Anaesthetics Flashcards
what are the 4 stages of anesthesia?
- induction
- maintenance
- emergence
- recovery
what are the main observations (5) taken while someone is under general anesthetic
- ECG (3 lead or 5 lead in vascular)
- 02 saturation (finger, ear, lip, probes)
- Non-invasive BP
- End Tidal C02 (amount of C02 breathed out during a normal breath)
- airway pressure (patency of airway)
Why is end total C02 volume measured?
- patent airway - if gas is leaving the lungs
why is supplemental oxygen given before being put to sleep? (pre-oxygenation)
Safety - remain oxygenaed between awake-sleep
- increase the time until desaturation occurs
- reduced functional residual capacity under anaesthesia (what is left in lungs after a normal breath) important volume because it allows 02 to continue to go into the blood when you are not breathing
- mechanics of breathing decrease (all muscles relax/reduced tension)
which two ways can induction medications be given?
IV injection
or gasesous (takes a little longer)
which 2 classes of drugs are given during induction
- analgesic (fast actin opiate)
- hypnotic
- muscle relaxantt (not always)
what are the planes of anaesthesia in regards to consciousness?
- conscious sedation (analgesia and amnesia)
- delirum to unconsciousness (disinhibited)
- surgical anestheisa*** - no movement or response
- Apnoea to death (not breathing, autonmoic dysfunction, arrythmias, CV instability)
why is airway management important?
- there is a loss of airway reflex
- and relaxation of tissues
(no longer cough in response to secretions being in the larynx, swallow or protect lungs) - all of the soft tissues are relaxed
what is the triple airway manouvere
- head tilt
- jaw thrust
- open mouth
*this is done everytime
an endotracheal tube (ETT) passes beyond the vocal cords
a. true
b. false
a. true
stops anything going into patients lungs - FULLY PROTECTS THE AIRWAY and is positive pressure management
what device is needed to fit an endotracheal tube?
laryngoscope
reasons to intubate a patient?
- fully protect airway - from aspiration
- need for muscle relaxation
- shared airway (Surgery in the airway)
- need for tight C02 control -
- minimal acess to patient
if complete control is needed!
name three ways patients breathing can be described
- spontaneous ventiliation - breathes for themselves
- controlled ventilation - you do it for them
- supported ventilation - help/halfway boost
how often is BP checked
every 5 minutes
risks associated with anaesthetics
- anaphylaxis (lots of IV drugs)
- regurgitation and aspiration (stomach content - into lungs) - manage airway
- airway obstruction and hypoxia (pre-oxygenate)
- larnygospasm (stimulates vocal cords - snap shut)
- cardiovascular instability
- cardiac arrest
- eye trauma
- VTE
- pressure injury
- hypothermia
- nerve injury
-> also awareness (sounds, pain,)
why are the eyes taped shut?
risk of corneal abrasion
there is a risk of hypothermia
a. true
b. false
a.true
- open body cavity, exposed
(cover all areas, blow hot air)
which nerves are often at risk due to long term positioning
the common perineal nerve (fibula head)
ulnar nerve (elbow)
brachial plexus
how is anaestheisa maintained
- vapour - gas
- IV anaesthesia (TIVA) continuous infusion
what is documented
- prescription record of drugs used
- observation NEWS chart
- Ventilation chart
- fluid balance
how does emergent phase occur
reversal of neuromuscular blocks
anaesthic agent is stopped
(there is return of spontaneous breathing and airway reflexes i.e. swallowing and couhging, suction and removal of airway device) transfer to recovery
what happens in recovery
- manage ABC until awake
- analgesia
- management of nausea
- handover to ward
what is the triad of drugs in anaestheisa
- analgesia
- hypnotics
- paraylsis
outline IV induction phase
- propofol + opiod
+/- muscle relaxant
outline inhalational induction
volatile (Sevoflurane)
outline inhalation maintance
volatile (sevoflurane) +/- opioid
outline IV maintainece
propofol +/- opioid (TIVA)
+/- muscle relaxant
which label colour are for induction agents?
