ACCS Flashcards
What is major trauma?
Serious and often multiple injuries where there is a strong possibility of death or disability
What is the injury severity score (ISS)?
Anatomic severity scale based on Abbreviated Injury Scale (AIS) and developed specifically to score multiple traumatic injuries - retrospective
What is the most common cause of major trauma?
Fall from < 2m
Followed by RTC
What are the commonest causes of preventable or potentially preventable deaths?
Bleeding
Multiple organ dysfunction syndrome - untreated bleeding
Cardiorespiratory arrest
What is the acronym for the initial assessment you should do in major trauma?
CABCDE
C = control catastrophic haemorrhage
A = airway with C-spine protection
B = breathing with ventilation
C = circulation with haemorrhage control
D = disability - neurological status
E = exposure/environment
What are the 4 main types of mechanisms that can lead to major trauma?
Blunt force injury
Penetrating trauma
Sports
Blast injuries/explosions
What is the mechanism of injury in an RTC?
Cervical spine injury
Blunt thoracic and cardiac injury
Hollow viscus perforating/solid organ injury
Pelvic/acetabular/femur/long bone injuries
Motorcycles - literally anything, PELVIS
What is the mechanism of injury in an assault?
Head injuries
Beware stamp to abdomen/chest
What is the mechanism of injury in a fall from a height?
Anything
Depends on how you fall
What is the mechanism of injury of a stabbing?
Follows track of the knife
Better outcomes
What is the mechanism of injury in a shooting?
Rare in UK
Type of weapon used and how far away weapon was changes mechanism of injury
Depends on bullets/kinetics
Bullet can tumble/cause displacement of tissues
Higher risk of damage further away from entry wound
What is the mechanism of injury in a sports injury?
Depends on the sport
May carry specific and recurrent risks
What risks of injury are there in rugby?
Splenic/renal ruptures
C-spine
What risks of injury are there in football?
Hamstring rupture
What is the mechanism of injury in blast injuries/explosions?
Primary = blast disrupts gas filled structure
Secondary = impact airborne debris
Tertiary = transmission of body (thrown)
Quaternary = all other forces
What are the priorities in major trauma and what order are these in?
- Stop bleeding
- Prevent hypoxia
- Prevent acidaemia - lots of important systems require normonaemia
- Avoid traumatic cardiac arrest or treat correctly
What other key factors are there in major trauma?
Save time = save lives
Good pre-hospital care
Teamwork
Consultant led trauma team
Consultant led in-patient care
MDT approach
Early rehabilitation
What is the acronym for transfer of information in major trauma? What does this stand for?
A = age
T = time (when did it happen)
M = mechanism
I = injuries found/suspected
S = sigs (obs)
T = treatments
What is the management of catastrophic haemorrhage?
Figure out what/where is bleeding
Clear any clots obscuring bleeding source
Direct pressure +++++
Indirect pressure - occlude arterial flow more proximally
Torniquet (ensure bleeding stopped and no distal pulse)
Haemostatic agents
What is the NICE expected time frame for securing airway in major trauma?
45 minutes
How might you secure an airway in major trauma?
Rapid Sequence Induction (RSI) of anaesthesia
What are the absolute indications for intubation?
Inability to maintain and protect own airway regardless of conscious level
Inability to maintain adequate oxygenation with less invasive manoeuvres
Inability to maintain normocapnia
Deteriorating conscious level
Significant facial injuries
Seizures
What should you do in terms of airway in burns?
Consider whether airway is compromised or at risk
What signs might there be to show the airway may be compromised or at risk in burns?
Hypoxaemia/hypercapnia
Deep facial burns
Full thickness burns
Burns the throat
What are the relative indications for intubation?
Haemorrhagic shock, particularly in presence of evolving metabolic acidosis
Agitated patient (hypoxia and hypovolaemia can cause agitation)
Multiple painful injuries
Transfer to another area of hospital/expected clinical course
What are the criteria for high risk of c-spine injury in major trauma?
65 or older
Dangerous mechanism of injury - fall from height > 1m or 5 steps, axial load to head eg diving, bike collision
Paraesthesia in upper/lower limbs
Down’s syndrome/RA/spondylitis
What are the criteria for low risk of c-spine injury in major trauma?
Minor rear-end motor vehicle collision
Comfortable sitting
Ambulatory at any time since injury
No midline cervical spinal tenderness
Delayed onset of neck pain
Unable to actively rotate neck 45 degrees to L and R - only assess if low risk and no high risk factors
What are the criteria for no risk of c-spine injury in major trauma?
Have one of low risk factors and able to activity rotate neck 45 degrees to L and R
What should be done during A assessment?
Immobilise C-spine if high risk
Provide O2
Assess airway - look, listen, feel
Jaw thrust if c-spine immobilised not head tilt chin life
Proceed to RSI if indicated
What is the mnemonic for life threatening thoracic injury? What does it stand for?
ATOM FC
A = airway obstruction/disruption
T = tension pneumothorax
O = open pneumothorax
M = massive haemothorax
F = flail chest
C = cardiac tamponade
How might someone with tension pneumothorax present?
Diminished breath sounds
Hyperresonance
Distended neck veins
Deviated trachea (very late sign, often peri-arrest, not reliable)
Hypoxia
Tachycardia
Hypotension
Consistent history - blunt/penetrating trauma
Air hunger/agitation
How is a tension pneumothorax treated?
Needle thoracentesis 2nd IC mid-clavicular line or thoracostomy + large bore chest drain (preferred)
What is an open pneumothorax?
Wound to chest wall communicating with pleural cavity
>2/3 aperture of trachea (air more likely to go out of hole than trachea)
Air moves down pressure gradient to pleural space
Wound seals on expiration
Leads to tension pneumothorax
How is an open pneumothorax treated?
Seal chest
What is a massive haemothorax?
<1500ml blood in chest
How might someone with a massive haemothorax present?
Reduced air sounds
Hypo resonant
Consistent Hx
How do you treat a massive haemothorax?
Obtain IV access prior to decompression - to replace vol
> 1500ml blood or >200ml/hr consider urgent thoracotomy
What is a flail chest and what does it lead to?
Fracture of 2 or more ribs in 2 or more places
Floating section of ribs
Moves paradoxically during respiration
Ventilation failure
What is the triad of symptoms in cardiac tamponade?
Beck’s triad = hypotension, diminished heart sounds, distended neck veins
What is the cardiac box?
Superiorly - clavicle
Inferiorly - xiphoid
Laterally - nipples
When should you consider a cardiac wound?
Wound in cardiac box
How do you treat cardiac tamponade?
Resuscitating thoracotomy
Name 3 secondary suvery injuries
Simple pneumothorax
Aortic injuries
Diaphragmatic injuries
Fractured ribs
Lung contusion
Cardiac contusion
How are secondary survey injuries identified?
Imaging
What issues may you deal with during circulation assessment?
Sweaty/diaphroetic
Anxious/confused
Pallor/peripherally cool
Tachycardia/tachypnoea
>CRT
Narrow pulse pressure
Hypotension
Bradycardia
Arrest
What are the main sources of bleeding that will kill you within minutes to hours?
‘Blood on the floor and 4 more’
External haemorrhage
Chest
Abdomen
Pelvis
Long bones
What can cause abdominal bleeding?
Blunt force trauma/penetrating trauma to abdomen
What injuries can lead to abdominal bleeding?
Liver
Spleen
Retroperitoneal
What signs are there of abdominal bleeding?
Not always peritonitic but can be
If older less likely to show signs
How do you diagnose abdominal bleeding?
CT
All but most unstable patient
What are the indications for an emergency laparotomy?
Peritonism
Radiological evidence of free air
GI haemorrhage
Persistent/resistant haemodynamic instability
How do you treat potential pelvic bleeding?
