Anaesthetics Flashcards

(123 cards)

1
Q

Why doe sthe patient need to be fasted before general anaesthetic

A

Reduces the reflux of stomach contents into oropharynx (throat) then aspiration into trachea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does reflux then aspiration lead to pneumonia

A

gastric contents in lungs creates aggressive inflammatory response

leads to pneumonitis - inflammation of lung tissue

then aspiration pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When is there the highest risk of aspiration during general anaesthetic

A

before, during intubation
at extubation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the fasting rules for operations under general anaesthetic

A

6 hours no food or feeds
2 hours no clear fluids - fully nil by mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is preoxygenation

A

100% oxygen for a few minutes before being put under so they have a reserve for the period when they lose consiousness and are successfully intubated and ventilated

in case they are difficult to intubate or anaesthetist has difficult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three classic classes of medications that patients may be given before anaesthetics

A

Benzodiazepines - relax muscles and reduce anxiety - midazolam

Opiates - fentanyl / alfentanyl - reduce pain and hypertensive response to laryngoscope

Alpha-2-adrenergic agonists - clonidine - help sedation and pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is used in emergency scenarios to get control of the airway

A

rapid sequence induction/intubation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What maneouvres can be used to prevent aspiration in RSI?

A

press down on cricoid cartilage (cricoid pressure) to press the oesophagus down

Position the patient pore upright

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the triad of general anaesthesia

A

Hypnosis
muscle relaxation
analgesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can hypnotic agents be delivered

A

intravenous
inhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do hypnotic agents do

A

make the patient unconscious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the intravenous options for hypnotic agents

A

propofol (most common)
ketamine
thiopental sodium (less common)
etomidate (rare)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the inhaled option for general anaesthetic

A

Sevoflurane (most common)
Desflurane (less favourable - bad for environment)
Isoflurane (rare)
Nitrous oxide (kids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are volatile anaesthetic agents

A

liquids at room temperature and need to be vapourised into a gas to be inhaled

e.g. sevoflurane, desflurane and isoflurane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What acts quicker, inhaled or IV general anaesthetic agents?

A

IV agents

Commonly, an intravenous medication will be used as an induction agent (to induce unconsciousness), and inhaled medications will be used to maintain the general anaesthetic during the operation. Inhaled medications need to diffuse across the lung tissue and into the blood, where it takes a while for them to reach an effective concentration. IV agents have a head start, as they are infused directly into the blood and so can quickly reach an effective concentration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is TIVA?

A

Total intravenous anaesthetia used for induction and maintenance - most commonly propofol

nicer recovery compared with inhaled options

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the two classes of muscle relaxants

A

Depolarising
Non-depolarising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are some examples of muscle relaxants?

A

Suxamethonium (depolarising)
Rocuronium and Atracurium (Non-depolarising)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the purpose of muscle relaxants in general anaesthetic?

A

To relax and paralyse muscles
Makes surgery and intubation easier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can you reverse muscle relaxants

A

Neostigmine - cholinesterase inhibitor for depolarising muscle relaxants - for suxamethonium

Sugammadex for non-depolarising ones - rocuronium and vecuronium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where do muscle relaxants act?

A

At the neuromusclular junction - Acetylcholine is blocked from stimulating a response from the muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which opiates are most frequently used

A

Fentanyl
Alfentanil
Remifentanil
Morphine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which antiemetics are given post-procedure for prophylaxis

A

Ondansetron
Dexamethasone
Cyclizine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What class of drug is ondansetron

