Final Exam Review Flashcards
Should you plug electrical devices into the back of the anesthesia machine?
No, never!
What are the 3 pressure systems in the anesthesia machine?
- High pressure (think back of the machine)
- Intermediate pressure (machine itself)
- Low pressure (connections to patient)
Pressure ranges for high pressure system
750-2200 psi
Pressure ranges for intermediate pressure system
40-50 psi
Pressure ranges for low pressure system
16 psi
Cylinders/hanger yoke are part of the ___ pressure system
High
O2 flush valve is part of the ___ pressure system
Intermediate
Vaporizers are part of the ___ pressure system
Low
Cylinders should be left in the ___ position
Off—reserve for emergency use only
Oxygen cylinder color, PSI, and E-cylinder capacity
Green, 1900-2200 psi, 660 capacity
Nitrous oxide cylinder color, PSI, and E-cylinder capacity
Blue, 745 PSI, 1600 capacity
Air cylinder color, PSI, and E-cylinder capacity
Yellow, 1800 PSI, 600 capacity
Pin index safety system (PISS) is meant to prevent ___
Misconnections of cylinders
Oxygen pin index on the yoke =
2,5
Nitrous oxide pin index on the yoke =
3,5
___ orients the cylinders
Hanger yoke
What is the most fragile part of the anesthesia machine?
Cylinder valve
Oxygen in the pipeline is supplied at ___
50 psi
What happens if oxygen pressure is lost?
Oxygen low-pressure alarm sounds; fail-safe valves stop delivery of other gases
What should you do if the oxygen pipeline supply fails?
Use backup oxygen cylinder, disconnect pipeline supply, use low flow O2, turn off vent, bag patient manually…do NOT reconnect pipeline supply until it has been tested
What are three valves on the anesthesia gas machine?
- Free-floating valve
- Ball and spring valve
- Diaphragm valve
Which type of valve moves in the direction or push of gas flow; prevents gas from leaking out of the system; and prevents the emptying of gases into an empty cylinder or from wall oxygen coming into a cylinder (“safety” valve)?
Free-floating valve
Failure to open the cylinder valve on the free-floating valve results in ___ to the anesthesia machine
No gas flow
Which type of valve prevents mixing of nitrous oxide and oxygen and contains the oxygen fail-safe device?
Ball and spring valve
The oxygen fail-safe device will turn off the flow of other gases (i.e.: nitrous oxide) if the oxygen pressure falls below ___
25 psi
What type of valve is the oxygen flush valve?
Ball and spring valve
How much oxygen (L/min) flushes through the oxygen flush valve?
35-75 L/min
What type of valve reduces pressure in the system?
Diaphragm valve
What are two types of diaphragm valves?
- First stage regulator
- Second stage regulator
First stage regulator reduces pressure to ___ psi
40-50 psi (intermediate pressure)
Second stage regulator reduces pressure from ___ psi to ___ psi
40-50 psi to 16 psi (intermediate to low pressure)
Should you use a vaporizer if it tips over?
NO!!! More liquid vapor will get into the chamber and carry more agent to the patient (can be a lethal dose)…DO NOT USE
What type of breathing system do we use?
Semi-closed system—patient hooked up to anesthesia machine; anesthetic gas remains in system, no room air inspired, expired air exits through scavenging system
What color does soda lime turn when exhausted?
Purple
What inhalation agent generates compound A when degraded?
Sevo
What are HMEs?
Heat and moisture exchangers—retain heat and moisture in anesthesia circuit; effective bacterial/viral filters
HMEs increase ___ and ___
Dead space and work of breathing
What can occur if HME becomes blocked?
Obstruction
Two types of HMEs?
Hydrophobic and hygroscopic
What are two types of bellows in the AGM?
- Ascending
- Descending
Ascending bellows ___ on expiration
Ascends
Descending bellows ___ on expiration
Descends
Which bellows is safer?
