2025 Intro to Clinical Anesthesia Exam 3

Question 1

Neuraxial Anesthesia

Answer 1

Some studies show that neuraxial anesthesia reduces postoperative morbidity, and to a lesser extent decreases in intraoperative mortality.

It decreases the amount of intra-op narcotics needed
Leads to decrease in the incidence of atelectasis, hypoventilation, and aspiration pneumonia.

Increases tissue blood flow, improving oxygenation to those tissues

Suppresses the neuroendocrine stress response to surgery.

Gives the provider another option when dealing with a pt. that might not do well under a heavy General anesthesia.

Plays a HUGE role in Obstetric anesthesia.

Question 2

VERTEBRAL COLUMN ANATOMY

Answer 2

Question 3

SPINAL CORD ANANTOMY

Answer 3

KNOW THE LAYERS

Question 4

Spinal Cord Anatomy

Answer 4

Question 5

MECHANISM OF ACTION

Answer 5

Spinal into CSF - why it is quicker

Epidural bathing the nerves in the epidural space - why takes longer

Question 6

Autonomic vs Somatic Nervous System

Answer 6

Involuntary - make them vasodilate

Question 7

SOMATIC BLOCKADE

Answer 7

Neuraxial Blocks =
work so well because they interrupt the afferent (sensory receptors to the CNS) transmission of painful stimuli

They also block efferent (from CNS to muscles) impulses responsible for muscle tone.

DIFFERENTIAL BLOCKADE= sympathetic blockade (temp sensitivity) about two segments or more, cephalad than the sensory block(pain light touch) which in turn is several segments more cephalad than the motor block

This occurs because the concentration of the LA decreases the farther away from the site of injection it goes.

Question 8

AUTONOMIC BLOCKADE

Answer 8

The interruption of efferent autonomic transmissions that neuraxial blockade causes, leads to many different manifestations throughout the body:
Cardiovascular
Pulmonary
GI
Urinary Tract
Metabolic and Endocrine

Question 9

Cardiovascular changes Neuraxial

Answer 9

MOST COMMON

Hypotension- upwards of 40% of spinal anesthetics as result of decreased SVR, peripheral blood pooling with decreased venous return to heart or both.

Factors such as pt. positioning and a pregnant pts uterus weighing on the vena cava can make this hypotension even worse.

Decreases the effective circulating blood volume, often leading to Decreased CO

Higher level of block = ↑ chance of hypotension

Risks for hypotension include hypovolemia, Age >50 yrs., emergency surgery, obesity, chronic alcohol consumption, and chronic hypertension.

A high sympathetic block leads to more vasodilation because it blocks the bodies compensatory vasoconstriction pathways.

Bradycardia- occurs in 10-15% spinal anesthetics.
Either direct (blockade of cardiac accelerators T1-T4)
Or indirect- decreased output of myocardial pacemaker cells from ↓ venous return
Those at higher risk of bradycardia
Baseline HR <60 bpm, ASA 1, age <50. current beta blocker therapy

Healthier the patient, more at risk for bradycardia

Neuraxial blocks CAN NOT block the vagus nerve!!
Unopposed vagal tone may explain the sudden bradycardia, complete heart block, or cardiac arrest that is rarely seen with spinal anesthesia more than epidural anesthesia.

Question 10

How do we prevent/treat hTN (hypotension) Neuraxial

Answer 10

If the pt is previously hypovolemic, then volume loading has been shown to work well.

LUD ( left uterine displacement) helps prevent decreased venous return

Quick temporary fix can be to lower the pts head or even put them in head down position.

Excessive symptomatic bradycardia should be treated with Atropine

hTN should be treated with Vasopressors

Question 11

Pulmonary Neuraxial

Answer 11

Respiratory Mechanics- NA block to mid thoracic level has minimal respiratory effects.

High spinal- May paralyze accessory muscles impairing cough and active exhalation. Worse for those with pulmonary secretions and/of obstructive pulmonary disease.

C3,4,5- stay alive- Innervation of the diaphragm. If you knock this out prepare for intubation.

Change angle of bed to counteract rising spinal. Individual anatomy plays a roll in this

Have patient squeeze hand- C6 thumb, C7 middle finger… C5 pinky numb, need to adjust angle of bed????

Question 12

GI and Urinary Tract Neuraxial

Answer 12

The sympathectomy that allows Vagal dominance leads to a small contracted gut with active peristalsis.
Can lead to better operating conditions during intestinal surgery.

The decrease in narcotics needed also helps the return of GI function after surgery.

