Neuro: Inhalation Anesthetics Flashcards
Define MAC
MEDIAN ALVEOLAR CONCENTRATION:
- standard reference for inhaled anesthetics
- end-tidal concentration of inhaled anesthetics to eliminate movement in 50% of PTs
- ***median effective dose (ED50) of the anesthetic drug
Nitrous Oxide
“laughing gas”
- used in combo with oxygen
- does not depress respiration
- maintains CV hemodynamics and muscular strength
- Can be used with inhalation agentf fg
Malignant Hyperthermia
- exposure to waht causes this
- comon/uncommon?
uncommon–in small percent of PTs
- hapens when PT exposed to halogenated hydrocarbon anesthetics
- rare life threatening condition
- rxn only to the inhaled
TX for malignant Hyperthermia?
Dantrolene–muscle relaxant
IV anesthetics
-when to use
- when CO is reduced, body compensaties by diverting more cardiac output
- basically give a decreased dose of anesthetic when CO reduced
What is the first choice for induction of general anesthesia and sedation
Propofol
Propofol
- what is it
- onset of action
- half life
- what does it provide and not provide
- what can sometimes occur with it
- post-op complications?
- cleared?
- rely on tissue detistribution?
- excreted?
- IV sedative/hypnotic
- smooth induction–30-40 seconds
- T1/2: 2-4 minutes
- does NOT provide analgesia ** supplement this with some narcotics
- occasionally contributes to EXCITATORY PHENOM–muscle twitching, yawning, hiccups
- post-op complications of N/V is low
- not rely on tissue redistribution for recovery
- cleared: LIVER —not rely on tissue redistribution
- excreted KIDNEYS
Benzodiazepines
- long medium or short acting?
- routes of admin
- induces what properties?
- what does it not produce
- what is it given with?
- anatgonist??
MIDAZOLAM: MC used -short acting CNS depressant -IV or rectal routes -Does not produce analgeisa -induces ***AMENSIA**** and sedation -given with neurmuscular blocking agents FLUMAZENIL---recepetor antagonist
Which benzo is the MC used for induction of anesthesia
Midazolam—-Versed
Opioids
-IND: analgeisa
MC one is fentanyl—if an analgesic is needed for GA
what is standard reference for inhaled anesthetics
MAC
Medium Minimal Alveolar Concentration
When is MAC less?
when intravenous anesthetics enhance inhibitory receptors and antagonize excitatory receptors
POTENCY of the drug=
smallest alveolar concentration of drug that keeps the PT immobile
MAC=
ED50
MAC wil be small for what kind of anesthetics
potent ones
*and MAC»»for less potent
The more lipid soluble an anesthetic….?
the lower the concentration needed to produce anesthesia
HIGHER THE POTENCY
the higher the MAC means?
the PT is more resistant to the effects of the durg
factors that raise MAC
hyperthermia
drugs that increase CNS catecholamines
chronic ETOH
the lower the MAC means?
the PT is more sensitive to drug
factors that lower MAC?
hypothermia age pregnancy sepsis acute intoxication concurrent IV anesthetics alpha 2 recp agonists
what hapens to body during MH?
uncontrolled increase in skel muscle oxidative metabolism–>overhwlems body;s oxygen supply/removal of co2–>cannot regulate temp—–leads to circulatory collapse and death it not tx
Dantrolene
muscle relaxant to tx MH
**blocks CA
Susceptible PTs to developing MH
burn victs muscular dystrophy myopathy myotonia osteogenesis can be inherited as autosomal dominant disordr
SE of opioids
Sedation Euphoria Dysphoria----depression anxiety unease Miosis constipation urinary retention N/V Mood changes incease pressure on gall bladder RESP DEPRESSION* *do not depress cardiovascular system but can cause: BRADY AND HYPOT
Ketamine -\_\_\_acting MOA drug class produces?? does not produce? recovery pd s/s?
Good for wht PTs?
short acting DISSOCIATE anesthetic
produces good analgesia**
does not produce skel muscle relaxation
MOA:
-inhibits excitatory pathway via NMDA receptor, stimulates SNS (w/ incr BP and CO), BRONCHODILATOR (good for asthmatics)
recovery PD can have vivid dreams and hallucinations
MOA for local anesthetics
low vs high doses
LOW DOSES:
-blocks nerve conduction of sensory impulses—reduces response to pain
HIGHER DOSES:
-blocks motor impulses from periphery to CNS—impairs motor nerve function
VASODILATOR **
what happens when you add Epinephrine to local anesthetic?
reduces the rate of the local anesthetic absorption and diffusion
- -minimizes toxicity and increase DOA of anesthetic***
- –EPI IS A VASOCONTRICTOR!!
List the ESTER local anesthetics
Benzocarine Procraine Chloroprocaine Tetracaine Cocaine
AMIDE local anesthetics
Lidocaine Bupivacaine Prilocaine Ropivacaine Mepivacaine
How to remeber estehr vs amide local anesthetics
ESTER—-one “i” in each
AMIDE—two “i” in each
Amide or Ester has longer DOA
Amide
Amide or Ester metabolized by LIver? Enzymes in skin/blood?
met by liver=amides
enzymes in skin/blood=esters
Onst of action is fast for ____anestetics and ____ for the other
FAST onset for AMIDES
SLOW onset for ESTER