Ascending—will not fill if disconnect occurs; descending bellows will continue upward/downward motion despite disconnect (must have CO2/apnea alarm)
4 ventilator modes:
- Volume control
- Pressure control
- Synchronized intermittent mandatory ventilation
- Pressure support
Volume control—constant ___ delivered per breath
Tidal volume
Pressure control—constant ___ with each breath
Inspiratory pressure
Synchronized intermittent mandatory ventilation—preset ___
Respiratory rate
Pressure support—adds preset ___ during inspiration, can also provide a preset ___
Pressure, PEEP
What are 3 single cartilages in the airway?
- Epiglottis
- Thyroid
- Cricothyroid
What are 3 paired cartilages in the airway?
- Arytenoid
- Corniculate
- Cuneiform
What is the only full ring of the trachea?
Cricoid ring
What is the thryomental distance?
Measure from upper edge of thyroid cartilage to chin with the head fully extended
Should be 2 fingers
A short thyromental distance =
An anterior larynx, not an easy intubation
Thyromental distance > 7 cm =
Easy intubation
Thryomental distance < 6 cm =
Difficult airway
Mallampati-Class 1
Tonsillar pillars/fauces, uvula, soft palate
Mallampati-Class 2
Tonsillar fauces ONLY, uvula, soft palate
Mallampati-Class 3
Soft palate
Mallampati-Class 4
Hard palate only
What is the normal A-O (Atlanto-occipital) angle?
35 degrees
How does having no teeth affect mask ventilation vs. intubation?
Difficult mask ventilation, easy intubation
Cormack/Lehane View-Grade 1
Full view of epiglottis, glottic opening, and vocal cords
Cormack/Lehane View-Class 2
Partial view of epiglottis and vocal cords
Cormack/Lehane View-Grade 3
Epiglottis only
Cormack/Lehane View-Grade 4
Soft palate only
Amount of air to inject in LMAs
10 x the size of the LMA minus 10
LMA size 3
20 ccs, for children 30-50 kg
LMA size 4
30 ccs, adults 50-70 kg
LMA size 5
40 ccs, adults 70-100 kg
LMA size 6
50 ccs, adults over 100 kg
Obtain ___ when doing a spinal or epidural and patient has a history of taking anticoagulants
Coagulation screen
How do seizure disorders affect MAC?
Increase MAC value—patient may require higher doses of meds d/t seizure meds being CYP inducers
What should you do if a patient has pre-existing nerve injuries?
Document them!
What are METs?
How we can assess a patient’s CV function—exercise tolerance in metabolic equivalents
We want at least ___ METs
4 = good functional capacity
Examples:
- Light/heavy housework
- Climbing a flight of stairs without stopping
- Walking or running a short distance
- Moderate recreational activities
Want to maintain patient within ___ of their baseline BP
20%
Should wait at least ___ days after an MI for elective surgery
60 days
What puts a patient at greatest risk for non-cardiac surgery MI?
Aortic stenosis
Always want patient to continue taking their scheduled ___
Beta-blocker—if they didn’t take it, have to give beta-blocker pre- or intraoperatively to reduce the risk of perioperative ischemia
Risk of ___ increases as surgical site approaches the diaphragm
Pulmonary complications
Length of surgery > ___ increases risk for pulmonary complications
2-3 hours
Patients with OSA have difficult with ___
Mask ventilation
Risk for ___ in patients with asthma—be prepared
Bronchospasm
STOP-BANG questionnaire assesses what?
OSA risk
STOP-BANG stands for…
S-Snore loudly? T-Tired during daytime? O-Observed not breathing when asleep? P-blood Pressure high? B-BMI > 35 A-Age greater than 50 N-Neck circumference greater than 40 G-Gender = male?
Chest x-ray pre-op only if active ___, ___ surgery, age > ___
Active chest disease, intrathoracic surgery, age > 60
High risk for ___ in SBO
Aspiration—RSI intubation, Sellick’s maneuver (cricoid pressure)
Previous gastric bypass = NO ___
NGT
Active or uncontrolled GERD = NO ___
LMA
Aspiration pneumonia is AKA ___
Mendelson syndrome
Fasting guidelines before surgery—no ___ or ___ after midnight
Chewing gum or candy
Fasting guidelines—clear liquids up to ___ hours before surgery
2 hours
Fasting guidelines—breast milk up to ___ hours before surgery
4 hours
Fasting guidelines—no infant formula, nonhuman milk, or light meal for at least ___ hours before surgery
6 hours
Fasting guidelines—prescribed medications can be administered with ___ ml water for adults (up to ___ ml for children) up to ___ hour before anesthesia
150 ml; 75 ml; 1 hour before
For total joint procedures, always check ___ during procedure, regardless if patient is diabetic or not
Blood glucose
If patient is taking metformin, when should they stop taking it before surgery and why?