YELLOW
most common induction agent?
propofol (hyponotic) 1%
yellow label - activates inhibitory channels (GABA-A)
sevoflurane (hypnotic) for inhaled
propofol reduces the resting membrane potential
a. true
b. false
a. true
-90-> more negative - cannot get excited
what colour of label are opiates in
blue
usually given with an induction agent , thoughtout and at the end
when are opioids usually given
with induction agent, throught and end
short acting opiates
fentanyl
afentanyl
given as bolus -do not accumulate
morphine is a weaker opiate with slower onset (5 mins IV),
a. true
b. false
a. true
has a longer duration of action
what is remifentanyl
opioid often given as part of TIVA as infusion because it does not accumulate
what colour of labour are muscle relaxanats
red label
- work at neuromuscular junction (block ACh receptors)
- only given once asleep/when sleeping
How does anaesthetics affect CVS
reduces MAP because it reduces
HR and SV (reduced BP)
reduces systemic vascular resistence
MAP = CO x SVR
effect of anaesthetis on RR
RR and tidal volume are reduced due to depresison of respiratory centres
why patients are ventilated or tube
type 1 respiratory failure
oxygenation failure
- give 02 and it will go up
hypoxaemia (PaO2 <8 kPa / 60mmHg) with normocapnia (PaCO2 <6.0 kPa / 45mmHg)
type 2 respiratory failure
oxygenation and ventilation
- C02 clearance is also poor - usually something needing to be fixed re. mechanisms of breathing
hypoxaemia (PaO2 <8 kPa / 60mmHg) with hypercapnia (PaCO2 >6.0 kPa / 45mmHg)
BiPAP
more commonly used in type 2 respiratory failure because it provides two levels of pressure: a higher inspiratory pressure (IPAP) and a lower expiratory pressure (EPAP). This helps to assist both ventilation (getting rid of CO2) and oxygenation (getting O2 into the lungs).
CPAP
e helpful in maintaining airway pressure and preventing collapse of alveoli, is more commonly used for oxygenation support in conditions like type 1 respiratory failure (hypoxemic respiratory failure).
what is shock
acute circulatory failure with inadequete distributed tissue persuion resulting in cellular hypoxia
cardiogenic shock is due to
pump failure - of heart (HF, ACS)
What is hypovolaemic shock due to
loss of blood - GI, or high output from stomas
response to septic shock
dilated BP vessels cause BP to drop
-> give fluids
what 3 factors affect Stroke volume
- preload
- contracility
- afterload
where might an arterial line be inserted
radial, brachial, femoral
- blood samples for ABG
where might central line be inserted
big vessels near the heart
metoclopramide mechanism of action?
Dopamine antagonist - via D2 receptors in chemoreceptor trigger zone
also 5HT3 antagonist in CTZ
XparkinsonsX
treatment for toxicity of local anaesthetisia
IV intralipid (binds to and neutralises the local anaesthetic agents)
COCP advice before surgery
stop 4 weeks before
how to manage patients on regular steroids over surgery
increase steroids (IV) - prevent adrenal sufficiency
and restart oral once 48-72 hours post op
increase to account for stress response in surgery.
