General Anesthesia

Question 1

Describe the 1st stage of anesthesia

Answer 1

Analgesia

- initiation –> loss of consciousness

Question 2

Describe the 2nd stage of anesthesia

Answer 2

Delirium/Excitement

• initial loss of consciousness to onset of regular breathing and loss of lid reflex
• uninhibited –> external stim –> vomiting, laryngospasm, patient movement
• breathing irregular with forced exhalation
• pupils dilated and divergent
• muscles are tense
• lid reflex intact

Question 3

Describe the breathing, pupils, muscle tone and lid reflex in stage 2 of anesthesia

Answer 3

Breathing = irregular with forced exhalation

Pupils = dilated, divergent

Muscle tone = tense

Lid reflex = intact

Question 4

Describe stage 3 of anesthesia

Answer 4

Surgical anesthesia

• 4 planes
• regular respiration –> tachypnea –> shallower as depth increases
• loss of various reflexes

Question 5

Describe stage 3, plane 1 of anesthesia

Answer 5

Ocular movement

decreased dilation of pupils w/ reaction to light present in ether anesthesia, but absent in isoflurane anesthesia.

flushing of skin may be observed

swallowing and lid reflexes are abolished

Question 6

Describe stage 3, plane 2 of anesthesia

Answer 6

cessation of eye movement

pupils coming toward midposition

decrease in respiratory tidal volumes

risk of laryngospasm decreases once in plane 2

muscle tone continues to decrease.

Question 7

Describe stage 3, plane 4 of anesthesia

Answer 7

decrease in diaphragmatic muscle strength

flaccid muscle tone

onset of dilation of pupils

respirations very shallow

Question 8

What are the components of general anesthesia?

Answer 8

unconsciousness
amnesia
analgesia
immobility
attenuation of autonomic responses to noxious stimulation

Question 9

Define MAC

Answer 9

alveolar partial pressure of a gas at which 50% of patients do not respond to surgical incision

only applicable to inhaled anesthetics

Question 10

Describe the benefit of EEG over MAC in quantifying depth of anesthesia

Answer 10

applies to both inhaled and IV anesthetics

no benefit in preventing awareness under anesthesia vs. MAC