A

5HT3 receptor antagonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
When is ondansetron avoided
in patients with a risk of prolonged QT interval
26
When should dexamethasone be avoided
in diabetics or immunocompromised patients
27
What class of drug is cyclizine
Histamine (H1) receptor antagonist
28
When should cyclizine be avoided
Elderly patinets and heart failure
29
How can you test if the muscle relaxant has worn off
Nerve stimulator Ulnar nerve - thumb movements / twitches Facial nerve stimulation for orbiulares oculi muscle movement (stimulate four times - Train-of-four)
30
What is the Train-of-Four stimulation
nerve is stimulated four times if it remains strong, muscle relaxant has worn off If it weakens, it hasn't worn off Medication can be used to reverse the effects of the muscle relaxant
31
Whata re the risks of general anaesthesia
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
32
What is malignant hyperthermia
Fatal hypermetabolic response to anaesthesia
33
Which drugs have a higher risk of causing malignant hyperthermia
Volatile anaesthetics (isoflurane, sevoflurane and desflurane) Suxamethonium Antipsychotics - NMS
34
What are some signs of malignant hyperthermia
Increased body temperature (hyperthermia) Increased carbon dioxide production Tachycardia Muscle rigidity Acidosis Hyperkalaemia
35
How cna you treat malignant hyperthermia
Dantrolene
36
How does dantrolene work
Interupts the msucle rigidity and hypermetabolism by interfering with movement of calcium ions in skeletal muscle
37
What is central neuraxial anaesthesia
it is a spinal anaesthetic / spinal block
38
What is central neuraxial anaesthesia used for
Hip fracture repairs Transurethral resection of the prostate C-sections
39
Into which area is the anaesthetic injected for central neuraxial anaesthesia?
Subarachnoid space into CSF Usually into L3/4 or L4/5
40
How long will it take for central neuraxial anaesthesia to wear off
1-3 hours
41
What is epidural anaesthesia and when is it used?
in pregnant women in labour and post-operatively after a laparotomy
42
What medication is used in epidural anaesthesia?
Levobupivicaine with or without fentanyl
43
Where is the epidural anaesthetic injected
into the epidural space outside the dura mater, separate from the spinal cord and CSF
44
What are some adverse effects of epidurals
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, including meningitis Haematoma (may cause spinal cord compression)
45
What are some dangers of epidural in pregnancy
Prolonged second stage Increased probability of instrumental delivery
46
What is allodynia
pain is experienced with sensory inputs that don't cause pain
47
How do you treat local anaesthetic toxicity
IV 20% lipid emulsion
48
What does pain threshold mean
It's the point at which a sensory input is reported as painful, e.g. temperature applied to akin to measure the pain at which the heat is interpretted as pain
49
What is a pain tolerance
a person's response to pain biological, psychological and social factors
50
What are the two groups of nerve fibres that transmit pain
C fibres - unmyelinated and small diameter A-delta fibres - myelinated and larger diameter
51
How do C-fibres transmit pain
Slowly and they produce a dull and diffuse pain sensation
52
How do A-delta fibres transmit pain
Fast and they produce a sharp and localised pain sensation
53
Up which spinal tracts does pain get transmitted?
Spinothalamic and spinoreticular tract
54
Where in the brain is pain interpreted
Thalamus and cortex
55
What is neuropathic pain
Abnormal functioning or damage of the sensory nerves
56
What are some features of neuropathic pain
Burning Tingling Pins and needles Electric shocks Loss of sensation to touch of the affected area
57
What are the two common scales to measure pain
Numerical rating scale (NRS) Visual analogue scale (VAS)
58
What are the three steps of the WHO analgesic ladder
Step 1: Non-opioid - paracetamol and NSAIDs Step 2: Weak opioids - codeine and tramadol (tramadol has multiple mechanisms of action, including being an SNRI and agonist of opioid receptors) Step 3: Strong opioids - morphine, oxycodone, fentanyl and buprenorphine
59
Which medications can be used for neuropathic pain, or as adjuvants with the analgesic ladder?
Amitriptyline - TCA Duloxetine - SNRI Gabapentin - anticonvulsant Pregabalin - anticonvulsant Capsaicin cream (topical) - from chilli peppers
60
What are the main side effects of NSAIDs
Gastritis with dyspepsia (indigestion) Stomach ulcers Exacerbation of asthma Hypertension Renal impairment Coronary artery disease, heart failure and strokes (rarely)
61
Contraindications of NSAIDs
Renal failure Asthma Heart disease Uncontrolled HTN Stomach ulcer
62
Side effects of opioids
Constipation Skin itching (pruritus) Nausea Altered mental state Respiratory depression
63
What medication is used to reverse opioids
Naloxone
64
How do you calculate the rescue dose of an opioid for somone in chronic pain?
Rescue does is 1/6 of the background 24-hour dose
65
How is subcut opioid dose converted to IV?
IV is 1/10 the dose of subcut
66
Which opioids can be given as patches?
Buprenorphine (5mcg = 12mg oral morphine) Fentanyl (12mcg = 20mg of oral morphine)
67
What needs to be on-hand when administering patient-controlled anaesthesia
Naloxone - resp dep Antiemetics - nausea Atropine - bradycardia
68
What options are there for managing chronic pain (NICE guidelines 2021)
Supervised group exercise programs Acceptance and committment therapy (ACT) CBT Acupuncture Anidepressants (amitriptyline, duloxetine or SSRI)
69
Which medications should patients not be started on for Chronic Primary Pain?
Paracetamol NSAIDs Opiates Pregabalin Gabapentin
70
What medications can be used in chronic secondary pain?
1. Paracetamol and topical NSAIDs 2. Oral NSAIDs +/- PPI 3. Opiates - e.g. codeine
71
What questionnaire is used to assess neuropathic pain
DN4 questionnaire
72
What is the first-line medication for trigeminal neuralgia?
Carbamazepine - refer to specialist if this doesn't work
73
