Theatre Anaesthetics Flashcards
What are the 4 different techniques of regional anaesthesia. Which is used most often? give 2 examples of that one.
Local aesthetic field block
Peripheral nerve block
Nerve Plexus block
Central neuraxial block e.g. spinal or epidural
At what level does the spinal cord in adults end?
At what level does the spinal cord end in children?
Adults: L1/L2
Children: L3/L4
At what vertebral level is epidural anaesthetic inserted? How about spinal anaesthetic?
At what level is the epidural anaesthetic inserted in labor
The epidural anaesthetic can technically be inserted anywhere along the spine as it does not affect the the spinal cord. In labor L3/L4
The spinal cord ends at L1/L2 in adults => Spinal anaesthetic must be inserted at L3/L4 or L4/L5 or lower.
The components of general anaesthesia are sometimes called the ‘triad of anaesthesia’. What is this triad? Give examples of each
Hypnotic: Propofol, SEV (Sevoflurane)
Analgesic: Fentanyl, Oxynorm
Muscle relaxation: Depolarising (Suxamethonium)
Non-depolarising: Rocuronium
Take me through when a patient arrives for surgery until induction
1) Patient starts int eh pre-operative area where they should be reviewed and assessed by the anaesthetist
2) They are then brought to the operating room/induction room (if present). There the WHO safe checklist will be completed, monitoring devices are applied and IV cannulation is established
3) Anaesthesia is administered (GA, RA, Sedation),
Extra: the patient is intubated (I-gel or LMA - laryngeal mask airway), analgesia snd/or muscle relaxants are administered.
What are the 2 methods of induction. State the agent used in each and the indication for the use of each
IV: Propofol is the standard agent
Inhalation: Sevoflorane gas is used
Inhalational anaesthesia is only used in induction over IV in paediatric practice (don’t like it), cases of difficult airway, difficult venous access, or inhaled foreign body
What are the 2 the two types of muscle relaxants used in aneaesthesia. Give the example that is most used in practice. For each example state whether it is slow or fast acting.
Muscle relaxation: Depolarising: Suxamethonium - Fast acting
Non-depolarising: Rocuronium
What is the main risk when administering suxamethonium? How is it reversed?
Give some other SE of administering this drug.
Malignant hyperthermia
Dantrolene
Other: Hyperkalemia, anaphylaxis
Briefly explain Rapid Sequence Induction including:
indications
Preparation
actual sequence
Indications:
Apnea or severe respiratory failure
MAIN: Patient not fasting/full stomach/at risk of aspiration e.g. Emergency, obstetric emergency, Hx of reflux
Patient with altered mental status - GCS <9 (8 or less) (TBI, OD, poison)
Airway anatomy
Preparation: Pre-oxygenation to withstand during apneic period, sniffing position (Ear Canal in line with sternum)
Sequence: Pressure is applied to the cricoid bone (to close oesophagus and prevent aspiration -40N) Propofol is given along with fentanyl followed by suxamethonium or Rocuronium
Intubation may then take place.
What is the reversal agent of Rocuronium?
Sugammadex (only works on this and vecuronium)
How can you confirm the correct placement of airway? what is the gold standard?
Visualising the passage through the cords
Listening for breath sounds bilaterally
GOLD STANDARD: Capnography. End-tidal CO2 over 5 ventilatory cycles (no need for specifics)
How would you tell that a muscle relaxant is starting to wear off?
Deep cleft/depression on end-tidal CO2 waveform
The I-gel is a 2nd generation Laryngeal mask airway and is not separate from the inflatable one. Where does it sit. What is another method of securing the airway?
Suprglottic devices
Other = endotracheal intubation. Note that the ET tube can be passed through some LMAs
There is another hole on the top of the I-gel. What is it for
It is a gastric channel
What is MAC?
MAC or minimal alveolar concentration, is the alveolar concentration of a volatile agent which when given alone, prevents movement in 50%. Note that this is when given alone. When giving other agents such as propofol, it will also prevent movement.
Give one hypnotic other than propofol
Thiopentone (must know this one)
Etomidate
What are the systemic effects of general anaesthesia?
They are all respiratory depressants and depress airway reflexes
Vasodilation => reduced BP
Negative isotropy and chronotropy (reduced contractility and HR)
What anti-emetics are used in anaesthesiology?
Ondansetron
Dexamethasone - Steroid, anti-emetic, and potentiated regional anaesthesia.
What must be completed before emergence?
When is extubation performed?
Before emergence, stop delivery of hypnotic (SEV) and administer adequate analgesics (oxynorm) and anti-emetics (ondansetron). Lastly, ensure that neuromuscular junction function has been restored if a muscle relaxant was used
Extubation is performed following:
Suction of oropharynx
Patient is spontaneously generating good tidal volumes
Patient is awake and is able to protect own airways
What is the triad of Malignant hyperthermia?
Hypercapnia, hyperthermia, leadpipe muscle rigidity.
State all the steps involved in preoperative assessment (7)
Full medical history
Physical examination
Investigation
Risk assessment
Consultation with other medical specialties (if required)
Optimisation
Premedication
What will you ask in the full history of the patient in pre-op assessment? Say as much as you can. Everything is included in the answer. 5/5 if you state all the major points not the specifics unless important
1) History of surgical problems (previous airway surgeries, joint surgery - for positioning problems, surgery problems)
2) Medical history:
Cardio: Sx of angina or CHF (SOB, orthopnea), HTN, pacemaker or ICD, exercise tolerance
Resp: Asthma, recent URTI, COPD…
Neuromuscular: Hx of TIA, stroke, seizure, sx of raised ICP, myasthenia gravis, myopathies
Endocrine: Diabetes, thyroid
Renal: Renal failure, dialysis dependency
GIT: GORD, Cirrhosis
3) Medications and Allergies
4) Previous anaesthesia history (difficult airway management, drug reaction, difficult epidural, post-dural puncture headache, post-op nausea/vomiting)
5) Family History related to anaesthesia e.g. malignant hyperthermia, sickle cell disease or cardiology
6) Social History (pre-issue exercise, smoking, alcohol, substance abuse)
7) Fasting hours (last oral intake)
What classification is used in Cirrhosis?
Child-pew classification of cirrhosis
MOA of ACE inhibitors
Give 2 examples of ACE inhibitors
Inhibits Angiotensin converting enzyme which is responsible for converting Ag1 into Ag2 which then acts to vasoconstrict (in which the drug will cause vasodilation => reduced BP)
Enalapril
Lisinopril
Ramipril
