MAC - Exam 3 Flashcards
Leading cause of death and severe nervous system injury during MAC
hypoxia from suppression of spont respiration from sedatives
Risk factors for burns around head and neck from MAC
-electrocautery
-O2
-alcohol prep
-flammable drapes
Which of the following anesthetic agents provide amnesia, analgesia, anxiolysis and hypnosis with an acceptable margin of safety and ease of titratability for MAC?
none
T/F MAC defines the continuum of depth of sedation
false
“Nonanesthesia sedation practitioner” =
physician, dentist, podiatrist who have training and licensure to give MODERATE sedation
Nonanesthesia providers should not intend to attain a level of sedation in which a pt is _
unresponsive
T/F If pt loses consciousness and ability to respond purposefully, it is then considered GA regardless of whether airway instrumentation is required
PER BARASH: true
-Holly gave us a similar question that was dicey, pt needed airway help but didnt mentions ability to respond and answer was “deep”; she also said to forget about it tho…
Unlike MAC, “moderate sedation/analgesia” is a service directed by _ who are preoccupied in focusing on successfully completing procedure
proceduralist
T/F MAC should be subject to same lvel of payment as GA or regional
true
Per ASA, MAC should be requested by the _ _ and be made known to the pt in accordance with accepted procedures of the institution
attending physician
Per ASA, MAC services include:
-performing preanesthetic eval
-prescription of anesthetic care
-participation in entire plan of care
-continuous physical presence of anesthetist
-proximate presence of anesthesiologist for emergencies
-usual noninvasive cardiocirculatory and resp monitoring
-O2 administration PRN
-admin of necessary pharm therapies by the judgment of anesthetist
Conditions that make pt a poor MAC candidate (lots of gray areas, remember!)
-CV disease (pulm HTN)
-ANXIETY (claustrophobia, etc; NEED AIRWAY PLAN)
-Chronic pain (narcotic use)
-OSA (NEED AIRWAY PLAN)
-Morbid obesity (NEED AIRWAY PLAN)
-Chronic renal/ hepatic failure
-Adv. chronic lung disease
-Elderly (>70y)
-ASA III or IV
-Use of opioids, sedatives, or rec drugs
-pt doesn’t want MAC
-pt cant lay flat/still
-dementia or cognitive dysfunction
-tremors
NO MAC ; not a gray area
-Asp risk (NPO status, obese, esoph conditions, symptomatic GERD)
-Diff airway(hx neck radiation, limited mouth opening/neck extension, oropharyngeal issues)
-poor pt access for CRNA (head/neck cases, prone, etc)
Risk factors for difficult mask vent:
-beard
-mallampati III or IV
-hx of snoring
-limited mandib protrusion
-etc (y’all know the rest)
T/F MAC pts don’t need to fast
false!
should follow GA guidelines for fasting
-high asp risk = poor MAC candidate
3 reasons verbal communication is vital during MAC
-helps monitor cardiorespiratory function (also if sedation needs titration)
-explain to/reassure pt
-talk when pt is needed to cooperate
General things to consider for MAC
-depth of sedation needed (paralysis?)
-case length (tourniquet time)
-fire risk
-ease of airway accessibility
Factors that will halt procedure/ risk pt safety and require switch from MAC to GA
-combative pt/ not staying still/ AMS
-resp depression causing hypoxia or CV compromise (hypercarbia, coughing)
-aspiration
-loss of IV access
-increased sedation needs
-regional anesthesia failure
-procedure complications (prolonged time, surgeon request)
Things to tell pts about possible MAC procedure:
-they can say yes or no to this
-may be awake, slightly sedated, AWARE, responsive, have memories, have to participate
-we CANNOT promise amnesia and hypnosis
-possibility of conversion to GA for their safety
Define MAC
an anesthesia service in which and anesthesia provider continuously monitors and supports the patient’s vital functions, diagnoses and treats clinical problems that occur, administers sedative, anxiolytic, amnestic, or analgesic medications, and coverts to GA PRN
Is a primarily regional case considered MAC?
NO
-principles of sedation for MAC will apply to regional tho
When non anesthetist gives moderate sedation it is moderate sedation and when an anesthetist gives moderate sedation it is _
MAC
PAUSE. Stop for a sec and imagine 3 doors in your head. Behind each door is a version of you, 3 years in the future, happy, thriving. What are you doing behind those doors?
