Awareness

Question 1

Awareness

Answer 1

postoperative recall of events occurring during general anaesthesia

Question 2

Awareness with recall (AWR)

Answer 2

refers to both intraoperative consciousness & explicit recall of intraoperative events with or without pain

Question 3

Classification of Awareness

Answer 3

• Class 0  no awareness
• Class 1  auditory perceptions
• Class 2  tactile perceptions (surgical manipulations or ET tube)
• Class 3  pain
• Class 4  paralysis (feeling that one cannot move, speak, or breathe)
• Class 5  paralysis & pain

NB they will ask to classify based on scenario

Question 4

Consequences of Awareness

Answer 4

Sleep disturbances, nightmares, flashbacks, anxiety, irritability, preoccupation with death

Question 5

Aetiology of awareness

Answer 5

too little anaesthesia for that human being
1. Inadequate delivery  accidental
2. Inadequate delivery  deliberate
3. “Normal” delivery  requirements increased

Question 6

Inadequate delivery > deliberate

Answer 6

o Hypotension  avoid worsening cardiac function, hypovolaemia, trauma
o C-section  to avoid foetal depression & uterine hypotonia (NB  has been asked a lot)

Question 7

Inadequate delivery  accidental

Answer 7

o Physician technical error
o Alertness
o Equipment malfunction  machine / vaporiser / circuit / TIVA pump
o Patient difficulty  difficult airway

Question 8

“Normal” delivery  requirements increased for anaesthesia

Answer 8

o Acquired tolerance  drug abusers
o Redheads  require 10 – 20% more anaesthesia

Question 9

Monitoring for awareness

Answer 9

based on monitoring end-tidal anaesthetic concentration (ETAC) of inhalation agents and / or neuromonitoring with electroencephalographic (EEG) indices may reduce the incidence of AWR

Question 10

Clinical monitoring for awareness

Answer 10

Physiologic parameters such as respiratory pattern, muscle tone, and response to a noxious stimulus are monitored.
Movement
BP, HR, RR: Tachy or HPT
Tearing response looks like they are crying
Equipment problem:
1. Vaporiser empty
2. Syringe driver empty
3. Disconnect
4. Malfunction

Question 11

MAC principles of awareness

Answer 11

MAC recall is lower than MAC movement it is NB to recognise this
we expect the patient to move before experiencing recall.

*GO look at the MAC graph
At 1 MAC, 50% of patients may move, but none will remember. At 0.8 MAC, many will move but none will remember

Question 12

Brice questionnaire

Answer 12

1. What was the last thing you remember before going to sleep?
2. What was the first thing you remember on waking?
3. Do you remember anything between going to sleep and waking?
4. While you were sleeping during surgery, did you dream?

You are supposed to do this thrice  once immediately after surgery, once after 24 hours, and once in 7 days

Question 13

High risk pts for awareness

Answer 13

• Previous awareness
• Anxiety
• Substance use / abuse
• Redheads

Give prophylactic benzodiazepines. Increase your monitoring modalities.