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272 Cards in this Set

  • Front
  • Back
How many curves to the spine?

Where are they located?
4

C5, T5, L5, S2
How many vertebrae are there?

How many in each division?
33

7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal
Layers from skin to cord
skin, fascia, muscle, ligaments, dura mater, arachnoid mater, pia mater, cord
3 ligaments
Supraspinatous: C7-sacrum
Interspinous: between vert.
Flavum: foramen to sac. hiatus
How do angles of spinous processes differ between regions?
Horizontal at cervical, ~60 deg. in thoracic, horizontal in lumbar, sacral hiatus open vertically from bottom
How far does epidural space go?
From foramen to caudal canal
What structures does the epidural space contain?
Lymphatics, veins, adipose tissue
At what level does cord end in adults?
L1-2
At what level does dural sac end?
S-2
What artery is a major feeder of cord?
Artery of Adamkiewicz
What is total csf volume?

Daily csf production?
120-150ml

~150ml
How much csf in subarachnoid space?
20-80ml (wide variation)
Composition of CSF?

Sp. gravity of csf?
Glucose, Proteins, Electrolytes

1.003-1.009
Motor block in relation to sensory block
2 dermatomes below sensory
Sympathetic block in relation to sensory block
2-6 dermatomes higher than sensory block
C4 dermatome landmark
clavicle
C8 dermatome landmark
4th & 5th digits
T4 dermatome landmark
nipples
T6 dermatome landmark
xiphoid
T10 dermatome landmark
Umbilicus
T7 posterior dermatome landmark
Bottom of Scapula
Cervical nerves composing brachial plexus
C5,6,7,8, & T1
# of roots
# of trunks
# of divisions
# of cords
# of branches
5
3
6
3
5
Superior trunk formed by
C5 & C6
Middle trunk formed by
C7
Inferior trunk formed by
C8 & T1
What trunk should be blocked for shoulder surgery?
Superior, C5&6
Where do the divisions start?
1st rib by the clavicle
What nerves form the medial cord?
C7 & T1
What nerves form posterior cord?
All: C5,6,7,8 & T1
What nerves form lateral cord?
C5,6,7
What cervical nerves compose the musculocutaneous nerve?
Motor innerv.?
Sensory innerv.?
C5,6,7
Motor: biceps (flex)
Sensory: Lateral forearm
What cervical nerves compose the axillary nerve?
Motor innerv.?
Sensory innerv.?
C5,6
Motor: deltoid (chicken wing)
Sensory: Upper lateral arm
What cervical nerves compose the radial nerve?
Motor innerv.?
Sensory innerv.?
C5,6,7,8 & T1
Motor: Extension of forearm, wrist extension
Sensory: posterior arm & forearm, thumb & dorsal surface of hand
*Largest nerve in arm, protected by humerus as moves down
What cervical nerves compose the median nerve?
Motor innerv.?
Sensory innerv.?
C6-8 & T1

Motor: flex forearm & wrist
Sensory: Palmar surf. of hand and dorsal fingertips thumb & 2 fingers
What cervical nerves compose the ulnar nerve?
Motor innerv.?
Sensory innerv.?
C8 & T1

Motor: Abduct fingers
Sensory: Little finger & medial ring finger
What ampereage indicates proximity to nerve and ok to inject anesthetic?
0.5 mAmps
L2-3
Nerves that form lateral femoral cutaneous nerve

Sensory ONLY for anterolateral aspect of thigh
L2,3,4
Nerves that form femoral nerve & saphenous nerve

They also form obturator
L4-5, S1,2,3
Form Sciatic nerve
Sciatic divides into
Common peroneal and tibial
common peroneal and tibial contribute to form
sural nerve
common peroneal nerve splits to form
Superficial and deep peroneal
How do you locate the femoral nerve?
Palpate femoral artery and move 1-2cm lateral.