Know that this career you’re busting your ass for will open those and many other doors you can’t even imagine yet. You didn’t make it this far to only make it THIS far. YOU GOT THIS! Now go give NA 1 some hell. <3
Continuous visual, tactile, and auditory assessment of physiologic function during MAC involves
-observing rate, depth, pattern of respiration
-palpation of arterial pulse
-assessment of peripheral perfusion via temp, cap refill, diaphoresis, pallor, cyanosis, shiver, AMS
T/F Use of only qualitative measurement of oxygenation is mandated by ASA standards for intraoperative monitoring
false, BOTH qualitative and quantitative
_ usually precedes cardiac arrest in MAC cases
cyanosis
Risk factors for arterial desaturation during MAC:
obesity
pre-existing upper airway obstruction
pre-existing resp disease
increased metabolic rate
GA
age extremes
surgical site
pt positioning
sedatives/opioids
protective airway reflexes
_ events constitute the single largest source of adverse outcomes in MAC cases
respiratory
Which main airway monitoring tools are crucial for preventing respiratory events in MAC cases?
pulse ox and capnography!
-all MAC cases should have both
Desaturation signs could be delayed with supp O2, what would help you catch these signs early during a MAC case?
Capnography!
-in most if not all cases really
-resp depression is 17.6 x more likely to be caught while using cap
-catches obstructions, apnea, other events quicker than you can
T/F You can’t monitor capnography during MAC cases
false
-should absolutely do this!
-sidestream capnography exist that works w NC, face masks, and nasal airways FOR MAC
EKG must be displayed _ and BP measured/recorded Q _ min at a minimum for MAC cases
continuously
5min
Pulse should be monitored in MAC cases in at least one of 3 ways:
-ascultation
-palpation
-pulse ox
T/F It is an ASA standard for any pt receiving anesthesia to have temp monitored when clinically significant changes in body temp are intended, expected, or suspected.
true
T/F Hypothermia is less of a risk with MAC cases
false, just as prevalent
-shivering, behavior changes and vasoconstriction can still happen
Without reliable temp monitoring, possible first indication of hypothermia could be _
shivering
-late sign
Sensation of _ could be a first indicator of hypoxia, hypercarbia, cerebral ischemia, LAST, and myocardial ischemia in MAC cases
hyperthermia
Minimal sedation =
-normal response to verbal stim
-airway, spont vent and CV function are unaffected
Moderate sedation(AKA conscious sedation) =
-purposeful response to verbal or light tough stim
-airway, spont vent
-CV function are preserved
Deep sedation =
-purposeful response to REPEATED or painful stim but may lose response to verbal or light touch stim
-COULD need help with airway patency
-CV function maintained usually
GA=
-pt is unarousable to painful stim
-airway support is REQUIRED and spont ventilation is usually inadequate, needing PPV
-CV function could be altered
Ramsay Sedation Scale (RSS)
-what inspired the creation of the RASS scale
-observed sedated ICU pts
-6 levels; 3 w pt awake, 3 w pt asleep
Richard Agitation Sedation Scale (RASS)
-assesses LOC and agitated behavior in ICU pts
-10 levels, 3 steps:
observation
response to auditory stim
response to physical stim
-high interrater reliability
-not used much in procedural sedation
Modified Observer’s Assessment of Alertness/Sedation Scale (OAA/S scale)
4 areas of observation:
-responsiveness, speech, facial expression, eyes
score 1= deep sleep, score 5= alert
-USED FOR PROCEDURAL SEDATION(mods by ASA)
BIS and EEG have limited ability to evaluate pt response to anesthesia/sedation when pt has neuro deficits such as:
-aphasia
-deafness
-paralysis
BIS has been shown to correlate with _ scale during propofol induced sedation for regional anesthesia
OAA/S
Typically, lower BIS number, more _ pt is.
sedated
-typically absence of recall assoc w BIS <80 (BARASH) or <60 (Anesthesiology?)