Closing potential space
Use of binder -> mandatory in haemodynamically unstable blunt trauma patients
What are the long bones?
Femur, humerus, radius, fibula, tibia, metacarpals
What are the most important long bones to consider in major haemorrhage?
FEMUR
Humerus
Tibia
How do you treat potential long bone injuries?
Bring bones back to anatomical position - close potential space
What is permissive hypotension?
Want to maintain perfusion to vital organs so don’t want BP to peripheries too high
Can lose more blood, dilutes blood, lower clotting factors
Let hypotension until bleeding stopped
What is the best MAP to maintain in major trauma bleeding patients?
50mmHg
> 60mmHg death from bleeding
< 40mmHg death from hypoperfusion
What should you replace volume with in major blood loss?
Physiological fluids
What drug is very useful in major trauma bleeding?
Tranexamic acid
Prevents fibrinolysis and therefore helps prevent trauma induced coagulopathy
What are the indications for blood products in trauma?
Consistent
- Systolic BP < 90
- HR > 130
- Reduced GCS
- Obvious massive ongoing blood loss
What is the triangle of death from trauma?
Coagulopathy
Acidosis
Hypothermia
What can lead to coagulopathy?
Haemorrhage
What can lead to hypothermia?
Injury -> exposure -> hypothermia
What can lead to acidosis?
Haemorrhage -> hypoperfusion -> acidosis
How do you treat haemorrhage?
Stop bleeding
Pelvic binder
Splint long bone fractures
Permissive hypotension
Tranexamic acid 1g 10 min than 1g infusion
Emergent damage control surgery
Interventional radiology
Limit crystalloids
What is an acceptable systolic in major haemorrhage?
50-90
What needs to be assessed in disability?
Assessment of neurology in primary survey (before RSI)
Head injury assessment
How can you assess neurology?
A(C)VPU
Pupillary size and response
Motor score of GCS most predictive outcome
Sensory level if able (usually lower later on, earlier can find better)
What is the difference between a primary head injury and secondary head injury?
Primary = incident
Secondary = hypoxic injury/hypoperfusion - can be caused by interventions (make sure to adequately oxygenate), poor outcomes
What is the CPP trade off in head injury and major trauma?
CPP = MAP - ICP
Don’t want MAP too high incase of bleeding but need high enough to perfuse brain
When ICP > MAP brain no longer receives enough O2
Sympathetic nervous system activates + parasympathetic nervous system activates = Cushing’s triad
What systolic is better in a head injury?
> 100
What is Cushing’s reflex and when does it happen?
Bradycardia + hypertension + irregular bleeding pattern
Happens physiologically if raised ICP
Widening pulse pressure (increased difference between systolic and diastolic BP)
Triad = bradycardia, irregular respiration, widened pulse pressure
What are the main aims in dealing with a head injury?
Prevent secondary brain injury
Secure airway GCS < 8
Maintain normal everything else as long as systolic around 100
What do you do in exposure assessment?
Look for obvious limb threatening injuries
Ensure patient being kept warm
Consider a few bedside tests
Don’t forget pain - uncontrolled pain linked to PTSD from major trauma, difficult as can do weird things to BP and RR
How do the elderly differ from younger people?
Osteoporosis
Polypharmacy
Muscle wasting
Rigid and painful joints
Changes in proprioception
Less able to protect themselves if they fall
Respiratory differences
Cardiovascular differences
What respiratory differences do older people have?
Less able to adapt
Respiratory muscle weakness
Kyphosis thoracic spine
Chest wall rigidity
Impaired central response to hypoxia
Reduced alveolar gas exchange surface ares
What cardiovascular differences do older people have?
Reduced SV
SV product of pre-load (total body water often less in older people), afterload (total peripheral resistant rigid and non-compliant peripheral circulatory system), and contractility (cardiac power index, HR can’t do the same as normally does, cardiac muscle replaced by collagen)
What is important to remember about hypotension in older people?
150-160 systolic normal in elderly
Hypotensive for elderly patient could be 120
What polypharmacy medications may older people be on?
Anticoagulation
Cardiovascular drugs affecting heart and renal function
Long term steroids - impaired healing, suppressed adrenals so poorer response to trauma
Lots of nephrotoxic drugs
Opiates - constipation, UTIs, sedation
NSAIDs - bad for kidneys
B-blocker
What is the relationship between polypharmacy and falls?
More drugs on, more likely to have fall within the next 6 months
What is important to remember about head injuries and older patients?
Tolerate more blood in their head as smaller brains
Prognosis of severe brain injury decreases age > 65
Why are elderly patients at higher risk of cervical spine injuries?
Fixed joints
Softer bones
What is important to remember when immobilising an elderly patients c-spine?
Can be hazardous due to kyphosis
Maintain patients normal
What is the difference between thoracic injuries in the elderly and younger people?
Same injuries seen in younger patients as elderly
Otherwise minor injuries carry large risk to older patients
Decreased amount of force required to cause trauma to ribs
What is the relationship between rib fractures and mortality in the elderly?
> 3 rib fractures, each additional rib fracture has 10% mortality rate
What is the difference between thoracic injuries in children and thoracic injuries in elderly?
Children -> lung contusions, few factures
Elderly -> rib fractures
What is the difference in abdominal injuries in older people compared to younger?
Lower ribs and pelvic brim weaker
Abdominal examination unreliable
Pain not as well localised in elderly
CT scan lower threshold in elderly
Why is a dip stick not reliable in the elderly?
Likely to have physiological bateruria as urinary stasis
How do you diagnose a UTI in older people if a dip stick is not reliable?
New urinary symptoms or fever with change in urinary character or haematuria, or loin tenderness
Unexplained confusion + unexplained raised inflammatory markers
What is a FAST scan?
Focussed Assessment with Sonography for Trauma
Important role in triage when managing multiple SIPs simultaneously or in a major incident - who gets priority
What is the trauma series in plain films?
AP chest, pelvis and c-spine
Extremity imaging can wait
CXR - portable, can use in resus, can see flail chest, massive pneumothorax, haemothorax
What kind of trauma is flail chest related to?
High impact trauma
When does flail chest occur?
3 or more contiguous ribs are fractured in 2 or more places
What other injuries is flail chest often associated with?
Pulmonary contusion/laceration
Pneumothorax
Haemothorax
What does a flail chest look like on examination?
Paradoxical chest movements
What does a widened mediastinum indicate?
Aortic injury - often dead
What should you look for if you find a pelvic fracture and why?
Another pelvic fracture
Ring so must break in at least 2 places
What other complications may you see after a pelvic injury?
Bladder/urethral rupture
Rarely perforation
What is AP compression?
Crush injury resulting in disruption of pubic symphysis and pelvis opens like a book
Pubic rami may be fractured in vertical orientation instead of disruption of pubis symphysis
May also get sacroiliac joint issues
What is a vertical sheer injury?
Results in vertical, unilateral fractures of pubic rami and vertical fracture of sacral foramina on the same side
Malgaigne (ipsilateral)/bucket handle (contra-lateral)
What is a lateral compression injury?
Lateral force causes sacral fracture with diastasis of pubis symphysis
Force results in oblique fractures of pubic rami bilaterally, impacted fractures of sacral foramina ipsilateral to the force, infolding of hemipelvis
What is a Jefferson fracture?
Fracture of C1
Space between odontoid peg of C2 and lateral masses of C2 widened on both sides
Lateral masses of C1 both laterally displaced and no longer align with lateral masses of C2
Often due to blunt force trauma to top of head
What is a hangman fracture?
Fractures of C2 (axis) may involve odontoid peg, vertebral body, or posterior elements
Results from high force hyperextension injury
Involves pedicles of C2 and often anterior displacement of body and peg of C2
What is a flexion teardrop fracture?