NAVy
Sensory innervation of femoral nerve
ant. thigh and knee
Termination of femoral nerve
saphenous nerve
Motor action of obturator
adduction of leg
At cephalad portion of popliteal fossa, the sciatic nerve divides into what nerves?
Peroneal and Tibial
Sensory innerv. of tibial nerve
bottom of foot
Sensory innerv. of Peroneal nerve
top of foot and lateral aspect of lower leg
Foot drop is caused by injury to what nerve?
Peroneal
Motor assessment of tibial nerve
Point toes down "Tippy Toes"
Motor assessment of peroneal nerve
Point toes up
Advantage of block vs. general or epidural?
Avoid sympathetic interruption
Hypothermia occurs at what temperature
36 deg. C
96.8 deg. F
What area of the brain controls body thermostat?
anterior/preoptic hypothalamus
What fibers carry cold sensations?
A delta fibers
What fibers carry heat sensations?
unmyelinated C fibers

C fibers also carry pain impulses, so body can't tell pain from intense heat
Rank order of forms of heat loss (most to least)
Radiation
Evaporation
Convection
Conduction
Sympathetic mediated response to heat loss
Inc. reased BMR, increased thyroxine secretion from thyroid
Vascular response to heat loss
vaoconstriction, AV shunt to deeper tissues, piloerection
Neonate response to heat loss
NE secretion and increased Brown fat thermogenesis

Neonates cannot shiver!!
Primary means of heat production in adult
shivering

Can increase metabolic demand up to 500%
Greater body surface area to weight ratio
Neonates
Age related changes in temp. management
Thin skin, dec. BMR, dec. sympathetic response
Most accurate non-invasive core temp. measurement
Esophagus

Best combination of performance and safety
Most accurate core temp. measurement
PA catheter
Effect of hypothermia on ODC
shift to left
Therapeutic hypothermia temp.
33-35 deg. C
91-95 deg. F

Decreases metabolic demands during ischemic time to prevent damage
Causes of hyperthermia
thyroid storm
pheochromocytoma
malignant hyperthermia
sepsis
Transfusion reaction
ETOH withdrawl
Impaired sweating
Operative stimulation
Tumor comp. of hypothalamus
Malignant hyperthermia
Occure w/ inh. anesthesia/sux
1 in 50,000
Genetic disorder: Ryanodine 1
Stop agent, dantrolene, cool body, give O2, support
Temp. for heat stroke
105-108 deg F
Treatment for postop shivering
Miperidine & warming
Phase 1 of heat loss
1 hour

heat transferred away from core to periphery, no vasoconstriction due to anesthetic induced vasodilation
Phase 2 of heat loss
2-4 hours

heat loss exceeds production
Phase 3 of heat loss
equilibrium

heat loss = heat production
Affect of neuroaxial anesthesia on tmp. regulation
body thinks anesthetized dermatomes are warm due to lack of signals, alters temp. regulation
Causes a burn pt. to lose the most heat?
Evaporation
Supports, insulates & protects against heat loss
Skin
Location of center for heat loss
Anterior preoptic hypothalamus
Location of center for heat gain
Posterior hypothalamus
Why does hypothermia decrease RR?
CO2 production drops, and CO2 level provides respiratory drive
Why does hyperthermia increase RR?
CO2 production increases, and CO2 level provides respiratory drive
Blood flow to spinal cord
Anterior artery, 2/3

2 posterior arteries, 1/2
Minium frequency for BP & HR measurement during anesthesia
q 3-5 min.
Method using pulsations of blood flow on inflated cuff to measure BP
Oscillometric BP
Doppler effect
Change in sound frequency when source moves relative to observer
Method of using turbulent flow sound to determine blood pressure
Auscultated BP
Turbulent flow sounds
Korotkoff sounds
Gold standard for arterial BP measurement
intra-arterial monitoring
Variations of BP during respiratory cycle
Pulsus alternans

Indicated hypovolemia
Wavelength that oxyhemoglobin absorbs infra-red light
940nm
Wavelength that deoxyhemoglobin absorbs visible red light
660nm
Beer-Lambert Law
There is a linear relationship between absorbence and concentration of an absorbing species
Pressure at which 50% of Hgb is saturated (P50)
27 mmhg
Every 1 mmHg drop on pressure = _______drop in O2
3%
Sat below which pulse ox is no longer accurate
70% (cyanosis)

