Exam 1

Question 1

Absolute Contraindications for regional anesthesia

Answer 1

ABSOLUTE
Patient Refusal
Sepsis or Infection at injection site
Coagulopathy or Anticoagulation
Elevated ICP or Cerebral Edema

Question 2

Relative contraindications for regional

Answer 2

RELATIVE
Patient Appropriateness
Local Infection near injection site
Hypovolemia
CNS Disease
Chronic Back Pain or Prior Laminectomy
Prior SAB with difficulty

Question 3

Precautions for regional (pt populations)

Answer 3

3rd Degree HB w/o pacemaker
Fixed volume cardiac states
IHSS, Severe atrial stenosis, mitral stenosis, aortic stenosis

Question 4

IV Block - “Bier” block

Answer 4

Injection of local anesthetic intravenously for anesthesia of an extremity
Uses
any surgical procedure on an extremity
Advantages:
technically simple, minimal equipment, rapid onset
Disadvantages:
duration limited by tolerance of tourniquet pain, toxicity

Question 5

Peripheral nerve block

Answer 5

Injecting local anesthetic near the course of a named nerve
Uses:
Surgical procedures in the distribution of the blocked nerve
Advantages:
relatively small dose of local anesthetic to cover large area; rapid onset
Disadvantages:
technical complexity, neuropathy

Question 6

Plexus Blockade

Answer 6

Injection of local anesthetic adjacent to a plexus, e.g. cervical, brachial or lumbar plexus
Uses :
surgical anesthesia or post-operative analgesia in the distribution of the plexus
Advantages:
large area of anesthesia with relatively large dose of agent
Disadvantages:
technically complex, potential for toxicity and neuropathy.

Question 7

Central Neuraxial Blockade - “Spinal”

Answer 7

Injection of local anesthetic into CSF
Uses:
profound anesthesia of lower abdomen and extremities
Advantages:
technically easy (LP technique), high success rate, rapid onset
Disadvantages:
“high spinal”, hypotension due to sympathetic block, post dural puncture headache.

Question 8

Central Neuraxial Blockade - “epidural”

Answer 8

Injection of local anesthetic in to the epidural space at any level of the spinal column
Uses:
Anesthesia/analgesia of the thorax, abdomen, lower extremities
Advantages:
Controlled onset of blockade, long duration when catheter is placed, post-operative analgesia.
Disadvantages:
Technically complex, toxicity, “spinal headache”

Question 9

Which patients may most benefit from spinals?

Answer 9

Patients with co-existing Asthma or COPD; long history of pulmonary disease or a heavy smoker
Patient fearful of GA
OB patient for a C-section
Patient with a history of thrombophlebitis or at an increased risk of developing thrombophlebitis
Any patient with an obviously difficult airway and who is undergoing a procedure that can be done under spinal

Question 10

Spinal advantages / disadvantages

Answer 10

Advantages

• Quicker to perform
• Less painful to patient
• Fast Onset

Disadvantages

• Fixed Duration
• PDPH

Question 11

Epidural advantages

Answer 11

Advantages

• Continuous infusion
• Postoperative pain management

Disadvantages

• More painful
• Longer to perform
• Slower Onset

Question 12

Normal INR / PT

Answer 12

PT = 10-14 sec
INR = 2.0-3.0

Question 13

CSF makeup

Answer 13

CSF total volume =150cc
-30-50cc in the Spinal Cord at any given time
CSF pH = 7.32 approximately.
CSF secreted at a rate of 30cc/hr by EPENDYMAL cells of the Choroid Plexus
CSF is replaced once every 3-4 hours

Question 14

Spinal canal anatomy

Answer 14

Spinal CORD:
-Foramen Magnum to L1

Spinal CANAL:
-Foramen Magnum to Sacral Hiatus

Beyond L1:
-The Cauda Equina

Question 15

Spinal Chord - Gray & White Matter

Answer 15

Gray matter - composed of neuronal cells and unmyelinated fibers.
-A large number of Interneurons are found in the Gray matter

