Anesthesia

Question 1

Anesthesia

Answer 1

Absence of sensation

Question 2

Hypnosis

Answer 2

Loss of consciousness

Question 3

Analgesia

Answer 3

Absence of pain

Question 4

Amnesia

Answer 4

Absence of memory

Question 5

Immobility

Answer 5

Muscle relaxation

Question 6

Where are hypnosis and amnesia mediated

Answer 6

In the brain

Question 7

Where are immobility and analgesia mediated

Answer 7

In the spinal cord

Question 8

The stages of Anesthesia

Answer 8

1) Stage of analgesia/induction
2) Stage of delirium/excitement
3) Stage of surgical anesthesia
4) Stage of medullary depression (toxic or danger state)

Question 9

Plane 1 of Surgical Anesthesia

Answer 9

Light anesthesia, patient still has blink and swallowing reflexes and normal respiration

Question 10

Plane 2 of Surgical Anesthesia

Answer 10

“Surgical” anesthesia, patient loses blink reflexes, pupils become fixed, and respiration is normal

Question 11

Plane 3 of Surgical Anesthesia

Answer 11

Deep anesthesia. The patient starts losing the ability to use the respiratory muscles and breathing becomes shallow, may require assisted ventilation

Question 12

Plane 4 of Surgical Anesthesia

Answer 12

Patient loses all respiratory effort and breathing may stop entirely

Question 13

Induction

Answer 13

Includes intravenous injection to induce unconsciousness and a neuromuscular blocker to facilitate intubation

Question 14

Maintenance

Answer 14

Primary agent used for maintenance anesthesia is an inhaled agent (e.g. Isoflurane) or Propofol during total intravenous anesthesia

Question 15

Emergence

Answer 15

Removal or reversal of agents to allow a smooth rapid wake-up

Question 16

Inhaled agents

Answer 16

Used for maintenance of anesthesia. I.e. Iso, Des, Sevo

Question 17

Nitrous oxide

Answer 17

Good for amnesia, fast acting, good for cardiovascular stability with no decrease in blood pressure

Question 18

MAC

Answer 18

Minimum Alveolar Concentration. 1 Mac = the amount of agent required to prevent movement in 50% of patents when exposed to painful stimulation (incision)

Question 19

MAC awake

Answer 19

The amount of inhaled agent required to simply produce unconsciousness (approx 0.5)

Question 20

ED50

Answer 20

For intravenous agents. The amount of drug required to have desired effect in 50% of patients.

Question 21

Propofol

Answer 21

Hypnotic; a GABA agonist. Gives hypnosis, but not immobility of spinal cord

Question 22

Narcotics/Opiods

Answer 22

Used for analgesia (light blue label). Cause latency increase and mild decreases in amplitude. Respiratory suppression at high doses. Ex: Sufentanil, Fentanil, Alfentanil, Remifentanil, Morphine

Question 23

Benzodiazepines

Answer 23

Used for sedation (tranquilizers). Good for hypnosis and amnesia, no analgesic effect. Decrease in amplitude, increase in latency. Respiratory suppression. Ex: Midazolam (Versed), Diazepam (Valium), Lorazepam (Ativan), Clonazepam (Klonopin), Nitrazepam

Question 24

Barbiturates

Answer 24

Used as an induction agent - very short acting. Used for neuroprotection during potential brain ischemia (cerebral aneurysm). Causes decrease in amplitude, increase in latency, except perhaps in large bolus. Respiratory and cardiovascular suppression. Ex: Sodium pentothal (thiopental), methohexital, phenobarbital, pentobarbital

Question 25

Etomidate

Answer 25

Non-barbiturate induction agent. Hypnotic, GABA agonist, can be used for induction and maintenance of anesthesia. Minimal cardiovascular effects. At LOW doses, it increases SSEP cortical amplitudes & latency.

Question 26

Ketamine.

Answer 26

Non-barbiturate induction agent. Dissociates brain’s ability to process stimuli, provides anesthesia and analgesia. Can increase SEP amplitudes, increases intracranial pressure, as well as cerebral metabolic rate and blood flow. Causes hallucinations

Question 27

Dexmedetomidine

Answer 27

Aka Precedex. Provides both sedation and analgesia with a MAC sparing effect. Does not diminish the amplitude of the evoked potentials. Useful for opiod tolerant patients. But can cause bradycardia and hypotension.

Question 28

Lidocaine

Answer 28

Sedative and analgesic properties. Contributes to immobility, though cause is unclear. Seizures (low doses reduces, high doses increases). Unclear if it helps with amnesia. Compatible with SSEP and TcMEP.

Question 29

Neuromuscular blockades

Answer 29

Used to keep patient relaxed (prevent movement and facilitate surgical retraction). Bind to acetycholine receptors in the motor end plate thereby blocking activation via acetycholine

Question 30

Depolarizers

Answer 30

Cause depolarization when binding to the acetycholine receptors without the ability to depolarize again until released

Question 31

Non-depolarizers

Answer 31

Bind to the acetycholine receptors without causing depolarization

Question 32

Depolarizer example

Answer 32

Succinyl-Choline - Short acting (15-20 min)

Question 33

Non-depolarizer examples

Answer 33

Atracurium (Trachrium), Vecuronium (Norcuron), Cis-Atracurium (Nimbex), Rocuronium (Zemuron) - Intermediate (30-60 min); Pancuronium (Pavulon) - Long-acting (60-90) min

Question 34

2 Cardiac drugs

Answer 34

Nitroprusside (decreases blood pressure), Heparin (Anticoagulant)

Question 35

Desired anesthesia for SEPs

Answer 35

Less than 1 mac is acceptable. Prefer Halogen at 0.5 MAC, no N2O. Fentanyl or Remi, supplemental Prop or Versed as necessary. TIVA recommended for some patients.

Question 36

TIVA

Answer 36

Total Intravenous Anesthesia. 100-200 micrograms of proposal or 50 micrograms of Midazolam. Narcotics as needed

Question 37

Anesthetic Effect on Modalities

Answer 37

VEPs > TcMEPS > SSEPs > ABRs > EMGs

Question 38

Burst suppression

Answer 38

Pattern of EEG showing periods of flat EEG interrupted by bursts of large amplitude EEG activity due to deep anesthesia.