Anaesthetics & critical care Flashcards
three types of anaesthesia?
- general
- regional
- local
three components of general anaesthesia (GA)?
AAA
Amnesia
- lack of response and recall to noxious stimuli (Unconsciousness)
Analgesia
Akinesis
- immobililsation / paralysis (nb don’t need this in every surgery)
What are the 5 stages to general anaesthesia (in chronological order)?
1) Monitoring
2) Intravenous access (To give anaesthetic drugs)
3) Start the process:
- analgesia
- Induction of anaesthesia (Induction agents)
- Start the muscle relaxation (if needed)
4) Maintain the process
- Maintenance agents for amnesia / analgesia / muscle
relaxation, replace fluid & blood loss
5) Reverse the process
- Reverse muscle relaxation
- Maintain post operative
analgesia
What are the MINIMUM things you should monitor during a GA?
- airway gases? 3
- only if a muscle relaxant is used? 1
- other things? 5
airway gases
- oxygen
- carbon dioxide
- vapour
nerve stimulator (if muscle relaxant used)
- airway pressure
- SpO2 (sats)
- ECG
- BP (non-invasive)
- temperature monitoring (if indicated)
Why do you monitor airway pressure during GA?
to detect if a blockage in airways occurs (eg tube kinks)
Also will detect any other problems like clots etc in thorax
How long can people be hypoxic before irreversible brain damage occurs?
3-5 minutes
Which operations should you monitor temperature in?
any op lasting >30mins
nb if low temp then will delay wound healing as get coagulopathies
Why is IV access harder to get preoperatively
people have been fasting and / or are sick
How long do induction agents take to work?
Induce loss of consciousness in one to two
arm-brain circulation times
10-20 secs
What are the 4 most commonly used induction drugs?
- propofol
- thiopentone
- ketamine
- etomidate
Propofol
- what does it look like?
- pros? 2
- unwanted effects? 3
most commonly used induction agent
white emulsion (only thing that’s white)
pros:
- excellent suppression of airway reflexes
- decreases incidence of PONV
unwanted effects
- marked drop in HR & BP
- pain on injection
- involuntary movements
nb involuntary movements are normal - don’t mean need more propofol
what is PONV?
post-operative nausea & vomiting
What effect does each of the 4 induction agents have of BP & HR?
propofol
- lowers BP
- lowers HR
thiopentone
- lowers BP
- raises HR
Ketamine
- raises BP
- raises HR
(also bronchodilation)
Etomidate
- no significant change to BP
- no significant change to HR
Thiopentone
- type of drug?
- mainly used for?
- advantages? 2
- unwanted effects? 4
Barbituate
rapid sequence induction (though propofol can also be used)
- faster-acting than propofol
- anti epileptic properties (& protects brain)
unwanted effects:
- Drops BP but rise in HR (think of it like drops BP as normal but because used for ‘‘rapid’ induction, HR increases)
- rash / bronchospasm
- if do intraarterial injection: thrombosis & gangrene
- contraindicated in porphyria
“thioPENtone - haven’t got time to WRITE before they go to sleep, also you use your BRAIN to use a PEN”
Ketamine
- what type of amnesia does it provide?
- which operations most commonly used for?
unwanted effects? 4
Dissociative anaesthesia
- anterograde amnesia & profound
use as sole analgesics for short procedures (as short, can get away with lower doses, which are much less likely to induce emergence phenomenon)
- slow onset (90secs)
- rise in BP & HR (also bronchodilation)
- nausea & vomiting
- emergence phenomenon (ie hallucinations / vivid dreams)
“ket is a stimulatant so explains rise in BP, HR & bronchodilation - also want to throw up after seeing weird hallucinations”
Etomide
- when mainly used?
- advantages? 3
- unwanted effects? 4
If heart failure or very unstable heart
(due to its haemodynamically stable properties)
- rapid onset
- haemodynamic stability (no big effect on BP or HR)
- lowest incidence of hypersensitivity reaction
unwanted effects - pain on injection - spontaneous movements - adreno-cortical suppression (can cause post-op adrenal collapse up to 72hrs after surgery) - high incidence of PONV
“ETO sounds like ISO - so keeping cardiac obs the same!”
Best induction agent for:
- pt requiring a burn dressing change?
- pt undergoing arm operation under GA with an LMA?
- pt with history of heart failure?
- pt with intestinal obstruction requires emergency laparotomy?
- pt with porphyria comes for inguinal hernia repair?
pt requiring a burn dressing change
= ketamine
pt undergoing arm operation under GA with an LMA?
= propofol
pt with history of heart failure?
= etomidate
pt with intestinal obstruction requires emergency laparotomy
= thiopentone (can do modified RSI with propofol)
pt with porphyria comes for inguinal hernia repair
= propofol (no thiopentione)
how long to induction agents work?
What two ways can you maintain amnesia after this? 2
4-10 mins
total intravenous anaesthesia
- propofol infusion
inhalational anaesthesia
- inhalational agents
Three most common inhalational agents for maintenance of amnesia?
suffix?
when are they stopped?
isoFLURANE
sevoFLURANE
desFLURANE
suffix = -flurane
“FLU keeps you wiped out”
(nb also enflurane but this rarely used)
can be continued to the end of the operation
MAC:
- what does it stand for in anaesthesia
- what is it / does it mean?
MAC = minimum alveolar concentration
CONCENTRATION of the anaesthetic vapour that PREVENTS the REACTION to a standard surgical STIMULUS (traditionally a set depth & width of skin incision) in 50% OF SUBJECTS
100% will have amnesia at this concentration though
Inhalational agents
- 3 most common and their main useful properties (and thus what they’re used for)
SevoFLURANE
- sweet smelling
- inhalational induction (especially when child or needle phobic)
- “S for Sweet Smelling”
desFLURANE
- low lipid solubility (so rapid onset & offset)
- used for long operations
- “DESmond tutu lived for a LONG time - used for LONG ops”
isoFLURANE
- least effect on organ blood flow
- used for organ retrieval from a donor
- “ISO stays in the SAME place, ie in the blood, not the organs”
Bets inhalational agent for:
- a long 8-hour finger re-implantation?
- chubby child, no IV access?
- organ retrieval from a donor?
a long 8-hour finger re-implantation
= DESflurane
chubby child, no IV access
= SEVOflurane
organ retrieval from a donor
= ISOflurane
Why do you use analgesia during GA? 3
- insertion of airway (LMA or IV) - suppress response to laryngoscopy
- intraoperative pain relief
- post-op pain relief
Two different types of STRONG opioids used in surgery:
- drug examples?
- drugs most commonly used?
- what each type used for?
SHORT-ACTING OPIOIDS
used for: - intra-op analgesia - suppress response to laryngoscopy - surgical pain RAPID onset, HIGH potency
Examples:
- remiFENTANIL
- alFENTANIL
- FENTANYL (commonest)
LONG-ACTING OPIOIDS
used for
- intra-op analgesia
- post-op analgesia
- morphine
- oxycodone (commonest)
When do you start giving analgesia in an operation?
BEFORE anaesthetic induction drug given (so analgesia has time to work before you intubate someone - which is v painful)
Other analgesia (ie not strong opioids) used in and peri-surgery?
which 2 most commonly used?
- paracetamol (common)
NSAIDS
- diclofenac
- parecoxib
- ketorolac
weaker opioids
- tramadol
- dihydrocodeine (common)
Which two NSAIDs are given IV?
parecoxib
ketorolac
most commonly used analgesic?
paracetamol
most commonly used ORAL opioid in adults?
codeine
Which surgeries do you need to give muscle relaxant for?
ones where pt is INTUBATED
***I think - check this though!!
What are the two TYPES of muscle relaxant?
what’s different about them physiologically?
