 minutes initially

Asseess until desired level is attained

Fast onset, usually

Takes ~10 min

Question 9

_{Spinal Anesthesia: Assessment of block}

Once block established, reassess block level every

Answer 9

30-45 minutes

Question 10

_{Spinal Anesthesia - Physiology of local anesthetic neural blockade}

Local anesthetics block conduction of:

Answer 10

Electrical impulses along nerves

Question 11

_{Spinal Anesthesia - Physiology of local anesthetic neural blockade}

Local anesthetics block conduction of Impulses along nerves. However, exact location of action is:

Answer 11

Unknown

Question 12

_{Spinal Anesthesia: Neurophysiological effects - Differential Blockade}

Different nerve fibers serving different functions display varying sensitivity to LA blockade. What’s the order of sensitivity? in other words, what the first thing to be blocked? what’s the last thing to be blocked?

Answer 12

ANS>Pain>Temperature>Touch>Motor

_{“A PTT M”}

Question 13

_{Spinal Anesthesia: Neurophysiological effects - Differential Blockade}

The mechanism of action of differential blockade is:

Answer 13

Not clearly known!!!

Question 14

_{Spinal Anesthesia: Neurophysiological effects - Differential Blockade}

Which factors affect the mechanism of action of LA?

Answer 14

Nerve fiber diameter is one factor but not the only

Decrease in LA concentration in CSF as function of distance from injection site

Question 15

_{Spinal Anesthesia: Neurophysiological effects}

Differential Blockade manifests as a spatial separation in sensations blocked. How does Sympathetic block extend in reference to sensory block?

Answer 15

2 dermatomes higher than sensory block

Question 16

_{Spinal Anesthesia: Neurophysiological effects}

Differential Blockade manifests as a spatial separation in sensations blocked. Where is Sensory block localized in reference to Motor block?

Answer 16

2 dermatomes higher than Motor block

Question 17

_{Spinal Anesthesia: Neurophysiological effects}

Patients & surgeons can appreciate the differential blockade and can find it worrisome. This could be evidenced by which statement from a pt?

Answer 17

“Don’t let him start. I can still move my foot!!!”

The pt fail to recognize the difference between sensory and motor

Question 18

_{Spinal Anesthesia: Assessment of block}

Which three methods are used to assess differing blockade?

Answer 18

Autonomic nervous system response

Sensory response

Motor response

Question 19

_{Spinal Anesthesia: Assessment of block}

Autonomic nervous system blockade manifest as:

Answer 19

Skin flushing

Warm skin

Vasodilation

Question 20

_{Spinal Anesthesia: Assessment of block}

Which object/instruments could be used to assess Sensory nerves blockade?

Answer 20

Broken tongue blade

^{works well to determine sensory block level}

Alcohol swab to detect temp response

Question 21

_{Spinal Anesthesia: Assessment of block}

Methods to assess differing blockade: How do you assess Motor nerves?

Answer 21

Ask patient to move lower extremities to assess motor block level

Question 22

_{Spinal Anesthesia: Cardiovascular Physiology}

Blockade of SNS efferent fibers to vascular smooth muscle could cause:

Answer 22

Hypotension (40% ± incidence)

^{Hypotension is the most common side effect encountered}

Bradycardia (10-15%)

2nd and 3rd degree heart block

Question 23

_{Spinal Anesthesia: Cardiovascular Physiology}

Hypotension caused by Blockade of SNS efferent fibers to vascular smooth muscle is the result of:

Answer 23

Arterial dilation (decreased SVR)

Venous dilation (decreased preload=decreased CO)

Question 24

_{Spinal Anesthesia: Cardiovascular Physiology}

Which block factor determines Extent of Hypotension caused by blockade of SNS efferent fibers to vascular smooth muscle?

Answer 24

Level of block

Question 25

_{Spinal Anesthesia: Cardiovascular Physiology} Which factors may amplify _Effect_ of **Hypotension** caused by Blockade of SNS efferent fibers to vascular smooth muscle?

Answer 25

**Age** \> 50 Concurrent **GA** **Obesity** **Hypovolemia**

Question 26

_{Spinal Anesthesia: Cardiovascular Physiology} Effect of Hypotension caused by Blockade of SNS efferent fibers to vascular smooth muscle may be worse in patients on which drugs?

Answer 26

**ACE inhibitors**

Question 27

_{Spinal Anesthesia: Cardiovascular Physiology} Bradycardia caused by Blockade of SNS efferent fibers to vascular smooth muscle is the result of:

Answer 27

Blockade of sympathetic cardioaccelerator fibers originating from T1-T4 Bradycardia starts to be seen with T6 sensory level blocks

Question 28

_{Spinal Anesthesia: Cardiovascular Physiology} Bradycardia caused by Blockade of SNS efferent fibers to vascular smooth muscle is the result of Blockade of sympathetic cardioaccelerator fibers originating from T1-T4. Why is it noted with T6 sensory level blocks?

Answer 28

Sympathetic block level is 2 dermatomes higher than sensory level block

Question 29

_{Spinal Anesthesia: Cardiovascular Physiology} How does Bradycardia caused by Blockade of SNS efferent fibers to vascular smooth muscle manifest?