-BIS can vary depending on meds given so not perfect
BIS target for MAC=
60-80
BIS target for GA=
40-60
T/F Isolated hypoventilation requires large increases in supp O2 to restore O2 sat to adequate levels
false, MODEST, not significant
-only in isolated hypoventilation, not pt w resp disease/complication
T/F A pt may have significant underlying alveolar hypoventilation despite acceptable O2 sat and minimal O2
true
-hence why we like capnography
A normal A-a gradient is _ which is low. If it becomes higher, this could indicate a _.
10mmHg
shunt
T/F My patient is not requiring supp O2 in MAC case so I don’t need to monitor capnography
false!!!
Most common equipment related problem in MAC cases:
cautery fires around head and neck
Fire risk score components=
-heat
-fuel
-O2
Key risks for fire in OR (1 point each, 3pts = high fire risk)
-surg site/ incision above xiphoid
-open O2 source (supp O2)
-ignition source (electrosurg unit, laser, FIS, cautery)
-score 3= all 3 present
-score 2= procedure is in the thoracic cavity, the ignition source is remote from an open oxygen source, the ignition source is close to a closed oxygen source, or no supplemental oxygen is used.
-score 1= just supp O2
2nd most common cause of injury in MAC cases:
cautery fires
-really?!
Factors contributing to fire risk
-supp O2
-cautery
-alcohol prep
-flammable drapes
-drapes tenting with O2 inside
Fire risk prevention:
-avoid tenting drapes, open face draping
-lowest acceptable supp O2
-using compressed air instead of O2 to prevent CO2 accumulation
-stop O2 flow for 60sec before cautery
-avoid alcohol prep solutions
-awareness of fire causes
Venturi masks and fire risk:
-causes entrainment of O2 rich gas if under drapes
-just avoid this mask if cautery will be happening near face
Pain agitation may be the result of:
-pain
-anxiety
-hypoxia
-hypercarbia
-impending LAST
-cerebral hypoperfusion
-noxious stim like temp extremes, itch, full bladder, IV infiltration, prolonged pneumatic tourniquet
Continuous infusions are generally _ to intermittent bolus dosing. Why?
superior
-They produce less fluctuation in drug concentration, reducing number of episodes of inadequate or oversedation and prompts sooner recovery
After IV admin of drugs, distribution occurs simultaneously to the vessel-rich groups and tissues like _ and _
muscle and skin
-fat and bone is later and accumulate there if lipophilic; could cause delayed recovery if takes a while to redistribute back to central compartment
Elimination half life is only reliable in _ -compartment pharmacokinetic models because only factor changing drug concentration in these models is elimination
single
T/F In multi-compartmental pharmacokinetic models useful parameters include: elimination half life, distribution half life, distribution volume, intercompartmental rate constants etc.
false, these are not reliable, play a minor role
-context sensitive half time is more useful
During early parts of infusion of lipophilic drugs, distributive factors _ plasma concentrations as drug is sent to unsaturated peripheral tissues, then _ infusion is discontinued, drug will return from peripheral tissues and re-enter central circulation.
decrease
after
Context sensitive half time (CSHT) =
time needed for plasma drug concentration to decline by 50% AFTER stopping infusion of particular duration
-a function of the LENGTH of infusion too
Context sensitive half time reflects the combined effects of _ and _ on drug disposition
distribution and metabolism
T/F The context sensitive half times of all drugs bear constant relationship with their elimination half times
false
-ex) fentanyl has shorter elimination half life than sufentanil but its context-sensitive half time is much longer than sufentanil after 2 hr, lasts in system longer
T/F Context sensitive half time is significantly increases in propofol and thiopental
FENTANYL and thiopental
- not propofol; despite lipophilic nature and slow return from peripheral tissue, context sensitive half time is short due to its rapid metabolic clearance
T/F context sensitive half time helps determine how long it will take for pt to recover from MAC
false; partly
-effect site (brain) concentration decay describes this
-CSHT only describes how long it will take for plasma concentration of drug to drop by 50%
-pt still has 50% of drug left in plasma
Awakening from MAC anesthesia is usually a function of:
effect site (brain) concentration decay
AKA when drug leaves effector site!
-CSHT , length of infusion, and cardiac output can play a role
-can show a variable time lag behind changes in plasma drug concentration
The delay in onset of drug effects upon IV injection is the result of
distribution
t1/2ke0 is the half-time of equilibration of drug concentration in blood and effect.
