taxonomy of an anesthetic/MAC Flashcards
anesthesia definition
a drug-induced reversible depression of the CNS resulting in loss of response to and perception of all external stimuli
not simply a deafferented state
-amnesia and unconsciousness also important
components of anesthesia
- amnesia
- analgesia
- immobility - muscle relaxation
also unconsciousness
attenuation of autonomic response to noxious stimuli
types of anesthesia
- monitored anesthesia care
- general anesthesia
- regional anesthesia
room prep
- gas machine
- suction
- monitors
- OR table/arm boards
- warming devices
- all equipment needed for case
- set up cart
what are all the things you need to do pre-op
pre-op visit pre-op orders pre-op notes consultations anesthesia care plan
what do you do during a preop visit
identify surgical procedure med history physical exam develop plan (ASA status, choice of technique) informed consent preop note
what are the goals for pharmcologic premed
anxiolysis sedation analgesia amnesia antisialagoue antiemetic increase gastric pH decrease gastric fluid volume - prokinetic antibiotics prophylaxis against allergic reaction
induction steps
preoxygenate/denitrogenate reconfirm patient for surgery/anesthesia sweep of monitors and equipment - SUCTION "PATIENT IS FIT FOR ANESTHESIA" administer meds 1. hypnotic 2. narcotic 3. induction agent * confirm unconsciousness, patient apneic, position head, and assess ability to mask ventilate 4. muscle relaxant
airway management steps
establish airway
confirm adequate ventilation (bilat breath sounds, presence of ETCO2)
DO NOT FORGET TO VENTILATE PATIENT
turn on anesthetic gases
secure airway
don’t forget continuous monitoring of patient
post airway/induction prep for start of surgery
stabilize VS
apply additional monitors
positioning and prep
abx given?
rapid sequence induction differences
do not mask ventilate during induction - may precipitate vomiting and aspiration
suction must be readily available
cricoid pressure applied as induction agent administered and maintained until ETT placement confirmed
intraoperative management
maintain vigilance
anticipate surgical stimulus, bleeding, med limits
evaluate t response to surgery and anesthetic
fluid replacement/ monitor blood loss
record keeping
waking the patient
timing
anesthetics discontinued/reversed
patient placed on 100% O2
allow spontaneous breathing
extubation criteria met for safe removal of ETT
assure patent airway and make sure you have adjuncts
failure to emerge possiblities
residual NMBD excess opioid/benzo intraop CVA pre-existing patho electrolyte abnormalities acidosis hypothermia
leaving the OR
patient must be stable before leaving OR keep monitoring transport on O2 you're responsibility does not end until patient is safely handed off to PACU -patient history -surgical procedure -intraop course -fluid balance
why choose MAC
Therapeutic or diagnostic procedures that may be uncomfortable or unsafe without the presence of an anesthesia provider and where general anesthesia is not wanted
When patients need the cocktail of anxiolytic, hypnotic, analgesic, and amnestic medications
When you want less physiologic disturbances and a more rapid recovery
Can be used alone or in combo with regional techniques
Can you lose protective reflexes with MAC?
YES
What is conscious sedation/moderate sedation
Sedation technique that maintains adequate cardio respiratory function and ability to purposefully respond to verbal/tactile stimulation
THIS IS LIGHTER ANESTHESIA THAN MAC so doesn’t require anesthesia provider
What is the most common cause of brain injury with MAC
Inadequate ventilation
How is MAC different from conscious sedation
MAC includes an anesthesia assessment, and the provider delivering anesthesia must be qualified and prepared to convert to general when necessary
To be qualified to provide MAC you must be able to rescue the airway
You must have 1. Preop eval 2. Intra-op monitoring 3. Anesthesia provider
What does MAC help to do
Relieve anxiety and apprehension
Prevent recall of unpleasant period events
Characteristics of minimal anesthesia - “anxiolytics”
Normal response to verbal stimulation
Airway patency unaffected
Spontaneous ventilation unaffected
CV function unaffected
Characteristics of moderate sedation “conscious sedation”
Purposeful response to verbal/tactile stimulation
Airway patency requires no intervention
Adequate ventilation spontaneously
CV function usually maintained
Characteristics of deep sedation (MAC?)
Purposeful response following repeated or painful stimuli
Intervention may be required to maintain airway patency
Spontaneous ventilation may be inadequate
CV function usually maintained
characteristics of general anesthesia
Unarguable even with painful stimulus
Intervention often required to maintain airway patency
Spontaneous ventilation frequently inadequate
CV function may be impaired
Preop considerations for MAC
Patient must be able to cooperate and remain motionless during procedure
Thorough preop evaluation
Pre-procedural fasting guidelines must be maintained in case patient must be converted to general
Planning for MAC -
- Room setup: general anesthesia is always plan B so set up for that
- Preop and eval studies are necessary to help evaluate/anticipate difficult airways
- Intraop monitoring/vigilance is necessary
- Loss of lash reflex also means loss of protective airway reflexes
Required MAC monitors
BP EKG Pulse ox Assess adequacy of vent Qualified anesthesia provider
Additional: Precocial stethoscope Temp monitor Capnography BIS
Meds frequently used for MAC
Versed: anxiolytics and amnesia
Fent/remifent: analgesia
Prop: sedation
Local: block
Versed considerations during MAC
Given first Titration to effect Anxiolysis/amnesia Synergistic with opioids May have paradoxical effect in elderly or patients with dementia
What 3 things make med amounts highly variable during MAC
Surgical stimulus
Surgeon experience
Patient PMH
Opioid considerations during MAC
May cause resp depression/Brady
Helps to alleviate pain with initial injection of local, but not appropriate as solo agent because large doses = resp depression
Pain management enhancer
Propofol considerations during MAC
SUPERIOR drug
- sedative/hypnotic properties
- rapid on/off
- decrease PONV
Why choose a continuous infusion of propofol vs boluses?
Use less drug and gain steady state of drug
Reduces likelihood or inadequate/excessive sedation
Doses for prop, bonus vs continuous
10-20 mg prn bolus
25-75 mcg/kg/min titrate to patient response
positioning concerns for MAC
Can be done with any position, but remember general is your plan B, so prone can be a challenge if you need to convert to general
What cases would you see MAC
Pacemaker insertion Burr hole Simple GYN procedures Cataract procedures Simple hernia Urological procedures Skin & breast procedures Arthroscopic procedures AND MANY MORE
Why does MAC fail
Inadequate local anesthetic
Painful position
Uncooperative patient
Paradoxical effects from sedation
When can you NOT use MAC
Surgeon needs muscle relaxation that is not being provided by regional
Patients with potentially difficult airway where positioning may limit airway access
Peds
Pt with psych disorder
Uncooperative patients
What backup airway supplies will you need for MAC
Suction, oral/NP airway, LMA, ETT, laryngoscope blades and handles
What is the greatest danger during MAC
LACK OF VIGILANCE
