Anaesthetics

Question 1

Local anaesthesia

Answer 1

small area numbed to facilitate minor surgery for dental extraction or excision of skin lesion

Question 2

Regional anaesthesia

Answer 2

larger area numbed, can be divided into central neuraxial blockade and nerve blocks.
Central neuraxial blockade refers to spinal or epidural anaesthesia
Nerve block can result in a whole limb being numb in isolation.
patient can remain awake but it can also be combined with sedation or full general anaesthetic

Question 3

Spinal/Central Neuraxial anaesthesia

Answer 3

local anaesthetic is injected into the cerebrospinal fluid, within the subarachnoid space. L3/4 or L4/5 spaces.

Question 4

Epidural anaesthesia involves injection of local anaesthetic into the epidural space around

Answer 4

the L2-3 or L3-4 vertebral level.

Question 5

Adverse effects of epidural anaesthesia

Answer 5

Headache if the dura is punctured, creating a hole for CSF to leak from (“dural tap”)
Hypotension
Motor weakness in the legs
Nerve damage (rare)
Infection
Haematoma (may cause spinal cord compression)
Meningitis ( very rare, more so in spinal than epidural )

Question 6

General anaesthesia

Answer 6

patient rendered unconscious by IV or inhaled drugs. Described triad is hypnosis, analgesia and muscle relaxation

Question 7

Solid fasting guidelines

Answer 7

6 hours

Question 8

Clear fluid fasting guidelines

Answer 8

2 hours

Question 9

When Clopidogrel and aspirin should be stopped

Answer 9

7 days before surgery

Question 10

When warfarin should be (generally) stopped

Answer 10

5 days before surgery and instead patients should be on low molecular weight heparin until the night before

Question 11

When ACE inhibitors and ARBS should be stopped

Answer 11

the day before surgery

Question 12

When should The pill/HRT be stopped

Answer 12

4-6 weeks before surgery, and re-started at least 2 weeks after surgery (when the patient is mobile).

Question 13

Switch oral steroids to

Answer 13

50-100mg IV hydrocortisone
oral steroids may be started again 48-72 hours post-op provided the patient is eating and drinking again

Question 14

Diabetic patients and surgery

Answer 14

A HbA1c < 69mmol/mol within 3 months of surgery is the aim in the elective setting.
Hold all oral diabetic medication on the morning of the procedure.
If the patient is on insulin then switch to sliding scale infusion when they start NBM (restart when they can eat).
Restart all oral medication the morning after surgery.
For some operations (particularly those that do not require contrast media) metformin does not need to be stopped
minimise meals missed to 1, clear advice on regular medications,
monitor CBG every hour under general anaesthetic.
For the majority of patients, the variable rate i.v. insulin infusion (VRIII) is required to control the diabetes and maintain optimal glycaemic control of 6–10 mmol litre
Where possible patients with diabetes are put first on the list

Question 15

Diabetes drugs:

Answer 15

Insulin should be held on the day of surgery (only the short-acting preparations)
sulfonylureas should be held on the day of surgery
metformin can be given as normal for short procedures. For longer procedures when the patient is not eating and drinking for several days metformin should be held and variable-rate insulin prescribed.

Question 16

Safe to take before and on day of surgery

Answer 16

beta blocker
calcium channel blocker

Question 17

Anaemia classification

Answer 17

Haemoglobin <130g/L (men) or <120g/L (women)

Question 18

Pre-operative management of anaemia

Answer 18

Oral iron if >6 weeks until planned surgery
IV iron if <6 weeks until planned surgery
B12/folate replacement
Erythropoiesis‐stimulating agent (ESA) therapy
Transfusion if profound anaemia and surgery cannot be delayed

Question 19

Anaesthetic preoperative assessment

Answer 19

Functional status - exercise tolerance, ADL
Medical history
Medications and allergy
Preoperative tests- consider ECHO, group and save, crossmatch, ECG, bloods
Airway assessment
Previous anaesthesia