The shorter the t1/2ke0, the _ delay of onset it has due to it _ equilibrating with the brain.
shorter
rapidly
-allows for predictions of time course of equilibration of drug between blood and brain
-help determine bolus spacing so drugs reach peak effect without needing to rebolus
-peak effect time does NOT = t1/2ke0
Drugs with short t1/2ke0:
Thiopental
Propofol
Alfentanil (1.1 min)
Drugs with long t1/2ke0:
Midazolam
Sufentanil
Fentanyl (6.4 min)
A low cardiac output will _ drug arrival to site of action
delay
What dangerous effects does pre-existing or iatrogenic low cardiac output have the potential to cause if blood flow is reduced to typical redistribution sites for a drug?
-delayed drug effects
-prolonged drug effects
Plasma concentration of a drug at steady state needed to abolish purposeful movement at skin incision in 50% of pts (like MAC for volatile anesthetics) is its _
CPss50
In MAC cases, the max benefit of opioid supplementation in terms of potentiation of other sedatives will accrue when opioid is used in its _ dose range
analgesic
-~(0.6ng/mL)
-can reduce CPss50 of prop by 50% when used in conjunction with it
-can also increase risk of cardiorespiratory interaction
During MAC cases, using midazolam and fentanyl can put pt at high risk for
hypoxemia and apnea
-SYNERGISTIC! (this helps reduce CPss50 doses but comes with risks)
Goals of MAC:
-sedation/ hypnosis
-amnesia
-anxiolysis
-analgesia (consider how painful, stimulating procedure can be)
-minimize N/V, cardiorespiratory depression
-avoid delayed emergence
-just like GA but may have quicker recovery/discharge
T/F The rapid awakening from propofol is due to its metabolism primarily
false!
-while liver metabolizes it quickly, its rapid REDISTRIBUTION is the main cause
T/F The rapid onset from propofol is due to its rapid redistribution primarily
false, DISTRIBUTION for onset and redistribution for awakening
-redistribution is when drug goes from central compartment to peripheral
How to prevent propofol from burning on injection:
-use big vein (AC instead of hand IV)
-pretreat/mix with Lido + prox venous occlusion
-slow inject
-cool or give cooled saline (4*C) prior to injection
-dilute with 5% glucose or 10% intralipid
-inject into fast-running IV line
-DC IV fluid admin during injection?
-pretreat w opioid
Propofol can help with N/V when given in _ doses, especially with antiemetics
subhypnotic (~10mg)
Benefits of propofol for MAC
-fast on/off (short CSHT)
-easily to titrate to can convert to GA with an infusion or wean off and quickly recover
-better hypnotic than midazolam
-antiN/V
What is an ideal medication to treat anxiety during MAC?
Midazolam
-remember hypoxia and hypercarbia can also cause anxiety, treat the right cause
What does Midazolam give and what does it not give?
-anxiolysis, amnesia, hypnosis/sedation (high doses)
-does NOT give analgesia
Midazolam is best given in small doses of _-_mg IV before going to OR or for short MAC cases ~ _ mins in length.
0.5-2mg
15 mins
Midazolam is’t great for longer cases and repeat doses bc it can cause:
-confusion
-prolonged sedation
-amnesia
When is midazolam contraindicated in MAC?
-long MAC cases (longer than 2hr-just do GA)
-as sole anesthetic
-old pts (can give 50% of dose if necessary)
-children or pregnant pts
-if pt is anxious due to hypoxia, hypercarbia, or LAST
-when prop is being used(prop is usually enough)
Most popular med for hypnosis during MAC?
propofol
Short MAC case=
~15 min give or take
Long MAC case =
~2hr give or take
-prolly just do GA at this point
Which MAC method gives faster recovery, boluses or infusion?
infusion
Novel techniques for MAC:
Target controlled
-uses pt demographics to dose -age, wt, ht
-not yet FDA approved in US due to varying pharmacokinetics?
Closed loop delivery systems
-use single or multiple inputs (BIS, BP, etc) to control single or multiple outputs (rate of admin)
T/F Considering age when giving midazolam, the difference in dose requirements for elderly pts is primarily related to pharmacokinetics
false,
pharmacodynamics
The effects of midazolam can recur after _ mins following flumazenil
90
-don’t prematurely discharge pts who were reversed!
