PreOp Meds: Benzodiazepine concepts

Question 1

Differentiate sedatives and hypnotics.

Answer 1

• Sedatives: induce calm/sleep
• Hypnotics: induce hypnosis/sleep

Question 2

When is anesthesia awareness most common?
What are the rates of this occurring?

Answer 2

• During sedation cases and during emergence.
• 1:1000 (or 1:10,000 per some studies)

Question 3

What is the mechanism for less EEG activity seen during anesthesia/sedation?

Answer 3

• Less cerebral blood flow (CBF) and cerebral metabolic requirement of oxygen (CMRO₂) = less metabolism = less EEG activity.

Question 4

What was the first compressed EEG?
Give the details of the study exploring its use.

Answer 4

• Bispectral analysis
• 1500 subjects w/ 5000 hours of EEG signaling

Question 5

What drugs were utilized in the bispectral analysis study?

Answer 5

• Isoflurane/ O₂
• Propofol/nitrous
• Propofol/alfentanil

Question 6

Which drugs exhibit a strong correlation between BIS change and patient movement?
Which drugs do not exhibit this correlation?

Answer 6

• Hypnotic drugs
• Narcotics

Question 7

In the BIS study, what reading indicated that a patient was for sure unconscious?

Answer 7

• <58

Question 8

In the BIS study, a reading of <65 indicated a ___% of return to consciousness within the minute.

Answer 8

• 5%

Question 9

What is a normal BIS range?

Answer 9

• 40-60

Question 10

What are the four parameters (other than the BIS itself) noted on a BIS monitor?

Answer 10

• SQI
• EMG
• EEG
• SR

Question 11

What is the SR noted on a BIS monitor?
What would an SR of 60 indicate?

Answer 11

• Suppression Ratio (how many seconds per minute that the EEG is flat)
• SR of 60 means EEG is completely flat (could be brain death).

Question 12

Name drugs that could suppress EEG activity.

Answer 12

• Hypnotics, volatiles, NMBDs, Opioids
• β-blockers

Question 13

Name drugs that could enhance EEG activity.

Answer 13

• Ketamine, epinephrine