Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL ONE
TUTORIAL 1 : TRIGGER 1
PRESENTATION
It is 10.30 pm on a Friday night, when two medical students see the car ahead of
them run off the road and crash into a tree. They stop and run to the scene. A
young male, covered in blood, is struggling to get out of the driver's seat of his
wrecked car. There is blood spurting from a wound in his left thigh.
"What should we do?"
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL ONE
TUTORIAL 1: TRIGGER 2
FIRST AID & INITIAL EXAMINATION
The students have moved the driver, Mark B., away from the wrecked car. He is
bleeding profusely from the wound in his left thigh. One of the students manages
to control the bleeding by pressing on the open wound with his hands.
Throughout, Mark is conscious and complains of feeling thirsty and cold.
An ambulance and the police arrive soon after. On examination, he is conscious
but confused, groaning in pain and complaining of difficulty breathing. Other
observations are:
- systolic BP 70 mmHg (diastolic too low to measure)
- Pulse 135/min, thready
- respiratory rate 30/minute
- airway intact
- chest extensively bruised and tender
- deformity of the left thigh with substantial bleeding
- numerous bruises and lacerations of both lower limbs
- extreme pallor - pale face, conjunctiva and palmar creases - and cold, sweaty
extremities
- no obvious head injury, no neck pain, pupils equal and reactive to light.
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL ONE
TUTORIAL 1: TRIGGER 3
INITIAL TREATMENT
The ambulance officers provide oxygen therapy and begin an intravenous
infusion. One of them says “This is the fourth accident we’ve been called out to
this week.” They set off on the twenty minute journey to the nearest country
hospital.
One of the medical students accompanies the patient in the ambulance. "What is
the best IV fluid to start with? Is he going to bleed more if we give him a lot of
fluid?" asks the student.
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL TWO
TUTORIAL 2 : TRIGGER 1
EMERGENCY DEPARTMENT
History &Assessment
Mark’s brother, Paul, arrives at the hospital shortly after Mark is brought into
A&E. Paul states that Mark is 19 years old. He usually works as a barman but is
currently unemployed. He smokes 30 cigarettes a day. He is a binge drinker,
taking as much as 200 grams of alcohol (20 standard drinks) in a single sitting,
once or twice weekly. Mark’s father also has a history of heavy alcohol
consumption.
On assessment in Emergency, Mark is found to have a compound fracture of the
left femur with partial laceration of the left femoral artery. His blood alcohol level
is 0.18 g/dl. He has no significant past medical history and subsequently proves
negative for HIV, hepatitis B and C.
Y1W1&2_ Blood on the Road
What we know
Trigger 1 (above)
 Admitted to ED (Paul’s
brother arrived)
 Mark, 19
 Worked as barman, now
unemployed
 Smokes 30 cigarettes
 Binge drinker (200 g/20
standard drinks per session,
once or twice a week)
 Father has history of heavy
alcohol consumption
 On assessment in Emergency
– compound fracture of left
femur, partial laceration of
left femoral artery
Needs to go to the OR
 BAL 0.18 g/dl
Normal alcohol level 0.05
Can’t anaesthetise
(alcohol CNS depressant)
 No significant past medical
history
 Negative for HIV, Hepatitis B
&C
Trigger 2
 Vital signs not improving
 Haemopneumothorax seen
on erect CXR
What we need to know
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Trigger 3
 Open chest surgery – repair
lac to left main bronchus & a
TRIGGERS

MED 1000
Hypotheses
How BAL relates to risk of having MVA
(RTA – Driver Qualification Test)
http://www.rta.nsw.gov.au/licens
ing/downloads/driver_qualificatio
n_handbook.pdf
exponential relationship between
relative crash risk & BAC
Age & sex related risks to having MVA
In above website
Does he abuse other illicit drugs?
Is alcohol hypo/hyper/isotonic
The effect of alcohol on the body
E.g. immune system (chemotaxis),
cardiovascular system, etc
Can we control bleeding & wait?
At what BAL can we do Sx (surgery)?
Should we give antibiotics or tetanus
immunisation?
Alcohol impairs immune system
Chest X-ray (CXR)
GCS score
Abdominal assessment
What is a haemopneumothorax?
Different opacities in CXR
Darkest thing is air (black – lungs
are nearly black)
Grey (darker grey is fatty tissues,
lighter grey is muscles)
Calcified tissues or bones
Very white – metal objects
CXR
Right side of patient is your left
side
Normal – lungs, should be able to
count 9 ribs (taken with full
inhalation)
Pt – darker due to compressed air
Emphysema – lungs will be darker
(air trapped in the lungs, blood/air
contact surface area destroyed,
i.e. alveoli)
Gastric bubble – normal on left
side, always abnormal on right
side (liver)
Could patient have a different type of
shock? (e.g. septic shock)
Septic shock (infection) – does he
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Ribs have
punctured the
lung
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Septic shock
How it
happens?
Y1W1&2_ Blood on the Road
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pulmonary vein
Large intravenous fluid
replacement (plasma
expander, blood), not
stabilised before surgery
(accumulating blood & air in
pleural space, ongoing blood
loss)
Profound hypotension in
surgery (fluid replacement
unable to keep up with
losses)
Surgery also included
stabilization of fractures
Anaethetist says – not
keeping ahead of this guy’s
losses
Pulse 120
Systolic BP (SBP) 90
Peripheral perfusion is
poor
Have we missed something?