DEPOLARISING
- Ach mimic, depolarises post-synaptic membrane at NMJ a lot, overstimulates muscle until it exhausts and stops
- get fasiculations then flaccid paralysis
NON-DEPOLARISING
- blocks Ach receptors on post-synaptic membrane, preventing any depolarisation
- just get flaccid paralysis
Depolarising muscle relaxant:
- examples?
- speed?
- what used for?
- adverse effects?
- reversal needed?
DEPOLARISING
- SUXmethonium
- “it SUCKS apart from when stomach has stuff in so could do with a SUCK”
- rapid onset, rapid offset
- used for rapid sequence induction
adverse effects
- muscle pains
- fasiculations
- hyperkalaemia
- malignant hyperthermia
- rise in ICP, intra-occular pressure & gastric pressure
“all these side effects make sense as these drugs stimulate lots of muscle action till it’s ‘worn out’”
no reversal needed
Non-depolarising muscle relaxant:
- examples?
- speed?
- what used for?
- adverse effects?
- reversal needed?
NON-DEPOLARISING
short acting
- atraCURium
- mivaCURium
intermediate acting
- veCUROnium
- roCUROnium
long-acting
- panCUROnium
“CURare is the muscle relaxant used in the amazon”
“CURE is better, these are better than depolarising”
“ROCuronium ROCKS, so is often used in preference to SUX, even in RSI”
slower onset & variable duration
INTERMEDIATE ones normally used for most surgeries then repeat dose if need to
less side effects (?any?**)
yes, reversal needed
What reversal drugs are used to reverse non-depolarising muscle relaxants? 3
which is the best, but expensive, one?
normal ones used with most ops:
- neoSTIGmine AND glycoPYRrolate TOGETHER
SUGGAmadex (expensive, but fast, use in emergencies)
“a SUCKER for the most expensive drugs”
Common drugs used to treat HYPOtension during surgery? 3
which used when?
(these are all vasopressors)
what are these drugs also known as
epipHEDrine
- raises BP AND HR
- “gets blood to the HEAD by increasing both”
phenylEPHerine
- raises BP (no effect on HR)
- “EH can only be bothered to raise BP”
^two most commonly used
“sounds like epinepherine - ie adrenaline which is also a vasopressor”
metaraminol
- raises BP (no effect on HR)
aka INOTROPES
- they increase the contractility of muscles, and so increase the contractility of the heart but also cause vasoconstriction as muscles in blood vessel walls also constrict
Vasopressor drugs used to treat SEVERE HYPOtension, and in ICU? 3
- noradrenaline
- adrenaline
- dobutamine
Best vaso-active agents to treat hypotension:
- low BP, high HR?
- low BP in severe sepsis?
- low BP, low HR?
low BP, high HR
= phenylephrine, metaraminol
low BP in severe sepsis
= noradrenaline, adrenaline
low BP, low HR
= ephedrine
post-op nausea & vomiting:
- how common after GA?
- 1st, 2nd & 3rd line anti-emetics?
- other anti-emetics can sometimes use? 2
20-30% after GA
1st line = ONDANSETRON
“lots of cancer pts need surgery, also use ondansetron with chemo”
2nd line = DEXAMETHASONE
“surgery causes swelling, want to reduce this with steroids”
3rd line = CYCLIZINE
“after you’ve cycled through the first 2, you get to cyclizine”
others:
- prochlorperazine (stemetil)
- metoclopramide
Which IV drugs do anaesthetists commonly prepare for a surgery? 8
(some they may use, others ‘just in case’)
1) anaesthetic (eg propofol)
2) analgesia (eg alfentanyl)
3) muscle relaxant (eg rocuronium)
4) 1st antiemetic (eg ondansetron)
5) 2nd antiemetic (eg dexamethasone)
6) drug that raises BP & HR (eg Ephedrine)
7) drug that raises just BP (eg phenylephrine)
8) antibiotic (eg co-amoxiclav)
What is the process of waking someone up from a GA? 5 steps
1) stop anaesthetic vapours
2) give oxygen
3) perform throat suction
4) reverse muscle relaxant
5) extubate (as they start coughing) and replace with oxygen mask
When handing over to recovery team after a GA:
- what to administer while transferring? 1
- what information to handover to recovery team? 3
- what to prescribe? 4
administer O2 during transfer
handover the pt
- brief history
- any problems anticipated
- intraoperative analgesia and PONV prophylaxis
prescribe
- rescue analgesia
- rescue antiemetics
- fluids
- other medications, as indicated
What should you always do before a surgery to prevent hypoxia?
pre-oxygenate everyone!
What is the purposes of a pre-op assessment?
1) allay patients fears & anxieties
2) identify potential anaesthetic difficulties and medical conditions
3) improve safety by assessing & quantifying risk
4) optimise & plan of the peri-operative care
5) provide an opportunity for explanation & consent
so basically:
1) reduce pt anxiety
2) identify comorbidities & potential difficulties
3) make clear plan for peri-operative care (when to stop drugs etc)
4) consent the pt
How would you approach a history for a pre-op patient?
A-E plus DRUGS (“as anaesthetists love drugs”)
conditions / past surgeries that affect each one
eg A is any conditions that affect the airway
examine airway bits but apart from that examine relevant system but don’t need to - depends on severity of comorbidity etc
What things would you ask about assessing the ‘A’ of a pre-op assessment:
- PMHx? 3
- exam? 3
- previous anaesthetics? 4
AIRWAY
basically think mouth, jaw, neck (order the IV goes in) then ask about any previous anaesthetics and FHx
history
- any dental work? caps or crowns?
- any problems with your jaw
- any problems with your neck? arthritis etc
exam
- Mallampati score
- ask pt to move jaw side to side (also note beards but don’t ask to shave unless really serious)
- ask patient to fully extend & flex neck (& side to side & rotate?)
Previous anaesthetics?
- any previous PMHx of GA? any severe reaction? any PONV? pain relief problems? (also what did they have done)
- any FHx of any problems with GA?
How do you assess someone’s mallampati score?
which class is what?
ask pt to open mouth as WIDE AS POSSIBLE and stick tongue out
Class I - complete visualisation of the soft palate - incl the pillars (ie there is a space under the uvula)
Class II - complete visualisation of the uvula
Class III - only the top (ie base) of the uvula can be visualised
Class IV - only hard palate visible
What things would you ask about assessing the ‘B’ of a pre-op assessment history:
- chronic airway conditions? 1
- chronic lung conditions? 3
- acute lung problems? 1
- social history?
RESPIRATORY SYSTEM
chronic airway conditions:
- obstructive sleep apnoea
chronic lung conditions: - COPD - asthma - any restrictive lung disease (take a full hx of whatever you find to assess severity & risk with GA)
acute lung problems
- any cough? new breathlessness? fever? other signs of infection?
social history
- how far can you walk on the flat? (why do you stop? SOB or joint pain etc?)
- smoking (current or past) - PERSUADE THEM THAT LONGER THEY STOP BEFORE SURGERY, EVEN IF JUST A DAY, THE BTTER THEIR RECOVERY WILL BE!
What things would you ask about assessing the ‘C’ of a pre-op assessment history:
- chronic CV conditions? 5
- questions to assess severity? 4
CARDIOVASCULAR HISTORY
chronic CV conditions:
- high blood pressure (find out their normal)
- angina
- previous heart attacks
- previous heart surgery
- heart failure
Qs to assess severity
- chest pain (on exertion or random)
- paroxysmal nocturnal dyspnoea
- orthopnoea
- exercise tolerance (if not already asked)
What things would you ask about assessing the ‘D’ of a pre-op assessment history:
- neuro PMHx? 3
- other ‘disability’ PMHx? 3
DISABILITY
neuro PMHx
- epilepsy
- neuromuscular disorders
- nerve damage (mainly to protect yourself)
other ‘disability’ PMHx
- diabetes (DON’T FORGET!!)