Question 20

Premedications in general anaesthesia

Answer 20

Oxygen
BDZ- relax muscles,reduce anxiety
Analgesia- at least paracetamol
Opiates -reduce pain and reduce the hypertensive response to the laryngoscope
Alpha-2-adrenergic agonists (e.g., clonidine)- help with sedation and pain
PPI/H2 antagonists - Managing regurgitation and aspiration risk for high risk patients.
Antimuscarinics- infrequent use,reduce airway secretions in certain patient groups or prevent bradycardia in paediatric patients

Question 21

Rapid Sequence Induction/Intubation

Answer 21

used to gain control over the airway as quickly and safely as possible where a patient is intubated in an emergency scenario and detailed pre-planning is not possible

designed to ensure successful intubation with an endotracheal tube as soon as possible after induction to protect the airway

Question 22

steps forming the sequence of RSI

Answer 22

Preparation
Preoxygenation
Pretreatment
Paralysis- induction agent (e.g. Propofol or Sodium Thiopentone) and paralysing agent (e.g. Suxamethonium or Rocuronium)
Protection and positioning- Cricoid pressure,In line stabilisation in some cases.
Placement and proof- Intubation is performed via laryngoscopy, with proof obtained (direct vision, end-tidal CO2, bilateral auscultation)
Post-intubation management- Taping or tying the endotracheal tube, initiating mechanical ventilation and sedation agents

Question 23

compartment syndrome presents with the 5 P’s:

Answer 23

P – Pain “disproportionate” to the underlying injury, worsened by passive stretching of the muscles eg passive flexion of the toes. pain medications are not effective.
P – Paresthesia
P – Pale
P – Pressure (high)
P – Paralysis (a late and worrying feature)

Question 24

Sodium thiopentone

Answer 24

Extremely rapid onset of action making it the agent of choice for rapid sequence of induction
Marked myocardial depression may occur
little analgesia

Question 25

Ketamine

Answer 25

NMDA receptor antagonist May be used for induction of anaesthesia Has moderate to strong analgesic properties Produces little myocardial depression making it a suitable agent for anaesthesia in those who are haemodynamically unstable May induce state of dissociative anaesthesia resulting in nightmares

Question 26

Etomidate

Answer 26

favorable cardiac safety profile No analgesic properties Unsuitable for maintaining sedation as prolonged (and even brief) use may result in adrenal suppression Post operative vomiting is common Causes less hypotension than propofol and thiopental during induction and is therefore often used in cases of haemodynamic instability

Question 27

Thiopental

Answer 27

A type of barbiturate (potentiates GABAA) Adverse effects: Laryngospasm Highly lipid-soluble so quickly affects the brain useful in head trauma as it can lower the intracranial pressure;

Question 28

Nitrous oxide

Answer 28

May act via a combination of NDMA, nACh, 5-HT3, GABAAand glycine receptors Adverse effect is that it ​​may diffuse into gas-filled body compartments → increase in pressure. Should therefore be avoided in certain conditions e.g. pneumothorax

Question 29

Muscle relaxants

Answer 29

block the neuromuscular junction from working given to relax and paralyse the muscles. This makes intubation and surgery easier. There are two categories: Depolarising (e.g., suxamethonium) Non-depolarising (e.g., rocuronium and atracurium)

Question 30

Sugammadex

Answer 30

used specifically to reverse the effects of certain non-depolarising muscle relaxants (rocuronium and vecuronium).