Blood is shunted away from skin to vital organs
Pa02 of 30 = SaO2 of
Pa02 of 60 = SaO2 of
Pa02 of 85 = SaO2 of
60
90
96.5
Location for pulse ox probe with least amount of lag time between oxygenation changes and display changes
Ear lobe
Finger 2nd
Cause of continuous sat of 85% unresponsive to increase in FiO2
CO Poisoning
COHgb effect on Sat
Gives false high because COHgb absorbs infra-red light at same wavelength (660nm) as oxyhemoglobin
Methemoglobin effect on Sat
Gives false high if sat is less than 85% and false low if sat is above 85%
Gold standard for ETT placement
Capnography
CO2 / PaCO2 relationship
within 5-7 mmHg of each other
Rebreathing due to exhausted CO2 absorbant
Issue?
Rebreathing due to exhausted CO2 absorbent
Issue
Reactive airway
Issue?
None. Normal Mechanical vent. waveform
Issue?
Reactive Airway/Possible Apnea
Issue?
None. Normal Spontaneous breathing pattern
Issue?
3 methods of etCO2 measurement
Infrared Absorption
Mass Spectrometry
Calorimetric detection
Only location in the body where CO2 is located in large quantities
Lungs
Calorimetric detection
Easy cap

Turns yellow when exposed to CO2 (only determines Presence of CO2)
Mass Spectrometry drawbacks
Always have a leak
pooled equipment
Expensive
H2O and drugs may damage unit
Mass Spectrometry advantages
Measures CO2, Inh. Agent and O2 indpendently
Mass Spec. draw for sampling
~150ml/min for adults

~50ml/min for peds
Causes of decreased etCO2
Dead
Severe bronchospasm
Decreased metabolism
4 parts of ventilation assessment
visual inspection-chest mvmt.
vol. of gas-spirometry
alarms-audible
metabolic byproducts-etCO2
Most common location for vent. cicuit disconnect
y-piece
Causes of increase etCO2
Rebreathing
Increase metabolic process
hypoventilation
High points
C5 & L5
Low points
T5 & S2
Caudad
Toward bottom
Cephalad
Toward head
Structures that form vertebral foramen
2 pedicles projecting from body & 2 lamina that connect pedicles forming foramen
Landmark for sacral epidural
Sacral hiatus
Landmark to find scral hiatus
Sacral cornu on either side of hiatus
What nerve innervates the biceps and brachialis muscles?
Musculocutaneous
Supplies sensory innervation to the lateral aspect of forearm below the wrist and elbow
Musculocutaneous
Innervates deltoid muscle
Axillary nerve
Supplies sensory innervation to upper lateral arm
Axillary nerve
Assess motor of Musculocutaneous nerve
Flex biceps
Assess motor for axillary nerve
"make a chicken wing"
Roots that contribute to Musculocutaneous
C5-7
Roots that contribute to Axillary
C5&6
Roots that contribute to Radial
C5-8 & T1
Roots that contribute to Median
C6-8 & T1
Roots that contribute to Ulnar nerve
C8 & T1
Largest nerve in upper extremity
Radial nerve
Motor innervation of radial nerve
triceps, and supinator and extensors of forearm
Sensory innervation of Radial nerve
triceps region down forearm to thumb & dorsal surface of hand
If motor is blocked what can you assume?
Can assume that sensory is also blocked
Root contribution to Median nerve
C6-8 & T1 (no C5)
Motor innervation of Median nerve?
flexion of wrist
Sensory innervation of Median nerve?
Palmar surface of hand, index & middle fingers
Root contribution to Ulnar nerve
C8 & T1
Motor innervation of ulnar nerve
Spreading of fingers
Sensory innervation of Ulnar nerve
little and medial ring finger
4 primary approaches to blocks of brachial plexus
Axillary
Interscalene
Supraclavicular
Infraclavicular
Approach most frequently used to block forearm and hand
Axillary
Most frequently used approach to block shoudler & upper arm
Interscalene
Best way to establish needle tip location in relation to nerve
nerve stimulator
Motor response at____mA indicates needle in corect position for injection
0.5 or less
Purpose of test dose
assess for intravascular location
Increase in HR of 20%, reposition needle
Which local anesthetics have 2 i's in their names
Amides
All locals are_____ ______
Weak bases
sigificance of lower pKa
more non-ionized (lipid soluble) drug, faster onset
How are most local anesthetics degraded?
By circulating pseudochoinesterase in blood
What fiber types carry pain impulses?
A-delta and C fibers
What drug is limited to surgical epidural anesthesia only
Etidocaine
Rank of LA and max doses
BE My Little Prostitute Child
Bupivicaine 2.5-3 mg/kg
Etidocaine 5 mg/kg
Mepivicaine 5 mg/kg
Lidocaine 5-7 mg/kg
Procaine 7-9 mg/kg
Chlorprocaine 9-12 mg/kg
Local anesthetics for topical anesthesia
Tetracaine, Cocaine, Benzocaine
2% solution, how many mg per cc?
20 mg/cc
.5% solution, how many mg per cc?
5 mg/cc
.1% solution, how many mg per cc?
1 mg/cc
Acronym for blood flow ranking
TICPEBSS