s
side effect of suxamethonium (muscle relaxant)
malignant hyperthermia
(Can occur due to some general anesthesia meds)
- rapid increase in body temperature, muscle regidity and metabolic acidosis, tachycardia, increased exhaled nitric oxide
autosomal dominant mutation in ryanodine receptor 1
sign of malignant hyperthermia
- rapid rise in body temperature
- muscle rigidity
- metabolic acidosis
- tachycardia
- increased exhaled nitric oxide
due to mutation autosomal dominant in the ryanodine receptor 1
recommended fluid intake per day
25-30ml/kg
consider deficits when calculating
e.g 500ml in deficient (need to add + 500ml to total)
what is assessed in GCS
“EVM = 4-5-6” rule:
🔹 Eye Opening (4 points) → “4 eyes” 👀
🔹 Verbal Response (5 points) → “5 voices” 🗣️
🔹 Motor Response (6 points) → “6 moves” 💪
eye opening assessment in GCS
1️⃣ No response
2️⃣ To pain
3️⃣ To voice
4️⃣ Spontaneous
verbal response assement in GCS
1️⃣ No response
2️⃣ Incomprehensible sounds
3️⃣ Inappropriate words
4️⃣ Confused
5️⃣ Oriented
motor response assement in GCS
1️⃣ No response
2️⃣ Abnormal extension (decerebrate)
3️⃣ Abnormal flexion (decorticate)
4️⃣ Withdraws from pain
5️⃣ Localizes pain
6️⃣ Obeys commands
reccomended flui balance per day
25-30ml/kg
what reading is used to confirm sucessful intubation?
End-tidal C02 - confirms tube is in the right locations
measures PC0 at the end of expiration - built into ventilators and used in anesthetics
best management of patient presenting with C-spine injury
maintain neural neck position and CT spine
patient has altered mental status and responsiveness
+ airway obstruction due to tongue falling back
which is most appropritate airway adjunct to use?
oropharyngeal OPA
maintains open airway in unconscious or semi-conscious patients by preventing the tongue from falling back and obstructing the airway
suitable in decreased responsiveness
laryngeal mask used when other adjucvents fail
when is nasopharyngeal airway appropriate
maintained gas reflexes
- better tolerated/less likely to induce vomiting
airway management when high risk of aspiration
endotraheal tube
when is NIV used in COPD
acute hypercapnic respiratory failure
e.g. respiratory acidosis < pH < 7.35 with an elevated PC02
treatment for isolated hypoxemia with low PC02
oxygen therapy
when not to do a head tilt /chin lift
potential for C-spine injury in head trauma
when in oropharngeal airway used
in unconscious patients with an airway obstruction after basic manouveres
when to use suction
vomit, blood, secretions or foregin body
turn patients onto side if vomiting (and no C-spine injury)
(First-line in unconscious patients without trauma)
head tilt-chin lift
(no C-spine injury)
if trauma is suspected -> jaw thurst (suspected C spine injury)
2 Airway Adjuncts (If maneuvers are not sufficient) and when would you use them
Oropharyngeal Airway (OPA) – For unconscious patients with no gag reflex.
Nasopharyngeal Airway (NPA) – For semi-conscious patients or those with a gag reflex
how is OPA adjuent measured before insertion
incisors to the angle of the jaw
inserted upside down and rotated 180 degrees to hold the tongue away from posteror pharynx
when is NPA adjunt contraindicated?
base of skull fracture
what is a supraglotti ariway management
larnygeal mask airway (LMA) or i-gel
- flexible plastic tube with inflatable cuff sits over the top of the larynx
- can be used with ventilation machine
where is the placement of supraglotti airway management
Above the vocal cords (larynx)
when is the placement of enotrachial tube
Inside the trachea (through the vocal cords)
degree of airway protection in supraglotti airway
Partial (no protection from aspiration)
degree of airway protection in endotracheal tube?
full - protects from aspiration
. If the patient requires definitive airway protection & mechanical ventilation
endotracheal tube ETT
stages of anaesthesia
- perioperative assessment and planning (nurse clininc of aneastehtist)
**2. Preparation (machince , equipment heck , medication and patient positioning)
**3. induction
- maintaince
- emergece
- recovery (area of threate)**
- post-operative care
key stages
1, preparation
2. induction
3. maintainence
4. emergence
5. recovery
PIMER
what is the triad of anaesthesia in induction
- analgesia
- hyponotic
- muscle relaxant
what analgesia may be used in induction
* remifentanil
* fentanyl
* afentanil
hypnotic drugs used in induction
propofol - IV (Gold standard)
thiopentone
katamine
muscle relaxant used for induction
reocuronium
(not always used)
inhaled method of hynotic induction in adults
Sevoflurane
is a volatile inhalational anesthetic commonly used for induction and maintenance of general anesthesia. It is widely preferred due to its rapid (less rapid than propofol) onset, quick recovery, and minimal airway irritation.