White matter - contains the various tracts

• Ascending- dorsal white matter = ascending sensory tracts
• Descending - lateral and ventral white matter = descending motor tracts

Question 16

31 spinal cord

Answer 16

Cervical (8)
Thoracic (12)
Lumbar (5)
Sacrum(5)
Coccyx (1)

Question 17

Spinal Cord Roots

Answer 17

DORSAL ROOT: carries all afferent signals heading INTO the spinal cord and brain

VENTRAL ROOT: carries all efferent signals heading out to the periphery

They fuse together to form the main nerve root that exists at the spinal cord at that particular level

Question 18

NERVE ROOT

Answer 18

The NERVE ROOT is the primary site of action of the Local Anesthetics, both with Spinals AND Epidurals. The only difference is WHERE the root is being anesthetized, either Subarachnoid or in the Epidural space

Question 19

Nerve type and fiber determine the order of block

Answer 19

Sympathetic/Parasympathetic – small fibers (C fibers; B fibers, preganglionic; afferent & efferent)

Sensory – small & middle intermediate diameter fibers (C, A-delta and A-Beta; afferent & efferent)

Motor – large, thick diameter fibers (A alpha, efferent) (A beta, afferent & efferent) (A gamma, efferent)

Question 20

SOMATIC PNS

Answer 20

Contains sensory neurons for control of skin, muscles and joint movement
Motor fibers arise from the motor neurons in the ventral horn, their axons exiting the spinal cord via the Ventral root
A few centimeters out, the somatic motor fibers join with incoming sensory fibers to form a mixed nerve root which eventually becomes one or many peripheral nerves

Question 21

SOMATIC system contains:

Answer 21

INCOMING (afferent) sensory neurons for pain, proprioception, pressure, touch, etc.

OUTGOING (efferent) motor fibers to skeletal muscles for movement, both reflexive and purposeful

Question 22

AUTONOMIC nervous system divisions

Answer 22

SYMPATHETIC – (stimulating)

PARASYMPATHETIC – (relaxing)

Question 23

Sympathetic nerves originate in

Answer 23

intermediolateral gray matter of T1-L2 spinal cord segments

• -These sympathetic neurons run with the corresponding spinal nerve- just beyond the intervertebral foramen where they exit to join the sympathetic chain ganglia
• **The parasympathetic nerves only originate in the Cranial nerves or the Sacral nerves

Question 24

Preganglionic nerve fibers

Answer 24

Sympathetic system - end in the sympathetic chain, in one of the many sympathetic ganglia

Parasympathetic system preganglionic fibers actually end IN the organ that they innervate.

Question 25

SNS - Alpha, Beta and Dopamine receptors

Answer 25

Primary neurotransmitters are Norepinephrine and Dopamine The Parasympathetic nervous system has Nicotinic and Muscarinic receptors with Acetylcholine as its primary neurotransmitter

Question 26

Spinal Anesthesia interrupts ?

Answer 26

SENSORY, MOTOR AND SYMPATHETIC nervous system innervation LA blocks the small C fibers of the sympathetic system first and gradually diffuses into the interior of the nerve where the larger fibers are for sensory and then motor

Question 27

Goal of a Spinal?

Answer 27

Anesthesia to a region of the body Level of Block ``` Sympathetic 1st (2 levels above) ========== Sensory 2nd ========== Motor 3rd (2 levels below) ```

Question 28

segmental level of block T-4 to T-6

Answer 28

IntraAbdominal

Question 29

segmental level of block T-6 to T-8

Answer 29

GU, Low abdominal

Question 30

segmental level of block T-8 to T-10

Answer 30

GU, A/R, Legs

Question 31

Segmental Level of Block Required: Cutaneous= 5th digit (Segmental level & signifigance)

Answer 31

C8: All Cardioaccelerater fibers (T1-T4) blocked

Question 32

Inner aspect of arm and forearm (Segmental level & signifigance)

Answer 32

T1-T2: some cardioacelerater blocked

Question 33

Apex of axilla (Segmental level & signifigance)

Answer 33

T3: easily determined landmark

Question 34

Nipple (Segmental level & signifigance)

Answer 34

T4-T5: possibility of cardioaccelerator blockade

Question 35

Tip of Xiphoid (Segmental level & signifigance)

Answer 35

T7: Splanchnics (T5-L1) may be blocked)

Question 36

what the hell does splanchnic mean?