Tracheal
Intercostal
Caudal
Paracervical
Epidural
Brachial
Subarachnoid, Sciatic, Femoral
Subcutaneous
Toxic manifestions of bupvicaine at 3-4 mcg/ml
Circumoral/tongue numbness
Lightheadedness, tinitus
Toxic manifestions of bupvicaine at 10 mcg/ml
Unconciousness
Toxic manifestions of bupvicaine at 26 mcg/ml
Cardiovascular collapse
Treatment for Methemoglobinemia
Methylene blue 1.5 mg/kg iv
Causes of Methemoglobinemia
Prilocaine doses >500mg
Benzocaine (Hurricane Spray)
Factors affecting potency of LA
Lipid solubility
Factors affecting duration of action of LA
Protein binding
Max dose of Epi
10mcg/kg in peds

200-250mcg in adults
Contraindication to use of Epi as adjunct to L.A.
Marginal collateral flow

Hx of cardiac disease
Addition of NaHCO3 to LA
Speeds time of onset
Rule for additives to spinals or epidurals
Must be preservative free

Drugs in glass vials are usually preservative free

Fentanyl is preservative free
Sympathetic preganglionic fibers
B fibers
Sympathetic postganglionic fibers
C fibers
Evidence of intraneural injection
Searing pain and screaming patient.

Withdraw and reposition
Supraspinous ligament
Runs C7 to Sacrum

Strong fibrous cord

Thickest/Broadest in lumbar region
Interspinous ligament
Thin/membranous

Runs length of spinal column

Thickest and broadest in Lumbar region
Ligamentum Flavum
Short segments between spinous processes

Thickest at Midline and furthest from meninges
Potential space composed of mostly fat and veins
Epidural space
Length of Epidural space
Runs from Foramen magnum to sacral hiatus
Widest level of epidural space

Narrowest level
L2

C5
3 layers of the meninges (from outside in)
Dura, Arachnoid, Pia
Space for spinal drugs to be injected
Subarachnoid space, just between the arachnoid mater and pia mater
Dura mater
outer, toughest layer
Arachnoid mater
Middle non-vascular layer

Serves as principle barrier to drugs moving between epidural and subarachnoid space
Pia mater
Delicate, highly vascular

Don't touch with the needle
Where does the spinal cord end?
At L1 in adults

At L3 in newborns~1yr. and in 10% of adults
What anchors the spinal cord?
Filum terminale
What nerve group is located in the lower dural sac?
Cauda Equina
Do nerve roots exit above or below the vertebrae?
Cervial nerves exit above the vertebrae (hence 8 cervical nerves), and the rest exit below the vertebrae

