Conduct of anaesthesia Flashcards
What are the components of the ‘check-in’ done prior to surgery?
Correct patient
Correct procedure
Correct (and marked) site
Consent
What 5 measurements must an anaesthetic machine give?
(ie what is the minimum standard for the association of anaesthetists)
ECG - 3 lead
NIBP - non-invasive blood pressure
Sats
ETCO2 - end tidal CO2
Airway pressure
What is pre-oxygenation and why is it needed?
Pre-oxygenation is done just before anaesthetic is given to a patient about to have surgery
Initially under GA - patients often become apnoeic (ie stop breathing)
Pre-oxygenation is to increase the proportion/amount of oxygen that remains in a patients lungs (as they only have FRC) so that there is a greater time before desaturation would occur
Induction can be performed either IV or through inhalation
When is IV used and when is inhalation used?
IV is used in most adults
Inhalation is generally used in paediatrics as they tend not to tolerate IV input
For IV induction - what drugs are typically given?
Analgesic and hypnotic usually given, but Muscle relaxants rarely used for induction
Analgesic:
- Fentanyl
- Alfentanil
Hypnotic:
- Propofol (the white one)
- Thiopentone
- Ketamine
What are the 4 planes of anaesthesia?
How does IV and inhaled anaesthetic differ in relation to this?
1 - Analgesia & amnesia
2 - Delirium to unconsciousness
3 - Surgical anaesthesia (the aim)
4 - Apnoea to death
In IV induction - everything happens too fast to see the planes
In inhaled induction - clearly see the patient descend through the planes
How do the airways change in patients under anaesthetic?
Relaxation of upper airway muscles causing some collapse of soft tissues
- meaning all GA patients have some degree of airway obstruction
Loss of airway reflexes
What are the types of intubation?
(from most basic onwards)
Triple airway maneuver (jaw thrust)
Anaesthetic mask (with jaw thrust^)
Oropharyngeal airway - ‘**Geudel’
LMA - Laryngeal mask airway
ETT - Endotracheal tube - best protection for aiways
What are the reasons to intubate?
Prevent aspiration - esp in unfasted patients
If on muscle relaxants
Shared airway procedure - moof surgery etc
Tight CO2 control
Minimal access to patient
How can breathing be controlled in surgery?
Spontaneous ventilation - we do nothing
Controlled ventilation - paralysed, we do the work
Supported ventilation - mixture of ^
Ventilation is monitored using Sats, ETCO2 and airway pressure monitoring
How is the haemodynamic state (circulation) monitored in patients under anaesthetic?
Haemodynamic changes common under GA…
NIBP at least every 5 minutes
Vasoactive drugs can be administered if needed
What are the risks of induction?
Anaphylaxis
Regurgitation & aspiration
Airway obstruction & hypoxia
Laryngospasm
Cardiovascular instability
Cardiac arrest (rarely)
Aside from the risks of induction, what other main risks can happen related to/during general anaesthetic?
Awareness
Eye injury
Hypothermia
Pressure injury
VTE
Nerve damage
Maintenance is the phase of anaesthesia in which hr anaesthetist is keeping the patient asleep (ie during the surgery)
What are the ways in which this can be done?
Vapour “gas” - inhaled anaesthetic
Intravenous anaesthesia (TIVA)