Stop taking 48 hours prior to surgery d/t risk for renal impairments
If patient is on insulin, take ___ or ___ of dose morning of surgery
1/4 or 1/2 dose
What is goal for patients who are hyperthyroid before surgery?
Get them euthyroid!
Anti thyroid meds for 6-8 weeks pre-op, followed by iodine for 1-2 weeks pre-op
May need to use what medication intraoperatively for patients who are hyperthyroid?
Beta-blockers—usually propanolol
What about patients who are hypothyroid and having surgery?
No recommendations
If patient is on long-term steroids, they may need ___ for the procedure
Stress dose steroids
Acute alcohol intoxication ___ anesthetic requirements
LOWERS
Alcohol withdrawal ___ anesthetic requirements
INCREASES
Avoid ___ in cocaine users
Beta blockers! Will have unopposed alpha stimulation—accelerated HTN
What type of medication should you use in cocaine users instead of beta blockers?
Calcium channel blockers to manage tachycardia/HTN
What medication is the most common cause of intraoperative allergic reaction?
Rocuronium
ASA Class I
Healthy patient
ASA Class V
Surgery is a last effort in this patient—i.e.: PE, uncontrolled hemorrhage from AAA, head injury with increased ICP
ASA Class VI
Declared brain dead patient donating organ
What ASA Class is this? — mild to moderate systemic disease—i.e.: essential HTN, diabetes, chronic bronchitis, anemia, morbid obesity, age extremes
ASA Class II
What ASA Class is this? — severe systemic disease that limits activity—i.e.: poorly controlled HTN, DM with vascular complications, angina pectoris, history of previous MI
ASA Class III
What ASA Class is this? — severe systemic disease that is constantly life threatening (i.e.: CHF, persistent angina, advanced pulmonary, renal, or hepatic dysfunction)
ASA Class IV
Failure to obtain consent = breach of ___
Duty
Performing a procedure without proper consent = ___
Battery
Anesthesia can proceed without consent in emergencies—doctrine of ___
Doctrine of implied consent
SOAPM for all anesthetics
S-suction O-oxygen A-airway supplies P-positive pressure/pharmacy M-monitors/medications
Standard I =
Perform pre-operative assessment
Standard II =
Obtain informed consent
Standard III =
Form patient-specific anesthesia care plan
What are 2 contraindications for esophageal stethoscope?
- Esophageal varices/strictures
- History of bariatric surgery
Red light = ___ nm, ___
660 nm, deoxyhemoglobin
Infrared light = ___ nm, ___
940 nm, oxyhemoglobin
What Law is the basis for pulse oximetry?
Beer Lambert’s Law
ETCO2 is ___ mm Hg (higher/lower) than PaCO2 on ABG
2-5 mm Hg LOWER
D point on ETCO2 waveform =
End tidal measurement
Normal PR interval =
0.12-0.2 sec
Normal QRS
0.06-0.10 sec
Normal QT interval
< 500
How do anesthetics affect thermoregulation?
Inhibit central thermoregulation by interfering with hypothalamic function
How can you tell if patient is spontaneously breathing based on ETCO2 waveform?
Curare cleft
Low pressure alarm =
Disconnect, leak
High pressure alarm =
Kink, mucus plug
High pressure alarm is usually set at ___
40
Is EKG a measure of heart function?
NO
Stimulation of ulnar nerve = contraction of ___
Adductor pollicis muscle
Stimulation of facial nerve = contraction of ___
Orbicularis oculi
Which muscle recovers faster from neuromuscular blockage—adductor pollicis or orbicularis oculi?
