Anesthesia Flashcards
What is anesthesia?
Loss of sensation/pain
What is local anesthesia?
Anesthesia of a small confined area of the body (e.g. lidocaine for an elbow laceration)
What is epidural anesthesia?
Anesthetic drugs/narcotics infused into epidural space
What is spinal anesthesia?
Anesthetic agents injected into the thecal sac
What is regional anesthesia?
Blocking of the sensory afferent nerve fibers from a region of the body (e.g. radial nerve block)
What is general anesthesia?
- Unconsciousness/amnesia
- Analgesia
- Muscle relaxation
What is GET or GETA?
General EndoTrachael Anesthesia
What are common local anesthetics?
Lidocaine, bupivacaine (Marcaine)
What are common regional anesthetics?
Lidocaine, bupivacaine (Marcaine)
What are common general anesthetics?
Isoflurane, enflurane, sevoflurane, desflurane
What is a common dissociative agent?
Ketamine
What is cricoid pressure?
Manual pressure on cricoid cartilage occluding the esophagus and thus decreasing the chance of aspiration of gastric contents during intubation.
Also called Sellick’s maneuver.
What is rapid-sequence anesthesia induction?
- Oxygenation and short-acting induction agent
- Muscle relaxant
- Cricoid pressure
- Intubation
- Inhalation anesthetic
What are common induction agents?
Propofol, midazolam, sodium thiopental
What are contraindications of the depolarizing agent succinylcholine? Why?
Patients with burns, neuromuscular diseases/paraplegia, eye trauma, increased ICP.
Depolarization can result in life-threatening hyperkalemia and also increases intra-ocular pressure.
Why doesn’t lidocaine work in an abscess?
Lidocaine does not work in an acidic environment
Why does lidocaine burn on injection and what can be done to decrease the burning sensation?
Lidocaine is acidic, which causes the burning.
Add sodium bicarbonate to decrease the burning sensation.
Why does some lidocaine come with epinephrine?
Epinephrine vasoconstricts the small vessels, resulting in a decrease in bleeding and blood flow in the area.
This prolongs retention of lidocaine and its effects.
In what locations is lidocaine with epinephrine contraindicated?
Fingers, toes, penis because of the possibility of ischemic injury or necrosis resulting from vasoconstriction
What are the contraindications to nitrous oxide?
Nitrous oxide is poorly soluble in serum and thus expands into any air-filled body pockets.
Avoid in patients with middle ear occlusions, PTX, SBO, etc.
What is the feared side effect of bupivacaine?
Cardiac dysrhythmia after intravascular injection leading to fatal refractory dysrhythmia
What are the side effects of morphine?
Constipation, respiratory failure, hypotension (from histamine release), spasm of sphincter of Oddi (use Demerol in pancreatitis and biliary surgery), decreased cough reflex
What are the side effects of meperidine (Demerol)?
Similar to those of morphine but causes less sphincteric spasm and can cause tachycardia and seizures
What is the limit to the duration of meperidine (Demerol) postoperatively?
Build up of the metabolites (normeperidine)
What medication is a contraindication to meperidine (Demerol)?
Monoamine oxidase inhibitor
What metabolite of Demerol breakdown causes side effects?
Normeperidine
What is the treatment of life-threatening respiratory depression with narcotics?
Narcan IV (naloxone)
What are the side effects of epidural analgesia?
Orthostatic hypotension, decreased motor function, urinary retention
What is the advantage of epidural analgesia?
Analgesia without decreased cough reflex
What are the side effects of spinal analgesia?
Urinary retention, hypotension
What is the side effect of inhalational (volatile) anesthesia?
Halothane: hypotension (cardiac depression, decreased baroreceptor response to hypotension, peripheral vasodilation), malignant hyperthermia
What is malignant hyperthermia?
Inherited predisposition to an anesthetic reaction, causing uncoupling of the excitation-contraction system in skeletal muscle, which in turn causes malignant hyperthermia.
Hypermetabolism is fatal if untreated.
What is the incidence of malignant hyperthermia?
Very rare
What are the causative agents of malignant hyperthermia?
General anesthesia, succinylcholine
What are the signs and symptoms of malignant hyperthermia?
Increased body temperature; hypoxia; acidosis; tachycardia; increased PCO2
What is the treatment for malignant hyperthermia?
IV dantrolene, body cooling, discontinuation of anesthesia
What are some of the non-depolarizing muscle blockers?
Vecuronium, pancuronium
What are the antidotes to the non-depolarizing neuromuscular blocking agents?
Edrophonium, neostigmine, pyridostigmine
How do antidotes to the non-depolarizing neuromuscular blocking agents work?
They inhibit anticholinesterase
Which muscle blocker is depolarizing?
Succinylcholine
What is the duration of action of succinylcholine?
< 6 minutes
What is the antidote to reverse succinylcholine?
Time.
Endogenous blood pseudocholinesterase (patients deficient in this enzyme may be paralyzed for hours).
What is the maximum dose of lidocaine with epinephrine?
7 mg/kg
What is the maximum dose of lidocaine without epinephrine?
4 mg/kg
What is the duration of lidocaine local anesthesia?
30-60 minutes (up to 4 hours with epinephrine)
What are the early signs of lidocaine toxicity?
Tinnitus, perioral/tongue numbness, metallic taste, blurred vision, muscle twitches, drowsiness
What are the signs of lidocaine toxicity with large overdose (> 10 ug/mL)?
Seizures, coma, respiratory arrest, LOC, apnea
When should the Foley catheter be removed in a patient with an epidural catheter?
Several hours after the epidural catheter is removed (to prevent urinary retention)
What is a PCA pump?
Patient-Controlled Analgesia:
A pump delivers a set amount of pain reliever when the patient pushes a button.
What are the advantages of a PCA pump?
Better pain control; patients actually use less pain medication with a PCA.
If given a moderate dose without a basal rate, patients should not be able to overdose.
What is a basal rate on the PCA?
Steady continuous infusion rate of the narcotic (e.g. 1-2 mg of morphine) continuously infused per hour.
Patient can supplement with additional doses as needed.
What is used to reverse narcotics?
Naloxone (Narcan)
What is used to reverse benzodiazepines?
Flumazenil
What is fentanyl?
Very potent narcotic
What is a common IV NSAID?
Ketorolac (Toradol)