- thyroid problems?
- stroke / TIA
What things would you ask about assessing the ‘E’ of a pre-op assessment history:
- GI history? 4
- other history? 3
EXPOSURE
GI history
- reflux? (could affect airway)
- any other problems with liver? gut?
- time of last meal (if operation imminent)
- alcohol consumption?
other history
- any kidney problems?
- ANY CHANCE YOU COULD BE PREGNANT?
- any other reasons you see the GP or been into hospital or surgeries?
What things would you ask about assessing the ‘DRUGS’ of a pre-op assessment history:
- general opening questions? 2
- specific drugs to ask about? 2
1) ANY ALLERGIES?
2) What medications do you currently take?
other drugs to ask about:
- blood thinning medications,warfarin, LMWH, DOACs (also ask re aspirin / clopidogrel)
- insulin or hypoglycaemic medication
What is ASA grading? how many grades are there?
physical status classification for assessing fitness for surgery
6 grades
nb add ‘E’ suffix if surgery is emergency
What are the ASA grades? 6
ASA GRADES
Grade 1
= healthy pt with no systemic disease
Grade 2
= mild systemic disease only, without substantive functional limitations (incl social drinkers, obesity & depression)
Grade 3
= severe systemic disease with substantive functional limitations
Grade 4
= Severe systemic disease which is a CONSTANT THREAT TO LIFE
Grade 5
= moribund pt who is not expected to survive with or without surgery
Grade 6
= A brainstem-dead pt whose organs are being removed for donation
nb 2 and 3 are most common - sometimes hard to differentiate between them
What are the different ‘surgical grades’? 4
give examples
SURGICAL GRADES:
GRADE 1 (minor): excisions skin lesion, abscess drainage, toenail removed etc.
GRADE 2 (intermediate): inguinal hernia, knee arthroscopy, tonsillectomy
GRADE 3 (major): hysterectomy or thyroidectomy
GRADE 4 (major+/complex): Joint replacement, C-section, thoracic operations, radical neck dissection
What should you do before a GA in a pre-menopausal woman?
a pregnancy test - with their consent!
What is the CEPOD (actually NCEPOD) classification of surgery? 4
IMMEDIATE / EMERGENCY
- immediate life, limb or organ-saving intervention
- (eg repair of ruptured AAA, post-op tonsillectomy bleed, fasciotomy)
- within MINUTES
URGENT
- Intervention for acute onset or clinical deterioration or potentially life or limb threatening conditions
- (eg appendicitis, ruptured ectopic pregnancy)
- within HOURS
EXPEDIATED / SCHEDULED
- pt requires early treatment where condition is not immediate threat to life or limb
- (eg excision of tumour with potential to bleed or obstruct, acute cholecystectomy, NOF fracture)
- within DAYS
ELECTIVE
- intervention planned in advance of routine admission to hospital. Timing to suit pt, hospital & staff
- (eg resection for non-obstructing bowel ca)
- within 18 WEEKS
How to ask about exercise tolerance in a pre-op assessment?
How much can you do physically (just dressing, walking, running - how far?) AND what stops you? (eg lungs or legs etc)
What sort of things prolong gastric emptying?
- metabolic causes? 2
- anatomical causes? 2
- mechanical causes? 2
- trauma? 2
- others? 3
metabolic causes
- diabetes (as probs have a bit of gastric autonomic neuropathy)
- end stage renal failure
anatomical causes
- pyloric stenosis
- reflux
mechanical causes
- pregnancy (also higher progesterone which dilates lower oesophageal sphincter)
- obesity
trauma (as body goes fight or flight so doesn’t digest)
- road traffic accident
- head injury
others
- high fat content
- recent consumption of alcohol
- anxiety (again fight or flight)
What fluids can patients have before surgery?
How much?
Up to when?
exceptions? 2
Translucent fluids (eg can have orange squash, black tea but not orange juice)
however much up to 2 hours before surgery
children: up to 1 hour before surgery
if up to 30ml (to take with tablets) then up the the surgery
How long before surgery can people have:
- solids & non-clear drinks?
- breast milk?
- alcohol?
- boiled sweets / chewing gum?
solids & non-clear drinks
= 6 hours
breast milk
= 4 hours
alcohol
= 24 hours (delays gastric emptying)
boiled sweets / chewing gum
= try & avoid as leads to increased gastric volume & acidity - but carry on with surgery if someone has had
What is the indication for a rapid sequence induction?
what is the objective?
full stomach for any reason
aim is to reduce the risk of aspiration
Who always gets a RSI?
Women over 20 weeks pregnant
Rapid sequence induction:
- Which drugs do you use in a typical RSI? 2
- Which drugs are more commonly used in RSI (aka a modified RSI)? 2
- which drug is used in both?
Typical RSI
- thiopentone (fast induction agent)
- suxmethonium (muscle relaxant - but lots of side effects)
modified RSI
- propofol (induction agent, slightly slower but still fast)
- rocuronium . (muscle relaxant - fewer aside effects)
opioids - norm fentanyl or alfentanyl
Rapid sequence induction:
aside from choice of induction agent and muscle relaxant what else do you do during RSI:
- before induction? 1
- during induction? 2
- after induction? 1
- what should have at the ready throughout? 1
before induction
- preoxygenate with 100% oxygen (to increase O2 in lungs so meaning have longer time to intubate without ventilation)
during induction
- don’t ventilate! (just fills up stomach with air -> increased risk of aspiration)
- cricoid cartilage pressure (aka Sellick’s manouvere)
after induction
- ensure tube is in correct place, then remove cricoid pressure
have suction at the ready - if they vomit, release cricoid pressure, tilt head down and suction!
nb can give PPIs / H2 agonists if worried about reflux
How can you tell that you have intubated in the correct place? 5
which of these is the gold standard? 1
1) Visualisation of vocal cords (during intubation)
2) Chest rising bilaterally
3) Auscultation of breath sounds
4) Fogging of tube
5) EtCO2 trace on the monitor
Who should be preoxygenated?
tbh everyone - can get pt to look at the screen and do it themselves to reduce anxiety
but especially important in RSI
What is the RAT system for pain?
Recognise (that someone is in pain)
Assess (the type of pain & it’s cause)
Treat (the underlying cause and/or the pain)
Which groups of patients often have unrecognised pain? 6
Who should you ask about pain in?
- stoic older pts
- learning difficulties
- language barriers
- dementia
- sedation
- unconscious
EVERYONE!!
Why is it important that people have good pain control post-operatively?
because they need to be able to take deep breaths and cough to avoid getting pneumonia!
people take shallow breaths and don’t cough when in pain - as it hurts more to breath deeply and cough
ALSO pain gets worse if pts feel like their pain is getting dismissed
How do you assess pain?
SOCRATES
- trying to work out cause of pain AND the type of pain - both guide tratment
What are the two broad types of treatment for pain?
pharmalogical and non-pharmological
What is pain?
need to know this!!!
An UNPLEASANT sensory and/or emotional experience associated with actual OR potential TISSUE DAMAGE, or described in terms of such damage!
What are non-verbal signs that you can use to tell that someone is in pain?
How can you tell if a child is in pain?
- frowning
- wincing
- shallow breaths
- sweating (people sweat when in pain)
ask parents if child is acting normally!