colour of hypnotic agent labels
yellow
IV hypnotic agents
propofol
rapid induction 30/40seconds
also ant-emetic
inhaled hypnotic agents
1.sevoflurane
(or nitric oxide)
colour of opiod analgesia labels
blue
opiod agents of analgeisa commonly used? in anaesthetics
- remifentanil -potent, quick acting, rapid offset, doesnt accumulate due to extremely short half life (often used for TIVA)
fentanyl/alfentanil also rapid onset/offset
morphine - weak/sloweronset/ longer duration of action
label colour for muscle relaxants
red e.g.
suxamethonium (depolarising acetylcholine receptor agonist)
key role of anesthetists
peri-operative care
peri-operative assessment
pain medicine
critical care/ICU
anaesthesia
most common cause of malignant hyperthermia
autosomal dominant mutaition in the ryanodine receptor 1
triggered by some inhaled anaesthetics (Sevoflurane or suxamethonium)
common side effect of central line insertion
pneumothroax - (direct trauma to pleura)
-> pleuritc type chest pain
medicatons of neuropathic pain
amitrpytyline -TCA
duloxetine- SNRI
pregabalin
gabapentin
investigationof choice for base of skull fractures
CT head
why is oral morphine not good for acute pain?
slower onset of action (and gastric absorption may be unreliable in acutely unwell patients) - if concerns about abdominal trauma
need IV (IV opiods preferred for immediate pain relief for moderate-severe pain)
signs of sepsis – treatment
iniate sepsis6!!!
+ a-e
treatment of trigeminal neuralgia
carhamazepine
How is the rescue dose of opioids calculated when used for pain management in palliative care? (1)
1/6 of the background 24-hour dose
pain ladder steps + 2 examples
Step 1: non-opioid medications
E.g., paracetamol
E.g., NSAIDs
Step 2: weak opioids
E.g., codeine
E.g., tramadol
Step 3: strong opioids
E.g., morphine
E.g., oxycodone
Which inhaled medication is most commonly used to maintain general anaesthesia? (1)
Sevoflurane
What effect do vasopressors have on the cardiovascular system? (1)
They cause vasoconstriction, increasing the systemic vascular resistance and consequently mean arterial pressure (MAP)
Which class of drug, used as premedication, can help reduce the hypertensive response to the laryngoscope during intubation? (1)
opiates
What effect do positive inotropes have on the cardiovascular system? (1)
improve contractiliy
How is the size of an oropharyngeal (Guedel) airway measured to ensure the correct size for the patient? (1)
From the centre of the mouth to the angle of the jaw
Which term refers to the volume of air pushed in per breath during mechanical ventilation? (1)
tidal volume
What is the most extreme form of respiratory support, where respiratory failure is not adequately managed by intubation and ventilation? (1)
Extracorporeal membrane oxygenation (ECMO)
What is the difference between CPAP and non-invasive ventilation (or BiPAP)? (1)
CPAP provides constant pressure and NIV provides a cycle of high and low pressure to correspond to the patient’s inspiration and expiration
What is the treatment for malignant hyperthermia? (1)
dantrolene
Where is the anaesthetic agent injected to achieve spinal anaesthesia? (1)
CSF in subarachnoid space
Which term refers to the amount that the heart muscle is stretched when filled with blood just before a contraction? (1)
preload
How long do patients typically need to avoid eating before a general anaesthetic? (1)
6 hours
What is sugammadex used for? (1)
To reverse the effects of certain non-depolarising muscle relaxants (e.g., rocuronium and vecuronium)
treatment for BPH
Alpha-blockers (e.g., tamsulosin), which relax smooth muscle, giving a rapid improvement in symptoms
5-alpha reductase inhibitors (e.g., finasteride), which gradually reduce the size of the prostate
type of bladder cancer
Schistosomiasis is a risk factor for squamous cell carcinoma of the bladder. SCCs are more common in countries where schistosomiasis is present.
