anesthesia Flashcards
- general anesthesia via vaporizer and carrier gas
- when inhaled partial pressure of gas = blood and goes through body
- dose is percent end-tidal agent and MAC is end-tidal level of gas needed to prevent movment to noxious stimulate in 50% of patients
inhaled anesthesia
3 cardiac effects of inhaled agents
decreases 3 things: contractility, SVR and MAP
- ischemia in pt with fixed stenotic lesions
- valvular heart disease
- cardiomyopathy
- congenital defects
these are implications of cardiac effects of what type of anesthesia?
inhaled agents
what MET level are you concerned about with a patient going into surgery?
less than 4 METs
3 signs of CHF
JVD
L.E edema
crackles
4 pulm effects of inhaled agents
- bronchodilation
- decreased respiratory drive
- increased respiratory rate with decreased tidal volume
- atelectasis
- increased CO2 threshold to breathe– issue for OSA
decreased breath sounds suggests what 4 conditions might be at play?
atelectasis
infection– could also have crackles or rhonchi
COPD
pneumothorax
2 CNS effects of inhaled agents
- increased cerebral blood flow & ICP
- decreased cerebral metabolic demand
4 neuro labs/imaging to get
CT/MRI for mass effect
plasma levels of anticonvulsant meds
carotid US for detection of carotid dz
MRI for ischemic changes
fam h.o prolonged medication reactions is indicative of …
pseudocholinesterase deficiency
fam h.o high fevers, unexplained cardiac arrest is indicative of …
malignant hyperthermia
what is this condition? what 3 things can happen as it progresses?
- autosomal dom defect in ryanodine receptor that releases calclium
- hypersensitive to releasing stimuli & hyposensitive to inactivating signals
malignant hyperthermia
- acidosis, hyperK, arrhythmia
2 triggering agents of MH
- volatile anesthetic gasses– sevo-, iso-, des-flurane
- succinylcholine (nondepolarizing muscle relaxant)
2 things you see with MH
- increased: RR, CO2, HR, temp
- myoglobinuria
how is MH tx
- stop agent, give DANTROLENE 2.5mg/kg
- support: decrease temp, manage hyperK
3 components of general anesthesia
analgesia
hypnosis
muscle relaxant
2 muscle relaxants
succinylcholine
NDMR
propofol is what type of GA
IV hypnotics
phases of GA (9)
- pretreatment
- monitoring
- time out
- pre-oxygenation
- induction
- airway mangement
- maintenance
- emergence
- recovery
what phase of GA is this
- goal is to reduce complications
- meds commonly given prior to patient arriving in the OR
pretreatment
- anxiolytics (midazolam)
- olanzapine, meclizine, scopolamine
- Na bicitrate, famotidine– aspiration risk reduction
- metoclopramide
- albuterol
pretx meds
Every patient shall have arterial blood pressure and heart rate determined every __ minutes
5
goal pre-ox
90%
What is the gas agent used in mask inductions?
Sevoflurane
most common supraglottic airway
Laryngeal mask airmway (LMA)
- they are placed in posterior oropharynx above the glottis
- less secure than ETT & doesn’t protect from laryngospasm and aspiration
- no need for muscle relaxant
- doesn’t irritate the trachea
- less coughing and bucking
supraglottic airways
- can cause HTN and tachy on placement/removal & can be hard to place
- irritating to the trachea causing coughing, bronchospasm
- can still move air if patient laryngospasms
ETT
- spinal/subarachnoid block
- epidural block
- combined spinal-epidural (CSE)
neuraxial regional anesthesia
which spinal anesthetic lasts longest? shortest?
longest: tetracaine
shortest: chloroprocaine
used in:
- c section
- knee & hip replacement surgery
- foot & ankle surgery
- urology surg
- below umbilicus if not candidate for GA
spinal anesthesia
- rapid onset w/ very low dose with no CNS effect
- can cause rapid drop in BP
- if high can cause bradycardia & profound hypotension (T1-4), paralyze the diaphragm (C3-5)
spinal anesthesia pros and cons
- used in lumbar or thoracic space
- higher concentration for surgical anesthesia; lower for analgesia
- can be enhanced by adding narcotic or epi
epidural
uses:
- labor & post op analgesia
- csection if in place for labor
- L.E or urology w/ uncertain duration
- thoracic and abdominal procedures intra and post op
epidural uses
- can be used for indeterminate op. length
- used intraop and postop
- sympathectomy more controlled
- slower onset & less dense block; more finicky
- larger dose of LA needed ; potential for dural puncture or epidural hematoma d/t larger needle
epidual pros and cons
- avoid general anesthesia if used as primary anesthetic
- better post-op pain control
- less narcotic need while blocking; faster discharger
- increased blood flow to surgical site
- Cannot be used for breast surg or paravertebral blocks
- potential for permanane nerve injury and local anesthetic systemic toxicity (LAST), bleding, infection
peripheral regional
- combo of IV agents for deep sedation used to make patient comfy for procedures
- risks: awareness & unprotected airway
- agents: BZD, narcotics, hypnotics, ketamine
MAC (monitored anesthesia care)