Question 31

Suxamethonium

Answer 31

Binds to nicotinic acetylcholine receptors resulting in persistent depolarization of the motor end plate choice for rapid sequence induction for intubation

Question 32

Suxamethonium adverse effects

Answer 32

Malignant hyperthermia, Hyperkalaemia(normally transient) May cause fasciculations Contraindicated for patients with penetrating eye injuries or acute narrow angle glaucoma, as suxamethonium increases intra-ocular pressure

Question 33

Non depolarising

Answer 33

Competitive antagonist of nicotinic acetylcholine receptors Egs include Tubcurarine, atracurium, vecuronium, pancuronium Adverse effect of Hypotension Acetylcholinesterase inhibitors (e.g. neostigmine) can reverse

Question 34

Significant risks of general anaesthesia include:

Answer 34

Accidental awareness (waking during the anaesthetic) Aspiration Dental injury, mainly when the laryngoscope is used for intubation Anaphylaxis Cardiovascular events (e.g., myocardial infarction, stroke and arrhythmias) Malignant hyperthermia (rare) Death

Question 35

Malignant hyperthermia

Answer 35

Rare but potentially fatal hypermetabolic response to anaesthesia autosomal dominant mutation

Question 36

Malignant hyperthermia presentation

Answer 36

Patients typically present at the induction of general anaesthesia with - increased body temperature - muscle rigidity - metabolic acidosis - tachycardia - increased exhaled carbon dioxide. Rhabdomyolysis can lead to myoglobin in urine--> dark brown

Question 37

risk of malignant hyperthermia is mainly with

Answer 37

Volatile anaesthetics (isoflurane, sevoflurane and desflurane) Suxamethonium

Question 38

Malignant Hyperthermia treatment

Answer 38

treated with dantrolene, a muscle relaxant

Question 39

Local anaesthetic toxicity features

Answer 39

Numbness or tingling around the mouth Restlessness/agitation Tinnitus Shivering Vertigo/dizziness Subtle tremors of the face and extremities Hypertension Tachycardia Decreased consciousness Respiratory depression Hypotension Apnoea Seizures Sinus bradycardia Ventricular arrhythmias Asystole

Question 40

Local anaesthetic toxicity management

Answer 40

Stop administration of local anaesthetic! ABCDE approach including ECG monitoring Lipid emulsion (20% intralipid) 1mL/kg every 3 minutes up to a dose of 3mL\kg Initiate lipid emulsion infusion at a rate of 0.25mL\kg\min Maximum total dose = 8mL\kg

Question 41

Suxamethonium apnoea

Answer 41

occurs in individuals who have a defect in the plasma cholinesterase enzyme which normally breaks down Suxamethonium. Leads to sustained action of the drug

Question 42

Suxamethonium apnoea clinical features

Answer 42

prolonged period of paralysis following administration of Suxamethonium. Rapid desaturation and apnoea.

Question 43

three steps to the analgesic ladder:

Answer 43

Step 1: Non-opioid medications such as paracetamol and NSAIDs Step 2: Weak opioids such as codeine and tramadol Step 3: Strong opioids such as morphine, oxycodone, fentanyl and buprenorphine

Question 44

Hyoscine butylbromide

Answer 44

muscarinic antagonist that will act to decrease pain, nausea and secretions by acting to block muscarinic receptors that cause increased gastric secretions and motility

Question 45

ASA classification

Answer 45

ASA I-A normal healthy patient eg Healthy, non-smoking, no or minimal alcohol use ASA II- A patient with mild systemic disease eg obesity (BMI 30 - 40), well-controlled Diabetes ASA III - A patient with severe systemic disease eg COPD,End-Stage Renal Disease (ESRD) undergoing regularly scheduled dialysis ASA IV- A patient with severe systemic disease that is a constant threat to life ASA V - A moribund patient who is not expected to survive without the operation eg ruptured abdominal/thoracic aneurysm ASA VI- A declared brain-dead patient whose organs are being removed for donor purposes

Question 46

Propofol

Answer 46

Hypnotic IV agents induction agent (to induce unconsciousness) GABA receptor agonist