Answer 36

greek for Organ : visceral organs- intestines: GI tract

Question 37

Umbilicus (Segmental level & signifigance)

Answer 37

T 10: Sympathetic nervous system blockade limited to legs

Question 38

Inguinal ligament (Segmental level & signifigance)

Answer 38

T 12: No sympathetic nervous system blockade

Question 39

Outer side of foot (Segmental level & signifigance)

Answer 39

S1: Confirms block of the most difficult nerve root to anesthetize

Question 40

Spinal CV effect

Answer 40

Hypotension directly proportional to degree of sympathetic blockade Brady - decrease CO - decrease BP ======= T-4 Level ======= Dilate - decrease SVR - decreased VR

Question 41

Spinal Resp effect

Answer 41

``` Increasing height may block intercostals Phrenic (Aa) resistant Loss of abdominals RESP Dz most effected SOB - éCO2 - êO2 Keep level below T-7 ```

Question 42

Distribution of Local Anesthetic solutions in CSF is dependent on:

Answer 42

``` 1 Baricity 2 Contour of the spinal cord 3 Position of the patient during and in the first few minutes after placement of the drug into the subarachnoid space 4 Dosage of LA used 5 Other contributing factors (see chart) ```

Question 43

CSF baricity

Answer 43

(specific gravity) of 1.003-1.008 at normal body temperature

Question 44

Hyperbaric Solutions:

Answer 44

Prepared by adding glucose (dextrose) in amounts sufficient to increase the density of the LA above that of CSF Lidocaine 5% and Bupivicaine 0.75% are usually premixed with dextrose and come in a Hyperbaric Solution in your Spinal tray Being heavier (more dense) than the CSF, the solution settles in the most dependent aspect of the subarachnoid space This is determined by the position of the patient. When supine, the solution tends to gravitate to the thoracic kyphosis, the average position being T6

Question 45

“Saddle Block”

Answer 45

S3, S4, S5 Use Hyperbaric solution Sitting position - allowed to stay sitting, produces low sensory levels of anesthesia (saddle block) “Saddle Block” - numbs the area that would be in contact with a saddle when riding a horse

Question 46

Hypobaric Solutions

Answer 46

Prepared by adding 6 to 8cc of sterile water to the LA After injection, the LA “Floats up” since it is now lighter (less dense) than the CSF Rarely used other than in an Academic setting to demonstrate the technique

Question 47

Isobaric Solutions

Answer 47

Created by diluting the LA with CSF Useful if you do not need your block to go much above L1 (hip/knee surgery) Again, is rarely used except in Academic settings to demonstrate the technique

Question 48

Supine, head slightly down will push your level up to

Answer 48

T4-5

Question 49

Supine level will give you what level?

Answer 49

T6-7

Question 50

Supine with head slightly up will usually give you what level?

Answer 50

T10-T11

Question 51

factors that can effect the level of blockade:

Answer 51

Scoliosis – alter “LOW” point Kyphosis/Kyphoscoliosis – alter low point Previous back surgery – post surgical anatomic change can effect the level either higher or lower than expected

Question 52

Spinal - condition will push your level much higher than you anticipate

Answer 52

Age related decreases in CSF volume may push your level higher than expected in the elderly Any condition that lowers the amount of CSF in the cord by increasing intraabdominal pressure and causing engorgement of the epidural veins, applying outside pressure on the spinal cord a) Pregnancy b) Ascites c) Large abdominal or pelvic tumors