What is the standard ET tube size for men and women
7 - 7.5 mm for women 8 - 8.5 mm for men
74
What can be used to check the pressure in the cuff of an ET tube?
Manometer
75
What part of the tube can provides security in the event that the main opening at the tip of the ETT becomes occluded?
Murphy's eye - an extra hole in the side of the tip that gas can flow through
76
What is a laryngoscope with a camera called?
McGrath laryngoscope
77
What can be used to assist intubation if the vocal cords cannot be visualised?
Bougie The bougie is inserted into the trachea. The endotracheal tube slides along the bougie into the correct position in the airway. The bougie is then removed, and the endotracheal tube remains in place.
78
What is the name given to pain and restriction in opening the jaw
Trismus
79
What types of supraglottic airway devices are there?
Inflatable cuff SADs = laryngeal mask airways Non-inflatable SADs = I-gel (moulds to the larynx)
80
What is a guedel
an oropharyngeal airway
81
What is a contraindication for inserting a nasopharyngeal airway
Base of skull fracture
82
How do you measure the correct size for a OPA and NPA?
OPA = from centre of mouth to angle of jaw NPA = edge of the nostril to the tragus of the ear
83
What are the stages to do in the cases of an unanticipated difficulty intubating a patient according to the Difficult Airway Society (DAS) guidelines 2015?
Plan A – laryngoscopy with tracheal intubation Plan B – supraglottic airway device Plan C – face mask ventilation and wake the patient up Plan D – cricothyroidotomy
84
Why would you want an arterial catheter
Measuring blood pressure real-time ABG samples
85
Where is a central venous catheter inserted?
Internal jugular vein Subclavian vein Femoral vein
86
Where does the tip of the CVC sit?
vena cava
87
Which medications would need to be given through a CVC?
inotropes amiodarone high-potassium fluids
88
What are Swan-Ganz catheters?
Pulmonary artery catheters
89
What is used to monitor pulmmonary artery wedge pressure?
Pulmonary artery catheter
90
What is a portacath?
central venous catheter There is a small chamber (port) under the skin at the top of the chest that is used to access the device. This chamber is connected to a catheter that travels through the subcutaneous tissue and into the subclavian vein, with a tip that sits in the superior vena cava or right atrium. The port can be seen as a bump on the chest wall and felt through the skin a needle is inserted through the skin into the port, allowing injections to be given or infusions to be set up
91
Which type of CVC lasts the longest?
Portacath low chance of infection, fully internalised under the skin
92
What scoring systems can predict mortality at time of admission to ICU
APACHE (Acute Physiology and Chronic Health Evaluation) SAPS (Simplified Acute Physiology Score) MPM (Mortality Prediction Model)
93
What are the types of respiratory failure?
- Low PaO2 indicates hypoxia and respiratory failure - Normal pCO2 with low PaO2 indicates type 1 respiratory failure (only one is affected) - Raised pCO2 with low PaO2 indicates type 2 respiratory failure (two are affected)
94
What does a raised bicarbonate indicate?
Chronic CO2 retention - COPD patients
95
Why do patients in acute exacerbation of COPD become acidotic?
Kidneys cannot keep up with rising level of CO2 The patient then becomes acidotic despite having higher bicarb than someone without COPD
96
In respiratory alkolosis, how can you differentiate between hyperventilation syndrome and PE?
PE = low PaO2 Hyperventilation syndrome = high PaO2
97
When will there be a reduced bicarbonate?
Renal failure Type 2 renal tubular acidosis Diarrhoea
98
Which patients will get metabolic alkalosis?
Loss of H+ ions Increased activity of aldosterone in kidneys Vomiting - stomach produces HCl
99
Which conditions cause an increased activity of aldosterone?
Conn's syndrome Liver cirrhosis Heart failure Loop diuretics Thiazide diuretics
100
What electrolyte abnormality can suxamethonium cause
Hyperkalaemia
101
How does lidocaine work
Blocks sodium channels
102
When might suxamethonium be contraindicated
Hyperkalaemia Penetrating eye injury Acute narrow angle glaucoma
103
What intervention reduces incidence of intra-abdominal lesions
Laparoscopic approach over open surgery
104
What monitoring equipment measures the concentration of CO2 exhaled during intubation
Capnography
105
What is the likely organism in a wound infection post-surgery?
Staph aureus
106
Should COCP / HRT be stopped before surgery? If so, when?
Stopped 4 weeks before surgery
107
What might be the cause of isolated fever in a patient 24hrs post surgery
Physiological response to surgery
108
What two differentials would you want to exclude in a patient presenting with pyrexia 24hrs post surgery?
Thrombosis Infection
109
At what time frame would a wound infection present post-operatively?
48 hrs
110
What is the medication of choice for rapid sequence induction?
Suxamethonium
111
At what BMI are patients classed ASA II?
30 - 40
112
When is the "time out" stage of the WHO checklist
Before the first skin incision is made
113
What is the imaging modality used in an anastomotic leak
Abdo CT
114
Which anaesthetic agent has inherent anti-emetic properties?
Propofol
115
How should total parenteral nutrition be administered?
Subclavian line Because it is strongly phlebitic
116
If a patient has diabetes, what management protocol is normally used for surgery?
Put them first on the list Prevents complications of poor BM control
117
What complication can occur in long-term mechanical ventilation in trauma patients?
Tracheo-oesophageal fistula
118
What is the inheritance pattern in malignant hyperthermia
50%
119
When should dalteparin sodium be started for VTE prophylaxis
at least 6 hours post surgery
120
Which induction agent should be used in trauma patients to avoid drops in BP?
Ketamine - doesn't cause a drop in BP
121
What should be used to clean surgical wounds 0-48hrs post-surgery
Sterile saline
122
After how many hours post-surgery may a patient shower safely?
48 hours
123