Why is asking the severity (eg 1-10) of pain useful? 2
allows you to compare patient’s pain over time
- especially before / after analgesia
guides which analgesics you will use
What is the definition of CHRONIC pain?
pain lasting > 3 months
difference between nociceptive and neuropathic pain?
including descriptions of character
Nociceptive
- obvious tissue damage or injury
- has a protective function
- – sharp and/or dull
- – well localised
Neuropathic
- nervous system damage or abnormality (not obvious tissue damage)
- does not have a protective function
- – burning
- – shooting
- – numbness, pins and needles
- – not well localised
Examples of neuropathic pain? 4
- complex regional pain syndrome
- sciatica
- nerve damage (eg secondary to chemo)
- trigeminal neuralgia
Which nerve fibres does these types of pain tend to travel down:
- sharp pain?
- dull pain?
sharp pain
= A nerves
- faster, more heavily myelinated)
dull pain
= C nerves
- slower, less myelinated
“A students work faster and are ‘sharp’”
Describe the nerve pathway of pain from the injured tissue to the brain
including modulation
sensory nerve 1 (A or C nerve) travels in the dorsal horn in spinal cord (body is in dorsal route ganglion)
2nd nerve desiccates and travels up the contralateral side of the cord in the SPINOTHALAMIC TRACT to the thalamus
3rd nerve travels from thalamus to the relevant area in the brain (eg cortex, limbic system, brainstem)
modulation is the descending pathway from braiun to dorsal horn
- usually inhibits pain signals from the periphery
which is the ‘better’ drug - codeine or dihydrocodeine? why?
dihydrocodeine is a better drugs as is a pure drug
codeine is a prodrug and is affected by CYP240 and metabolises slow or fast depending on person - so hard to predict response
so dihydrocodeine has a more predictable response
What are the pain non-drug treatments for acute pain? 4
RICE
rest
ice
compression
elevation
which groups of people should you exercise caution in giving NSAIDs to? 5
- old people (dt kidneys & bleeding risk)
- kidney problems
- stomach problems
- bleeding problems
- ASTHMATICS (20% have bronchospasm with it - check if had before, if have and no problem then is fine)
which of oxycodone and morphine is better for:
- renal impairment?
- hepatic impairment?
renal failure = oxycodone is better
hepatic failure = morphine is better
why is the pain in trauma a problem?
how do you overcome this?
because pain in one place often distracts from pain elsewhere
make sure you do a full primary and secondary survey
If someone has traumatic pain, what should you always check?
check that they are neurovascularly intact distal to injury
- cap refill
- pulses
- sensation
- power etc
When you give a patient IV morphine, what expectation should you give the pt?
that the maximum effect takes 20 minutes to come - though start to feel effects sooner
(so don’t give 2nd dose of morphine until 20 mins after the 1st)
manage these expectations when you give!
patient controlled analgesia (PCA)
- how do they work?
- when should you discuss with patient?
- what is the biggest problem with them? and how to avoid?
- what do you use instead for kids?
A syringe pump containing the analgesic (norm IV morphine) is connected to pts IV cannula and the pt uses a button to request a bolus of analgesia
- machine records how much they press the button
- is a lock out period between doses
discuss with patient before surgery (norm use after surgery)
biggest issue is that pt goes off to sleep and (because don’t press button in sleep) wake up in a lot of pain
- educate patient and tell them to press lots before they go to sleep, even if not curently in pain
use NCA (nurse controlled analgesia) with paeds
How do local anaesthetics work?
block the transmission of the nerve impulse transiently
inhibition of SODIUM channels in AXON, preventing the transmission of a nerve impulse
(ie these work on axons, not at synapses)
What are the two types of local anaesthetic?
give examples?
which more commonly used?
how do you tell if a drug is one or the other?
Amides = more common = if there is an 'i' before the 'caine' then it's an amide (if not, is an ester) - lidocaine / lignocaine (same thing!) - bupivacaine - levobupivacaine - prilocaine
Esters
- procaine
- amethocaine (ametop - cream used in kids)
- benzocaine
- tetracaine
- cocaine
(nb don’t bother learning names of esters - do learn amides though and how to tell diff between amide and ester)
Why are vasoconstrictors used alongside local anaesthetics? which is most commonly used?
so that the local anaesthetic stays in a specific area - reduces the risk of local anaesthetic toxicity
adrenaline
What are the maximum doses for the following local anaesthetics, with AND without adrenaline:
- lignocaine?
- prilocaine?
- bupivacaine?
- levobupivacaine?
which are longer acting? 2
which short acting? 1
lignocaine
- without adrenaline = 3mg/kg
- with adrenaline = 7mg/kg
prilocaine
- without adrenaline = 6mg/kg
- with adrenaline = 9mg/kg
bupivacaine AND levobupivacaine
- with OR without adrenaline = 2mg/kg
nb all of these are amides
NEED TO KNOW THESE - AND ALSO HOW TO CALCULATE DOSES
bupivcacaine and levobupivacaine are longer acting than others (“they take me longer to type/spell!”)
lidocaine / lignocaine are short acting
Calculate the maximum dose of bupivacaine (WITHOUT adrenaline) you can use in a 75kg woman who needs it around her wound site:
- using 0.25% bupivacaine?
- using 0.5% bupivacaine?
0.25% bupivacaine = 2.5mg per ml safe dose = 2mg/kg 2 x 75 (weight of woman) = 150mg 150/2.5 = 60ml max
0.5% bupivacaine = 5mg per ml safe dose = 2mg/kg 2 x 75 = 150mg 150/5 = 30ml max
Calculate the maximum dose of lignocaine (WITH adrenaline) you can use in a 50kg man who needs it around his wound site using 2% lignocaine?
2% lignocaine = 20mg/ml safe dose (WITH adrenaline) = 7mg/kg 7 (max dose) x 50 (weight of man) = 350mg 350/20 = 17.5ml max
Calculate the maximum dose of prilocaine (WITHOUT adrenaline) you can use in a 90kg man who needs it around his wound site using 2% prilocaine?
2% prilocaine = 20mg / ml safe dose (WITHOUT adrenaline) = 6mg/kg 6 (max dose) x 100 (weight of man) = 600mg 600/20 = 30ml max
what routes can local anaesthetics be given? 3
and not given? 1
sub cut OR spinal OR epidural
NOT IV - this will cause toxicity (nb some anaesthetists do this - but very controlled!)
Initial symptoms of local anaesthetic toxicity? 8
Later symptoms? 7
Circum-oral and/or tongue numbness.
Metallic taste.
Lightheadedness.
Dizziness.
Blurred vision
Tinnitus.
Disorientation.
Drowsiness.
+ bradycardia
+ arrythmias
+ muscle twitching
+ seizures
+ coma
+ respiratory arrest
+ cardiac arrest
If someone says they have an allergy to local anaesthetic, what should you ask?
what was the reaction
as people often get a fast heart rate from the adrenaline used alongside the anaesthetic (especially with dental procedures)
If you see signs of local anaesthetic toxicity, what do you do? 5 (incl drug ask for)
how does this drug work?
1) Call for help (say this is local anaesthetic toxicity!) & tell surgeon to stop
2) Send for crash trolley AND INTRALIPID (there’s a protocol)
3) A-E approach
4) 100% oxygen
5) start IV fluids
intralipid works by reducing the conc of free LA by absorbing it up from the blood (can also be used for other poisonings)
Which drugs is always in a spinal and epidural anaesthesia?
Which drug is often added?
ALWAYS a local anaesthetic
OFTEN an opioid too
At what spinal level do you normally do a epidurals and spinals at?
what surface landmark do you use to find this?
L3 / L4
line between the top of the two iliac crests
nb can do any level though - normally do lowest level possible to get adequate anaesthesia (as higher you do it, more chance of damage to cord)
Differences between spinal and epidural:
- where does each go?
- how administered?
- speed of onset of block?
- what type of block does it provide?
- duration of block?
- what each used for?