Renal function is pretty much unchanged with normal SBP’s

Neuraxial Anesthesia at the lumbar and sacral levels causes loss of Autonomic bladder control which can lead to Urinary retention.

Question 13

Metabolic and Endocrine Neuraxial

Answer 13

The trauma from surgery produces a Systemic Neuroendocrine Stress Response.
This response causes things like; Intra-op HTN, tachycardia, hyperglycemia, suppressed immune responses and altered renal function.

NA can PARTIALLY suppress this response in major invasive abdominal and thoracic surgeries

NA can TOTALLY BLOCK this response during lower extremity surgery

Question 14

Indications for Neuraxial Anesthesia

Answer 14

Neuraxial blocks can be used alone or in conjunction with General anesthesia and Peripheral nerve blocks.

Someone with decreased pulmonary function may be a good candidate for NA, as long as the level required for the surgery isn’t high enough to bring into effect the pulmonary issues that can come with NA.

Question 15

Contraindications for Neuraxial Anesthesia

Answer 15

Major contraindications
Lack of Consent
Coagulation abnormalities
Severe hypovolemia
Elevated intercranial pressure (especially with intercranial masses)
At risk for cerebral herniation with spinal anesthesia
Infection at the site

Relative contraindications
Severe Aortic or mitral stenosis
Severe Left ventricular outflow obstruction (Hypertrophic obstructive cardiomyopathy)

Question 16

Performing Neuraxial Anesthesia: Selling It

Answer 16

During you Pre-op interview you should investigate into possible contraindications for NA

You need to thoroughly explain the process of placing and Neuraxial block and what the pt can expect to experience after the block is placed.

The ability to minimize anxiety and explain the block/ answer questions with confidence is big.

Question 17

Performing Neuraxial Anesthesia: Surface anatomy/landmarks

Answer 17

Your best friend is the palpable spinous process ( even better if they are visible) they will define the midline of the spine.

First palpable Cervical spinous process is C2. (C7 is most prominent)

Spinous process of T7 is usually at the same level as the inferior angle of the scapulae.

If you draw a line between the highest points of the iliac crest that would cross the body of L4 or the space of L4-5.

Question 18

Positioning is Vital

Answer 18

Question 19

Performing Neuraxial Anesthesia Patient Positioning: Sitting

Answer 19

Question 20

Performing Neuraxial Anesthesia Patient Positioning: Laying on Side (lateral decubitus)

Answer 20

Baricity tells you whether it rises, sinks or sits where it is

Question 21

Performing Neuraxial Anesthesia: Prep

Answer 21

GO TIME!!!!

Strict Aseptic Technique for Spinal and Epidural Anesthesia

Wear Cap and Mask

Remove Jewelry

Wash Hands prior to procedure

Consider bouffant hat for patient

Clean patient’s back with chlorhexidine/alcohol mini-prep stick

Apply sterile gloves

Sterile drape on patient’s lumbar spine

Question 22

Performing Neuraxial Anesthesia: Midline Approach

Answer 22

Midline Approach
Most commonly used approach

Palpate space between two spinous processes

Topicalize with lidocaine in midline, in lower 3rd of interspace.

Infiltrate subq tissues and interspinous ligament

Introduce introducer at slight cephalad angle until form tissue is felt.

Insert spinal needle through introducer

Needle passes through ligamentum flavum, then epidural space, and then dura/arachnoid.
*Changes in resistance felt at each layer. Pop usually felt at dura
Depth of dura is 5-6 cm in normal body habitus

If CSF does not appear, may rotate pencil tip needle, advance, redirect.

Once CSF appears you gently attach your LA syringe and aspirate CSF into your LA this mixture will create a swirl called barbitage.

You then slowly inject the LA and remove everything, take off plastic drape and lay the pt. down.

https://youtu.be/SZ2TClYz4zI

Troubleshooting Midline Approach:
If bone is contacted at shallower depth
Likely hitting more cephalad process, redirect caudally

Bone contacted deeper
Likely hitting caudad spinous process, redirect cephalad

Bone in contacted at same depth
Likely contacting lamina, ie off midline.
Patient can usually perceive needle off to one side

Question 23

Performing Neuraxial Anesthesia: Paramedian Approach

Answer 23

Troubleshooting the paramedian approach:

If bone is contacted at a shallow depth it is most likely the medial part of the lower lamina so the needle must be redirected cephalad and a little more lateral

If you contact bone at a deeper level, that’s usually the lateral part of the lower lamina so you only need to redirect cephalad

Question 24

Different spinal needles

Answer 24

PDPH - post dural puncture headache

22g - do not need introducer

Question 25

NEEDLE We Use

Answer 25

Notch is always up

Question 26

What affects the level of a spinal block?