Orbicularis oculi
You don’t lose twitches until ___% of muscles are blocked
70%
4/4 twitches =
70% paralyzed
3/4 twitches =
75-80% paralyzed
2/4 twitches =
80-85% paralyzed
1/4 twitches =
90-95% paralyzed
0/4 twitches =
100% paralyzed
Only thing that will NOT affect pulse ox reading is ___
Fetal hemoglobin
Succinylcholine =
Depolarizing agent, does NOT cause fade, causes fasiculations
Non-depolarizing agents cause ___
Fade (i.e.: rocuronium, vecuronium, pancuronium)
TOF =
2 Hz for 2 seconds, every 0.5 seconds
Double burst =
50 Hz, 2 short bursts, every 0.75 seconds
Tetany =
50 or 100 Hz for 5 seconds
Which twitch monitoring method is used to see if patient is on their way to waking up?
Tetany
Will see ___ with tetany if non-depolarizing blocking agents are used
Fade
___ provides early evidence of ischemia intraoperatively
EEG
Goal is to titrate concentrations of anesthesia to maintain BIS near ___
60
Light moderate sedation = BIS ___
80
BIS < 60 =
Unresponsive
What monitor should you use during carotid surgery to monitor oxygen levels?
Cerebral oximetry monitor
What alters evoked potentials?
General anesthesia
What are 4 types of evoked potentials?
- Visual
- Auditory
- Somatosensory
- Motor
Perioperative mortality = death that occurs within ___ days after surgery
2-30 days
Top 3 ASA closed claims:
- Death
- Nerve injury
- Brain damage
3 emerging claim areas:
- Regional
- Chronic pain management
- Acute pain
What is the most common airway injury from anesthesia?
Dental injury
What can contribute to peripheral nerve injury?
Positioning
How can you prevent corneal abrasion?
Tape/lubricate eye
How can you prevent retinal ischemia when prone?
Avoid pressure on globe
Brachial plexus, radial, and ulnar palsies can occur in ___ position(s)
Any
Common peroneal palsy can occur in ___ positions
Lithotomy/decubitus positions
How can you avoid nerve palsy injuries?
Use padding over bony prominences and avoid stretching/compression of these areas
What are 3 high-risk cases for intraoperative awareness?
- Major trauma*
- Obstetrics
- Cardiac surgery
Up to 10x risk
3 risk factors for Intraoperative awareness
- Female
- Younger
- Obese
What is the most common transient eye injury?
Corneal abrasion
What is the most common cause of post-operative loss of vision?
Ischemic optic neuropathy (ION)
Caused by optic nerve infarction d/t decreased oxygen delivery to the optic nerve
ION is commonly reported after what 4 surgeries?
- Cardiopulmonary bypass
- Radical neck dissection
- Abdominal and hip procedures
- Spinal surgeries in prone position*
What positions contribute to ION?
- Prone
- Head down
- Compressed abdomen
All compromise venous return to the heart*
ION onset
Immediately post-op through 12th post-op day
What are 4 types of allergic rxns?
Type I-IV
Type I allergic reaction
Immediate—anaphylaxis*
Type II allergic reaction
Cytotoxic (antibody-mediated, blood type incompatibilities) i.e.: hemolytic transfusion reactions, autoimmune hemolytic anemia, heparin-induced thrombocytopenia
Type III allergic reaction
Immune complex (i.e.: RA, SLE)
Type IV allergic reaction
Delayed, cell-mediated, cytotoxic (i.e.: contact dermatitis)
Anaphylactoid reaction does NOT depend on ___
IgE antibody interaction with antigen (anaphylaxis does)
Anaphylactic/anaphylactoid reactions can be clinically ___ and equally ___
Clinically indistinguishable; equally life threatening
What is the most common cause of anaphylaxis during anesthesia?
Muscle relaxants
What are two hypnotic agents that can cause allergic reactions?
- Propofol
- Pentothal
What is the second most common cause of anaphylaxis during anesthesia?
Latex!
What 6 foods cross-react with latex?
- Mango
- Kiwi
- Passion fruit
- Banana
- Avocado
- Chestnut
Airway mortality is NOT due to difficulty ___, it is due to failure to ___
Intubating; failure to ventilate
What is a late sign of MH?
Core temperature rise as much as 1 degree Celsius every 5 minutes
What causes MH?
Uncontrolled release of Ca from the sarcoplasmic reticulum, leading to constant muscle contraction
What triggers MH?