Question 53

DIFFERENTIAL block

Answer 53

Epidural: dependent on the volume and site of injection

Question 54

Spinal block area affected

Answer 54

EVERYTHING distal to the level of the block

Question 55

``` From skin (memorize) (Regional Anesthesia) ```

Answer 55

Supraspinous Ligament 2) Interspinous Ligament 3) Ligamentum Flavum 4) Epidural Space (potential) 5) Dura 6) Arachnoid 7) Sub-arachnoid space (our target) 8) Pia Mater

Question 56

Local Anesthetics Mechanism of Action:

Answer 56

Local anesthetics produce conduction blockade of neural impulses Prevent passage of sodium ions through ion selective sodium channels in nerve membranes They bond to the sodium channel itself and keep it in the active or open position

Question 57

Epinephrine or Phenylephrine in regards to local

Answer 57

are frequently added to LA’s to prolong their duration of action Epinephrine dose is 0.1-0.2mg Phenylephrine dose is 2-5mg Can prolong spinal anesthesia by up to 50% by causing localized vasoconstriction and decreasing the amount of vascular absorption

Question 58

Identify anatomic landmarks Spinous processes Iliac crest

Answer 58

In 95% of patients, this level corresponds to the body of L4

Question 59

Spinal patient positioning

Answer 59

Sitting (midline/paramedian,hyperB) Lateral (+UP-hypo/isoB OR +DOWN-hyperB) Prone (jackknife, hypo/isoB)

Question 60

Complications of Spinals

Answer 60

HYPOTENSION - IV Fluid & Pressors HIGH SPINAL - Treat symptoms Nausea/Vomiting - BP vs. Vagal PostOP - Urinary, Backpain, PDPHA

Question 61

Epidural Space

Answer 61

``` Space that surrounds the spinal meninges Potential space Ligamentum Flavum Binds epidural space posteriorly Widest at Level L2 (5-6mm) Narrowest at Level C5 (1-1.5mm ```

Question 62

Spinal meninges

Answer 62

``` Dura Mater Outer most layer Fibrous Arachnoid Middle layer Non-vascular Pia Inner most layer Highly vascular Sub Arachnoid Space Lies between the arachnoid and pia ```

Question 63

Spinal Pharm: Vasoconstrictors

Answer 63

Prolong duration of spinal block No increase in duration with lidocaine & bupivacaine Significant increase with tetracaine (double duration)

Question 64

Factors Effecting Distribution | Spinal

Answer 64

``` Site of injection Shape of spinal column Patient height Angulation of needle Volume of CSF Characteristics of local anesthetic Density Specific gravity Baracity Dose Volume Patient position (during & after) ```

Question 65

Elimination determines duration of block

Answer 65

Lipid solubility decreases vascular absorption | Vasoconstriction can decrease rate of elimination

Question 66

Blockade of Sympathetic Preganglionic Neurons

Answer 66

``` Send signals to both arteries and veins Predominant action is venodilation Reduces: -Venous return -Stroke volume -Cardiac output -Blood pressure ``` T1-T4 Blockade - Causes unopposed vagal stimulation - Bradycardia - Associated with decrease venous return & cardioaccelerator fibers blockade - Decreased venous return to right atrium causes decreased stretch receptor response

Question 67

Spinal Hypotension Treatment

Answer 67

Treatment Best way to treat is physiologic not pharmacologic Primary Treatment Increase the cardiac preload Large IV fluid bolus within 30 minutes prior to spinal placement, minimum 1 liter of crystalloids Secondary Treatment Pharmacologic Ephedrine is more effective than Phenylephrine

Question 68

Midline Approach

Answer 68

``` Skin Subcutaneous tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Epidural space Dura mater Arachnoid mater ```

Question 69

The parasympathetic nerves only originate in the

Answer 69

Cranial Nerves or the Sacral nerves

Question 70

Sympathetic nerves originate in the

Answer 70

intermediolateral gray matter of T1-T2 spinal cord segments

Question 71

Parasympathetic system preganglionic fibers end

Answer 71

IN the organ that they innervate

Question 72

SNS: Alpha, Beta and Dopamine receptor

Answer 72

Neurotransmitters: noreipinepherine and Dopamine

Question 73

Parasympathetic nervous system NT

Answer 73

Nicotinic and Muscarinic receptors with acetylcholine as primary NT

Question 74

What blocks are considered to be central blocks?