Fracture of c-spine caused by sudden pull of anterior longitudinal ligament on the anterior, inferior aspect of vertebral body following extreme hyperextension of neck
Very unstable, high risk of slipping, bad results
What is a burst fracture?
From axial loading most often secondary to motor vehicle accidents and falls
Usually produced by a comminuted, vertical fracture through vertical body
Anterior wedging
Convexity to posterior vertebral surface
Fragments may be retropulsed into spinal canal injuring the cord
How do you tell how old blood is on a CT scan?
Hyperacute (first hour) appear isodense to adjacent cortex with a swirled appearance due to mixture of clot, serum, and ongoing clotted blood
Acute - high attenuation to brain parenchyma (6-24 hours) bright
Chronic - clot starts to degrade and density drops
Which types of head injury are highly related to encephalitis, meningitis, and epilepsy?
Skull fractures with depression
Pneumocephalus skull fractures
When should you CT in major trauma?
Gold standard of imaging
Polytrauma indications
- Haemodynamic instability
- Mechanism of injury -> more than one system/body part, RTC with fatalities
- Findings on plain film/FAST scan are inconclusive or suggestive on injury
- Obvious severe injury
What is important to remember about significant injuries in more than one body region?
Likely to be more so look for more!
What is V/Q mismatch?
Ventilation and perfusion not the same throughout both lungs therefore patient becomes hypoxic
Issue with delivering O2 into the blood stream
What are the 3 main causes of respiratory failure?
Alveolar collapse
Oedema
Bronchoconstriction
What can cause alveolar collapse?
Pneumonia
Anaesthesia
Lying down
Pneumothorax
What can cause bronchoconstriction?
Asthma
COPD
What is the difference between type 1 and type 2 respiratory failure?
Type 1 = O2 between 12 and 8, low pO2 and normal/low pCO2
Type 2 = low O2, high CO2
How does type 1 respiratory failure occur?
Breathing harder to increase O2 but normal/low CO2
CO2 can drop as breathing harder
As exhaust from breathing harder, CO2 can normalise (one of the criteria in acute life threatening asthma)
Still able to effectively ventilate as can clear CO2 but failing to oxygenate
How does type 2 respiratory failure occur?
Can’t breath as fast as body telling you to as you exhaust
Not getting rid of CO2 fast enough
Failure of ventilation and oxygenation
What does a high CO2 mean?
Poor ventilation
What does a low O2 mean?
V/Q mismatch
What is EPAP?
Expiratory pressure applied
Prevents alveolar collapsing helping to treat respiratory failure
Pushes fluid back into blood in oedema
What is EPAP for?
Low O2/V/Q mismatch
What is EPAP also known as?
CPAP (continuous positive airway pressure)
What is IPAP?
Inspiratory pressure so you take a bigger tidal volume and bigger minute volume
What is IPAP used for?
High CO2
Poor ventilation
What is BiPAP?
EPAP + IPAP
What is BiPAP treatment for?
Type 2 respiratory failure
What is Non-Invasive Ventilation (NIV)?
BiPAP
CPAP
What are the indications for NIV?
Collapsed alveoli
Oedema - LVHF pulmonary oedema
What is NIV not used for?
Asthma
Pneumothorax
Agitation
Airway loss
Why is NIV not used for asthma?
Can push too much air in which has no way of leaving due to bronchiole constriction, can cause alveolar rupture
What is the definition of a patient who is critically ill?
Patient at high risk for developing actual or potential life-threatening health problems
What is see-saw breathing?
Anterior chest wall inwards and downwards as abdomen expands
How to you assess airway?
Look, listen, feel
What should you look for when assessing airway?
Working hard - usage of accessory muscles
See saw breathing
Blue colour
What should you listen for when assessing airway?
Snoring noises - tongue falls back into pharynx
Extra noises
Wheeze/stridor
Gurgling
What should you feel for when assessing airway?
Can you feel air being moved?
How do you treat a compromised airway?
Head tilt, chin lift
Jaw thrust if concerns about stability of c-spine
Gentle suction for gurgling and secretions
Airway adjuncts if still struggling
Recovery position, nasal airway, intubation
Careful of gag reflex
How do you assess breathing?
Look, listen, feel
What should you look for when assessing breathing?
RR
Difficulty breathing (dyspnoea)
Sats
Cyanosis
Symmetry of chest expansion
What should you listen for when assessing breathing?
Air entry
Added sounds - crackles, wheeze
What should you feel for when assessing breathing?
Trachea
Symmetry of chest expansion
Percussion
Generally before listening
How do you treat breathing issues?
High flow O2 - reservoir mask/non-rebreathe + 15L/min O2
If resp absent or inadequate bag and mask ventilation
How do you assess circulation?
Look, listen, feel
What should you look for when assessing circulation?
Perfusion - sats, peripheral cyanosis, CRT
Bleeding
Other organ perfusion - brain = reduced level of consciousness, kidney = urine output adequate?
What should you listen for when assessing circulation?
Heart sounds
What should you feel for when assessing circulation?
Pulses - peripheral and central, rate, rhythm, volume
BP - hypotension
What is the definition of hypotension?
Low if SBP < 90
Low if SBP > 40 lower than normal - use more for older people
MAP > 65
How do you treat circulation issues?
Fluid challenge unless HF or major haemorrhages
Large bore IV access and appropriate bloods
2 x 250ml fluid challenge rapidly
Repeat obs -> if no change then further fluid challenge
Restoration of tissue perfusion
How do you assess disability?
Level of consciousness - AVPU/GCS
Pupils
Glucose
How do you do exposure?
Focussed clinical examination
Based on past history of patient
What do you do after completing a full A->E assessment?
Are ABCDE stable -> if not start again
Full assessment + management plan if stable
What should the ongoing management of a stable patient be?
Ongoing observations
Review of notes, charts, and investigations
IV Abx if required
IV fluids
Further investigations -> CXR, ECG, CT abdo?
Discussion with seniors
At what NEWS2 score should you escalate a patient to the surgical reg?
NEWS2 > 7
What should you do if a patients NEWS2 score is > 7?
Escalate to surgical reg
Immediate medical review
Hourly fluid monitoring
Sepsis screen
Contact critical care outreach team
2222 if immediate assistance required
What occurs in shock?
Circulatory failure
Tissue hypoperfusion
Energy deficit
Accumulation of metabolites
What are the 3 main categories of shock?
Fluid
Pump
Pipes
What can cause shock related to fluids and how is it treated?
Hypovolaemia/haemorrhage
Replace fluids
What are the 2 different types of pump issues causing shock?
Obstructive
Cardiogenic
What can cause obstructive causes of shock?
Tension pneumothorax
PE
Tamponade
What can cause cardiogenic shock?
Ischaemia
Arrhythmias
Other
How is cardiogenic shock treated?
Inotropes but difficult to manage
What can cause shock related to the pipes?
Septic
Distributive -> neurogenic/endocrine
Anaphylactic
How do you treat shock related to pipes?
Vasopressor
Septic + fluids
How do you treat shock?
Call for help
ABC
O2
Treat the underlying cause
What can cause reduced GCS?
CNS - seizure, infection, SOL, CVA
CVR - low CO state
Resp - hypoxia, hypercapnia, CO poisoning
MET - uraemia, hepatic encephalopathy, hypoglycaemia, hypo/hypernatraemia, hypothyroidism, hypothermia
Pharm - opiates, benzos, tricyclics, alcohol
How do you manage a patient who has reduced GCS?
ABCDE
C-spine immobilisation
Assess level of consciousness - AVPU, GCS, glucose
Neurological examination secondary survey
CT
What should you do in a neurological examination secondary survey?
Vitals
Gross neurological deficit
Head to toe examination in A-E approach
CN II-XII
TPR CS
What does TPR CS stand for?
Tone, Power, Reflexes, Coordination, Sensation
What are the risks of head bleeds?