Answer 29

Diminished venous return and associated decreased stretch of intracardiac stretch receptors Severe bradycardia/asystole reported

Question 30

_{Spinal Anesthesia: Cardiovascular Physiology} What are risk factors for Bradycardia caused by Blockade of SNS efferent fibers to vascular smooth muscle?

Answer 30

Age \< 50 Any ASA Use of beta blockers

Question 31

_{Spinal Anesthesia: Cardiovascular Physiology} What's the treatment for Bradycardia caused by Blockade of SNS efferent fibers to vascular smooth muscle?

Answer 31

**Epinephrine**

Question 32

_{Spinal Anesthesia: Cardiovascular Physiology} What's the major risk factor for **2nd** and **3rd degree heart block** caused by Blockade of SNS efferent fibers to vascular smooth muscle?

Answer 32

Preexisting **1st degree heart block**

Question 33

_{Spinal Anesthesia: Treating CV hemodynamic changes} When is it recommended to initiate treatment for CV hemodynamic changes?

Answer 33

BP is decreased more than 25-30% baseline SBP\<90 in normotensive pt HR falls below 50-60 beats/min Pt becomes symptomatic

Question 34

_{Spinal Anesthesia: Treating CV hemodynamic changes} Which vasopressors are used to treat CV hemodynamic changes from spinal blockade?

Answer 34

Ephedrine Phenylephrine

Question 35

_{Spinal Anesthesia: Treating CV hemodynamic changes} What's the dose and and what are the effects of Ephedrine when used to treat CV hemodynamic changes from spinal blockade?

Answer 35

**5-10mg** _Ephedrine_ (**IV**) Alpha and beta adrenergic activity (inc HR) Increases CO (venous return) and SVR

Question 36

_{Spinal Anesthesia: Treating CV hemodynamic changes} Dose and effects of _Phenylephrine_ when used to treat CV hemodynamic changes from spinal blockade?

Answer 36

**50-100 mcg** _Phenylephrine_ (**IV**) Primary alpha-agonist activity Increases SVR (may decrease CO)

Question 37

_{Spinal Anesthesia: Treating CV hemodynamic changes} Fluid Administration when used to treat CV hemodynamic changes from spinal blockade. Prehydration with:

Answer 37

**Crystalloid** solution ## Footnote **500-1000 mL**

Question 38

_{Spinal Anesthesia: Treating CV hemodynamic changes} When treating CV hemodynamic changes from spinal blockade, why must we be cautious placing in head up position to decrease cephalad spread?

Answer 38

**Exaggerates decreased BP** by decreasing **venous return**

Question 39

_{Spinal Anesthesia: Treating CV hemodynamic changes} NYSORA Recommendations in the treatment of CV hemodynamic changes from spinal blockade

Answer 39

NYSORA Recommendations

Question 40

_{Spinal Anesthesia} Complications:

Answer 40

Postdural puncture headache (PDPH) Backache Total spinal Neurologic Injury Transient neurologic syndrome (TNS) Spinal hematoma

Question 41

_{Spinal Anesthesia: Complications} Causes of Postdural puncture headache (PDPH):

Answer 41

Loss of CSF through meningeal needle hole (?) “Saggy Brain”

Question 42

_{Spinal Anesthesia: Complications} Characteristics of Postdural puncture headache (PDPH):

Answer 42

Bilateral in the frontal-occipital region Worsens with upright position Improves in supine position Photophobia Tinnitus N/V

Question 43

_{Spinal Anesthesia: Complications} Incidence of Postdural puncture headache (PDPH):

Answer 43

Increased in young patients, women, and parturient Decreases with increasing age Decreases with use of smaller diameter (larger gauge) spinal needle with noncutting tips Remaining supine does not decrease incidence

Question 44

_{Spinal Anesthesia: Complications} How should the cutting needles be inserted to decrease incidence of Postdural puncture headache (PDPH)?

Answer 44

With bevel aligned parallel to long axis of dural fibers

Question 45

_{Spinal Anesthesia: Complications} Treatment of Postdural puncture headache (PDPH):

Answer 45

Usually resolves over 48hr without invasive therapy Bedrest/fluids/analgesics/caffeine Epidural blood patch

Question 46

_{Spinal Anesthesia: Complications} When is backache a common complication?

Answer 46

After general anesthesia, but **More common after spinal** (11%)

Question 47

_{Spinal Anesthesia: Complications} Causes of Backache after spinal anesthesia?

Answer 47

Needle trauma Local anesthetic irritation Ligament strain secondary to muscle relaxation

Question 48

_{Spinal Anesthesia: Complications} The complication from spinal anesthesia that manifest as "Blockade of entire spinal cord and occasionally brain stem" is also known as:

Answer 48

**Total spinal**

Question 49

_{Spinal Anesthesia: Complications} Which pt's populations are more susceptible to "Total spinal", and why?

Answer 49

**Obese** & **Parturients** Relative **decreased CSF** volume a/w Obesity & Pregnancy LA spreads more

Question 50

_{Spinal Anesthesia: Complications} When does "Total spinal" occur?