Answer 74

Spinal, Epidural, Caudal

Question 75

What are central blocks?

Answer 75

Placement of local anesthetic solution onto or adjacent to spinal cord. o Advantages  Less overall opioid use  Less N/V  Less urinary retention  Greater mental awareness compared with general anesthesia

Question 76

Landmark for lumbar puncture:

Answer 76

A line drawn between both iliac crests usually crosses either the body of L4 or L4-L5 interspace. Counting spinous processes up or down from these reference points identifies other spinal levels.

Question 77

Bainbridge reflex

Answer 77

• If the block is high enough, sympathetic nerve fibers that innervate the heart (T1 to T4) become anesthetized. This effect results in slowing of the heart rate that is known as the Bainbridge reflex.

Question 78

• Preventive management of hypotension

Answer 78

administer nonglucose solutions before the regional technique is used - glucose solutions can act as diuretics which would further decrease the circulating volume IF HR is normal or slightly elevated: - USE alpha agonist (phenylephrine) - causes an increase of the SVR without further increasing the heart rate. IF Symptomatic bradycardia: - USE a mixed alpha and beta agonist (ephedrine) which increases the heart rate and causes an increase in PVR.

Question 79

• Total blockade

Answer 79

caused by the action of unopposed parasympathetic system

Question 80

Regional: intravascular injection

Answer 80

example if lidocaine is injected into the intravascular space, the patient might complain first of tingling at the lips and a strange taste in the mouth and then visual disturbances. Seizures can also occur.

Question 81

• Postdural puncture headache (PDPH)

Answer 81

o caused by a decrease in the amount of available CSF in the subarachnoid space → o causes the medulla and the brain stem to drop into the foramen magnum→ o stretching of the meninges and pulling on the tentorium may cause a headache

Question 82

• Spinal headaches

Answer 82

o usually occur one week after the spinal anesthetic. | o the earlier the headache occurs the more severe it is.

Question 83

• Factors that influence the occurrence of spinal headache

Answer 83

o size and type of needle o direction of the bevel o number of punctures that are made in the attempts to start the spinal anesthetic o dehydration o decreased intra-abdominal pressure o patient position o patient factors (such as age, race, sex, and history of headache).

Question 84

What emergency equipment needs to be available prior to administering a central blockade?

Answer 84

``` Functional laryngoscopes ETT’s Induction agents CV drugs (atropine, ephedrine, epinephrine) Suction Oxygen Ventilation equipment Noninvasive BP monitor Pulse Ox ECG monitoring ```

Question 85

Signs of intravascular injection of 0.5% to 0.75% bupivacaine (Marcaine) injection

Answer 85

o the first symptom: cardiac dysrhythmias. | o The most common dysrhythmias are of ventricular origin (Nagelhout & Zaglaniczny, p. 980).

Question 86

Spinal (midline approach):

Answer 86

Skin → Subcutaneous Tissue → Supraspinous Ligament → Interspinous Ligament → Ligamentum Flavum → Epidural space→Dura→ Arachnoid → Subarachnoid space

Question 87

Spinal (Lateral or paramedian approach)

Answer 87

The first resistance encountered is the ligamentum flavum instead of the supraspinous ligament. Skin→Subcutaneous Tissue →Ligamentum Flavum →Epidural space →Dura → Arachnoid →Subarachnoid space

Question 88

Epidural (midline approach):

Answer 88

Skin → Subcutaneous Tissue → Supraspinous Ligament → Interspinous Ligament →Ligamentum Flavum →Epidural space

Question 89

What are the 5 goals of the perioperative anesthesia period

Answer 89

``` ○ Amnesia ○ Immobility in response to stimulation ○ Attenuation of autonomic responses to painful stimuli ○ Analgesia ○ Unconsciousness ```

Question 90

How is general anesthesia defined?