Airway at risk
Secondary brain injury
Uncal herniation
What can cause secondary brain injuries?
Hypo/hyperperfusion
Autoregulation loss/CO2 reactivity loss
Vasospasm
Oedema/inflammation
Metabolic dysfunction
Excitotoxicity
Oxidative stress
Necrosis/apoptosis
What is the symptom of uncal herniation and why?
Mydriasis
Pressure on CN III
What can be done to treat raised ICP? Saying
Blood
Brain
Box
What can be done to the blood to treat raised ICP?
Head up to 30 degress
MAP = 90
Hypercapnia and hypoxia increased CBV
Avoid hypoxia
Aim for normocarbia
What can be done for the brain in raised ICP?
Mannitol/hypertonic saline
O2 consumption (temperature/seizures)
NMBD
Glucose
What can be done for the box in raised ICP?
Craniotomy/craniectomy
What are the 3 components of anaesthesia?
Hypnosis
Analgesia
Muscle relaxation
What are the 3 levels of hypnosis?
Awake -> local anaesthetics
Sedated -> sedation
Asleep -> general
What are the local techniques?
Local -> minor surgery, laceration or wound repair
Regional -> target specific nerves, usually for post-op pain relief
Neuroaxial -> subarachnoid block (spinal)/epidural, or intraoperative and postoperative use
What is the difference between a spinal anaesthetic and an epidural anaesthetic?
Spinal (/subarachnoid) -> needle into CSF in subdural space, through ligaments and dura, local anaesthetic injected as bolus lasts around 2 hours
Epidural -> needle into extradural space, catheter passed, local anaesthetic delivered as infusion
When can you use a spinal/epidural intraoperatively?
Incision below highest nerve root affected by the block -> normally below T10 dermatome
Incisions above this level require GA and lumbar epidural insufficient pain relief post op
How do local anaesthetics work?
Reversibly block Na+ channels
Inhibit generation of action potentials within nerve cells
Small diameter and unmyelinated nerve fibres blocked first
What is the order of block with local anaesthetics and what is the effect?
B fibres -> autonomic (vasodilatation)
C and A delta fibres -> pain and temperature
A beta fibres -> light touch and pressure
A alpha and A gamma fibres -> motor and proprioception
What is local anaesthetic often combined with and why?
Adrenaline
Adrenaline causes vasoconstriction therefore reduced bleeding, prolonged local anaesthetic effect through reduced absorption from tissues
What agents are there for local anaesthetic?
Lidocaine
Bupivicaine
When is lidocaine best used and why?
Immediate onset, 15 minute duration
Small procedures -> laceration repair, chest drains, big cannulae
When is bupivicaine best used and why?
Spinal/epidural (also regional)
10 minute onset
2 hours anaesthesia
12-24 hours anaglesia
What is the definition of a sedation drug?
Any drug given to reduce anxiety (anxiolysis), reduce consciousness, reduce irritability (of the airway), induce amnesia
Name a short-term sedation and when it may be used
IV midazolam
Endoscopy
Regional anaesthesia
Name a long-term sedation and when it may be used
Infusions IV propofol +/- alfentanil
Intensive care
Intubated patients for theatre or transfer
What are hypnotic drugs used for?
Induction and maintenance of anaesthesia
Name 3 inhalational anaesthetics and what they are used for
Generally used to maintain anaesthesia especially in adults
Isoflurane -> cheapest
Desflurane -> wears off quickly
Sevoflurane -> used to induce (in children) and/or maintain anaesthesia
Name 3 IV anaesthetic inducers and when they are used
Propofol -> quick onset, commonest, anti-emetic, fast redistribution so rapid recovery of consciousness (preferred)
Thiopenthal -> quick, emergencies
Ketamine -> CVS instability, analgesia
How is intubation carried out?
Induction -> muscle relaxation -> intubation
Why are muscle relaxants required for intubation?
Glottis relaxed for intubation, muscles relaxed enough for surgery, patients don’t fight ventilators
What are the 2 types of muscle relaxant?
Non-depolarising and depolarising
Name a non-depolarising muscle relaxant and when they are used
Atracurium
Rocunorium (rapid onset)
Vecuronium
120-180s onset
Routine and emergency anaesthesia
Name a depolarising relaxant and when it is used
Suxamethonium
30s onset
Emergencies
How do non-depolarising muscle relaxants work?
Competitively inhibit Ach by blocking binding site and preventing depolarisation and contraction
How does suxamethonium work?
2 Ach molecules that bind to both Ach sites simultaneously
Non-competitive
Causes contraction and then keeps pore open preventing further contraction
What can be used to reverse neuromuscular blocks and where does it not work?
Anticholinesterases eg neostigmine
Doesn’t work for suxamethonium as just causes more build up of ACH
Sugammadex reverses suxamethonium
What are the 2 methods of managing an airway?
Spontaneous breathing
Controlled ventilation
Name a method of basic airway management
Airway manoeuvres - head tilt, chin lift, jaw thrust
Bag-mask ventilation
Guedel airway (oropharyngeal) for BMV aid
Nasopharyngeal - for BMV air
Name a complex airway method
Laryngeal mask
Endotracheal - theatre, ITU
Tracheostomy - ITU
Name a definitive airway
Cuffed tube below vocal cords creating a seal and preventing aspiration - correctly positioned ET tube or tracheostomy
When is NIV used?
Supplemental O2 falling - resp failure
When is CPAP used?
T1RF
What is T1RF?
pCO2 low/normal
pO2 normal
Caused by problem with inadequate oxygenation
Due to alveolar collapse eg pneumonia or fluid in alveoli eg LVHF
What is CPAP?
Continuous positive airway pressure
Maintains minimum airway pressure
Holds alveolar open and/or fluid forced out of lung
What is BiPAP used for?
T2RF
What is T2RF?
pCO2 high, pO2 low
Inadequate ventilation
Alveolar expansion limited eg COPD, musclular dystrophy
Name 2 types of invasive ventilation
Endotracheal tube
Tracheostomy
What are the 2 types of ventilation that invasive ventilation can achieve?
Volume control
Pressure control
What is volume control ventilation?
Pressure increases
Target volume reached
Ventilator stops
Expiration occurs
Where is volume control ventilation used?
Theatres
What is pressure control ventilation?
Pressure constant
Target time reached
Ventilator stops
Expiration occurs
Protects lungs from too high pressure (ITU, children)
Where is pressure control ventilation used?
Theatres
ITU almost exclusively
How do anticholinergics work?
Inhibit Ach therefore inhibiting vagus nerve (parasympathetic) leading to increased HR
Treats bradycardia
Name an anticholinergic
Atropine -> crosses BBB, quick acting
Glycopyrrolate -> doesn’t cross BBB, slower acting
How do beta-adrenoceptor agonists work?
Stimulate beta receptors in myocardial cells leading to increased HR and contractility
Name a beta-adrenoceptor agonist
Dobutamine - used in HR, ITU
How do alpha agonists work?
Stimulate alpha receptors found in peripherals, causes vasoconstriction increasing BP
Can cause reduced HR in response to increased BP
Name a peripheral acting vasoconstrictor given via cannula
Phenylephrine
Metaraminol
Name a central acting vasoconstriction given via central line
Noradrenaline
How does ephedrine work?
Combined alpha and beta adrenoceptor agonist therefore simultaneously raising HR and BP
Adrenaline also works like this but v potent
What are the maintenance fluids for adults roughly?
30ml/kg/day
What can be used for volume replacement?
Hartmann’s
Saline
What can be given for blood loss?
Blood
What can be given for hypoglycaemia?
Dextrose 10%
What is a vasocath?
Filter acting like a kidney
Into central vein and filters blood
What can be treated with a vasocath?
