Anesthesia Flashcards
Pre-Op Eval for Anesthesia
- includes what specifics
- the airway exam includes what
Eval.
- full ROS
- allergies, meds
- exercise tolerance
- relevent family hx. and previous anesthesia & outcome
- review labs/imaging/consulation/tests
- PE: airway eval.
- ASA class designation
Airway Exam
- Mallampati score
- condition of feeth and length of incisors
- neck mobility and length and thickness
- tongue size
- facial hair
- thyromental distance
- ability to protrude jaw
mallampati score for the mouth and soft plalate eval.
Cormack-Lehane grade for the view of vocal cords
ASA Scores
I: normal healthy individual
II: mild disease without much limitation
example = smoker, social drinker, well controled DM/HTN
III: patient with systemic severe disease
example: poor control DM/HTn, COPD, BMI > 40 , heaptitis, ESRN, MI,CVA or CAD
IV: severe sytemic disease that is life threatening
example: recent MI/CVA/TIA, stents/CAD, severe ARDS, ESRD
V: moribound pt. not expect to survive without this operation
example: AAA rupture, massive trauma etc.
VI: organ harverst
E added if its an emergency procedure
Anesthesia
- 3 phases
specifics of Induction
Phases
- induction
- maintenance
- emergence
Induction = sequence of events to ease pt. to sleep/sedated
- pre-oxygenate them
- administer induction agent (the sleep med.)
- test lash reflex
- mask ventilate them to make sure it works
- adminsiters paralytic (stop breathing and msucles)
- intubate
RSI
- those with risk of aspirating (full stomach emergency)
- skip the vent test (taht could bring stuff back up)
- apply cricoid pressure
- use fast acting paralytic: succinylcholine and rocuronium
- intubate
Maintenance & Emergence Phase of Anesthesia
maintain anesthesia
- inhalation agent (volatile agents)
- propofol drip (TIVA)
- or both
treat pt. responsed through surgery & pain
maintain paralysis, watch fluids and hemodynamics
Emergence
- reverse paralytics
- give antiemtics
- turn off anesthesia
- get pt. to breath spon.
- remove airway device
what is MAC: Monitored Anesthesia Care
MAC: “sedation” cases
MAC can be combined with other anesthesias like…
- regional
- spinal
- epidural
Patient’s ability during MAC
- breathing on their own (through NC or airway)
- patient may move: in response to pain if not locally anesthetized
- pt. are “asleep” and dont remember
Benzodiazepines: for anesthesia use
- what are they
- specifics of midazolam
Benzos
- activate GABA in CNS: cause hyperpolarization and decreased excitiability
Pharm effects
- anti-anxiety
- sedation
- anterograde amnesia
- anticonv.
- muscle relax
- watch respirtory depression, hypotension and pain with injection
Midazolam
- used for amensia and anxiolytic
- anti-anxiety in prep and holding
- sendation for nerve blocks and line placements
- helpful adjuct for when heavy anesthesia cant be used
- caution in neruo and elderly pt
- REVERSAL AGENT = FLUMAZENIL
Agents Used for Induction: Propofol
Propofol
- most common induction agent
- can also be used to maintain anesthesia (TIVA)
- “milk of amensia” since its white and lipid-like
Uses
- GA induction and maitenance
- MAC
- subhypnotic infuction (to prevent PONV)
Side effects
- apnea, decreasd TV, mocard. depression and myoclonus
- vasodilation, hypotension
- pain when injected: give lidocaine
- hiccups
Agents used for Induction: Etomidate
Etomidate
- used to induce anethesia: minimal effect on cardiovascular function: thus HR, CO, SVR, PAP, BP remain unchanged
- good for trauma and bad heart pt.s
Side Effects
- more PONV than propofol
- pain on injection
- HPA axis suppression for a few hours
Agents used of Induction: Ketamine
Ketamine
- dissciative amensia
- rarely used: but could be : this is the only agent WITH analgesic properties
USes
- ERAS protocol
- chornic pain
- those with opiod misuse disorder
- commonly an adjuct with GA
Effects
- no significant respiratory depression
- hallucinations, out of body effect (give with medazolam)
- salivation, increade HR and BP and ICp = side effects
Inahled Anesthestics
halogenated hydrocarbons
- create immobility (SC) and amnesia (in brain)
Minimum Alveolar Concentration (MAC) of inhaled
- concentration required to suppress movement in approx 50% of pt.