-All halogenated agents (so not nitrous oxide) + succs (depolarizing muscle relaxant)
What is the treatment for MH?
Dantrolene 2.5 mg/kg q 5 mins; max dose 10 mg/kg
How does dantrolene work?
Binds to ryanodine receptor and inhibits calcium release from the SR
What should you do if laryngospasm occurs?
- 100% O2
- Deepen anesthesia
- Positive pressure
What are two main signs of bronchospasm?
- High peak inspiratory pressures
- Wheezing
What should you do if bronchospasm occurs?
- 100% O2
- Deepen anesthesia
- Albuterol
- Treat the underlying cause
What are 3 causative agents of fire in the OR?
Oxygen + heat + fuel = fire
Oxygen = anesthesia Heat = surgeon’s cautery Fuel = surgical nurse’s alcohol prep
What should you do if there is a fire in the OR?
- Disconnect the circuit
- Pour sterile water/saline down ETT
- Replace patient’s ETT quickly
Keep FiO2 below ___ for tonsillectomy/ENT surgery
30%
Total body water = ___% total body weight
60%
Intracellular volume = ___%
40%
Extracellular volume = ___%
20%
ECF is comprised of what two compartments?
- Interstitial fluid (75% ECF)
- Plasma (25% ECF)
Interstitial fluid
75% ECF; fluid in tissue spaces
Plasma
25% ECF; intravascular fluid; high concentration of plasma proteins (albumin) that remain in vascular space
TBW is ___% male’s weight
55%
TBW is ___% female’s weight
45%
TBW is ___% infant’s weight
80%
ICF has high concentration of ___
Potassium
Also contains phosphate and magnesium
ECF has high concentration of ___
Sodium
Also contains chloride
___ is the main determinant of osmotic pressures
Albumin
What are 3 sources of intraoperative fluid loss?
- Insensible loss
- Third space loss
- Blood loss
What are insensible losses?
- Urine
- Feces
- Sweat
- Respiratory tract
Replace insensible fluid losses with ___ cc/kg/hr
Crystalloid 2 cc/kg/hr
Third space loss is fluid lost from ___ space to ___ space
Intravascular space (plasma) to interstitial space
Minimal trauma fluid replacement
3-4 cc/kg
Moderate trauma fluid replacement
5-6 cc/kg
Severe trauma fluid replacement
7-8 cc/kg
Third space losses become mobilized ___ day post-op
3rd day—may see increase in intravascular volume; caution in patient’s with limited cardiac reserve/renal dysfunction
Blood loss fluid replacement
Replace 3x blood loss with crystalloid
We do 3x because you have to replace intravascular loss + fluid loss from the extravascular (interstitial) space to replenish the intravascular loss during acute hemorrhage
How much colloid should be used to replace blood loss?
1:1 blood loss replacement
5% albumin is used for ___
Expansion of intravascular volume
25% albumin is used for ___
Treatment of hypoalbuminemia
Young healthy patients may lose ___% of circulating blood volume without demonstrating clinical signs
20%
Acute blood loss causes vasoconstriction of ___ vessels; blood volume loss of ___% can be masked by this compensatory response
Vasoconstriction of splanchnic/venous capacitance vessels; blood volume loss of 10% can be masked by this compensatory response
Indication for blood transfusion = increase ___ of the blood
Oxygen carrying capacity
Hgb < ___ g/dL = transfuse
< 6 g/dL
In acute hemorrhage, ___ preferred over PRBCs
Whole blood
PRBCs are used for treatment of ___ not associated with acute hemorrhage or shock; augments ___ of the blood
Acute anemia; augments oxygen-carrying capacity
Decreased risk for ___ with PRBC transfusion over whole blood transfusion
Citrate toxicity//allergic reaction
Platelet transfusion for platelet count < ___
50,000
Risks of platelet transfusion (3)
- Transmission of viral diseases
- Bacterial infection
- Sepsis
FFP = ___ portion of blood; contains all plasma proteins except ___
Plasma; contains all plasma proteins except platelets
When would you administer FFP (3)?