Question 47

Propofol benefits

Answer 47

Rapid onset of anaesthesia anti emetic properties

Question 48

Propofol adverse effects

Answer 48

Pain on IV injection hypotension Moderate myocardial depression

Question 49

Simple airway manoeuvres

Answer 49

Suction: if visible vomit, blood, secretions or foreign body Head tilt/chin lift Jaw thrust

Question 50

Oropharyngeal airway (OPA) e.g. Guedel

Answer 50

Device sits in pharynx and aligns to cover the airway Easy to insert and use No paralysis required Ideal for very short procedures

Question 51

Nasopharyngeal airway (NPA)

Answer 51

create an air passage from outside the nostril to the pharynx (throat). Useful in patients with a sensitive gag reflex when using OPA They are often used in emergency scenarios Contraindicated in base of skull fracture

Question 52

​​Laryngeal mask airway (LMA)

Answer 52

Supraglottic Airway Device with inflatable cuff Sits over the top of the larynx Very easy to insert Poor control against reflux of gastric contents Paralysis not usually required

Question 53

I-gel

Answer 53

a type of non-inflatable SAD that uses a gel-like cuff that moulds to the larynx.

Question 54

Endotracheal Intubation

Answer 54

The tip of the endotracheal tube is inserted through the mouth, throat (pharynx), larynx and vocal cords into the trachea Inserted using a laryngoscope. Used for prolonged mechanical ventilation.​​Provides optimal control of the airway once cuff inflated Paralysis often required Higher ventilation pressures can be used

Question 55

Tracheostomy

Answer 55

hole is made in the front of the neck with direct access to the trachea. A tracheostomy tube is inserted through the hole into the trachea and held in place with stitches or soft tie around the neck Reduces the work of breathing (and dead space) May be useful in slow weaning Percutaneous tracheostomy widely used in ITU Dries secretions, humidified air usually required

Question 56

Cricothyrotomy

Answer 56

incision made through the skin and cricothyroid membrane to establish a patent airway during certain life-threatening situations, such as airway obstruction by a foreign body, angioedema, or massive facial trauma

Question 57

Non-invasive ventilation options

Answer 57

CPAP (continuous positive airway pressure) BiPAP (bilevel positive airway pressure)

Question 58

CPAP

Answer 58

constant positive pressure added to the lungs to keep the airways expanded. It is used to maintain the patient’s airways in conditions where they are likely to collapse,T1RF adds,covid, sleep apnoea

Question 59

BiPAP

Answer 59

Bilevel positive pressure involves a cycle of high and low pressure to correspond to the patient’s inspiration and expiration T2RF not as commonly used

Question 60

Contraindications for Starting NIV

Answer 60

Facial burns Vomiting Untreated pneumothorax Severe co-morbidities Haemodynamically unstable Patient refusal

Question 61

Inclusion Criteria for Starting NIV

Answer 61

Patient awake and able to protect airway Co-operative patient Consideration of quality of life of patient

Question 62

Mechanical Ventilation

Answer 62

other forms of respiratory support (e.g., oxygen and NIV) are inadequate/ contraindicated. used to move air into and out of the lungs. Patients generally require a level of sedation , as it can be uncomfortable/ distressing. endotracheal tube (ETT) or tracheostomy is required to connect the ventilator to the lungs

Question 63

Extracorporeal Membrane Oxygenation (level 3)

Answer 63

most extreme form of respiratory support and is very rarely used. used where respiratory failure is not adequately managed by intubation and ventilation Blood is removed from the body, passed through a machine where oxygen is added and carbon dioxide is removed, then pumped back into the body.

Question 64

medications that should continue before surgery include

Answer 64

antiepileptics, Parkinson’s medications, asthma inhalers, beta-blockers, proton pump inhibitors, thyroid medications, steroids, immunosuppressants and cancer drugs.

Question 65

medications that should be stopped include

Answer 65

ACE inhibitors, angiotensin-II receptor antagonists, diuretics, antiplatelet/anticoagulant medication, lithium and nonsteroidal anti-inflammatory drugs, coco