Below L1, they for the cauda equina and exit further below
What is the order of blockade for sympathetic, motor and sensory nerves?
Sympathetic is blocked first, Sensory second and Motor is blocked last
What is differential blockade?
Blockade of Sympathetic (B fibers), Sensory, and Motor blockade at different levels
What is the manifestation of a sympathetic block?
Decreased BP due to unopposed parasympathetic outflow
In a differential block, if motor is blocked at T6, what level could you expect the sympathetic and sensory blocks to be?
Sensory at T4 and Sympathetic at T2
What is one of the 1st signs of a high spine?
Bradycardia (due to sympathetic block)
Preoperative interventions in anticipation of hypotension
500-1000ml of fluid
Respiratory implications of high block
Decreased FRC due to paralysis of abd. muscles

impaired secretion clearance to due intercostal paralysis
Major artery feeding the spine
Artery of Adamkiewicz, originating from aorta

Provides 2/3 of blood supply to spinal cord
Levels of tissue midline approach passes through
Skin
SubQ
Supraspinous
Interspinous
Lig. flavum
Epidural space-Epidurals here
Dura mater
Arachnoid mater-Spinals here
Dermatome/Landmark for chest surgery
C4 (clavicle), don't do this on purpose
Dermatome for Upper Abd. surgery (C-Section)
T4-5 (Nipples)
Dermatome for Lower Abd. surgery (C-Section)
T6-8 (Xiphoid)
Dematome/Landmark for abd. surgery
T8 (Bottom of ribcage)
Dematome/Landmark for TURP, Hip surgery, vaginal delivery
T10 (Umbilicus)
Dematome/Landmark for TURP, Lower ext. surgery
L1 (inguinal Ligament)
Dematome/Landmark for foot surgery
L2-L3 (Knee)
Dematome/Landmark for anal/perineal surgery
S2-S5 (perineum)
Define Spinal anesthesia
Small amount of anesthetic placed in subarachnoid space (CSF)

Single shot
Define epidural anesthesia versus spinal anesthesia
Larger doses and catheter placed in epidural space (no CSF)
Allows for segmental anesthesia/analgesia
Higher potential of systemic toxicity because of larger doses and epidural veins present in epidural space
Absolute contraindications to spinal anesthesia
Infection at site of injection
Pt. refusal
Coagulopathy
Severe Hypovolemia
increased ICP
Aortic/Mitral Valve stenosis (Can't inc. Hr to compensate for drop in BP)
Signs of CSF leak
Headache relieved by supine position, Photophobia, N/V
Most commonly used spinal needles
Sprotte & Whitacre 25 gauge to pierce ligaments
Consideration when placing epidural/spinal in older patients
Ligaments are calcified so use a cutting needle to penetrate ligaments
What level are sympathetic fibers that innervate heart?
T1-T4
Explain baricity of anesthetic solution
Specific gravity of anesthetic in relation to CSF.
How do you alter baricity of a solution?
Add glucose to increase baricity, and Saline to decrease baricity
Explain effect of baricity on movement of anesthetic solution
Hyperbaric solution drops when sitting or moves to the down side when lateral

Hypobaric solution rises in CSF or move to the high side when lateral

Baricity is irrelevant in epidurals
Where will isobaric solution move in a left lateral positioned patient?
It won't move. It has specific gravity = to CSF so it will remain in place
What is the realtionship between CSF volume and level of anesthesia?
They are inversely related.

Lower CSF volume = higher block level
Pervention of hypotension in patient before receiving neuroaxial anesthesia?
500ml-1L of lfuid
Best position for patient with hip fx?
Lat. decubitis with affected side down, use hyperbaric solution and wait 5-7 mins before turning patient
Best position for midline approach?
"Angry Cat"
Landmark for L4-L5 interspace?
Line between iliac crests
Indication that the needle has penetrated the arachnoid mater?
Free flow of CSF
You have free flowing CSF when performing a spinal, what would stop you from injecting drug?
Any heme or paresthesias noted
When would you choose a paramedian approach?
When it needs to be done quickly
Poor positioning with flexion of spine
A gamma and C fibers trtansmit these impulses
Noxious sensations
Variuos uses for epidural anesthesia
Surgical anesthesia
Analgesia for 1st stage of labor
Prolonged post-operative pain relief (indwelling catheter)
Extent of motor block in an epidural depends on what 2 factors
Volume of anesthetic