- When PT/aPTT > 1-1.5 x normal
- Reversal of warfarin therapy
- Correction of known factor deficiencies
Risks of FFP transfusion (2)
- Transmission of viral diseases
- Allergic reaction
Cryoprecipitate contains high concentration of ___
Clotting factors—i.e.: fibrinogen*
Cryo is given for ___
Clotting factor deficiencies (i.e.: fibrinogen deficiency)
Transfuse Hgb < ___ g/dL in patients with CV/pulmonary disease over the age of 65 years
7 g/dL
Transfuse Hgb < ___ g/dL in patients undergoing cardiopulmonary bypass
6 g/dL
Transfuse if > ___% blood volume loss
> 30% (1500 cc cumulative loss)
Transfuse platelets if platelet count < ___
< 50,000
Give FFP if INR > ___; PT ___ x normal; aPTT > ___x normal
INR > 2; PT 1.5 x normal; aPTT > 2x normal
Give cryo if fibrinogen < ___
< 80-100
Local anesthetics are weak ___
Weak bases
What is pKA?
The pH at which you have 50% ionized (charged) and 50% nonionized (uncharged)
Lower PKA = ___ onset of action
Faster (because you have more in the uncharged form)
Uncharged form = most ___
Lipid soluble—this is what accesses the axon
Local anesthetics block the influx of ___ into the cells to prevent conduction of action potentials
Sodium
THRESHOLD POTENTIAL IS NOT REACHED
Lipid solubility increases ___
Potency
High degree of protein binding = ___ duration of action
Longer
PKA determines ___
Onset of action
Lower PKA = faster onset because you have more nonionized form
___ fibers are more easily blocked than ___ fibers
Thin fibers, thick fibers
Which is more easily blocked—myelinated or unmyelinated axons?
Myelinated
Where is the block produced specifically—node of ___
Ranvier
Which type of locals are metabolized more quickly?
Esters are metabolized more quickly than amides (d/t cholinesterases in the circulation)
Half-life of esters
~1 min
Byproduct of ester metabolism = ___
PABA (p-aminobenzoic acid)
Where are amides broken down?
Liver—patients with severe hepatic disease may be more susceptible to adverse reactions
Half-life of amides
2-3 hours
What is baricity?
Density of local anesthetics compared to density of CSF
How does sodium bicarb affect local anesthetics?
Increases concentration of nonionized (free) base, thus increasing the rate of diffusion of the local/speeding onset of action
Ester anesthetics may trigger allergic reactions in persons sensitive to ___ or ___
Sulfonamides or thiazide diuretics
IV injection of ___ or ___ may result in CV collapse that is refractory to therapy because of high degree of tissue binding of these agents
Bupivicaine or etidocaine
Spinal anesthesia = injecting into the CSF within the ___ space
Subarachnoid/intrathecal space
What is the most common causative organism in epidural abscess? Which is a growing concern?
Most common = Staph aureus; MRSA is a growing concern
What are 6 absolute contraindications for a spinal?
- Patient refusal/lack of cooperation
- Increased ICP
- Coagulopathy
- Skin infection at the site
- Uncorrected hypovolemia
- Spinal cord disease
Aspirin and spinal
No contraindication
Plavix and spinal
Discontinue 7 days preoperatively
Heparin and spinal
Place catheter 1 hour before scheduled dose; remove catheter 1 hour before next dose
What are signs of spinal/epidural hematoma?
- New onset weakness to lower limbs and sensory deficit
- New onset back pain
- New onset bowel or bladder dysfunction
Must diagnose and surgically decompress hematoma within ___ hours for best outcome
Within 8 hours
Spinal needles are placed below ___, as the mobility of the spinal nerves reduces the danger of needle trauma
L2
CSF specific gravity =
1.004-1.009
What are 3 types of local anesthetic solutions?
- Hyperbaric
- Hypobaric
- Isobaric
Which type of local solution is most commonly used?
Hyperbaric
What is hyperbaric mixed with?
