Awareness under anaesthesia Flashcards
(12 cards)
What is the incidence of Awareness under General Anaesthesia?
1/19,000
What is the incidence of Awareness under General Anaesthesia if a neuromuscular blocking agent is used?
1/8,000
What is the incidence of Awareness under General Anaesthesia if NO neuromuscular blocking agent is used?
1/136,000
What is the incidence of Awareness under General Anaesthesia in Obstetrics?
1/670
What is the incidence of Awareness under General Anaesthesia in Cardiothoracics?
1/8,600
What drug factors increase the likelihood of awareness under anaesthesia
The use of any of the following:
TIVA
Thiopentone
A neuromuscular blocking agent
Rapid Sequence induction
What patient factors increase the likelihood of awareness under anaesthesia
Female Gender
Being a young adult
Obesity (difficulties with drug dosing and also possible difficult airway)
Previous awareness under GA (possible genetic component)
Difficult Airway
Sick / Cardiovascularly compromised patients(as often lower doses are given)
What surgical factors increase the likelihood of awareness under anaesthesia
Surgery for any of the following specialties
Obstetrics
Cardiothoracics (Can be split into Cardiac and Thoracics)
Neurosurgery
What organisational factors increase the likelihood of awareness under anaesthesia
Emergency Surgery
Junior Anaesthetic Doctor
Out of Hours Operating
What types of monitoring can be used to help reduce the incidence of accidental awareness under general anaesthesia
Train of four monitoring
End tidal anaesthetic gas monitoring
Monitors that specifically reflect the depth of anaesthesia for example processed EEG monitors
Standard patient monitoring which may indicate a sympathetic response to light anaesthesia and developing awareness eg, increasing heart rate, blood pressure and if not paralysed respiratory rate.
What types of monitoring can be used to help reduce the incidence of accidental awareness under general anaesthesia (Viva Answer)
Clinical Monitoring:
Presence of an anaesthetist throughout the case
Response to jaw thrust throughout the case
Eyelash reflex
Eye position
Pupiliary dilatation and reactivity to light
Sweating
Lacrimation
Tachypnoea
Movement
Retching on ETT or LMA
General Monitoring:
Full equipment checks and ongoing monitoring during anaesthesia (i.e. pumps, anaesthetic machine, vaporisers!)
HR, RR, BP and if not paralysed Tidal Volume
End tidal Anaesthetic gas monitoring
TIVA pump effect site or plasma site concentration
Train of four monitoring to ensure that neuromuscular blockade is reversible before ending anaesthesia
Patient weight
Monitoring that specifically reflects the depth of anaesthesia:
Processed EEG monitors that convert the frontal signal into a dimensionless number 1-100, with the BIS target for absence of postoperative recall being 40-60
Raw EEG, which is more rarely used
The isolated forearm technique
Other specific monitors using somatosensory evoked or auditory evoked potentials as a measure of depth of anaesthesia
What are the possible consequences that an episode of accidental awareness under anaesthesia can have on a patient
There may be immediate or delayed recall (or no recall in cases of implicit awareness)
Experiences may be auditory or tactile, they can include pain or an awareness of paralysis
Responses can be very varied ranging from neutral feelings to extreme distress at the time of the incident and subsequent post traumatic stress disorder with flashbacks, nightmares anxiety and depression which can impact on personal social and work life.
May cause avoidance of all medical settings certainly anaesthesia and a loss of trust in healthcare professionals
No recall may still cause long term problems with for example unexplained anxiety due to implicit memory.