SPINAL
- in CSF (ie in sub-arachnoid space)
- single shot injection (don’t want an in-dwelling catheter in spinal cord - risk of infection!!)
- rapid onset (5-10 mins)
- very dense , reliable block, particularly for motor (also sensory & autonomic)
- anaesthesia 2-3 hours, analgesia lasts longer
- c-sections, hip/knee replacements, laparotomy (use thoracic block)
EPIDURAL
- above the dura (epidural potential space)
- put a catheter in and can give boluses or longer infusions through this (and can top up)
- slower onset (15-30 mins)
- less dense block (can be unreliable / patchy, depends on position of catheter)
- titratable analgesia for up to 72 hours
- labour mainly (but other stuff too)
nb get hypotension with spinal (and often epidural) as also blocks autonomic system - nb epidural causes less so use instead of spinal in people with bad heart problems
nb have to sit up for these for a while to ensure none travel towards head when lie down (dt gravity)
who should NOT have epidurals or spinals? 2
- people with systemic infection
- people on anticoagulants
How do you know you’re in the right place when inserting an epidural?
For an epidural we use the landmark of the ligamentum flavum. Piercing through that is quite difficult and you will feel a pop. After that stop pushing any deeper and this will be in the right place
What drug do you treat epidural- or spinal-induced bradycardia with?
atropine
On ultrasound, what are the terms used to describe the appearance of:
1) structures like bones/needles?
2) structures like muscles?
3) structures like fluid/blood?
and what colour is each?
structures like bones/needles
= hyper-echoic (they reflect everything)
= white
structures like muscles
= isoechoic or hypoechoic
= grey
structures like fluid/blood
= an-echoic (don’t reflect any light)
= black
What do nerves look like on ultrasound?
honeycomb
What 5 things do you need to know to be able to work/use an ultrasound machine?
1) How to turn it on / off (norm same button - could be anywhere)
2) Which probe will you use
3) How to adjust DEPTH
(Start with high depth and decrease till see area of interest) - Norm a knob or slider
4) How to adjust GAIN
Basically make sound ‘louder’
Increase gain = more white, less gain = more dark
Norm a knob or slider
5) How to use colour / DOPPLER
Find out if something is a vessel or not
Towards the probe = red, away from probe = blue
Be careful which way you position the probe
What are the three types of ultrasound prob, what is each used for and what do they each look like?
High frequency probe
= shallow but more detail
- used to aid cannulation or for nerve blocks etc
= flat straight edge
Low frequency probe
= deeper but less detail
- used for pregnancy, abdominal structures
= long and curved probe
Cardiac probe
= for viewing heart
- as can avoid ribs
= ‘square’ end to probe, to go between ribs
What are the 4 common artefacts seen on ultrasound?
1) Acoustic shadowing (ie black behind a hyperechoic structure)
2) Acoustic enhancement (flaring) (ie white behind a anechoic structure - eg blood vessel)
3) Reverberation (you see successive structures - eg needles - underneath equally spaced apart, getting darker with each repeat)
4) Comet tail effect (similar to reverberation)
Where are the four places you look for free fluid in a FAST scan?
What are the major 2 disadvantages of the FAST scan?
1) Pericardium (aka subcostal or subxiphoid view)
2) Right upper quadrant (aka perihepatic view, Morison pouch view)
3) Left upper quadrant (aka perisplenic view)
4) Pelvic view (aka suprapubic view - looking into pouch of douglas)
disadvantages
- can’t visualise retroperitoneal fluid
- only sees fluid if more than 500ml in any particular area
nb it’s also not good for identify solid organ injuries
What are the different ‘levels’ of care when related to critical care etc?
Level 0 - normal ward
Level 1 - outreach are just keeping an eye on them on the ward
Level 2 - (on ITU) one organ failure, sometimes 2
Level 3 - (on ITU) ventilation or 2 or more organ failure or dialysis machine
What is the definition of death?
Irreversible loss of the capacity to BREATH coupled with the irreversible loss of the capacity for CONSCIOUSNESS
What are the three ways in which you can classify death?
- Circulatory criteria
- Neurological criteria
- Somatic criteria - eg if someone is decapitated, or terrible rigormortis (been dead for days)
What are the two types of organ donation? (excl live organ donors)
how do they differ in terms of the order in which processes in organ donation occur?
Donation after brainstem death (DBD)
- Diagnosis of death (using specific neuro tests) -> optimise -> mobilise team -> organ retrieval
Donation after circulatory death (DCD)
- Mobilise team -> stop support & wait for death -> diagnose death -> organ retrieval
What is the name of the specialist nurse who discusses organ donation with families?
Where do most organ donors come from? why?
SNOD = specilalist nurse for organ donation
ITU (or occasionally ED) as have to die while on a ventilator
Who has the final say about withdrawal of treatment?
Who has the final say about organ donation?
withdrawal of treatment = doctors (following an MDT)
organ donation = families
When are the FOUR WHO surgical checklists done?
Who is involved with each? roughly what is on each?
'HUDDLE' = before every list = everyone (presented by surgeon and anaesthetist) - introduce everyone - go through each patient and what need (incl surgical equipment, abx, which anaesthesia etc) - any equipment problems - predicting any blood loss etc - etc
SIGN IN CHECKLIST = before induction of anaesthesia = ODP and anaesthetist - check idenitification of patient - check name and site of procedure - allergies - any metalwork in body - etc
TIME OUT CHECKLIST = before skin prep of each patient = everyone (asked by anaesthetist and scrub nurse?) - check correct pt - check side of operation (L or R) - any allergies - check if giving abx and/or transaexamic acid - check if need insulin - etc
SIGN OUT CHECKLIST = after end of each operation = everyone (asked by anaesthetist, scrub and surgeon?) - name of procedure and that it's been recorded - specimens labelled - equipment counts complete - any predicted post-op issues? - etc
What vitals / things are measured on an anaesthetic machine? 7
and using what equipment?
heart trace
- 3 lead ecg (Red on R, yellow on L, green on L chest)
BP (mainly loking at the MAP = mean arterial pressure)
- non-invasive, using cuff
- invasive, using arterial line
O2 sats
- pulse oximeter
pulse
- oximeter
- ecg leads
ventilation and CO2
- using capnomonitor attached to airway
inspired and expired anaesthetic gases and MAC
- tubes
temperature
- temperature probe (only really used if long procedure)
nb can also use central venous catheter or lidco machine if worried about fluid status
nb can also use peripheral nerve stimulators (norm on face but can do on wrist) to measure neuromuscular blockage
anaesthesia and diabetes:
- how should manage diabetic meds, incl insulin, and fasting before an operation? 5 (be specific)
- how and how often should blood glucose be monitored peri-operatively?
- where should pts with diabetes be on the list?