Glucose
Hyperbaric flows ___
Down to most dependent part d/t gravity
Hypobaric solution is mixed with ___
Sterile water
Hypobaric solutions flow ___
Up to highest part
Hypobaric solutions are used for ___ procedures
Perineal procedures in prone
Isobaric solutions
Predictable spread through CSF independent of patient position
Increasing dose of isobaric anesthetic will affect ___, rather than spread to a higher dermatome
Duration of action
Lateral position—hypobaric/hyperbaric solutions
- Affected side UP if using hypobaric solution
- Affected side DOWN if using hyperbaric solution
Sitting position is often used with ___ anesthetics
Hyperbaric
Prone position is often used with ___ anesthetics
Hypobaric
Prone position is useful for procedures on ___, ___, and ___
Rectum, perineum, and anus
Increased resistance is felt with spinal needle as it passes through ___
Ligamentum flavum
As spinal needle is passed beyond the ligamentum flavum, a sudden ___ is felt
“Pop” or loss of resistance
Correct placement of spinal needle is indicated by ___
Free flow of CSF into the hub of the needle
Paresthesia occurring with placement of spinal needle requires ___
Immediate withdrawal of needle and repositioning
For onset of blockade, monitor BP, HR, and respiration’s every ___ until patient is deemed stable
Minute
Fixation of local anesthetic takes approximately ___ minutes
20
Neural blockade order of action
Autonomic > sensory > motor (difference of 2 segments, with autonomic fibers being highest level of blockade)
Epidural anesthesia = injection of local anesthetic into the ___
Epidural space
Onset of epidural anesthesia is ___ and ___
Slower and less intense than spinal
Provider has greater control of sensory/motor blockade with ___ vs. ___
With epidural vs. spinal
Epidural anesthesia is ___ dependent
Diffusion dependent
___ volumes used with epidural anesthesia
Larger—spinal dose is usually 2 ccs; epidural dose is usually 20 ccs
Epidural anesthesia takes ___ to achieve than spinal anesthesia
Longer
Epidural needle should always enter the epidural space ___ because the space is widest
MIDLINE—decreased risk for puncturing epidural veins, spinal arteries, or spinal nerve roots
Epidural test dose—if placed in epidural space, will have ___ effect
Little effect
Epidural test dose—if placed in the CSF, will rapidly behave like ___
Spinal
Epidural test dose—if injected into an epidural vein, a ___ in HR will be seen
20-30% increase in HR
DOA lidocaine
30 mins to 2 hours
DOA bupivacaine
2-4 hours
DOA ropivacaine
2-6 hours
Always have patient on standard hemodynamic monitors/supplemental oxygen when setting up peripheral block—T/F?
TRUE
What technique is this?—LA injection targets terminal cutaneous nerves; used to minimize incisional pain; don’t use this technique if local tissue is acidotic/infected; used in dental procedures.
Field block technique
What technique is this?—look for sensory nerve with needle, patient feels paresthesia, inject local
Paresthesia technique
What technique is this?—look for motor nerve with needle, muscle contracts, inject local
Nerve stimulator technique
What is the most favored method for peripheral anesthesia today?
Ultrasound
Hypoechoic
Dark, muscles
Hyperechoic
White, bone
Anechoic
No reflection, fluid and blood
Which probe is preferred and good for superficial nerves?
Linear probe
Which probe is good for deeper structures but provides a poorer image?
Curvilinear probe
What does the nerve look like on ultrasound?
Honeycomb structure; seen on short-axis
What alignment is this?—longitudinal/long-axis; can visualize needle better but need good hand-eye coordination; can lose image easily with any slight movement
In-plane needle alignment
What alignment is this?—transverse/short-axis; preferred for peripheral nerve blocks and central venous cannulation
Out-of-plane needle alignment
What does the needle tip look like in out-of-plane needle alignment?
Looks like a bright white dot on ultrasound
What nerves comprise the brachial plexus?
C5-T1
What are 4 types of brachial plexus blocks?
- Interscalene block
- Supraclavicular block
- Infraclavicular block
- Axillary block
Interscalene block is used for ___ surgeries; NOT for surgery ___
Used for shoulder/upper arm surgeries; NOT for surgery at or below elbow
Interscalene block targets ___
C5-C7 roots
How can you achieve complete anesthesia of shoulder with interscalene block?