Answer 90

Rendering the patient insensible to pain with loss of consciousness. Management of the patient’s airway with focus on induction, maintenance, emergence, and transfer.

Question 91

● Plane 1 (Light)

Answer 91

○ Blink and swallow reflex are intact | ○ Regular respirations with good chest motion.

Question 92

● Plane 2

Answer 92

○ Lose blink reflex ○ Fixed pupils ○ Still breathing on their own.

Question 93

● Plane 3

Answer 93

○ Starts to lose the ability to use chest and abdominal muscles for respiratory efforts ○ Breathing becomes shallow ○ May need assistance with repirations.

Question 94

● Plane 4

Answer 94

○ No chest or abdominal muscles in use ■ Only respiratory effort from diaphragm. ○ Requires assistance with ventilation.

Question 95

● Inhalation induction

Answer 95

○ Premedicate with midazolam if IV access is available ○ Pre-oxygenate ○ Administer 7% sevoflurane over 2 minutes ○ Place LMA or administer neuromuscular blockade and intubate.

Question 96

● Single breath induction

Answer 96

○ Pre-medicate with a benzo if access is available ○ Pre-oxygenate ○ Administer 8% sevoflurane in 60% nitrous oxide over 1 minute ○ Administer neuromuscular blockade and intubate.

Question 97

What clinical parameters may be used to monitor depth of anesthesia?

Answer 97

``` ○ EKG ○ Bp ○ CVP ○ PA cath readings ○ Pulse ox ○ Capnography ○ Evoked potentials ■ “Can you move your fingers?” ■ “Does this hurt?” ○ Temperature monitoring ○ Brain electrical activity monitoring ○ Anesthetic agent monitoring ■ via anesthesia machine ```

Question 98

step to follow for extubation following general anesthesia

Answer 98

The patient must have spontaneous ventilation. The effects of the neuromuscular blocking drugs should be fully reversed. The oropharynx must be suctioned before extubation. The ETT cuff must be deflated and the tracheal tube rapidly removed while a positive-pressure breath is delivered to help expel any secretions (to prevent aspiration of secretions). After tracheal extubation, oxygen is delivered by facemask.

Question 99

If a patient develops laryngospasm during extubation steps can be taken to manage this complication?

Answer 99

Positive pressure, jaw thrust small amt of positive pressure from the vent bag with 100% oxygen and mask. Initially IV lidocaine can also be given 1-1.5mg/kg. If the spasm is still present and pt is becoming hypoxic medicate pt with succinylcholine 0.25-1mg/kg. This will relax the laryngeal muscles allowing proper ventilation. (M, M &M 109-111)

Question 100

Define diffusion hypoxia. How is it prevented?

Answer 100

Diffusion hypoxia occurs when the inhalation of nitrous oxide is discontinued abruptly, thus leading to a reversal of partial pressure gradients so that nitrous oxide leaves the blood to enter alveoli. (Occurs when nitrous oxide administration is finished, and patients are allowed to inhale room air.) This initial high-volume outpouring of nitrous oxide from the blood into the alveoli can so dilute the PAO2 that the PaO2 decreases. Outpouring of nitrous oxide into alveoli is greatest during the first 1-5 minutes after its discontinuation at the conclusion of anesthesia. Prevented by: filling the lungs with oxygen at the end of anesthesia (when nitrous oxide administration is complete) to ensure that arterial hypoxemia will not occur as a result of PAO2 dilution by nitrous oxide.

Question 101

Define the practice of anesthesia.

Answer 101

Anesthesia is defined as rendering the patient unconscious and insensible to pain. It also includes management of airway, ventilation, oxygenation, cardio-vascular status, temperature, and neuromuscular function.