Fluid overload
Severe metabolic acidosis
Uraemia
Poisoning
Hyperkalaemia
What can be given for mild pain?
Paracetamol
NSAID
When should you be cautious with paracetamol?
Liver failure
Low weight (elderly and children)
How do NSAIDs work?
Inhibit COX enzyme therefore preventing production of prostaglandins from arachidonic acid
Phospholipase A2 -> arachidonic acid -> leukotrienes/prostaglandins
COX1 -makes protective prostaglandins -> protecting gastric mucosa, platelet aggregation
COX2 - infammatory prostaglandins
Increase leukotriene production = exacerbation of asthma
What are the S/E of NSAIDs?
Peptic ulcers
AKI
Blood thinning
How does aspirin work?
Inhibits thromboxane A2 preventing platelet aggregation
What can be given for moderate pain?
Codeine
Tramadol
What can be given for severe pain?
Morphine
What are the S/E of opiates?
CNS - sedation, miosis
CVS - bradycardia, hypotension
Respiratory - bardypnoea, apnoea
GI - N&V, constipation
Urinary - retention
Skin - urticaria
What type of opioids should you give pre-op?
Weak, strong, modified release
What opioids should you give intra-op?
Rapid onset/offset, ultrashort acting, long acting
What opioids should you give post-op?
Oral, IV, transdermal
What opioids are given in critical care?
Non-cumulative infusions
Name a weak opioid and it’s benefit
Codeine
Tramadol
Low dose, slow release morphine
Name a strong opioid
Morphine
Oxycodone
Methadone
Buprenorphine
Name a modified release opioid
Fentanyl patch
Morphine sulphate tablets
Oxycontin
What are the benefits of fentanyl and alfentanil?
Fentanyl more potent
Alfentanil works more rapidly but stops working more rapidly
Alfentanil best known for low accumulation for background pain relief
How does remifentanil work?
Ultrashort acting with rapid onset/offset
Metabolised differently to other opioids
Very wide therapeutic index
Which opioids can be given intrathecally?
Diamorphine
Fentanyl
What receptors does tramadol work on?
Noradrenaline
Opioid
Serotonin
What receptors are involved in stimulating the vomiting centre?
Serotonin - 5HT-3
Dopamine - D2
Histamine - H1
Where are serotonin 5HT3 and dopamine D2 receptors?
Solitary tract nucleus
Higher centres
Chemoreceptor trigger zone
GI tract
Where are histamine H1 receptors found?
Cerebellum
Solitary tract nucleus
Chemoreceptors trigger zone
Name an anti-emetic that works on the serotonin 5HT3 receptor
Ondansetron
Where does ondansetron work?
Chemoreceptor trigger zone
GI tract
How does ondansetron work?
Prevents stimulation of vagus nerve by emetogenic stimuli in the gut
What are the S/E and cautions with ondansetron?
Constipation, diarrhoea, headaches, prolonged QT interval
What are the indications for ondansetron?
CTZ stimulation -> drugs
Visceral stimuli -> gut infection, radiotherapy
PONV
Vomiting after acute opioid administration
Name a D2 receptor antagonist anti-emetic
Metaclopramide
Domperidone
Where do D2 receptor antagonist anti-emetics work?
Chemoreceptor trigger zone
Upper GI tract
How do D2 receptor antagonist anti-emetics work?
Prokinetic
Relaxes pylorus, reduces low oesophageal sphincter tones, increases gastric peristalsis
What are the S/E of D2 receptor antagonist anti-emetics?
Diarrhoea, extrapyramidal with metaclopramide eg acute dystonia (domeridone doesn’t cross BBB so no extrapyramidal S/E)
Where can D2 receptor antagonists be used?
Chemoreceptor trigger zone stimulation eg drugs, decreased gut motility eg opioids, diabetric gastroparesis
Metaclopromide -> long term opioid use (opioids cause gastric stasis)
Domperidone -> premedication for PONV
What are the CI of D2 receptor antagonists?
GI obstruction
Perforation
Name a H1 receptor antagonist anti-emetic
Cyclizine
Cinnarizine
Promethazine
Where doe H1 receptor antagonists work?
Vomiting centre
Vestibular system
What are the S/E of H1 receptor antagonists?
Drowsiness
Dry mouth
Blurred vision (anticholinergic effect)
Transient trachycardia after IV
What can H1 receptor antagonists be used for?
Motion sickness
Vertigo
Cyclizine -> PONV, motion sickness, vomiting after acute opioid administration
Prochlorperazine -> vertigo
Where should H1 receptor antagonists be avoided?
Prostatic hypertrophy as can precipitate urinary retention
What patient RF are there for PONV?
Female
Previous PONV
History of travel sickness
Non-smoker
What are the surgical RF for PONV?
ENT
Gynae
GI
What are the anaesthetic RF for PONV?
Peri-operative opioid use
Gastric insufflation during intubation
Volatile anaesthetics
NO2 use
Duration of anaesthesia
What are the risks of OSA?
Difficult airway
Aspiration risk
How can you diagnose OSA?
STOP BANG scoring
Sleep studies
What is the STOP BANG score?
For OSA
Snoring
Tiredness
Observed apnoea
Blood pressure - hypertension?
BMI
Age > 50
Neck circumference > 43.18cm in men or > 40.64cm in women
Gender - male?
Low risk < 3
Moderate 3-4
High > 5
What should you do with patients with suppressed adrenal axis?
Worried about bodies natural response to stress and getting through surgery
If major surgery -> supplement steroids, IV hydrocortisone for 24 hours after surgery, then resume oral steroids as soon as can tolerate (continue IV if can’t)
If minor -> continue taking PO steroids
How do you manage thromboprophylaxis with an epidural?
Worry of haematoma
No prophylaxis 12 hours prior to procedure
After > 4 hours of procedure can give prophylactic LMWH
Wait 12 hours after last dose of LWMH before epidural removal
What is the DASI score?
Duke Activity Status Index score
Scoring based on ability to do certain activities, the higher they score, the higher the functional status
Gives you their METs
What are METs?
Ratio of working metabolic rate relative to resting metabolic rate
Eg activity of 4 METs is burning 4x the amount of energy than at rest
Higher the METs the better the functional status
What are the features of previous MI on ECG?
Q waves
ST depression
Why is it important to check U&E pre-operatively?
Check kidney function for clearance of anaesthetic medications
Electrolyte abnormalities - giving fluids
Why are ACEi stopped before surgery?
Can cause persistent hypotension that doesn’t respond to vasopressors
What is the risk of anaesthesia and IHD?
MI
Low cardiac output due to reduced HR and BP (anaesthetic effect) therefore poor perfusion to heart
Which are you more worried about in terms of anaesthetics - stenotic or regurgitation and why?
Stenotic -> fixed cardiac output
Why does low blood volume lead to hypoxia?
Less perfusion to the lungs
V/Q mismatch
What is shock?
State of inadequate organ perfusion
What is haemorrhagic shock?
Acute reduction in effective intravascular volume due to bleeding
Which fluids should not be used for fluid resucitation and why?
Hypotonic fluids and dextrose (+colloids)
They won’t stay intravascularly where it is required
What is DIC?
Disseminated Intravascular Coagulation
Inappropriate activation of coagulation pathways causing intravascular thrombi and depletion of platelets and coagulation factors leaving patient more prone to bleeding
How much would you expect one unit of blood to increase the Hb by?
10 g/L
What is a major haemorrhage?
50% blood loss within 3 hours
Bleeding in excess of 150ml/min
Loss of more than one blood volume within 24 hours
Name 3 complications of a massive transfusion
Hypothermia
Electrolyte imbalances
Hypokalaemia, hypocalcaemia
Immune haemolysis
Depleted oxygenation (stored blood reduces ability to oxygenate, gets better over time)
Wrong blood
Blood transfusion specific S/E
Overload
How does a massive transfusion cause hypocalcaemia?