Transitional cell carcinoma accounts for 90% of bladder cancers in places where schistosomiasis is rare (e.g., the UK). Aromatic amines are worth noting as carcinogens that cause transitional cell carcinoma.
fine touch and vibration - which part of spine
dorsal column
how does propofol
Propofol primarily works by enhancing GABAergic inhibition in the central nervous system (CNS):
how does suxamthonium work?
depolarising muscle relaxant
nicotinic acetylcholine receptor (nAChR) agonist at the neuromuscular junction (NMJ).
ostsynaptic ACh receptors at the motor endplate, causing persistent depolarization.
fasting duration
6 hours food
2 hours no clear fluids
triad of anaesthesia
- hypnotic
- analgesia
- muscle relaxant
top hypnotic agents
1. IV
2. inhaled
- propofol
- sevoflurane
suxamethonium is a ?
depolarising muscle relaxant
sevoflurane is a?
volatile anaestheic agent
recoronium is ?
a non polarising muslce relaxant
neostigmine is a?
cholinesterase inhibitor
midazolam is a ?
benzodiazepine
how to measure oropharyngeal airway
centre of the mouth (incisors) to the angle of the jaw
how to measure nasopharyngeal airway
edge of the nostril to the tragus to the ear
spinal tracts that transmit pain?
spinothalamic
spinorecticular
analgesic ladder
- non-opiods (paracetemol/nsaids)
- weak opiods (coedine)
- strong opiods (morphine)
neuropathic drugs
amitryline
duloxetine
gabapentine
pregabalin
how to calculate the RESCUE dose of opiates?
1/6th of the BACKGROUND DOSE!!!
Central lines are placed in
large central veins to provide venous access for medications, fluids, and monitoring.
- internal jugular line
subclavian
PICC (upper arm basilic or cephalic) - long term IV
Arterial lines are placed in
arteries for continuous blood pressure monitoring and blood gas sampling.
Radial Artery Line Wrist (radial artery) Continuous BP monitoring, frequent blood gas analysis
what is Fi02
fraction of inhaled oxygen
normal Ph
7.35-7.45
amount the heart is stretched with blood before contraction
preload
resistance the heart must overcome to eject blood
afterload
resistance to blood flow in the systemic circulation
systemic vascular resistance
what is monitored to estimate preload
central venous pressure
what is given to increase preload
IV fluids
inotropes
increase contractility of the heart
vasopressors
cause vasocontriction , increasing systemic vascular resistance
indications for haemodialysis AEIOU
a- acidosis
e- electrolyte abnormalities (hyperkalaemia)
i- intoxication
o- oedema - severe pulmonary
u - ureamia - seizures/reduced consciousness
What is the treatment for malignant hyperthermia? (1)
Dantrolene
What is the difference between CPAP and non-invasive ventilation (or BiPAP)? (1)
CPAP provides constant pressure and NIV provides a cycle of high and low pressure to correspond to the patient’s inspiration and expiration
What adverse effect can epidural anaesthesia have on labour and delivery? (2)
Prolonged second stage
Increased probability of instrumental delivery
Which two factors contribute to the mean arterial pressure? (2)
CO×SVR
Which term describes anaesthetic agents that are liquid at room temperature and need to be vaporised into a gas to be inhaled? (1)
volatile
What position may help improve blood flow to the lungs and increase oxygenation in patients with acute respiratory distress syndrome? (1)
Prone positioning (lying on their front)
What is the most extreme form of respiratory support, where respiratory failure is not adequately managed by intubation and ventilation? (1)
Extracorporeal membrane oxygenation (ECMO)
What are the two categories of muscle relaxants that may be used during a general anaesthetic? (2)
Give examples of each. (2)
Depolarising
E.g., suxamethonium (depolarising)
Non-depolarising
E.g., rocuronium or atracurium (non-depolarising)
What is the triad of general anaesthesia? (3)
Hypnosis
Muscle relaxation
Analgesia
Which class of drug is typically used as premedication to relax the muscles and reduce anxiety before a general anaesthetic? (1) Give an example of this class of drug? (1)
