Anesthetics

Question 1

Inhaled anesthetics

Answer 1

N2O - gaseous
Volatile liquids:
Halothane
Enflurane
Isoflurane
Sevoflurane
Desflurane
(HEISD)

Question 2

Nitrous oxide

Answer 2

“laughing gas”. low solubility and low potency.
Advantages: cheap, does not irritate airways, fast induction and recovery, no hepatotoxicity, no effect on respiration of cardiovascular tissue, no effect on SMCs.
Disadvantages: hypoxia risk, increases pressure or volume of closed cavities, Megaloblastic anemia, cannot produce surgical anesthesia alone.
I: alone in dentistry and obstetrics (during delivery) - for analgesia

Question 3

Common features of halogenated hydrocarbons (volatile liquid anesthetics)

Answer 3

Relax skeletal muscles
Risk of malignant hyperthermia
Modulate circulation: lowers BP, and decrease CO
Resp. depression
Bronchoconstriction - isoflurane
Bronchodilation - halothane and sevoflurane

Question 4

Halothane

Answer 4

Inhalation anesthetic. High potency, quick induction and recovery.
Advantage: bronchodilation, relaxes the uterus, muscle relaxation
Disadvantage: dose dependent hypotension, bradychardia, sensitize the myocardium to NE, E (arrhythmia), malignant hyperthermia (mngmt: dantrolene), hepatotoxic
I: inhalation anesthetic in pediatrics (sevoflurane 1st choice). not used.

Question 5

Dantrolene

Answer 5

RYR receptor ATG - management of malignant hyperthermia

Question 6

Enflurane

Answer 6

inh. Anesthetic.
Advantage: does not irritate airways.
Disadvantage: depresses resp and circulation, sensitize heart to NE,E, hepatotoxic and kidney toxic (fluoride, metabolite), malignant hyperthermia
EPILEPTIC seizures!

Question 7

Isoflurane

Answer 7

Inhalation anesthetic. isomers of enflurane.
Advantage: good muscle relaxation, stabilize CO, no raise in ICP, no liver or kidney toxicity
diadvantage: resp. irritation (bronchoconstriction) so can only be used in maintenance in intubated patients, coronary steal syndrome, dose dependent hypotension.
I: preffered in neurosurgery

Question 8

Desflurane

Answer 8

inh. Anesthetic. fast induction and recovery.
Advantage: does not accumulate in fat tissue (obese patients), no renal or liver toxicity, rapid elimination (outpatient procedures)
Disadvantage: resp. irritation, tachychardia at start of admin,

Question 9

Sevoflurane

Answer 9

inh. anesthetic. high potency, fast induction and recovery.
Most commonly used inh. anesthetic.
Advantage: bronchodilation, no liver toxicity, cardiovascular stability
Disadvantage: potential kidney toxicity
I: induction and maintenance of anesthesia

Question 10

Intravenous anesthetics (6)

Answer 10

Propofol (prospero)
Fospropofol
Etomidate (the intimidator)
Ketamine (snaKE TAMINg)
Barbiturates (barber): Thiopental, methohexital
Benzodiazepines (Ben´s diner): Midazolam, Diazepam, Lorazepam

Question 11

Propofol

Answer 11

IV sedative/hypnotic. Given as emulsion (low water solubility). Rapid onset, termination due to redistribution.eliminated via kidney after conjugation in liver. Short context-sensitive half-life.
Action: potentiate chloride current in GABA-A
Effect: CNS depressant, no analgesic effect, pronounced systemic vasodilation, depresses respiration (O2 supply needed), antiemetic effect.
SE: pain at site of infusion, propofol infusion syndrome (lipid disturbances - metabolic acidosis - tach)
I: induction and/or maintenance of anesthesia (1st choice), sub anesthetic dose: post-op nausea and vomiting treatment.

Question 12

Fospropofol

Answer 12

IV anesthetic. Water soluble prodrug of propofol. longer onset of action compared to propofol.
I: sedation during monitored anesthesia, O2 supply needed.

Question 13

Barbiturates used as IV anesthetic

Answer 13

thiopental (the ol´ quick shave) and methohexital

Question 14

Thiopental and Methohexital

Answer 14

Are both ultra short acting Barbiturates, used as IV anesthetics.
Action: increase GABA-A duration of opening.
I: induction of anesthesia (replaced by others)
SE: gangrene at site of injection, periph. vasodilation, resp. depression (apnea, coughing, laryngospasm), bronchospasm,

Question 15

BZDs used as IV anesthetics (3)

Answer 15

Midazolam, Diazepam, lorazepam.
Action: facilitate amnesia, sedation, anticonvulsant, periph. vasodilation.
I: Midazolam - only one suitable for continuous infusions. Pre-op anxiolytics and sedative, IV sedation, induction of general anesthesia
SE: no analgesia nor sk.muscle relaxation

Question 16

Etomidate

Answer 16

(the intimidator) A hypnotic agent used to induce anesthesia. No analgesic effect. potentiate GABA-A mediated chloride current. No effect on c.v system.
SE: inhibits 11-bOHase (decreased cortisol and aldosterone levels), involuntary sk.m. movements (m:BZDs, opioids)
I: induction of anesthesia in patients with c.v. dysfunction, and in patients with hypovolemic shock (is a potent vasoconstrictor)

Question 17

Ketamine

Answer 17

(snaKE TAMINg nomade). A short acting IV anesthetic.
Induces a dissociated state; sedation, amnesia and immobility.
Action: inhibit NMDA receptor complex. stimulate sympt. outflow (increased BP, CO, HR, bronchodilation). Analgesic.
SE: increased cereal blood flow. hallucinations, increased salivation (mgmnt: anticholinergics)
I: hypovolemic shock. IV, IM, oral or rectal admin

Question 18

Dexmedetomidine and clonidine

Answer 18

are sedatives used in intensive care and surgery. Action: alpha2 AG in parts of brain - sedation, analgesia, sympatholytic, anxiolytic.
I: anesthesia in patients w/severe HTN, in ICU for short term sedation of intubated and ventilated patients.

Question 19

Neurolept analgesia

Answer 19

Droperidol (1st gen antipsychotic) + fentanyl (opioid)

Question 20

Neurolept anesthesia

Answer 20

Droperidol (1st gen antipsychotic) + fentanyl (opioid) + N2O