Contains citrate which is added to blood products to prevent coagulation
This binds to calcium causing a reduction in calcaemia
What are the starvation rules for theatre?
No solids consumed for 6 hours prior to anaesthesia
Oral clear fluids + oral meds up to 2 hours before surgery (omit any medications not allowed)
Which diabetic drug does not need to be omit before surgery and why?
Metformin -> low risk of hypoglycaemia/normoglycaemic ketoacidosis which are S/E of starvation on other diabetic drugs
What is VRII?
Variable rate IV insulin infusion + dextrose
5% dextrose + 50 units rapid acting insulin -> adjusted by taking BMs every hour than changed accordingly
If BM > 14 then dextrose changed to saline
Why might BM be elecated in an unwell surgical patient?
Part of stress response
Cortisol + adrenaline released -> stimulate gluconeogenesis and decreased glucose metabolism
What are the risks of hyperglycaemia in a diabetic patient?
Wound healing, infection risk
AKI - dehydrated, polydipsia
Risk of DKA
What are the criteria for a diagnosis of DKA?
Hyperglycaemia > 11
Ketonaemia > 3 (ketonuria 2+ on urin dipstick)
Acidosis pH < 7.3
What parameters indicate severe DKA?
pH < 7.15
GCS < 12
Pregnancy
Severe hypotension
Hypoxia, brady/tachycardia
Severe K+ abnormalities
Why is there hypokalaemia in DKA?
Push K+ into cells as giving insulin
At what rate should you give insulin in DKA?
0.1 units per kg per hour
What is the sepsis 6?
BUFALO
Blood cultures
Urine output
Fluids
Abx
Lactate
O2
What is MAP and how is it calculated?
Average arterial pressure throughout one cardiac cycle
MAP = DP + 1/3(SP - DP)
What is sepsis and what is septic shock?
Sepsis -> systemic inflammatory response associated with sepsis
Septic shock -> sepsis with evidence of hypoperfusion of organs (circulatory failure) eg tachypnoea, confusion/reduced GCS, AKI etc)
What is the qSOFA score?
Identifies high risk patients for in-hospital mortality with suspected infections outside of ICU
Altered metal status (GCS < 15), RR > 22, systolic < 100
>2 is high risk
What is the definition of shock?
Acute circulatory failure with inadequate tissue perforation causing cellular hypoxia
Name 3 types of shock
Haemorrhagic + hypovolaemic
Distributive
Cardiogenic
Anaphylactic
Neurogenic
What type of shock is septic shock?
Distributive (leaky capillaries)
How can you manage an AKI?
Maintain adequate BP
Maintain adequate fluids
O2
Monitor U&Es
Monitor electrolytes
When are vasopressors dangerous to use?
When someone is fluid depleted as will under perfuse tissues
(Flight/flight response, vasodilation required)
What are the benefits of epidurals?
Continuous pain relief
Good for lower body pain relief
Quick recovery
Probably requires a lot of opiates for the pain so therefore reduced risk of urticaria, constipation, respiratory depression, N&V etc as has epidural instead
What are the risks of epidurals?
Blocks sympathetic nervous system -> vasodilation -> low BP
Loss of bladder control temporarily/urinary retention
Inadequate pain relief
Post-puncture headache
Temporary/permanent nerve damage
Infection (abscess)
Haematoma (pushes on spinal cord - permanent paralysis)
Motor blocks
S/E of opiates
What happens if local anaesthetic gets into a blood vessel?
Blocks nerves so
-Arrhythmias
-Cardiac arrest
-Seizures
-LOC
What are the CI to an epidural?
Absolute -> patient refusal, allergy to local, technical difficulties (eg ankylosing spondylitis, previous scoliosis surgery), active site infection
Relative -> thrombophilia, bleeding risk, severe cardiac disease, raised ICP, previous back surgery to site
When should you avoid NSAIDs?
Asthma (unless take it regularly)
Dehydration
Renal impairment
Older people
Gastric problems
Pregnancy
When should you avoid tramadol?
Epilepsy
Lowers the seizure threshold
What opiates can be used in kidney failure?
Tramadol
Oxycodone
When should you not give oramorph?
Renal impairment
Cannot absorb opiates/cannot tolerate oral intake -> recent bowel surgery
Name 3 types of O2 mask
NRB
Nasal cannulas
Tracheostomy
Venturi
What % O2 are you delivering to a patient if you give 15l/min O2 via non-rebreathe mask with a reservoir bag?
85-90%
Why is glucose often high in patients that are quite unwell even if they do not have diabetes?
Release of cortisol and adrenaline as part of stress response
What can cause low capillary blood glucose?
Diabetes -> too much insulin, physical activity, alcohol
Acute liver failure
What is the treatment for paracetamol overdose? Include dose and administration
N-acetylcysteine IV
150mg/kg over 1 hour in 200ml 5% dextrose
Then 50mg/kg over 4 hours in 500ml 5% dextrose
Then 100mg/kg over 16 hours in 1L 5% dextrose
What is the definition of status?
Patient been fitting for > 5 minutes
What drugs could you give for a patient where you cannot get IV access for a patient in status?
Community -> 10mg buccal midazolam
Hospital -> rectal diazepam
If a patient is still fitting after midazolam/diazepam what drug would you give (with IV access)?
IV lorazepam (4mg given in small doses at a time to avoid s/e)
What is the S/E of lorazepam you are most worried about in fitting?
Respiratory depression
If benzodiazepines don’t work for a fitting patient what can you given next?
Phenytoin/keppra/valproate
What do you need to know about a patient before giving phenytoin?
Heart problems -> can cause arrhythmias (ECG)
Pregnant -> teratogenic in first trimester
Allergies
If already on phenytoin -> once giving loading dose could put into toxic levels of phenytoin
When is keppra perferred?
Practically -> all the time
Exams -> women of childbearing age
Name 3 causes of seizures
Metabolic -> hypoglycaemia, hyponatraemia, hypocalacaemia, low magnesium
Space occupying lesions -> primary/secondary brain tumours, haemorrhagic stroke
Drugs/alcohol -> overdose/withdrawal
Eclampsia
Epilepsy -> undiagnosed/subtherapeutic treatment/non-compliance/intercurrent illness
Infections -> intra-cranial (encephalitis/meningitis/brain abscess)/systemic
Non-epileptic seizures
Head trauma
Name 3 complications of seizures
Irreversible brain injury -> hypoxia
Death
DIC
Cognititive dysfunction
Metabolic acidosis/dehydration/hypoglycaemia
Muscle breakdown -> rhabdomyolysis therefore AKI and hyperkalaemia
Injury
What is the recommended limit of alcohol per week?
14 units per week with 2 days of abstinence
What are the features of early alcohol withdrawal?
Hand tremors, weating, tachycardia, N&V, headaches, anxiety, irritability, restlessness
What are the features of delirium tremens?
Acute confusion, agitation, delusions, lilliputian visual hallucinations, tremors
Autonomic -> tachycardia, hypertension, hyperthermia, ataxia, arrhythmias
How do you manage delirium tremens?
Continuation of care, big clock, well lit room
Pabrinex (thiamine) IV
Chlordiazepoxide (oral benzo)
What are the features of wernicke’s encephalopathy?
Ataxia, confabulation, ophthalmoplegia (CN VI)
Name 3 RF for ischaemic heart disease
Hypertension
Hypercholesterolaemia
Diabetes
Smoking
Obesity
Sedentary lifestyle
Family history
Ethnic background
What tools can be used to standardise risk of acute cardiac events?
HEART score
If someone has had an MI 2 hours ago, would you expect any cardiac enzyme levels to be raised on this initial sample?
Yes, can be raised within 6 hours of chest pain
What 2 drugs do you give for pain relief during an MI?