Supplement C3-C4
Caution using interscalene block in patients with ___ d/t possibility of phrenic nerve paralysis
Severe pulmonary disease (can result in dyspnea, hypercapnia, and hypoxemia
___ artery injection is a risk with interscalene block; what is a sign?
Vertebral artery injection; suspect if immediate seizure activity is observed
Interscalene block can cause what syndrome?
Horner’s syndrome—myosis, ptosis, anhydrosis (excessive constriction of pupil, lazy eye, and inability to sweat)
What lung complication is possible with interscalene block?
Pneumothorax
What nerve palsy can occur from interscalene block?
RLN palsy—hoarseness
Supraclavicular block is for surgeries at ___, NOT ___ surgeries
For surgeries at or distal to elbow; NOT shoulder surgeries
Supraclavicular block targets ___
C5-T1 divisions
Supraclavicular block has risk of ___ palsy in ~50% of patients
Ipsilateral (same side) phrenic nerve palsy
What syndrome can supraclavicular block cause?
Horner’s syndrome
___ artery puncture is a risk with supraclavicular block
Subclavian artery puncture
Supraclavicular block can also cause ___ and ___ (just like infraclavicular block)
Pneumo and RLN palsy
Infraclavicular block is for surgeries ___, NOT ___ surgeries
Surgeries at or distal to elbow, NOT shoulder surgeries
Infraclavicular block targets level of ___
Cords C5-T1
Axillary block targets ___ of brachial plexus
Large terminal branches of brachial plexus
Axillary block blocks ___
Entire arm distal to the elbow
What type of block is IV regional anesthesia?
Bier block
Bier block is good for ___ procedures
Short—45-60 mins; i.e.: carpal tunnel release
Bier block—tourniquet must be inflated for ___ minutes to avoid systemic toxicity
15-20 mins
Bier block—___ deflation of tourniquet
Slow incremental deflation
What are 4 contraindications for ALL brachial plexus blocks?
- Local infection
- Severe coagulopathy
- Local anesthetic allergy
- Patient refusal
___ and ___ are favored sites for blocks of terminal nerves
Elbow and wrists
Increased risk for ___ with regional blocks (like brachial plexus blocks) because the drugs are rapidly absorbed into the systemic circulation
Toxicity
Tibial nerve stimulation results in ___ of foot and toes; ___ of foot
Plantarflexion of foot and toes; inversion of foot (pushing foot down and inward)
Superficial peroneal nerve stimulation = ___ and ___ of foot
Abduction and eversion of foot (pushing foot outward)
Deep peroneal nerve stimulation = ___ of foot
Dorsiflexion of foot (flexing foot up)
What are 5 types of lower extremity nerve blocks?
- Femoral nerve block
- Sciatic nerve block
- Popliteal block
- Saphenous block
- Ankle block
What are 3 indications for a femoral nerve block?
- Anterior aspect of thigh procedure
- Superficial surgery on medial aspect of leg or below knee
- Knee arthroscopy*
What are 2 unique contraindications for a femoral nerve block?
- Previous ilioinguinal surgery (i.e.: femoral vascular graft, kidney transplant)
- Large inguinal lymph nodes or tumor
What are 4 contraindications for ALL lower extremity nerve blocks?
- Patient refusal
- Local infection
- Coagulopathy
- Neuropathy
Is neuropathy an absolute contraindication for a lower extremity nerve block?
No, but it definitely needs to be considered
What type of surgery would a sciatic nerve block be indicated?
Lower limb surgery
Sciatic nerve block is often combined with ___
Other blocks, i.e.: femoral
If doing a sciatic nerve block for the lower leg, it is preferable to go ___
Lower
What type of surgery would a popliteal block be used?
Lower leg surgery—especially foot and ankle
A popliteal block may require ___ coverage
Saphenous
Tendons of biceps femoris/semi-tendinosus muscle are ~ ___ cm from the popliteal fossa crease
~7cm
When would a saphenous block be used?
- Saphenous vein stripping/harvesting (for CABG)
- Analgesia for knee surgery in combo with other techniques
A saphenous block is typically used in combination with ___ nerve block to supplement medial foot/ankle surgery
Sciatic nerve block
*Popliteal block (used for surgery on foot/ankle) may also require saphenous coverage
When would an ankle block be used?
Foot surgery