- omit oral hypoglycaemic agents the morning of surgery
- take long-acting insulin in morning
- omit short-acting insulin day of surgery
- fast the normal amount of time
- give variable infusion of insulin if need to
BMs should be measured every hour before, during and after op, until eating and drinking again
- if BM >10 intra-op then give some insulin
patients with diabetes should be first, or at least near top, of list, to prevent hypos
anaesthesia and diabetes:
- what are the increased intra and post-op risks of surgery to consider? 5
and how to mitigate these
RISK OF ASPIRATION
- delayed gastric emptying (dt autonomic neuropathy) (also, if type 2 DM, then may also be overweight, further increasing risk)
- use an RSI if really concerned
HYPOS INTRA-OP
- monitor BMs and put first on list to prevent
- be hypervigilant as anaesthetic drugs will mask symptoms
RISK OF POST-OP MIs
- diabetes increases CV risk and most operation-related MIs occur post-op - also MIs in diabetes are often silent, so easier to miss
RISK OF POST-OP INFECTION
- optimise diabetes control pre-op
- ensure good wound care follow up
RISKS ASSOCIATED WITH RENAL FUNCTION
- test UandEs pre-op
- eg can retain more morphine than normal person, which abx use etc
nb they may also be tricky to intubate dt a large neck
diabetes and anaesthesia:
- pre-op questions to ask? 1
- pre-op blood tests to do? 4
- other pre-op tests to do/consider? 2
- current blood sugar control (HbA1c and normal BM range)
- UandEs
- HbA1C
- fasting blood glucose
- BMs
- urineanalysis (looking for proteinuria and microalbuminuria)
- ECG (any ischaemic signs)
nb these are all to establish baseline and understand level of end-organ damage
Which medications should be stopped pre-operatively? and how long pre-op? 7
ACEi / ARBs
- stop morning of surgery
COCP / HRT
- stop 4 weeks before, and start again 2 weeks after (can switch to POP)
aspirin / clopidogrel
- stop 1 week before (if non-essential)
DOAC / Warfarin / LMWH
- depends on pt, ideally switch warfarin to LMWH a week pre op then stop on day of surgery
- but continue warfarin if for prosthetic valves
- INR should be <1.5 really
- be really careful of these if spinal anaesthetic or spinal surgery as high risk of haematoma
MAOIs and lithium
- ideally stopped 14hours before surgery but not always
oral hypoglycaemic drugs
- stop morning of surgery
insulin
- have long-acting morning of surgery
- but stop short acting
What are the four different consent forms used in surgery? when is each used?
Consent form 1
- any investigation, treatment or procedure for an adult with capacity
Consent form 2
- surgery for child with impaired consciousness (sedation or GA)
Consent form 3
- surgery for child where there is not alteration in the child’s consciousness
Consent form 4
- surgery for an adult who lacks capacity to consent to the surgery
What type of consent do you need for any surgical procedure?
written explicit consent
what information should you give to the patient regarding anaesthesia before the operation? 10
(nb don’t need to say all the side effects of anaesthesia - will cover this in another flash card…)
- Environment of the anaesthetic room
- – Healthcare professionals present
- Need for IV access and drip
- Need for and any type of invasive monitoring
- What to expect
- Induction of anaesthesia
- – IV
- – Inhalation
Where they will wake up
- – Recovery unit
- – Critical Care
- Possibility of drains, catheters, drips
- Possibility of need for blood transfusion
- Information of any substantial risks associated with anaesthetic techiques involved
- Opportunity for questions
What are the side effects of GA to warn people about:
- common? 4
- rare? 6
common
- sore throat
- confusion
- PONV
- damage to lips or tongue
rare
- chest infection
- muscle pain
- dental damage
- awareness during operation
- nerve damage
- allergic reaction
Who is most at risk of PONV? 4
- previous PONV
- female
- non-smoker
- post-op opioids
(also young and hx of motion sickness and anxious)
What are the side effects of spinals to warn people about:
- common? 4
- rare? 3
common
- hypotension/dizziness
- prolonged paralysis (a few hours afterwards)
- urinary retention
- itching
rare
- headache
- nerve damage
- meningitis / encephalitis
Considerations for anaesthesia for laproscopic surgery:
- airway management? 2
- affects on vitals? 2
try to avoid bag and mask, or do lots of little breaths (as don’t want to inflate stomach)
always intubate (ie not LMA) as increased risk of aspiration
- drops BP (as pressure triggers parasympathetic response)
- increases CO2 (absorbed in through capillaries)
What are the 5 types of regional anaesthesia?
- peripheral nerve block
- plexus block
- spinal
- epidural
- combined spinal epidural
How do you prevent VTE in surgical patients? 2
- everyone wears teds or flowtrons during surgery
- LMWH if immobile for a long period post surgery
How long before an elective surgery do the pre-op assessments occur? 2
2-4 weeks before (specialist nurse or anaesthetist)
then anaesthetist sees them morning of the surgery
What is shock? and what are the four main types?
inadequate perfusion of blood and oxygen to tissues:
CARDIOGENIC
- drop in cardiac output
OBSTRUCTIVE
- obstructions to outflow of the heart
HYPOVOLOEMIC
- loss of circulatory volume
DISTRIBUTIVE
- abnormalities in peripheral circulation
- NB NEUROGENIC SHOCK IS A TYPE OF THIS
How does your body compensate for a low blood pressure normally? 2 main mechanisms
When our blood pressure drops our BARORECEPTORS (and chemoreceptors) are stimulated, this causes an increase in sympathetic activity (due to release of noradrenaline and later adrenaline) which all lead to VASOCONSTRICTION, INCREASED MYOCARDIAL CONTRACTILITY and INCREASED HEART RATE
Furthermore if there is a reduction in perfusion to the renal glomerulus it releases RENIN which through the power of aldosterone increases retention of salts and water to increase circulating volume. Also leads to production of ANGIOTENSIN which causes vasoconstriction
What is DIC and why is it a bad sign in shock?
When the body goes into shock the inflammatory markers will often also activate the CLOTTING CASCADE leading to SYSTEMIC PLATELET AGGREGATION and widespread microvascular thrombosis
This can be called DISSEMINATED INTRAVASCUALR COAGULATION (DIC) and it is something that is often watched out for in critical care because it heralds the beginning of multi-system organ failure
In DIC all of the products for coagulation are used up in the clots in the microvasculature and this means that there are no more platelets etc. for clotting elsewhere - it therefore presents with microvascular bruising or bleeding and extensive bleeding from surgical sites and wounds - microvascular HAEMOLYTIC ANAEMIA
What signs do you see in someone in hypovolemic shock:
- signs of poor end-organ perfusion? 3
- signs of compensatory mechanisms? 4
inadequate tissue perfusion:
- skin: cold, pale, slate-grey, slow cap refill, ‘clammy’
- kidneys: oliguria, anuria
- brain: drowsiness, confusion, irritability
compensatory mechanisms
- tachycardia, narrowed pulse pressure, weak/thready pulse
- sweating
- tachypnoea (to breath off acid)
- BP may be maintained initially but then drop
Signs of cardiogenic shock? 4
basically signs of heart failure
- raised JVP
- gallop heart rhythm
- basal crackles / pulm oedema
- peripheral oedema
Signs of obstructive shock? 3
think large PE or tamponade etc
- elevated JVP
- muffled heart sounds
- signs of large PE
Signs of anaphylactic shock:
- local? 6
- systemic? 4
- rash / urticaria
- erythema
- angio-oedema
- oedema of face, pharynx, larynx
- stridor
- cyanosis
- warm peripheries
- tachycardia
- low BP
- nausea and vomiting
signs of septic shock? 8
- pyrexia and rigors (rarely hypothermia)
- nausea and vomiting
- rash and menigism
- warm peripheries, fast cap refill
- bounding pulse
- jaundice
- bleeding dt coagulopathy (eg from vascular puncture sites)
- confusion and reduced consciousness
Inotropes:
- what are they?
- how do they work?
- when are they used and what for?
- examples? 2
vasopressors:
- how are they different?
- examples? 2
INOTROPES
- increase contractility of heart -> increased cardiac output this -> increased MAP -> increased tissue perfusion
- also optimise preload
- they act on the alpha and beta receptors
- ephedrine (mainly used during surgery)
- noradrenaline (mainly used in ICU - also adrenaline and dobutamine)
VASOPRESSORS
- similar drugs which increase contraction of blood vessels -> increased systemic vascular resistance -> increased MAP -> increased perfusion
- phenylephrine
- metaraminol
Where are these receptors and what occurs when each is ‘triggered’:
- alpha 1
- beta 1
- beta 2
ALPHA 1
- peripheral circulation
= vasoconstriction
BETA 1
- heart
= increase in contractility and heart rate
BETA 2
- lungs, peripheral circulation
= vasodilation AND bronchodilation
Who comes to ICU? 2
pts with an acute, POTENTIALLY REVERSIBLE clinical condition who cannot receive appropriate treatment by staying on the ward.
