Conduct of Anaesthesia Flashcards
Describe the process of anaesthesia
- Pre-op assessment
- Preparation
- Induction
- Maintenance
- Emergence
- Recovery
- Post-op care + pain management
2 drugs used in IV general anaesthesia
- Propofol
- Thiopentone
Describe IV induction
- Propofol or thiopentone used
- Rapid (1 arm-brain circulation = ~ 20s)
- No obvious planes
- Easy to OD
- Rapid loss of airway reflexes + apnoea is very common
Drug used in gas induction
-Sevoflurane
When is gas induction commonly used
Paediatric surgery
Describe gas induction
- Slow
- Obvious planes of anaesthesia
4 planes of anaesthesia
- Analgesia/sedation
- Excitation
- Anaesthesia: light => deep
- Overdose
or
Sleepy/excited/Anaesthetised
How is conscious level monitored
- Loss of verbal contact
- Movement
- Resp. pattern
- Processed ECG
- Planes of anaesthesia
Describe the triple airway manoeuvre
- Head tilt
- Chin lift
- Jaw thrust
3 simple apparatuses used to maintain an airway
- Face mask
- Oropharyngeal (“Guedel”) airway
- Nasopharyngeal airway
Describe the oropharyngeal (“Guedel”) airway
- Rigid plastic
- Only tolerated by unconscious patient
- Insertion in a “light” patient may cause vomiting or laryngospasm
Describe the laryngeal mask airway
- Cuffed tube with “mask” sitting over glottis
- Maintains but does NOT protect airway
- Sizes for adults and children
4 reasons for airway obstruction
-Ineffective triple airway manoeuvre
Airway device malposition or kinking
-Laryngospasm
-Foreign body
Describe a laryngospasm
- Forced reflex adduction of the vocal cords
- May result in complete airway obstruction
- Caused by airway (or other) stimulation in light planes of anaesthesia
- Often unrelieved by simple manoeuvres
Define maintaining and protecting an airway
- Maintained = Open + unobstructed
- Protected = protected from aspiration, only a cuffed tube in the trachea protects the airway from contamination
Describe endotracheal intubation
- Placement of a cuffed tube into trachea
- Oral route most commonly used
- Laryngeal reflexes must be abolished
- Classic method uses laryngoscope, muscle relaxant and “sniffing the morning air” position
- Possible in awake patient using local anaesthetic + fibre optic scope
6 reasons to intubate
- GCS < 8
- Protect airway from aspiration (unfasted patient)
- Need for muscle relaxation (laparotomy) therefore artificial ventilation
- Shared airway w/ risk of blood contamination (tonsillectomy)
- Restricted access to airway (max-fax)
- Need for tight control of blood gases (esp. CO2 levels in neurosurgery)
6 risks to unconscious patient
- AIRWAY, AIRWAY, AIRWAY!
- Temperature
- Loss of protective reflexes (corneal, joint position)
- VTE
- Pressure areas
- Consent + ID
What is monitored in the anaesthetised patient
- Basic “minimum” monitoring
- Resp. parameters
- Agent monitoring
- Temp, urine output, NMJ
- Invasive venous/arterial monitoring
What does basic monitoring involve
- SpO2
- ECG
- NIBP
- FiO2
- ETCO2
5 common anaesthesia related complications
- Airway
- Breathing
- Circulation
- Related to techniques and position
- Awareness
Describe the process of emergence/awakening
- Muscle relaxants reversed
- Anaesthetic agents off
- Resumption of spontaneous respiration
- Return of airway reflexes/control
- Extubation
- Can be v quick or v slow
4 types of local anaesthetic
- Spinal
- Epidural
- Plexus block
- Nerve block