GTN spray
IV morphine
Do you give O2 in an MI and why?
No
Shown to give worse outcomes
What ECG changes might you see in an anterior MI?
ST segment elevation with Q waves in (V1-6)
Hyperacute T waves
Reciprocal ST depression in inferior leads (III and aVF)
What ECG changes might you see in a lateral MI?
ST elevation in lateral leads (I, AVL, V5-6), reciprocal ST depression in inferior leads (III, aVF)
What ECG changes might you see in an inferior MI?
ST elevation in inferior leads II, III, and aVF
Hyperacute T waves
Reciprocal ST depression in aVL
Progressive development of Q waves in II, III, aVF
What ECG changes might you see in a posterior MI?
V1-3 horizontal ST depression, tall broad R waves (>30ms), upright T waves, dominant R waves V2
How quickly does PCI need to occur?
Within 2 hours of presentation
Name 2 drugs commonly used for thrombolysis
Streptokinase
Alteplase
What other drugs should be considered during the emergency treatment of acute coronary syndromes?
Aspirin
Ticagrelor
Fondaparinux
What bedside chemical test is important to do within a few minutes of the arrival of a semi-conscious/unconcious patient?
Blood glucose -> easily reversible cause
Name 3 intracranial causes of reduced conscious level
Haemorrhage
Infarction
Infection
Tumour
Post-ictal state
Head trauma
Psychiatric
Name a CVS cause of reduced conscious level
Shock
Hypertension
Name an infectious cause of reduced conscious level
Sepsis
Name 3 metabolic causes of reduced conscious level
Hypo/hyperosmolar state
Hypo/hyperglycaemia
Hypoadrenalism
Hypothyroidism
Hypopituitarism
Electrolyte abnormalities
Hypercapnia
Name drug/toxin causes of reduced conscious level
Sedatives
Analgesics
Alcohol
Name a physical injury cause of reduced conscious level
Hyper/hypothermia
Electrocution
Head injury
What does the typical rash in an allergic reaction look like?
Urticarial rash
Swollen, pale-red, or skin-coloured bumps
Blanching
What are the respiratory symptoms of an allergic reaction?
Wheezing
Reduced airway patency
SpO2
Angioedema
RR increased
Voice alterations
Chest tightness
Coughing
What are the ENT symptoms of an allergic reaction?
Conjunctivitis
Rhinitis
Headaches
What are the GI symptoms of an allergic reaction?
Difficulty swallowing
N&V
Diarrhoea
Abdominal pain
What are the skin symptoms of an allergic reaction?
Itching
Redness/flushing
Urticaria
What is the mechanism of an anaphylactic reaction?
Actions of mediators released from mast cells and basophil degranulation triggered by IgE or non-IgE mediators
Histamine + PAF released which acts of smooth muscle causing symptoms
What is the difference between anaphylaxis and anaphylactoid reactions?
Anaphylaxis -> IgE mediated immune response
Anaphylactoid -> mimics anaphylaxis but non-IgE mediated
What is refractory anaphylaxis?
No improvement in respiratory or cardiovascular symptoms despite 2 appropriate doses of IM adrenaline
What is a biphasic anaphylactic reaction?
2 phase anaphylactic event where you get return of symptoms without re-exposure to the allergen
2nd reaction can be less severe, more severe, or the same
What test can be used to diagnosed anaphylaxis and when can it be taken?
Blood test measuring tryptase level -> marker of mast cell degranulation
Within 3 hours of reaction
How are pre-hospital trauma alerts structured?
ATMIST
A - age and gender
T - time of incident/time of arrival
M - mechanism of injury
I - suspected injuries
S - signs and symptoms
T - treatment given thus far
What does the primary trauma survey consist of?
CABCDE
C - catastrophic haemorrhage
A - airway + c-spine controle
B - breathing
C - circulation and haemorrhage control (not catastrophic)
D - disability/glucose
E - everything else
What should you be aware of in younger people with shock?
BP will be maintained for a long time as they have better physiological reserve
Might just see tachycardia
What are the life-threatening chest injuries? ATOM FC
Airway obstruction/aortic disruption
Tension pneumothorax
Open pneumothorax
Massive haemothorax
Flail chest
Cardiac tamponade
How does tension pneumothorax cause shock?
Rise in pressure in thorax reduces the amount of blood returning from the body to the heart as the blood cannot force its way into the thorax, reduction in pre-load, therefore reduction in afterload, therefore reduced perfusion to organs = shock
What is CO maintained by?
CO = HR x SV
How is a tension pneumothorax treated?
Insertion of large bore needle into 2nd intercostal space in the midclavicular line (avoid neurovascular bundle)
How is an open pneumothorax treated?
Application of a 3-way dressing to the wound to allow for exhalation from the lungs but prevent air being breathed in through the opening in the chest wall
What is a massive haemothorax?
Blood volume of greater than 1000ml within the thoracic cavity
What is a flail chest?
3 or more contiguous ribs are fractured in 2 or more places
Injuries cause a segment of the chest wall to move independently of the red of the chest wall
Causes paradoxical breathing and leads to ineffective ventilation, pulmonary contusion, and hypoventilation
What is cardiac tamponade?
Fluid/blood builds up in the space between the heart and the pericardium
Prevents heart from pumping blood around the body properly
How does tranexamic acid work?
Anti-fibrinolytic, prevents breakdown of blood clots therefore reducing bleeding
Why should you not give crystalloid fluids in a massive haemorrhage?
Dilution of O2 carrying capacity (haemoglobin)
Dilution of clotting factors
What are the benefits of splinting a fracture?
Pain relief, reduced blood loss (long bones), if displaced can cause ischaemia and neuropathy by compromising neurovascular function, optimises outcomes
What are the land marks for chest drain insertion?
‘Safe triangle’
Anterior border of latissimus dorsi, lateral border of pec major, line superior to horizontal level of nipple and apex below the axilla
Name 3 risk factors for a PE that are in the wells score
Surgery in last 4 weeks/long periods of immobilisation
Clotting disorders FH/personal Hx
DVT signs and symptoms
Previous PE/DVT
Haemoptysis
Cancer treatment/active cancer in the last 6 months
Oral contraceptive
Pregnancy
Recent long distance travel
What is the difference between sensivity and specificity?
Sensitivity -> tests ability to designate an individual with a disease as +ve
Specificity -> ability to designate an individual who doesn’t have a disease as negative
What does it mean if a test has high sensitivity but low specificity?
Can rule out disease if -ve, but if +ve not certain that this is definitely the diagnosis
What scores can be used to determine peoples risk of bleeding vs risk of clotting?
CHADVASC = risk of clotting
HAS-BLED = risk of bleeding
What should you ask in a poisoning history?
When? What? How much? Anything else with it eg alcohol/street drugs? Why? Where? Who was with them? Collateral information?
What should you ask about mental health during a poisoning history?
High risk were actions? Actions around self-harm? Help seeking?
Previous self-harm/suicide attempt? Mental health background?
Intentions and feelings now?
Support available?
Home situation?
Capacity?
What examination should you do during a poisoning assessment?
ABCDE
Ensuring - pupils, temperature, glucose
What initial investigations should you do in a poisoning situation?
ECG
Blood gas
What should you look for in an ECG in a poisoning situation?
Conduction delays and ischaemia
QT interval
What should you look for in an blood gas in a poisoning situation?
Anion gap
Osmolar gap
What is an anion gap?
(Na + K) - (HCO3 + Cl)
Normal < 18
What is an osmolar gap?
Measured serum osmolality - calculated osmolality
Calculated = 2 x (Na + K) + glucose + urea
Normal < 10
What is the mnemonic for causes of a metabolic acidosis with a high anion gap? What does it stand for?