Midazolam binds to and activates the _ receptors
GABA
Remimazolam (from Barash, not Holly ppt)
-MOA
-metabolism
-elimination
short acting IV benzo
-activates gamma aminobutyric acid A (GABAa)
-is metabolized by nonspecific esterases
-albumin bound and excreted in urine
Remimazolam (from Barash, not Holly ppt)
-MAC recovery time
-reversal
5-20 min recovery
flumazenil
Remimazolam (from Barash, not Holly ppt)
-dose
initial: 0.2mg over 1 min
-repeat 0.2mg if desired LOC not achieved in 45 sec
-keep repeating PRN Q 1 min up to 1mg
What should you treat pain with during MAC cases?
-opioids or LA
When are opioids indicated in MAC?
-part of a balanced anesthetic (think about goal for pt)
- when regional or LA isn’t appropriate for procedure
Most common opioid used for MAC
-fentanyl
-alfentanil
-remifentanil (common infusion opioid-avoid bolus)
-typically used prior to painful/invasive technique
-if needing long-acting pain relief shoot for LA
Remifentanil has similar pharmacodynamic properties as other _ opioid receptor agonists but is metabolized by _ _
mu
non-specific esterases
-great for hepatic/renal impaired pts
Why give Remifentanil over infusion rather than bolus?
-infusion helps have tighter control of analgesia, improves conditions for proceduralist, and helps minimize resp depression
-if bolused, increases risk of cardiorespiatory effects such as chest wall rigidity and respiratory depression; if must give bolus, give over 30-90sec
CSHT and effect site equilibration time of remifentanil
CSHT: 3-5min
effect site equilibration time: 1-1.5 min
Good uses for Remifentanil
-analgesic component of sedation for LA and regional
-well suited for MAC cases
Good additions to remifentanil:
-midazolam (remember to give 1/2 dose remi with this; increased pt satisfaction, increased amnesia, decrease N/V, decreased anxiety)
-propofol
What is typical infusion rate change for remi, upward limit and how is it supplied?
adjust rate in increments of 0.025mcg/kg/min
upward limit of 0.2mcg/kg/min
supplied as powder, must be reconstituted
;Ketamine indications
-analgesia
-sedation/hypnosis
-amnesia
NO anxiolysis
Ketamine MOA
-blocks NMDA receptor, phencyclidine derivative
-dissociative state, nystagmus, high CV safety profile, airway reflexes
Ketamine
Pro tips
-give with versed to prevent hallucinations
-give with glyco 0.2mg IV to prevent secretions
Ketamine
-side effects
-contraindications
-pt may move still
-secretions
-hallucinations
CI: psych history, glaucoma, open-globe injury (increases IOP and ICP)
Ketofol
-pros
-balance each other’s side effects out pretty well
-analgesic ketamine reduces dose of propofol needed for procedure
-lower incidence of resp side effects
-decrease N/V
Dexmedetomidine
-MOA
selective alpha 2 receptor agonist
-depresses central sympathetic function resulting in sedation and analgesia
-“natural sleep”
-potentiates benzos, opioids, GA
Dexmedetomidine
-indications
sedation/hypnosis
analgesia
-“unreliable amnesia”
-help sedate for intubating diff airway
Dexmedetomidine
-pros
-resp stability (but decreases patency of upper airway
-decrease CMRO2
-“light”, natural sleep
Dexmedetomidine
-cons
bradycardia
HoTN
decreased CBF
onset 5-10 min
long half life
Most common cause of death during MAC is
excessive sedation leading to respiratory compromise
On insp, upper airway is subatmospheric, tending to collapse. Which mechanisms prevent this?