- allows use to understnad how much is needed
How they work
- intake in the lungs & to circulation & elminiated via lungs
- speed of induction and speed of emergence depend on tissue cncentration, minute ventilation and CO
Inahled Anesthetics: common ones
Sevoflurane
Desflurane
Isoflurane
Sevoflurane
- MC
- also a bronchodilator : can be used
Desflurane
- fast on/off but can irritate lungs
- $$$
- less potent
Isoflurane
- slower on/off
- good for cardiac surg.
side effects of volatile anesthesics
- hypotension (vasodilation)
- increased RR and decreased TV
- bronchodilation
- airway irritation
- muscle relaxant
- hepatic injury
- increase ICP if > 1 MAP
- can interfer with evoked potentials of neuro monitoring
Malign
use of Nitric Oxide gas
use in conjunction with other anesteic gases cannot be a single agent
Use
- will increasethe amount of the other gas in the lung to increase effectiveness = second gas effect
Watch out of
- expansion of airpockets elsewhere in body (bowel, brain, vessels)
Malignant Hyperthermia
a skeletal muscle disorder: ryanodine receptor = uncontrolled release of Ca2+ from SR
this triggers a hypermetabolic syndrome = death
- mucle contration/rigitiy
- rhambdo.
- metabolic and respiratory acidosis
- hypercarbia & tachycardia
- hyperthermia
- hemodynaic intability
Triggered by
- halogenated anesthesics
- succinylcholine
Signs
- unresponsive to increase MV with creeping up ETCO2
- tachycadia and pnea
- HTN
- muscle rigitiy + masster spasm
- hyperthermia (last sign)
Treatment of malignant Hyperthermia
- stop the surgery
- filter Co2
- hyperventilate
- IV dantrolene or ryanodex reconstitued
- ABGs
- bicarb for acidosis
- active cooling
- treat hyperkalemia and dysarrithmias
Opioid Use in Anesthesia
mu agonists = to decreased NT or inhibit excitatory NTs
Effects
- analgesics
- drowsy
- euphoria
Adverse
- constipation
- resp. depression
- bradycardia
- urinary retention
Opioid meds used in anesthesia
Fentanyl
-most common for analgesics = potent
helpful for maintaining hemodynamic stability
remifentanil
- rapid onset and short duration
morphine
- triggers histamine release with it: ithcy
- slower onset
- active metabolite: watch in reanl pt
hydromorphone
- more sedating, longer acting that fetanyl
Neuromuscular Blockers
two classes and meds in each
Depolarizing Muscle Relaxants
- succinylcholine
Nondepolarizaing Muscle Relaxant
- Rocuronium
- vecuronium
- cisatracurium
Twitch Monitoring
useful to look at the electrical impulses of the muslces during surgery
measure train of four
in a phase I Block: succylncholine
- all same strength as the depolarizing agent slow decreased the future flow of APs
in phase II Block: other
- a stepwise progression of decreased polarization as its blocking the reuptake from occuring as well
90% or higher = full strength
Succinylcholine
use as a muscule relaxant
Succinylcholine
- depolarizaing
- rapid onset = complete paralysis in 60 seconds but SHORT duration
- every wuicker onset at the larygneal muscles: so its used in induction
LOTS of Side Effects
- malignant hyperthermia
- HYPERKALEMIA
- lots of others
Rocuronium
muscle relaxant
Rocuronium
- steroidal compound
- most common nondepolarizing agent
- good intubation conditions in 45-90 seconds
- not used over succinycholine for RSI because succlynicholine has a more rapid metabolism and doesnt need a reversale agent to stop its effect, it wears off quick
Vercuronium & Cisatracurium
muslce Relaxant
Vercuronium
- steroidal compound
- longer action than rocuronium
- elimiated by liver
Cisatracurium
- intermediate acint
- elimiated in plasma not liver
- histamin release
- god for renal pt.