Benzodiazepines
Midazolam
What is sugammadex used for? (1)
To reverse the effects of certain non-depolarising muscle relaxants (e.g., rocuronium and vecuronium)
What are the two groups of nerve fibres that transmit pain? (2)
Which of these is myelinated? (1)
Which has a larger diameter? (1)
C fibres
A-delta fibres
A-delta fibres (myelinated)
A-delta fibres (larger diameter)
Which intravenous medication is most commonly used to induce general anaesthesia? (1)
propofol
Where are the most common sites for insertion of a central venous catheter? (3)
Internal jugular vein
Subclavian vein
Femoral vein
Give an example of an alpha-2-adrenergic agonist that may be used as premedication before a general anaesthetic. (1)
clonidine
What is the first step in maintaining cardiac function and cardiac output in an unwell patient? (1)
optimise fluid status
Which class of medications do the NICE guidelines (2021) state as an option for managing chronic primary pain? (1)
Antidepressants (e.g., amitriptyline, duloxetine or an SSRI)
What type of line is inserted into a peripheral vein and fed through the venous system until the tip is in a central vein (the vena cava)? (1)
Peripherally inserted central catheter (PICC line)
Give two examples of antimuscarinic medications used to treat bradycardia? (2)
Glycopyronium
Atropine
Which term describes the situation where pain is experienced with sensory inputs that do not normally cause pain (e.g., light touch)? (1)
Allodynia
Which term is used to describe the return of consciousness at the end of general anaesthesia? (1)
Emergence
class of drug is fentanyl
opioate
Commonly used in elective and emergency scenarios as an alternative to full intubation.
supraglottis airway device
Inserted and left in place during full intubation.
endotracheal tube
Lidocaine.
is a
local anesthetic
A product of cardiac output and systemic vascular resistance.
MAP
The resistance that the heart must overcome to eject blood from the left ventricle, through the aortic valve and into the aorta.
afterload
The amount that the heart muscle is stretched when filled with blood just before a contraction.
preload
Rocuronium
non depolarising neuromuscular blocking agent
Inserted into the oropharynx to create an air passage from in front of the teeth to the base of the tongue, maintaining a patent upper airway.
Oropharyngeal -> guedal
Sevoflurane.
volatile anaesthetic agent
volatile anesthetic agents, which are liquid anesthetics that evaporate into a gas and are administered via inhalation to induce or maintain general anesthesia. These agents are delivered through a vaporizer and inhaled by the patient, allowing for rapid onset and easy control of anesthesia depth.
A small tube inserted into the lower back, with the tip outside the dura mater, allowing local anaesthetic agents to be injected to provide pain relief in labour.
epidural
is a non-competitive (or depolarising) muscle relaxant, which works by inducing prolonged depolarisation of the skeletal muscle membrane. Clinically, this manifests as fasciculations (a number of un-coordinated muscle contractions/twitches) which last for a few seconds before profound paralysis occurs. Please note that succinylcholine tends to be used as a muscle relaxant only for select cases, usually for rapid sequence intubation in emergency settings. This is because it has one of the fastest onsets and shortest duration of action among the muscle relaxant drugs.
Suxamethonium
Binds to nicotinic acetylcholine receptors resulting in persistent depolarization of the motor end plate
Succinylcholine (also known as suxamethonium)
depolarising muscle relaxant
side effects of suxamethonium
Malignant hyperthermia
Hyperkalaemia (normally transient)
The muscle relaxant of choice for rapid sequence induction for intubation
May cause fasciculations
suxamethonium
Tubcurarine, atracurium, vecuronium, pancuronium
are
non depolarising muscle relaxants