upper airway dilator tone (increase diameter and reduce compliance of upper airway JUST before diaphragm contracts)
Sedative doses of _ can increase inspiratory subglottic airway resistance 3-4x and selectively suppress genioglossal muscle activity more than diaphragmic
benzos
-even more in elderly pt and COPD bc lack resp reserve to increase WOB
-risk for obstruction
T/F All sedative drugs reduce ventilatory responsiveness
false
-opioids (esp with benzos) and sometimes regional do
Complete recovery of swallow reflex occurs about _ min after return of consciousness from propofol but is significantly depressed for _ hrs after midazolam emergence
15min
2hr
For MAC cases and pts with high risk aspiration:
-try to keep as light as possible, NO PROPOFOL
-if pt can’t protect own airway/ recognize regurg, just intubate and go GA
Laryngospasm occurs usually from stimulation of the laryngeal mucosa sitting _ to the vocal cords excite the _ nerve via the internal branch of the _ _ nerve
superior
vagus
superior laryngeal
Motor response once laryngospasm is trigger is:
From RLN:
1. lateral cricoarytenoids contract and ADDuct/ medially rotate arytenoid cartilage
- thyroarytenoid muscles shorten vocal cords and cause glottic closure
From SLN
3. Cricothyroid muscle tenses VC via external branch of SLN
-splanchnic nerve may play a role too?
Laryngospasm closure can occur in 3 places:
-true vocal cords
-aryepiglottic folds
-vestibular folds
Laryngospasm is more common in young or old pts?
young
PPV helps break a lot of laryngospasms but if there is a complete closure can resist as much as _mmHg
140mmHg
-wow, will def just inflate stomach
How can hypercarbia help a laryngospasm?
depresses adductor activity with hypercarbia and severe hypoxemia (PaO2<50mmHg) inhibits laryngospasm eactivity
Definitive tx for laryngospasm:
sux or NDMR to paralyze
-don’t use 1st but use earlier than later to prevent a lot of harm
Why should you have emergency rescue meds ready with MAC cases?
risk of cardiac events increase, poss risk of resp depression, etc
Factors that can cause BP derangements and arrythmias during MAC cases:
-decreased arterial volume from NPO status
-vagal cardiac reflexes (oculocardiac reflex and trigeminovagal reflex)
-poor pain control
-poor sedation depth
-anxiety
-fluid overload
Pts most likely to suffer effects of LAST during MAC cases:
pts who weren’t fit for surgery -elderly, comorbidities, frail
LAST s/s
-increasing concentrations
Low:
-sedation and numbness of tongue and circumoral tissues
-metallic taste
-tachy/high BP
Increasing:
-restlessness, vertigo, tinnitis, difficulty focusing
High:
-slurred speech, skeletal musc twitching, tonic-clonic seizures, cardiac s/s - brady, low CO (sometimes seen 1st)
Things that can contribute to LAST in MAC
-low CO from other drugs decreasing hepatic flow and increasing amount of LA in serum
-hypercarbia sending more LA to brain and also potentiating cardiovascular toxicity of LA
-sedatives impairing pt ability to communicate something is wrong
Non-OR anesthesia (NORA) comes with challenges such as:
-unfamiliar room set up/ equipment
-poor lighting
-lack of resources or personnel
-room layouts impeding pt access
none of these excuse adverse events
Titrate sedation for MAC by :
pt ability to follow commands
T/F For deep sedation, ASA recommends an independent provider, different from person performing procedure, be dedicated to giving sedation and monitoring pt
false, ASA REQUIRES this
T/F Education and training providers for sedation is required
false, just recommended
-haha wtf
T/F With deep sedation ASA recommends a BLS trained person should be in the room
False,
ACLS, and they should be able to place an airway and maintain oxygenation and ventilation
Pts who should have a consult before going forward with sedation and analgesia with NONanesthesiologists
-uncooperative pts
-age extremes
-severe cardiac, pulmonary, renal, hepatic, or CNS disease
-morbid obesity
-OSA
-pregnancy
-drug/alcohol use disorders
CMS defines people who can provide deep sedation as:
-physician anesthesiologists
-MD/DO
-dentists
-oral surgeon
-CRNA
CAA
-nonanesthesiologists must get extra training
Which 2 types of sedation fall under “analgesia” services:
minimal and moderate
ASA mandates which drug restrictions for deep anesthesia:
-propofol, ketamine, and etomidate
-strictly for the use of deep sedation so only qualified personnel can use
LAST CPR
-initial priority
airway management
-want to prevent hypoxia and prevent resp and metabolic acidosis which would potentiate LAST
LAST CPR
-most important factor during
high quality CPR to perfuse heart and move around lipid to reduce LA concentration
LAST CPR
-why give less epi?