Answer 50

**Immediately** or **up to 60 mins** after injection

Question 51

_{Spinal Anesthesia: Complications} Symptoms of "Total spinal":

Answer 51

Profound **hypotension** and **bradycardia** **Apnea/respiratory arrest** (phrenic nerve paralysis)

Question 52

_{Spinal Anesthesia: Complications} Treatment of "Total spinal":

Answer 52

Protect the airway Vasopressors Anticholinergics Fluids Oxygen with controlled ventilation

Question 53

_{Spinal Anesthesia: Complications} T/F If managed appropriately, "Total spinal" will resolve without sequelae

Answer 53

True

Question 54

_{Spinal Anesthesia: Complications} Incidence of Neurologic Injury:

Answer 54

**Rare** (0.03-0.1% incidence) but Widely feared!!!

Question 55

_{Spinal Anesthesia: Complications} Causes of Neurologic Injury:

Answer 55

Direct needle trauma to spinal cord or nerves Spinal cord ischemia Introduction of bacteria or neurotoxic chemicals (prep solution) into SAS Toxic LA buildup “**Cauda Equina Syndrome**”

Question 56

_{Spinal Anesthesia: Complications} The condition that occurs when the bundle of nerves below the end of the spinal cord called cauda equina is damaged is known as:

Answer 56

**Cauda Equina Syndrome** Signs and symptoms include low back pain, pain that radiates down the leg, numbness around the anus, and loss of bowel or bladder control

Question 57

_{Spinal Anesthesia: Complications} T/F “Cauda Equina Syndrome” is the Result of subarachnoid injection through microbore, high resistant catheters

Answer 57

**True** Catheters produce little turbulence and the undiluted solution pools around cauda equina nerve roots

Question 58

_{Spinal Anesthesia: Complications} The painful condition of the buttocks and thighs with possible radiation to the lower extermities, beginning as soon as a few hours after spinal anesthesia and lasting as long as ten days is also known as:

Answer 58

**Transient Neurologic Syndrome** (TNS) Pain in buttocks or leg (posterior thigh usually) Pain can be mild to severe

Question 59

_{Spinal Anesthesia: Complications} What differentiates Transient neurologic syndrome (TNS) from "Cauda equina syndrome"?

Answer 59

**TNS** is exclusively a **pain syndrome** There is *no bowel or bladder dysfunction* Neurologic, MRI , and Electrophysiologic examinations are normal

Question 60

_{Spinal Anesthesia: Complications} All local anesthetics are implicated in Transient neurologic syndrome (TNS), except:

Answer 60

**Chloroprocaine** Risk \> with lidocaine

Question 61

_{Spinal Anesthesia: Complications} Which condition increase the risk of Transient neurologic syndrome (TNS)?

Answer 61

Lithotomy position Obesity

Question 62

_{Spinal Anesthesia: Complications} Pain from Transient neurologic syndrome (TNS) resolves in:

Answer 62

72hrs

Question 63

_{Spinal Anesthesia: Complications} What's the incidence of "Spinal hematoma"?

Answer 63

Rare (\<1 in 150,000)

Question 64

_{Spinal Anesthesia: Complications} How does "Spinal hematoma" manifest?

Answer 64

Lower extremity **numbness** Lower extremity **weakness**

Question 65

_{Spinal Anesthesia: Complications} Why is early detection "Spinal hematoma" critical?

Answer 65

**Delay \>8hrs** in _decompressing spinal cord_ Could lead to **decreases chance of neurologic recovery**

Question 66

_{Spinal Anesthesia: Anticoagulated Patients} Which anticoagulants present a very low risk in spinal anesthesia?

Answer 66

ASA NSAIDS SQ heparin

Question 67

_{Spinal Anesthesia: Anticoagulated Patients} After _low dose_ low-molecular-weight heparin (LMWH) administration, delay spinal anesthesia for:

Answer 67

**12 hrs**

Question 68

_{Spinal Anesthesia: Anticoagulated Patients} After _high dose_ low-molecular-weight heparin (LMWH) administration, delay spinal anesthesia for:

Answer 68

**24hrs**

Question 69

_{Spinal Anesthesia: Anticoagulated Patients} If taking twice daily, Post-op delay LWMH for:

Answer 69

**24 hrs**

Question 70

_{Spinal Anesthesia: Anticoagulated Patients} If taking once daily, Post-op delay LWMH for:

Answer 70

**6-8 hrs**

Question 71

_{Spinal Anesthesia: Anticoagulated Patients} After the last dose of **Ticlopidine (Ticlid)**, avoid spinal anesthesia for how long?

Answer 71

**14 days** _{Ticlopidine (Ticlid) is a blood thinner}

Question 72

_{Spinal Anesthesia: Anticoagulated Patients} After the last dose of **clopidogrel (Plavix)**, avoid spinal anesthesia for how long?

Answer 72

**7 days**

Question 73

_{Spinal Anesthesia: Anticoagulated Patients} For reference, consult:

Answer 73

American Society of Regional Anesthesia (ASRA)