Concentration of anesthetic
Approx. dose per level of epidural for full motor/sensory block
1-2ml (1.5ml)
How is doseage measured in epidurals vs. spinals?
In epidurals, dosage is ml

In spinals dosage is mg
Contraindication to epidural
Coagulopathy (hematomas)

Check Coags and BT
Difference in sympathetic effect between spinals and epidurals?
In epidural, sympathectomy can be dosed gradually and done slowly

In spinal, dose is given all at once, so no way to control onset of sympathectomy
Where is the venous plexus densest in the spinal column?
It is concentrated ventrally and laterally

A midline approach avoids the venous pelxus
Describe the epidural space
It is a potential space because it is filled with loose connective tissue surrounding epidural veins and spinal nerve roots
Hoe far does the epidural space extend?
From foramen magnum to sacral hiatus
In what population would a paramedian approach be more risky?
Pregnant women, because obstruction to venous return would cause engorgement of venous plexus
What populations have an increased risk of bleeding?
Preggers, Obese, Liver failure/Ascitic patients
In what types of surgeries would epidural anesthesia not be the best choice?
Foot and ankle.

The very large spinal nerves at L5 and S1 are difficult to block in the epidural space as opposed to the subarachnoid space
Define differential blockade
Differential Blockade: A chiefly sympathetic and sensory blockade with sparing of motor blockade. This is achieved by using a lower concentration of agent
Define segmental blockade
Blockade of sensation from the upper abdomen with sparing of the lower extremities
How does a segmental blockade work?
The L.A. is injected directly into the epidural space at the level where the segments to be blocked originate
Which epidural agents have fast onset?
Chloprocaine
Prilocaine
Which epidural agents have intermediate onset?
Lidocaine
Mepivicaine
Which epidural agents have slow onset?
Bupivicaine
Mnemonic for epidural agent onset time
CHeese Pickles LIght Mayo on my BUrger
Type of needles most common in Epidurals
Tuohy & Weiss
Hanging drop technique
Drop of saline hanging from end of Weiss needle, when needle enters the epidural space, drop is drawn into needle by negative pressure
In paramedian approach, what causes the most resistance felt during needle insertion?
The ligamentum flavum
What is the test dose?
3-5 ml of 2% lidocaine with epi 1:200,000

Can go through needle of threaded catheter
A 20% increase in HR 30-60 seconds after administration of test dose indicates what?
Intravascular injection

Withdraw and reposition needle
How long after subarachnoid injection shold you see signs/sx of spinal anesthesia?
Within 3 minutes
Proper technique for incremental dosing in epidural?
Inject about 5 ml of drug at a time with aspiration before and after injection to assess for CSF and blood with each incremental dose
Volume/Concentration relationship for motor vs. sensory block?
A high volume of low concentration L.A. results in high sensory level with less motor block

Lower volume of higher concentration L.A. will result in lower but denser sensory and motor block
For redosing epidural, what is the corrct amount of the initial dose to administer?
1/3 to 1/2 the volume of the 1st dose
How does weight affect epidural dose?
It doesn't, except in moribdly obese patient
How does poitioning/posture of patient during delivery of epidural affect dose needed?
It does not affect dose needed
How does age affect does of epidural?
Increased age means decreased dose
How would a platelet count of 75,000 affect epidural insertion?
epidural is contraindicated with plt count below 80K
At what level are the "cardiac accelerator" nerves found?
T1-T4
Caudal anesthesia is technically easier in what population?
Peds
How can an epiduralcatheter be placed with caudal approach?
If a tuohy is used successfully, an epidural catheter can be threaded
Positioning for caudal approach?
Pt. prone with hips higher than head and legs
How much anesthesia is neded to fill the sacral canal?
12-15 ml
Pediatric caudal anesthesia dose
Dose is 1-1.25 mg/kg of 0.25% bupivacaine with1:200,000 epi
Cardiovascular signs/symptoms of high spine in peds population?
There are no s/s of hypotension or bradycardia during a high spinal in the pediatric population.

Respiratory failure is the only s/s seen in high spinal
Relationship between FiO2 and PaO2?
PaO2 is roughly 5x the FiO2

If not, then there is a V/Q mismatch