An underlying level of long-term health and co-morbidity that is likely to allow the patient to survive, and BENEFIT from critical care.
In practise, a very difficult call to make which is why it should be done by a Consultant.
Explicit, or reasonably assumed, patient consent
Some admissions are pre-planned following major surgery
treatment of shock in ICU, what is the main way of increasing BP in:
- hypovolemic?
- cardiogenic?
- distributive?
hypovolemic
= give more fluid / blood
cardiogenic
= give inotrope
distributive
= give vasopressor (noradrenaline)
nb noradrenaline can only be given through a central line!!
What are the 6 parameters measured by NEWS?
- BP
- HR
- RR
- O2 (and FiO2)
- temp
- ACVPU
What are the two types of intra-vascular monitoring that occur on ICU?
- arterial line (measures BP and can get repeat ABGs from)
- central venous catheter (basically invasive measuring of JVP, can also give drugs like noradrenaline through)
What mechanical organ support is available of ICU? 5
- vasopressors / inotropes
- IABP (intra-arterial balloon pump)
- renal replacement therapy
- mechanical ventilation
- extracorporeal oxygenation
Purposes of critical care outreach team? 4
Who is it lead by?
1) Bringing critical care expertise to patients in ward environments
2) Prevent acute deterioration and provide timely transfer to critical care environments
3) Supporting patient rehabilitation following discharge from critical care
4) Education of hospital staff involved in patient care
lead by very experienced specialist nurses, with support from ICU consultant
What are the levels of care? 4
who’s on what level?
Level 0
- Normal ward based care IVI
- BD Obs
Level 1
- Patients needing additional clinical input
- Continuous oxygen
- Chest drains
- 4 hourly observations
- GCS 4 hourly
- probable involvement of outreach
Level 2 (on HDU/ITU) - Patient requiring single organ support - More than 50% O2 CPAP or BIPAP - Vasoactive drug infusions - Hourly observations for potential deterioration
Level 3 (on ITU) Advanced respiratory support (intubation) or more than one organ failure
What are the parameters that define systemic inflammatory response syndrome?
Suspect if NEWS is above 5
2 or more signs of inflammation:
- T >38 or <36
- HR >90
- WCC>12 or <4
- RR>20
- Altered conscious level
- BM >7.7 (if not diabetic)
If patient is neutropenic then just 1 of the above
nb this is highly sensitive and will pick up people without SIRS but could to be aware of
What things should you monitor in someone who is in / being treated for shock? 5
What should you do if no improvement?
- HR trends
- RR trends
- urine output
- repeated ABG and lactate
- conscious level monitoring
escalate to critical care outreach and / or decide on ceilings of care
When resuscitating someone with shock in ITU, what are your objective aims for:
- lactate?
- urine output?
- MAP?
- Central venous O2 sats?
- Central venous pressure?
Normalise lactate
Urine output ≥ 0.5 mL/kg/hr
Mean arterial pressure (MAP) ≥ 65 mm Hg (or higher if usually hypertensive)
Central venous oxygen saturation >70% (indicating the tissues are receiving adequate oxygen)
Central venous pressure (CVP) 8–12 mm Hg
What is the definition of type one and type two respiratory failure?
use values of PO2 and PCO2
type 1 (hypoxia)
- PO2 < 8 kPa ON AIR
- PCO2 < 6 kPa ON AIR
type 2 (hypoxia and hypercapnia)
- PO2 < 8 kPa ON AIR
- PCO2 > 6 kPa ON AIR
What accessory muscles to look out for when assessing breathing? 5
other signs of respiratory distress? 6
- pectoral
- SCM (sternocleidomastoid)
- abdominal muscles
- intercostal in-drawing
- tracheal tug (in kids)
- tripoding
- pursed lip breathing
- sweating
- pale or blue
- short sentences / not talking
- confusion / drowsiness
What is the normal inspiratory:expiratory rate ratio?
what happens to it in acute obstructive disease?
1:2
it gets longer, 1:3, 1:4 as have trouble expelling air
Apart from accessory muscle use and other signs of respiratory distress, what else should you INSPECT for when looking at someone’s breathing?
- FiO2
- respiratory rate
- depth of breathing (shallow or not)
- chest wall deformities (barrel chest, pectus excavatum, scoliosis)
- raised JVP
- abdo distension (pressure from abdo makes it harder to breath deeply)
When auscultating where must you not forget to listen? 3
high into right axilla
- as R middle lob pneumonia often missed here
also obviously do bases and apexes too!
What are the indications for:
- CPAP? 4
- BiPAP? 3
CPAP
- type 1 resp failure
- pulm oedema / fluid overload
- atelectasis
- chest infection
BiPAP
- hypercapnic COPD exacerbations
- MSK conditions with resp failure (as long as airway is secure)
- also used in chronic conditions, eg obesity hypoventilation syndrome, obstructive sleep apnoea
Acute respiratory distress syndrome (ARDS):
- what is it? 5
- describe the pathophysiology
- main feature
- main long-term consequence
- commonest cause
Can be defined as:
- Respiratory distress
- Stiff lungs (high inflation pressure required)
- New pulmonary infiltrates on chest radiographs
- No apparent cardiac cause of pulmonary oedema (pulmonary artery occlusion pressure <18mmHg)
- Gas exchange abnormalities
It is a reaction of the lungs to a variety of direct and indirect insult to the lungs. Most commonly this insult is sepsis and between 20-40% of patients with sepsis will develop ARDS
It is often seen as an early manifestation of the generalised inflammatory response and can often be warning factor for MSOF (multi-system organ failure)
The CARDINAL FEATURE is Pulmonary oedema that is not due to a cardiac cause - it is due to increased vascular permeability
PULMONARY HYPERTENSION is another feature of ARDS and this can be complicated by the development of right ventricular failure
Within days of the onset of this lung injury repair begins and fibroplasts accumulate in the interstitial spaces between alveoli - this leads to fibrotic changes in the lungs
Pleural effusions are also common in ARDS
Acute respiratory distress syndrome (ARDS):
- clinical presentation? 3
- management? 6
- Unexplained tachypnoea
- Followed by hypoxaemia and central cyanosis
- FINE CRACKLES through bilateral lung fields
- Mechanical ventilation
- Fluid restriction
- Use of diuretics
- HAEMOFILTRATION - to prevent fluid overload
- Changes in body position
- Inhaled NO
Common causes of type 1 resp failure? 7
- cardiogenic pulm oedema
- pneumonia
- ARDS
- asthma
- lung fibrosis
- septic shock
- inhalational injury
Common causes of type 2 resp failure? 5
- progression from type 1 resp failure
- COPD exacerbation, bronchiectasis, CF etc
- drug overdoses (eg opioids) that reduce resp drive
- resp muscle weakness (eg guillan barre)
- chest wall deformities
Indications for invasive ventilation (IV)? 5
- resp failure that is refractory to other treatment
- resp failure with low consciousness
- tiring on other treatment
- airway compromise
- other conditions (sepsis, trauma, head injury, post arrest etc)
Problems with CPAP:
- physiological? 2
- logistical? 2
- can expand pneumothoraces
- can cause hypotension
- difficult to apply if facial injuries
- patient tolerance
Problems with BiPAP:
- logistical? 2
- difficult to apply if facial injuries
- patient tolerance (need lots of pt education and reassurance)
Problems with invasive ventilation:
- logistical? 2
- physiological? 3
- others? 2
- requires sedation to almost anaesthetic levels
- limited to specialist areas (resus, ITU)
- hypotension
- gastroparesis
- immobility
^nb these all linked to the associated sedation - risk of VAP (ventilator-acquired pneumonia)
- psychological impact of pt and family!
