Anaesthetics Flashcards
Triad of analgesia
Hypnosis
Muscle relaxation
Analgesia
Most common IV Hypnotic agents
Propofol (the most commonly used)
Ketamine
Thiopental sodium (less common)
Most common inhaled Hypnotic agents
Sevoflurane (the most commonly used)
Desflurane (less favourable as bad for the environment)
Nitrous oxide (combined with other anaesthetic medications – may be used for gas induction in children)
volatile anaesthetic agents - explain
Liquid at room temperature
Administered inhaled and so need to be vaporised
Depolarising Muscle relaxant
suxamethonium
Non-depolarising Muscle relaxant
rocuronium and atracurium
Which drugs can reverse the effects of neuromuscular blocking medications
Cholinesterase inhibitors (e.g., neostigmine)
Which is used specifically to reverse the effects of certain non-depolarising muscle relaxants
Sugammadex
Malignant hyperthermia cause
hypermetabolic response to anaesthesia. The risk is mainly with:
Volatile anaesthetics (isoflurane, sevoflurane and desflurane)
Suxamethonium
Surgical anti-emetics
Ondansetron (5HT3 receptor antagonist) – avoided in patients at risk of prolonged QT interval
Dexamethasone (corticosteroid) – used with caution in diabetic or immunocompromised patients
Cyclizine (histamine (H1) receptor antagonist) – caution with heart failure and elderly patients
Malignant hyperthermia causes what symptoms?
Increased body temperature (hyperthermia) Increased carbon dioxide exhalation Tachycardia Muscle rigidity Acidosis Hyperkalaemia
Malignant hyperthermia Tx
dantrolene
Surgical analgesia
Fentanyl
Alfentanil
Remifentanil
Morphine
What is train-of-four (TOF)
nerve is stimulated four times to see if the muscle responses remain strong - (usually ulanr nerve or facial nerve)
Pre-surgical fasting
6 hours of no food or feeds before the operation
2 hours of no clear fluids (fully “nil by mouth”)
Central Neuraxial Anaesthesia location and why?
Caesarean sections
Transurethral resection of the prostate (TURP)
Hip fracture repairs
L3/4 or L4/5 subarachnoid spaces.
AKA spinal block - different to Epidural
Epidural Anaesthesia location
epidural space in the lower back. This is outside the dura mater, separate from the spinal cord and CSF
Usually Levobupivacaine is often used, with or without fentanyl.
When Epidural used for analgesia in labour, the risks include:
Prolonged second stage
Increased probability of instrumental delivery
Stages of difficult airway management
Plan A – laryngoscopy with tracheal intubation
Plan B – supraglottic airway device
Plan C – face mask ventilation and wake the patient up
Plan D – cricothyroidotomy
respiratory alkalosis most common causes
hyperventilation syndrome - High PaO2
PE - low PaO2
Causes of metabolic acidosis
Raised lactate – lactate is released during anaerobic respiration (indicating tissue hypoxia)
Raised ketones – typically in diabetic ketoacidosis
Increased hydrogen ions – due to renal failure, type 1 renal tubular acidosis or rhabdomyolysis
Reduced bicarbonate – due to diarrhoea (stools contain bicarbonate), renal failure or type 2 renal tubular acidosis
Metabolic alkalosis features
Raised pH
Raised bicarbonate
Metabolic alkalosis causes
Loss of H+ ions - from:
Gastrointestinal tract – due to vomiting (the stomach produces hydrochloric acid)
Kidneys – usually due to increased activity of aldosterone, which results in hydrogen ion excretion