Answer 26

Most Important factors affecting the dermatomal spread of you spinal LA Baricity of Anesthetic Solution Position of the patient During injection and immediately after injection Drug dosage Site of injection Other factors Age, curvature of the spine, drug volume, intraabdominal pressure, needle direction, pt height, and Pregnancy.

Question 27

Baricity

Answer 27

Can make something more dense by adding glucose = hyperbaric = to sink to make things lighter = so they rise = can add sterile water or fentanyl

Question 28

Baricity and Positioning

Answer 28

Head up position causes hyperbaric solution to settle caudad and hypobaric to ascend cephalad. The opposite goes for the head down/supine position. If you’re doing a spinal for a broken hip in the Lat. Decubitus position you can use a hypobaric solution to affect the up hip (broken hip) ISOBARIC solution tends to stay at the site of injection. Hyperbaric solution tends to move to the most dependent part of the spine T4-T8 when in the supine position.

Question 29

Baricity: What can you add????

Answer 29

Morphine- hydrophilic, dose 75-200 mcg, onset of analgesia 30-60 minutes duration 12-36 hours. Side effects- Nausea, vomiting, pruritus. Potential for respiratory depression (post-op pulse ox, decreased IV/PO opioid admin) Duramorph???? Fentanyl- Lipid soluble, dose 10-25 mcg. May decrease hypotension d/t spinal Epi- 100-200 mcg increases duration of sensory and motor block up to 30 minutes

Question 30

Dosages, uses, and duration of commonly used spinal anesthetics

Answer 30

M+M Page 1581

Question 31

Management after you rock the spinal!

Answer 31

Use your ears- listen for tachycardia secondary to vasodilation I start a phenylephrine infusion around 0.2 mc/mg/min right after spinal is placed Treat hypotension and Bradycardia aggressively Patient will feel nauseous before BP cuff displays hypotension Assess level of block with cold/pin prick Low-dose propofol common for total joint patients in line with hemostasis

Question 32

Epidural Anesthesia

Answer 32

Injection of local anesthetic into the epidural space Goal of anesthetizing spinal nerve roots that transverse the space Used for anesthesia of abdominal, thoracic, pelvic, and lower extremity procedures and post-op analgesia Sensory level required for each surgery depends on dermatome level of skin incision AND level required for surgical manipulation.

Question 33

Epidural Kit

Answer 33

With the tuohy needle you dont need an introducer

Question 34

OMG we got Loss of resistance LOR

Answer 34

LOR meaning???? Remove LOR Syringe and count visible markings on needle to calculate depth. Thread catheter until 20cm mark is at hub Remove needle over catheter making sure not to pull catheter out as well. Not mark on catheter at skin and withdraw to leave 4-6cm in the epidural space. Attach catheter connector and hold below insertion site to spot check no CSF (intrathecal) or blood (intravascular). Attach 3 cc Syringe and gently aspirate to confirm Test dose with 3 cc 1.5% Lido with Epi 1:200,000 Clear Occlusive Dressing

Question 35

Epidural Catheters

Answer 35

Question 36

Troubleshooting your Epidural

Answer 36

False LOR- can occur with loose connection between LOR syringe and needle. Can add 0.5ml air to saline in syringe and inject through needle Air bubble will compress because of resistance if in soft tissue Bubble will not compress if in epidural space Pass spinal needle through epidural needle If Dural puncture occurs, likely to be in epidural space Difficulty threading catheter Ask patient to take a breath while keeping gentle pressure, may open space at tip of Touhy Reinsertion of epidural needle at steeper angle Withdraw epidural needle and advance while applying downward pressure on hub Inject 5 cc Saline through needle into epidural space to open it Paresthesia during needle or catheter placement Stop further advancement If during needle placement, withdraw and reposition at angle away from paresthesia Common during catheter placement If it resolved continue threading catheter Blood in Epidural Needle/Catheter Remove needle and flush with saline Clotted blood can prevent LOR and increase risk of Dural puncture

