- Awareness
Link:www.nationalauditprojects.org.uk/NAP5_home
- Explicit awareness (1:3000 GAs - recall without pain is more common)
- Recall spontaneous or provoked by post-op questioning or events
- Commoner in cardiac and emergency procedures
- Implicit awareness
- Not consciously recalled but affects performance at a later date
- Twice as common if NMBDS used
Frequently due to poor anaesthetic technique - Consequences
- Insomnia, depression, anxiety, PTSD, flashbacks, fear of future GA
- Depth of anaesthesia monitoring
Link:EEG for depth of anaesthesia
- Clinical
- EtCO₂
- BIS
- Auditory evoked potentials
- Entropy
- Isolated forearm technique
- Lower oesophageal sphincter tone
- Forehead galvanometry
- Signs of awareness may be masked by diseases or medication
- Clinical examination remains important
- Tachycardia
- Hypertension
- Sweating
- Tear production
- Movement
- Tachypnoea
- Pupillary dilatation
- Equipment malfunction
- Breathing systems and vaporiser malfunction. IV cannula disconnection or pump failure
- Resistance to anaesthetic agents
- Pyrexia, hyperthyroidism, obesity, alcohol, drugs, smokers, young age.
- Selection of inadequate anaesthetic dose
- Associated with emergency surgery, cardiac surgery and C-section
- May be higher variability for 'MAC' values with IV agents. A MAC of >0.8 is unlikely to result in awareness. MAC >1 eliminates spontaneous recall
- CEACCP
Link:ceaccp.oxfordjournals.org/content/5/6/183.full.pdf