Reversal Agnents: for Emergence
Acetylcholinesterase inhibitors
- Neostigmine preferred
- edrophonium
- pyridostigmine
- they inhibit breakdwon of ACH to increase amount at NMJ
- increase ACH time in cleft
- changes the receptor: agonist ration
CEILING EFFECT
- a finite amount of cholinesterase to breakdown ACH - tus these can only block so much
- thus; if theres too much of the NMB med in the junction: this cant help
- need some natrual wearing off
NMB Reversal Agnet: Neostigmine
Neostigmine
- most comonly used
- 5mg ceiling
- paired with glycopyrrolate: to decreased peripheral effect on HR
- **can only be adminsitered when > 40% of train of four ratio*
NMB Reversal: Sugammadex
reversal agent for rocuronium and vecuronium
- NO ceiling effect
- larger moecule: doesnt go to NMJ: binds to free drug in plasma as they’re diffused away from NMJ
recovery in 3 mins with this
fastest reversal
Minimal SE
- N/V
- HA
- HTN
- doesnt linger as long
Local Anesthetics
these drugs works to block sodium channels and block the AP
Aminoamides
- lidocaine, bupivacaine, etc.
Aminoesters
- procaine, tetracaine, chlorprocaine
- these are more likely to cause allergic rxn
higher concentration = deeper effect the block will be
DUration of Action
- depends on blood flow to area (more flow, shorter time)
- protein binding
- addition of epi: vasoconstricts to decrease flow and increa time
why add epi?
- longer action
- able to detect intravascualr injection if you hit systemic: get systemic effects (when you want local)
Lidocaine specifics
Bupivacaine specifics
Exparel specifics
Lidocaine
- rapid onset and intermediate length
- can be given IV for anesthesia
- cannot be given spinal: cauda equina
Bupivicaine
- slower onset
- longer duration
- better pain block than motor block
- cardiotoxic!!!
Exparel
- prolonged 3+ day blockade
- cannot mix with other forms (lido or bupivacaine)
Local Anesthetic
- what is highest abosrbtion route of admin
- what is local anestheic toxicity
- signs of toxicity CNS and CV
IV = highest absorbtion
subcut = lowest (most often used)
Toxicity
- CNS toxicty: BBB rarely crossed with these
- canbe caused by systemic absorbtion or accidental intravascualr injection
- bupivacaine is higher risk
Signs of Toxicity (CNS)
- ringing in ears, metalic taste
- slurred speech and face tingling
- restlessness and seizure
Cardiac toxicity: takes more drug to created CV toxicity
- bupivacaine highest risk
Symptoms of Toxicity (CV)
- hypotension
- prolonge PR and widen QRS
- cardiovascualr collapse
Treatement of toxicity
- prevent it
- intralumen lipid = reversal agenet
nerve blocks of the arm
location and waht they cover
interscalene
- shoulder surgery and upper arm
- watch PTX and phrenic nerve
Supraclavicualr
- good for all upper extremity except shoulder
Infraclavicaulr
- good for distal to elbow
Axillary
- good for distal to elbow
Femoral Nerve Block
saphenous
popliteal
Femoral
- anteiro thigh and knee procedures
- combined with sciatic
Saphenous
- only sensory to medial lower leg
- combined with siatic
Popliteal
- good foot and ankely surgery
- combine with adductor canal or femoral for bloew the knee coverage
Neuraxial Anethesiad
epidural v spinal
NeuraxialBlock
- at the nerve root: blocks all sensation and motor at and below
Spinal
- injected into subarachnoid space: CSF where all the spinal nerves are
- fast onset
- dense block
Epidural
- larger volume into the epidural space
- slower onset
- has to diffuse though the layers from epidural inward
- mostly a sensory block, minimal motor blocking
