Anesthesia Flashcards
weak bases that block the voltage gated Na channels of excitable membranes
local anesthetics
local anesthetics affect smaller and myelinated fibers (C fibers) first and build to A. order that sensation is lost in
pain, cold, warmth, touch, deep pressure, motor
indications: skin irritation, hemorrhoids, mouth/gum irritation, poison ivy, sore throat, gag reflex suppression
topical benzocaine
contra: “Benzocaine (Orajel®, Dermoplast®)
Gels, sprays, liquids, and lozenges”
Oral formulations are not for children <2 years old
max doses for “Benzocaine (Orajel®, Dermoplast®)
Gels, sprays, liquids, and lozenges”
4 doses/day
local anesthetic FDA warning
FDA label warning about methemoglobinemia (oxidized iron in hemoglobin (confusion, discolored lips / nail beds/ skin, HA, SOB) on all OTC products
group: “Benzocaine (Orajel®, Dermoplast®)
Gels, sprays, liquids, and lozenges”
Cocaine
“Tetracaine
topical or inj”
esters
group: “Lidocaine(Icy Hot®,Salonpas®, Xylocaine®) max dose = 4mg/kg (NTE 300mg)
spray, patch, ointment, lotion, jelly, gel, mouthwash”
Bupivacaine (Marcaine®)
amides
indications: Great for nose and throat procedures/injuries (sometimes eye) applied topically
cocaine
lidocaine max dose
4mg/kg NTE 300mg
MOA: metabolised in liver. Quickest onset (1-5 min) and shortest duration (20-60 min). Bleeds less and lasts longer if combined w/ epi (120-240 min) due to vasoconstriction
lidocaine
lidocaine contra
AVOID epinephrine injection locally to digits in those with known PAD
LAST order of symptom presentation
drowsiness, paresthesias in mouth/tongue, tinnitus / auditory hallucination, muscular spasm, seizures, coma, resp arrest, cardiac arrest
how to make lidocaine injection sting less
warm to room temp, add Na bicarb
LAST treatment
IV lipid emulsion, secure airway, anticonvulsant
Bupivacaine (Marcaine®)
contra
Contraindicated for local infiltration in pregnant women
higher risk of cardiotoxicity if systemically absorbed: lidocaine or marcaine?
marcaine
effect of epi and Na bicarb on marcaine
nothing
AEs: nerve damage, bleeding from accidental arterial puncture, injection of LA into vessel (systemic toxicity)
Peripheral Nerve Blocks
Single injection of anesthetic drug into CSF (subarachnoid space)
Spinal block
Tiny catheter placed into epidural space and anesthetic can be slowly infused in
Epidural block
AEs: hypotension (in 50%), bradycardia, post-dural puncture HA, urinary retention
Neuraxial anesthesia (spinal and epidural)
dissociative sedative, analgesic, amnestic
ketamine
AEs: minimal cardiorespiratory depression. Does not inhibit protective reflexes. Symp stimulation, tachycardia, HTN (rare). Emergence reactions common (+/- n/v). Prolonged effect in elderly
ketamine
AEs: minimal hypotension and histamine release.
fentanyl
sedative, amnestic. No analgesia. Rapid onset and neuro recovery.
Propofol
AEs: resp depression, hypotension, inj site pain.
Propofol
special pop concern for propofol
Elderly: reduce dose by 20%, give slowly
sedative. No analgesia. Does not change BP, cardiac output or heart rate
Etomidate
Etomidate
indication
hemodynamically unstable pts
AEs: myoclonus, injection site pain, n/v
Etomidate
Etomidate
special pop concerns
lower dose in elderly, liver dz
sedative, anxiolytic. No analgesia. Slow onset.
midazolam (Versed)
midazolam (Versed)
special pop concerns
Prolonged effect in elderly, obese, liver dz
Block transmission of acetylcholine between motor nerve endings and skeletal muscle. Causes skeletal muscle paralysis. No sedation
Neuromuscular Blockers
indication:
Emergency / Surgical Procedures: Used w/ a sedative (induction agent); Facilitate endotracheal intubation; Facilitate muscle relaxation during surgery
Neuromuscular Blockers
pseudocholinesterase enzyme breaks down ___
“Depolarizing Blocker:
Succinylcholine (Anectine®) IV”
AEs: CV: bradycardia, hypotension (use atropine), arrythmias. Myalgia. Increased introcular and intragastric pressure. Malignant hyperthermia (rare; treat w/ dantrolene IV, autosomal dominant)
“Depolarizing Blocker:
Succinylcholine (Anectine®) IV”
who is at risk of low pseudocholinesterase enzyme
enzyme deficiency aquired in elderly, renal failure, malnutrition, liver failure, pregnancy
class that has AEs: “All: resp depression, prolonged paralysis.
Panc: muscle weakness, elevated HR and BP
Roc: mild hypotension
Cisat: mild hypotension, flushing”
“Non-depolarizing Blockers:
Rocuronium (Zemuron®)
vecuronium
Cisatracurium (Nimbex®)
Pancuronium (Pavulon®)”
how to reverse “Non-depolarizing Blockers:
Rocuronium (Zemuron®)
vecuronium
Cisatracurium (Nimbex®)
Pancuronium (Pavulon®)”
reverse w/ neostigmine
treatment for malignant hyperthermia
dantrolene IV
