Anesthesia Flashcards
What are some of the forms of anesthesia that used be used?
nitrous oxide
chloroform
ether (ether dome)
What are the 3 objectives to general anesthesia? Are these satisfied by one or multiple drugs?
hypnosis, analgesia and paralysis
multiple
What is conscious sedation? how is it usually accomplished? give an example.
hypnosis with an intact airway
ultra-short acting IV BDZs
Dental surgery or colonoscopy
What is given pre-procedure? What should not be given?
anxiolysis - BDZ
hold any NSAIDS, anticoags
What is managed in pre-op?
the patients physical and psych state, concurrent illnesses, drug therapy, IV access.
What 3 kinds of meds are given in pre-op?
induction agents
meds to decrease aspiration risk - PPI, H2RAs, prokinetics
Drying agents - anticholinergics
What meds are given for induction?
Opioid (fentanyl), then propofol
If intubation is required, what else do you have to administer?
neuromuscular blocker for paralysis
How do you maintain hypnosis?
volatile gas + O2, additional bolus doses of opioids and/or NMBs PRN
Total propofol anesthesia + fentanyl or remifentanyl
What do you give the patient post-op?
Reverse paralysis - stigmine or Bridion
pain relief
Where do the anesthetic agents generally act within the CNS?
RAS - midbrain
What is MAC and how is it used?
Minimum alveolar concentration required to prevent movement in response to a standard surgical incision in 50% of test subjects
Lower the MAC, the more potent the anesthetic agent
What 2 characteristics should volatile gases have?
non-irritating and non-flammable
What is the potential risk of using volatile gases?
Malignant hyperthermia - life-threatening sudden release of Ca»_space; muscle contractions, rhabdo, hypermetabolic state, hyperkalemia
How do you manage MH?
Dantrolene + Insulin/D5W (insulin reverses hyperkalemia)
How does dantrolene work to treat MH?
Direct acting skeletal muscle relaxer by blocking Ca
Nitrous Oxide has what 3 qualities?
Sweet-ish smell, non-flammable, non-explosive
T or F. Nitrous oxide produces deep anesthesia.
F - light
What is used for rapid induction and recovery (~4 mins) but still has strong analgesic properties?
Nitrous oxide
T or F. Nitrous oxide is cheap and rarely requires use of a second gas for general anesthesia.
F - $$$, used in conjunction with other gases, such as O2 (50-50)
More than 4h of continuous exposure of nitrous oxide may lead to what?
megaloblastic changes to the bone marrow - anemia
What is the most potent gas? least potent?
Halothone (MAC 0.74)
Desflurane (MAC 6)
What IV med is most commonly used in induction AND general anesthesia? Brand name?
Propofol (Diprivan)
What other indication does Propofol have?
What does it look like?
ICU agitation management
Milky - oil and water emulsion
What is the advantage of Propofol over thiopental?
It doesn’t accumulate like thiopental did
Describe the induction/recovery of general anesthesis when using propofol.
pleasant, within 30 seconds
rapid with little NV
What vital sign should be monitored when using propofol?
BP - it causes reduced vascular tone - hypoTN
What are 3 cons for using propofol (other than hypoTN).
$$$
Emulsion uses soy/eggs - allergy risk
CALORIES! 1 cal/mL
What are the 3 drug classes that can affect anesthesia?
aminoglycosides - potentiate NMB
Anti-HTN - hypotension
K wasting Diuretics - hypokalemia may potentiate As
What is the earliest local anesthetic used?
cocaine
Name the ideal properties for local As.
water soluble
Sterilized by heat
rapid on/off
non-toxic on systemic absorption
How do local As work?
they block transmission of nerve impulses
How long do most local As take to work? duration? how can you prolong their duration?
5 mins
1-1.5 h
add vasoconstrictor - Epi
Why don’t you use NE to prolong duration of local As?
it is too potent!
NE does not bind B2 (vasodilator), so it excites alpha 1 alone (vasoconstrictor)
Epi binds and excites both - less constriction
What body parts should not receive local Epi?
fingers, nose, penis, toes
Most every LA has _______ effects on the myocardium.
quinidine-like - arrhythmias `
T or F. Topical agents can undergo significant systemic absorption.
T
Name a topical LA that is used in derm and peds.
EMLA - eutectic mixture of prilocaine and lidocaine
T or F. LA cannot be used for nerve blocks because they aren’t potent enough.
F
Regional blockade almost always requires use of a _____ solution. Why does this matter?
Preservative free
most allergies are to the preservatives
What is the preferred agent for local anesthesia?
lidocaine
What is less toxic than lidocaine? Con?
Prilocaine - no longer comes as PF
What is the long acting LA?
Bupivacaine (3h) slow on/off
What is commonly used for regional blockade, such as epidurals?
Bupivacaine
