Anaesthetics Flashcards
How long should someone not be eating for before and operation?
6 hours
How long should someone be completely NBM for before an operation?
2 hours (no clear fluids!)
Which type of induction is done if someone cannot be fasted?
Rapid sequence induction
Why is preoxygenation done before being put under?
This gives them a reserve of oxygen for the period between when they lose consciousness and are successfully intubated and ventilated (in case the anaesthetist has difficulty establishing the airway).
Which types of medication are given as pre-medication before the patient is put under and why?
Benzos
Opiates (alfentanyl)
Alpha-2-adrenergic agonists (clonidine)
These are given to relax the patient and reduce pain which makes the intubation easier
What is the biggest concern in rapid sequence induction (RSI) and how is this overcome?
Aspiration
Cricoid pressure
What is the triad of general anaesthesia?
Hypnosis
Muscle relaxation
Analgesia
What are the two most common options for IV general anaesthetic?
Propofol
Ketamine
What are the common options for inhaled general anaesthetic?
Sevoflurane
Desflurane (bad for environment)
Nitrous oxide (for children)
Name a depolarising muscle relaxant?
Suxamethonium
Name 2 non-depolarising muscle relaxants
Rocuronium and atracurium
Which agent can be used to reverse the effects of suxamethonium?
Neostigmine
Which agent can be used to reverse the effect of non-depolarising muscle relaxants?
Sugammadex
Which agents carry the largest risk of malignant hypothermia?
Volatile anaesthetics (isoflurane, sevoflurane and desflurane) Suxamethonium
How is malignant hyperthermia treated?
Dantrolene
What are the symptoms of malignant hyperthermia?
Hyperthermia Increased CO2 exhalation Tachycardia Muscle rigidity Acidosis Hyperkalemia
Where is the local anaesthetic injected in a spinal block?
Into the CSF in the sub arachnoid space after the point where the spinal cord ends (usually between L3 and 4 or L4 and 5
What is the difference between an epidural and a spinal block?
In an epidural, local is injected outside of the dura mater so not in the CSF.
In a spinal, the LA is injected into the CSF in the subarachnoid space
Which agent is commonly used in an epidural?
Levobupivacaine (with or without fentanyl)
What are the common adverse effects of an epidural?
Headache (if the dura is punctured, this leads to a dural tap) Hypotension Motor weakness in the legs Nerve damage Infection Haematoma
How do you measure a guedel?
Mouth to angle of the jaw or tooth to tragus
What is the contraindication for inserting an nasopharyngeal airway?
Base of skull fracture
What are the 4 plans in a difficult airway?
A- laryngoscopy and tracheal intubation
B- supraglottic airway
C- face mask ventilation
D- cricothroidotomy
Which types of medications can be given through a central line but not a cannula?
Meds which are too irritating for peripheral circulation
Inotropes, amiodarone, fluids with high K+
What is chronic pain?
Pain which is present for 3 months or more
What is allodynia?
Allodynia refers to when pain is experienced with sensory inputs that do not normally cause pain (e.g., light touch).
Which fibres transmit dull pain?
C fibres
Which fibres transmit sharp pain?
A-delta fibres
Which tracts does pain travel up to the brain in?
Spinothalamic and spinoreticular
What are the two ways of measuring pain?
Visual analogue scale and numerical rating scale
What are the 3 steps of the analgesic ladder?
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
In which patients are NSAIDs contraindicated?
Asthma Renal impairment Heart disease Uncontrolled HTN Stomach ulcers
What are the key side effects of opioids?
Constipation Pruritus Nausea Altered mental state Respiratory depression
Which agent is used to reverse the effects of opioids?
Nalaoxone
What should the breakthrough dose of opioids be?
1/6 of the background dose
What are the key side effects of NSAIDs?
Gastritis Stomach ulcers Exacerbation of asthma Hypertension Renal impairment
What is the equivalent dose of 10mg of oral morphine for IV morphine?
5mg
What is the equivalent dose of 10mg of oral morphine for oral codiene
100mg
What is the equivalent dose of 10mg of oral morphine for oral tramadol?
100mg
What is the equivalent dose of 10mg of oral morphine for oxycodone oral?
6.6mg
What is the equivalent dose of 10mg of oral morphine for diamorphine?
3mg
What is the 3 step pain management programme for secondary chronic pain caused by osteoarthritis?
Oral paracetamol and topical NSAIDs
Oral NSAIDs and PPI
Opiates and codiene
What are the 4 first-line treatments for neuropathic pain?
Amitriptyline
Duloxetine
Gabapentin
Pregabalin
Why is TPN given through a central line?
It is irritating to veins so can cause thrombophlebitis
What are the short term complications of ventilator associated lung injury?
pulmonary oedema and hypoxia