Question 37

Local anesthetics and Adjuncts for Epidural Anesthesia

Answer 37

Bupivacaine the most properly

Question 38

Epidural Complications

Answer 38

Risk of permanent injury 4.2 per 100,000 (0.004%) Inadequate of Failed NA- defined as need to repeat NA, convert to general, or abort planned surgery High or total spinal- May result from unintentional injection of med intended for epidural space into subdural or subarachnoid (spinal) space. Signs and symptoms- rapid ascending sympathetic, sensory, and motor block with associated bradycardia, hypotension, dyspnea, dysphagia, dysphonia May progress to unconsciousness and respiratory depression Secondary to respiratory muscle paralysis and brainstem hypoperfusion OB questionable epidural -> pull catheter and place spinal with decreased dose before C-Section. Failed spinal and time -> place epidural, otherwise convert to GA Subdural injection- potential space between dura and arachnoid mater. May cause patchy block, may result in more extensive cranial anesthesia ie apnea, unconsciousness Nerve Injury- Rare and lower in OB patients as you are approaching below conus medullaris (usually L1) Paresthesias are common- indicate needle has touched nerve tissue. Halt advancement, if persistent withdraw needle Back Pain- local tenderness may be present for days after procedure, no difference in back pain 6 mo. out from delivery Post-dural puncture headache- positional headache worse when sitting upright. May have nausea, vomiting, dizziness, tinnitus, photophobia, hearing loss. Conservative treatment- IV fluids caffeine and cosnyntropin IV Debilitating PDPH- consider epidural blood patch 20-30cc Urinary retention- Blocks sensation of full bladder ->placement of urinary catheter for longer procedures/voiding before +/- bladder scan. Transient neurologic symptoms- pain or dysesthesia (prickling burning etc) in buttock/lower extremity after uncomplicated spinal anesthesia. Most common with lidocaine and mepivacaine Local anesthetic systemic toxicity- (LAST) much less likely with spinal vs epidural anesthesia. Usually result of accidental intravascular injection. Minor- Perioral numbness, tinnitus, twitching Major- seizures, coma, severe hypotension, arrythmias, asystole Spinal-epidural hematoma (SEH)- Hemorrhage into neuraxis exceptionally rare usually in patients with coagulopathy Can require emergency decompressing laminectomy to preserve function Infection- meningitis more common after spinal, epidural abscess more common after epidural anesthesia

Question 39

What exactly are peripheral nerve blocks????

Answer 39

Mostly used for limbs Single = 14-20hrs sometimes Interdwelling = can go for several days

Question 40

Benefits?? Very similar to Neuraxial anesthesia

Answer 40

Likes to tell pts, start taking pain meds once the block starts to wear off Will do General, but decrease how deep and narcotics

Question 41

Peripheral nerve block contraindications

Answer 41

If pre-existing deficit hard to tell if worn off

Question 42

Potential complications

Answer 42

Question 43

What to look for if you suspect Local anesthetic systemic toxicity

Answer 43

Need to know toxic dose of each local anesthetic with and without epi Tinnitus = is like a "train running by your ear"

Question 44

Management of local anesthetic systemic toxicity

Answer 44

Question 45

Management of local anesthetic systemic toxicity

Answer 45

Question 46

How does Lipid emulsion work??

Answer 46

Question 47

Review of Local Anesthetics durations

Answer 47

Question 48

Preparing for the block

Answer 48

Question 49

Why do we use Ultrasound?

Answer 49

Improves success rate of the block Decreases placement time Reduces volume of LA required for successful block Decreased chance of vascular puncture and local anesthetic systemic toxicity (LAST) Reduced incidence of pneumothorax and phrenic nerve block Less chance of nerve injury

Question 50

Common Upper extremity blocks

Answer 50

Question 51

Visual of Common Upper

Answer 51

Find a clearer Picture!!!

Question 52

Range of Blocks Upper

Answer 52

Find a clearer picture!!!

Question 53

Complications of Interscalene blocks

Answer 53

Question 54

Horner syndrome

Answer 54

Question 55

Supraclavicular complications

Answer 55

What one leads to potential for phrenic nerve knock out???

Question 56

Lower Extremity blocks

Answer 56

Adductor preferred for knee surgeries so they can get up and moving quickly

Question 57

Trunk/abdominal blocks

Answer 57

Can be used after surgery to help with pain post surgery Do not want patient moving, why done intraoperatively

Question 58

Trunk/abdominal blocks: Quadratus Lumborum

Answer 58

Question 59

Erector Spinae Blocks/Paravertebral block (PVB)

Answer 59

Erector spinae plane (ESP): Block is an interfacial plane block where a local anesthetic is injected in a plane preferably below the erector spinae muscle. It is supposed to work at the origin of spinal nerves  Paravertebral block (PVB): Is a technique where a local anesthetic is deposited into a space found on both sides of the spine, called the paravertebral space. Operating room... but also can be done in pre-op area

Question 60

Paravertebral block (PVB)

Answer 60