give doses <1mcg/kg bc it will increase afterload and impair gas exchange
-will cause unwanted vasoconstriction in small vessels too (leaving more LA in brain/heart)
LAST CPR
-drugs to avoid
-Epi (only give small doses <1mcg/kg)
-Lidocaine (obv)
-Vasopressin
-Procainamide
-CCB (cardizem, verapamil, nifedipine)
-beta blockers
LAST CPR
-first choice drug for Vfib/pulseless VT unresponsive to CPR, defib and vasopressor therapy
Amio
LAST CPR
-CPR may be prolonged and require:
VA-ECMO
LAST
-MOA
-reduces Na+ influx via v-gated ion channels from increasing energy barrier and steric hindrance, this happens from WITHIN cell and requires the LA to go thru lipid bilayer 1st
-also blocks Ca++ ion channels, protein kinase signaling for TNF-alpha and carnitine-acylcarnitine translocase in mitochondria (this seems extra)
LAST
-cardiac toxicity is from:
electrophysiologic and contractile dysfunction
LAST can occur at levels lower than expected because it accumulates in the _ and _ tissue 6x greater than the plasma
mitochondria and cardiac tissue
Most cases of LAST happen within _ but could be delayed more than _
1 min
1hr
Which LA has an increased risk of toxicity?
Bupivacaine
-more lipophillic
Where does LA usually “depot” in LAST?
skeletal muscle
Highest incidence of LAST occurs with _ _, then upper extremity, trunk, and lower extremity.
paravertebral blocks
Pts with a decreased serum level of _ are at risk of it indirectly increasing the level of LA causing LAST
albumin
-malnourished, liver/kidney failure
3 pillars of LAST tx:
-seizure management
-ACLS
-prompt admin of 20% lipid
You give your pt regional anesthesia and a few minutes later, they are seizing but VS are otherwise stable. Do you give them a benzo or propofol to help with the seizure?
Benzo-versed
don’t give prop bc CV effects may not have come yet and you will bottom them out more easily
Interlipid
-MOA
-scavenging effect, pulls LA with it and distributes it to sites where it can detoxify (fat)
-increases CO by increasing volume and direct cardiotonic effect that help restore CO once drug level drops below its ability to block ion channels
When to give Interlipid for LAST?
-given at earliest signs of LAST to improve resuscitative efforts
LAST
-prevention
-using US
-intravasc markers
-incremental injection w/ frequent aspiration
-less toxic drug and dose if poss
-TEST DOSE EPI 10-15mcg (if intravascular will see HR rise 10+ bpm and/ or SBP rise 15+mmHg)
Roughly _% of LAST cases are atypical and you will only see CV s/s first or will have delayed CNS s/s
50%
Lipid dose
-bolus and infusion
B: 1.5mL/kg IV
I: 0.25mL/kg/min (“JUST GIVE WHOLE BAG!”-Holly)
Fire protocols
-Anesthesia provider
-ensure full syringe of saline is nearby for oral cavity cases
-document O2 conc and flows
-use MAC circuit for O2 initially at FiO2 30% using FGF 12L/min
Is MAC right for this pt?
“after my last anesthetic my throat was sore, they said they had a hard time getting tube in”
Hell na
Is MAC right for this pt?
Airway eval= MP4, MO<2FB, TMD <6cm
NO!, MP4 is sketchy
Is MAC right for this pt?
Urgent EGD from hemopysis, ate lunch 4hr ago
Nah
Is MAC right for this pt?
“I was awake and heard everything last time they did my colonoscopy” >:(
Educate them why that was normal, yeah they can have MAC
Is MAC right for this pt?
After preop eval for cataract surg, you find out the pt has claustrophobia and is anxious AF
NAH
Is MAC right for this pt?
After preop eval for cataract surg, you find out pt is a little anxious
How anxious tho….. prolly no
Is MAC right for this pt?
Pt is acutely intoxicated and need foreign body removed from hand
nope
Is MAC right for this pt?
82 yo with stable Afib, in for a TEE/CV
yes
Is MAC right for this pt?
Pt has decompensating CHF
HELL NAW
T/F If primary anesthetic for a case is regional, this is considered MAC
FALSE