What are the main ‘end organs’ when you talk about perfusion and end-organ failure? 4
- kidneys
- brain
- skin
- heart
What are the two ways of diagnosing an AKI?
acute rise in serum creatinine
AND / OR
acute fall in urine output
beware that you can have AKI on top of chronic renal failure
What are the complications of AKI that come from uraemia? 3
what are other complications of AKI? 3
Uraemia
- Encephalopathy
- Pericarditis
- Coagulopathy
- Hyperkalaemia
- Fluid overload
- Metabolic acidosis
Indications for renal replacement therapy (normally in the form of dialysis / haemofiltration):
- renal?
- non-renal?
- rapidly rising serum urea and creatinine or the development of uraemic complications
- hyperkalaemia that’s unresponsive to medical management
- severe metabolic acidosis
- oliguria or anuria
- diuretic resistant pulmonary oedema
- clearing ingested toxins
- correcting severe electrolyte imbalanaces
- temperature control
- removal of inflammatory mediators in sepsis
nb main reason seems to be severe diuretic, unresponsive oliguria / anuria
What is the standard mechanism of renal replacement therapy in ITU?
continuous haemofiltration through a central venous catheter (either subclavian or femoral vein)
What are the patterns of: - FEV1 - FVC - FEV1/FVC ratio in: - normal lungs? - obstructive disease? - restrictive disease?
incl numbers if poss (% predicted and ratio as a decimal)
NORMAL
- FEV1 >80% predicted
- FVC >80% predicted
- FEV1/FVC ratio >0.7
OBSTRUCTIVE
- FEV1 <80% predicted (reduced)
- FVC >80% predicted (may be slightly reduced)
- FEV1/FVC ratio <0.7 (reduced)
RESTRICTIVE
- FEV1 <80% predicted (reduced)
- FVC <80% predicted (reduced)
- FEV1/FVC ratio >0.7 (normal)
What are the 5 different types of blood products?
what are each used for?
WHOLE BLOOD
- everything, incl clotting factors and plasma EXCEPT platelets
- rarely used but good for acute large volume bleed
PACKED RED CELLS
- blood without the plasma
- treating symptomatic anaemic and major acute blood loss (if give >4 units, give platelets too to ensure stability)
PLATELET CONCENTRATES
- just platelets
- used to correct a low platelet count or before a procedure if bleeding is a big risk
FRESH FROZEN PLASMA (FFP)
- plasma, incl clotting factors
- used for :
- – emergency reversal of warfarin
- – massive haemmorhage
- – intracranial bleed
- – DIC (to replace consumed clotting factors)
- – liver failure with bleeding
CRYPRECIPITATE
- specific clotting factors are centrifuged out of FFP
- used to treat specific deficit conditions - haemophilia, vWD, low fibrinogen levels, DIC
How much is a ‘unit’ of blood? (in mls)
450ml
Complications of blood transfusion:
- immediate? 6
- delayed? 5
IMMEDIATE:
- Urticaria
- ABO incompatibility
- Febrile non-haemolytic reaction
- – Sometimes there is an acute rise in body temperature when the blood is first run through
- Dilution coagulopathy
- – After giving too much packed red cells you can dilute the clotting factors to the point where the person is at a bleeding risk (This is why you give FFP after 4 units of placked red cells)
- Hyperkalaemia
- – Potassium is released during haemolysis and there will be some degree of breaking down of red blood cells in the bag and this will leak into the patient leading to elevated levels of potassium
- Hypocalcaemia
- – Calcium is needed for clotting and so when we store blood we put in a calcium collating agent to try and stop the blood from clotting. However this means there is very little or no calcium in the blood we are putting into the patient and so this can lead to a hypocalcaemia
DELAYED:
- Delayed haemolytic transfusion reaction
- Graft versus host disease
- Immunosuppression
- Viral infection
- Iron overload which can lead to hemochromatosis
What is post-intensive care syndrome (PICS)?
what are the three main difficulties? describe these
Some patients can develop, psychiatric, physical and/or cognitive difficulties after being discharged from the intensive care unit.
A patient with PICS might have symptoms from all three of these problems or just one.
1) ICU-acquired weakness (ICU-AW)
- about 25% of survivors
- a result of long-term immobility and sedation
- difficulties in ADLs
- joint contracture
- respiratory difficulties, incl decreased diffusing capacity and reduced lung volumes (atelectasis) (esp if been ventilated)
2) cognitive impairment
- struggle withmemory, problem solving, mental processing speed and attention
- about 80% of survivors
- most will improve within a year, but often hampers employment
3) psychiatric disorders
- anxiety, depression and PTSD are all very common!
What are the three groups of causes of secondary brain injury?
- hypoxia
- hypoperfusion
- hypoglycaemia
What infections are patients on ITU particularly susceptible to? 6
- Catheter associated UTIs
- Ventilator associated pneumonia
- Aspiration pneumonia
- Skin infections
- Pressure ulcers -> infections
- Line infections
What are the normal things you have to do to diagnose death? 7
how long should this take?
what’s the exception? (ie where more extensive tests are needed)
- look for signs of life / movement
- does patient respond to pain or voice?
- carotid pulse
- corneal reflex
- pupillary light reflex (fixed and dilated in death)
- check for breath sounds (for ?2 mins)
- check for heart sounds (for ?2 mins)
should take 5 mins total
if circulation is intact but you suspect brain stem death - must do more specific brain stem tests
What is the first question you must ask when determining if someone has capacity?
what are the four things someone must be able to do to demonstrate that they ave capacity? 4
Is there an underlying reason why this person would lack capacity?
- eg brain injury, dementia, mental illness etc
1) UNDERSTAND information given
2) RETAIN long enough to decide
3) WEIGH UP available information
4 COMMUNICATE their decision
What are the three types of futility of treatment? with examples
Physiological futility
- Giving adrenaline to a hypotensive patient with no response
Benefit-centred definition
- Quantitative, failed in the last x number of times it has been attempted
Qualitative, when a patient’s quality of life falls below the threshold considered minimal by general professional judgement
Cost-based futility
- Treatment is so unlikely to succeed that many people, both professionals and lay persons, would consider it not worth the cost.
nb first is quite objective, latter two are more subjective - ALL need opinions of more than one person to decide upon before withdrawing treatment
What is the most common indication for sedation in ITU?
other indications in ITU? 4
to allow for invasive ventilation
- to ease pain and discomfort
- to control agitation and anxiety
as treatment
- for myocardial protection
- protection of the brain
what 3 drugs / groups of drugs are normally used for this?
opioid
WITH
benzodiazepine OR propofol
nb can sometimes use clonidine in ITU too (instead of propofol)
What are the main indications for benzodiazepines? 6
what receptors do they act on?
- sedation
- insomnia
- agitation
- seizures
- muscle spasms
- alcohol withdrawal
act on the GABA receptors
What additional tests should be done to confirm brain stem death? 7
PUPILLARY REFLEX
- neither pupil is responding either directly or consensually to sharp changes in light
CORNEAL REFLEX
- no response to direct stimulation of the cornea
VESTIBULO-OCULAR REFLEX
- stimulating the inner ear with hold or cold impulses usually leads to eye movements
MOTOR RESPONSE TO CENTRAL STIMULI
- no response to supraorbital pressure
ABSENT GAG REFLEX
ABSENT COUGH REFLEX
- bronchial stimulation by catheter passed at least to the carina through endotracheal tube
- Absence of respiratory movements during the APNOEA TEST (slightly more to it, incl prexygenation etc, but basically no respiratory movements seen when the ventilator is turned off
