SE/Toxicities Flashcards
What happens if LA gets into the brain?
anxiety, confusion, tremors, convulsions (due to blockagde of inhibitory gaba-a receptors by LA in the brain which increases excitability)
What happens if LA gets into cardiovascular system?
depressed myocardial contractility, bradycardia, vasodilation, hypotension (not cocaine)
What happens with systemic toxicity of cocaine?
tachycardia, vasoconstriction (alpha1) and HTN because blocks NE transmitter which accumulated NE and stimulated the B1 receptor in the heart
What area has highest risk for systemic toxicity with LA?
lowest risk?
highest- intercostal
lowest- sciatic nerve
How do you treat convulsions when LA gets to brain and causes convulsions?
diazepam
When does systemic toxicity occur with LA?
when local anesthetics get absorbed into the vasculature and reach high enough concentration in the heart and/or brain to disrupt cardiac and CNS function
probability increases when injected in densely vascular area
What is used as an adjunct prior to LA use to prevent systemic toxicity?
epinephrine because it stimulates alpha 1 adrenergic receptors causing vasoconstriction and decreases likelihood of systemic absorption and increases half life of local anesthetic by 50%
What happens if there is direct injection of LA into vasculature?
temporary blindness, aphasia, hemiparesis, convulsions, respiratory depression, coma and cardiac arrest
What should you do is LA causes cardiovascular collapse?
cardiopulmonary rescusitation/bypass and inject IV lipid emulsions (Intralipia, Liposyn or Medialipia) which will soak up circulating LA
Adverse reaction of LA
allergies (rare), pain due to pH of solution to increase shelf life and tissue necrosis at site of injection
Benzocaine
Potential allergic reaction due to release of PABA-like derivatives
Anxiety, confusion, tremors convulsions due to blockade of CNS GABA-A receptors
Cardiovascular collapse – decreased myocardial contraction, bradycardia, vasodilation, hypotension
Procaine
Potential allergic reaction due to release of PABA-like derivatives
Anxiety, confusion, tremors convulsions due to blockade of CNS GABA-A receptors
Cardiovascular collapse – decreased myocardial contraction, bradycardia, vasodilation, hypotension
Cocaine
Potential allergic reaction due to release of PABA-like derivatives
Anxiety, confusion, tremors convulsions due to blockade of CNS GABA-A receptors
Increased myocardial contraction, tachycardia, ventricular fibrillation, vasoconstriction, hypertension
Lidocaine
Anxiety, confusion, tremors convulsions due to blockade of CNS GABA-A receptors
Cardiovascular collapse – decreased myocardial contraction, bradycardia, vasodilation, hypotension
Ropivacaine
Anxiety, confusion, tremors convulsions due to blockade of CNS GABA-A receptors
Cardiovascular collapse – decreased myocardial contraction, bradycardia, vasodilation, hypotension
Epinephrine
Localized tissue necrosis due to vasoconstrictor action
Nitrous Oxide disadvantages
Weak agent- can never use alone for surgery
Hypoxia may occur upon d/c -100% O2 should be administered to prevent this
Closed air spaaces may expand since NO exchanges with N2
Must be avoided in pts with pneumothorax, air embolus, obstructed bowel loop, intraocular air bubble, intracranial air
Enflurane disadvantages
Cardiovascular depression due to ↓ in contractility
Seizures- no permanent damage
Uterine muscle relaxant
Isoflurane disadvantages
More pungent than halothane
Progressive respiratory depression
Sevoflurane disadvantages
Some reports of toxicity