CATMUDPILES
- Carbon monoxide, cyanide
- Alcoholic ketacidosis
- Toluene
- Metforming, methanol
- Uraemia
- DKA
- Paracetamol, paraldehyde
- Iron, isoniazid, inborn errors of metabolism
- Lactic acidosis
- Ethanol, ethylene glycol
- Salicylates
How can metabolic acidosis result in a high anion gap?
Accumulation of organic acids
Impaired H excretion
What can cause a high osmolar gap?
Mannitol
Methanol
Ethylene glycol
Sorbitol
Polyethylene glycol
Propylene glycol
Glycine
Maltose
What drugs can prolong QT interval?
Most anti-depressants particularly SSRIs
Lithium
Clarithromycin, erythromycin
Amiodarone
What are the 4 stages of a paracetamol overdose?
Stage 1 (days 0-1)
Stage 2 (days 1-3) - liver injury develops
Stage 3 (days 3-5) - hepatotoxicity peaks, rapid and severe hepatic failure
Stage 4 (days 5-8) - recovery stage for those who survive stage 3
What symptoms might someone experience in stage 1 of a paracetamol overdose?
N&V, abdominal pain, sweating, general discomfort, pale colour
LFTs may be normal
What symptoms might someone experience in stage 2 of a paracetamol overdose?
Upper RQ pain
Raise in LFTs (ALT, AST, bilirubin, INR)
What symptoms might someone experience in stage 3 of a paracetamol overdose?
Encephalopathy
Hypoglycaemia
Glucose
Lactate
Phosphate abnormalities
Coma and death
What can be given if it is within 1 hour of an overdose?
Activated charcoal
What bloods should you do for a paracetamol overdose?
U&E, LFT, INR, FBC, clotting, paracetamol concentration
How does activated charcoal work?
Binds to poison in the GI tract and stops it from being absorbed into the blood stream
What is the difference between a staggered overdose and therapeutic excess?
Staggered overdose -> taking overdose over 1 hour or more
Therapeutic excess -> treating themselves above the recommended limit
Why are bloods taken after 4 hours?
To demonstrate risk of toxicity after 24 hours
4 hours is peak of paracetamol levels
How long does it take for paracetamol toxicity to occur?
24-72 hours
Which patients might be at particular risk of liver damage?
Alcoholics, malnutrition
Enzyme inducers -> carbamazepine, phenytoin, rifampicin, St John’s Wort
Underlying liver disease
Multiple previous paracetamol overdoses
CF
Immunosuppression eg HIV
How do you decide if someone who has taken a paracetamol overdose requires NAC?
Nomogram
When would you start NAC prior to seeing the paracetamol level?
Staggered overdose/therapeutic excess
If close to 8 hours/waiting for result will take you past 8 hours before seeing paracetamol level
Don’t know when they took it (unconscious/confused)
Why should NAC be given within 8 hours where possible?
A lot less effective when over 8 hours from ingestion
Almost 100% effective if started within 8 hours
Why does a previous paracetamol overdose put people at higher risk of liver damage?
Glutathione reductase level reduced
How does NAC work?
NAPQI = toxic metabolite of paracetamol
Further metabolised by glutathione reductase and then excreted
Increased NAPQI concentrations saturating glutathione reductase leaving the toxic metabolite
NAC stimulates glutathione synthesis
Why does NAPQI damage to liver?
Results in loss of activity of critical hepatic proteins and therefore hepatic cell death
What scoring systems can be used to evaluate self-harm risk?
SAD PERSONS
What criteria is used for consideration of a liver transplant after a paracetamol overdose?
King’s college criteria
What is the King’s college criteria?
Arterial pH < 7.3 or all of the following
PT > 100s
Creatinine > 300
Grade III or IV hepatic encephalopathy
What are the symptoms of an opioid overdose?
Reduced consciousness, respiratory depression, miosis
Reduced BP and HR
What is the antidote for opioid overdose?
Naloxone
What are salicylates?
Aspirin/other NSAIDs
What occurs in mild salicylate toxicity?
Irritate gastric lining
Ototoxicity
What occurs in moderate/severe salicylate toxicity?
Mixed metabolic respiratory alkalosis + metabolic acidosis
How does salicylate overdose lead to respiratory alkalosis?
Stimulate cerebral medulla = hyperventilation = respiratory alkalosis
How does salicylate overdose lead to metabolic acidosis?
Metabolism = anaerobic metabolism = lactic acid = metabolic acidosis
Also have acidic effects themselves
Hyperventilation worsens in response to acidosis until body can no longer compensate
How does salicylate overdose lead to pyrexia?
Metabolism = anaerobic metabolism = heat production = pyrexia
What are the symptoms of a mild salicylate toxicity?
N&V
Epigastric pain
Tinnitus
Dizziness
Lethargy
What are the symptoms of a moderate salicylate toxicity?
Sweating
Fever
Dyspnoea
What are the symptoms of a severe salicylate toxicity?
Confusion
Convulsions
Coma
What are the bedside Ix for a salicylate overdose?
Obs
ECG -> arrhythmias
BM
ABG
What are the lab Ix for a salicylate overdose?
Plasma salicylate conc + paracetamol
FBC, U&E, LFTs, coag, CK
What is the management for a salicylate overdose?
No antidote, supportive care
Moderate to severe consider ICU admission
If within 1 hour then active charcoal
IVI, K+ replacement
Bicarb, cooling measures, haemodialysis
Why give bicarb in salicylate overdose?
Reduces transfer of salicylates into CNS and enhances urinary excretion (aka urine alkalinisation -> monitor urine pH, aim pH > 7.5)
Can lead to hypokalaemia
What are the complications of salicylate overdose?
ARDS -> bilat pulmonary oedema with hypoxia, intubation + ventilation
Seizures -> benzos
Drug induced hepatitis
Cardiac arrest -> prolonged QT, polymorphic ventricular tachycardia and/or ventricular fibrillation
Name 3 drugs that are anti-cholinergics
Ipratropium/tiotropium
Oxybutynin
TCA
Low potency anti-psychotics
Ach receptor antagonists
What symptoms of an overdose/S/E of anti-cholinergics can you get?
Increased HR and BP
Pyrexia
Dilated pupils
Decreased bowel sounds
Decreased sweating
How do tricyclic antidepressants work?
Increased effect (reuptake inhibition) of serotonin (5-HT receptors) and noradrenaline (NA receptors)
Decreased effect (post-synaptic receptor antagonists of histamine (H1 receptors), A-1 adrenoceptors, acetylcholine receptors
What are the symptoms of toxicity/side effects of TCA?
Serotonin -> nausea, GI upset, sexual dysfunction
Noradrenaline -> tachycardia, tremors
Antihistamine -> sedation, weight gain
Anticholinergic -> dry mouth, blurred vision, confusion, constipation, tachycardia, urinary retention
Alpha-1 adrenergic -> postural hypotension, drowsiness, dizziness
Acts o fast Na channels in myocardial cells - Na channel blockage = cardiac arrhythmias, convusionals, coma
What bedside Ix can be done for TCA overdose?
Obs
ECG
BM
Blood case -> can cause mixed acidosis
What lab Ix can be done for TCA overdose?
FBC, U&E (hypokalaemia in overdose), magnesium + bone profile, LFT, paracetamol + salicylate levels
What is the management of TCA overdose?
Supportive
Metabolic acidosis = give sodium bicarbonate
Hypokalaemia = give K+
What are the symptoms of benzodiazepine overdose?
Agitation, euphoria, blurred vision, slurred speech, ataxia, slate-grey cyanosis
What is the antidote for benzodiazepine overdose?
Flumenazil
When should you be careful/not use flumenazil and why?
Long term benzo abusers -> induce withdrawal (including seizures)
How does flumenazil work?
Competitively binds to benzodiazepines
Half-life shorter than benzos so may require multiple doses/infusion