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TRIGGERS
have a fever?
Compensatory mechanisms in shock
Detected by baroreceptors
Renin-angiotensin-aldosterone
cycle
Not working!
From a certain level onwards,
compensatory mechanisms can
damage the body
Mechanisms of shock
How do we assess adequacy of fluid
replacement?
Vital signs – HR, resp rate, skin
colour
Urine output –
normal/increased/decreased?
Prophylactic (preventative)
antibiotics?
Generally not used, unless there
are specific requirements (e.g.
orthopaedic surgery – high risk of
infection)
Not used if surgery is completely
clean/sterile
Prophylactic antibiotics will
increase antibiotic resistance
Losing fluid – from where?
Check urine for blood?
Bleeding from abdomen?
Pt doesn’t have clinical signs
Oedema?
What is affecting blood pressure?
Is it affecting contractility of the
heart
Cardiogenic shock
Preload & afterload
Is the preload affected or not?
Afterload is probably not enough
(BP low, pulse high)
Look at pressure inside veins – JVP
JVP high – cardiogenic shock
MED 1000
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What is it?
More third
spacing?
Blood not
returning to
heart –
blockage?
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL TWO
TUTORIAL 2 : TRIGGER 2
EMERGENCY (cont’d)
Investigations
Despite extensive fluid replacement, Mark’s vital signs are not improving. A chest
X-ray taken in the supine position is hard to interpret. He is propped up and
another film taken in the erect posture.
X-ray shows a haemopneumothorax
Y1W1&2_ Blood on the Road
(see below for a normal chest x-ray for comparison)
TRIGGERS
MED 1000
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL TWO
TUTORIAL 2 : TRIGGER 3
SURGERY
Mark requires open chest surgery to repair lacerations to his left main bronchus
and a pulmonary vein.
Despite being given large volumes of intravenous fluid replacement (plasma
volume expander and then blood as soon as it was available from cross
matching), he could not be stabilised before surgery because of accumulating
blood and air in the pleural space, and ongoing blood loss. During surgery, he
continued to experience episodes of profound hypotension as fluid replacement
was unable to keep up with the losses.
As Mark is recovering consciousness after the surgery, which also included
stabilisation of his fractures, the anaesthetist says "We are still not keeping
ahead of this guy's losses. His pulse is about 120, systolic BP only 90 and his
peripheral perfusion is poor. Have we missed something?"
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL THREE
Tutorial 3 : Trigger 1
POST-OP
Mark's central venous pressure is monitored while his fluid replacement
continues.
The anaesthetist, who is also the hospital's intensivist, says "That is about as
high as we dare bring up the CVP. I wish we had a pulmonary wedge pressure
(PWP) to get the left ventricular filling pressure!"
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL THREE
TUTORIAL 3 : TRIGGER 2
PROGRESS
Mark's arterial blood pressure comes up to around 105/85, with pulse rate of 96
per min.
"Is he out of the woods now?" asks the student.
"After such a long period of hypotension, the worry is that he will deteriorate from
now on into irreversible shock no matter what we do..."
Echocardiography does not show any mechanical damage to the myocardium or
heart valves, but indicates that his left ventricular ejection fraction is down to
31%. When asked how bad this was the anaesthetist comments: "It could be
worse, but much below that they don't make it."
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
TUTORIAL FOUR
TUTORIAL 4 : TRIGGER 1
Eight hours after his crash, Mark is in a serious but stable condition.
He is transferred to a metropolitan hospital.
Arterial pressure: measure what the pressure is on arterial vessels- so what the pressure is that
the ventricles feel when ejecting blood. This will drop from the aorta to the capillaries.
Filling Pressure: Pressure in the right atrium- Differential only relevent when there is low
volume. When the heart pumps normally – need to have blood to pump from the atrium. Low
filling pressure – not much blood
Measure CVP in the right atria: Pressure of the blood returning to the heart. How the veins get
pressure- big veins taking a breath (intrathoracic pressure), some have their own arteries that
are contracting, muscle pumps, valves. Central venous pressure – not peripheral – final stage =
right atrial pressure.
Atrioventricular (Mitral and Tricuspid) Valves open because attached to the heart muscles and
will contract when the heart contracts- doesn’t happen due to pressure. Even if the heart was
empty the valves would still open.
Valves are in the lower vena cava but not in the superior vena cava. Don’t need valves in the
superior vena cava because of gravity. No valves between the inferior vena cava and the right
atrium because there are valves within in the vein itself. If everything is working properly there
should be the same pressure in the superior and inferior vena cava but when considering CVP
we measure from the right atrium.
CVP: The pressure of the blood within the superior and inferior vena cava, depressed in
circulatory shock and deficiencies of circulating blood volume, and increased with cardiac failure
and congestion of circulation.
Mean circulatory filling pressure a measure of the average (arterial and venous) pressure
necessary to cause filling of the circulation with blood; it varies with blood volume and is directly
proportional to the rate of venous return and thus to cardiac output
Heart is at more risk during shock than other organs because it is working harder (tachycardia)
and therefore needs more O2 but there is less available. – A reason why shock can become
irreversible. Heart can suffer ischaemia because works harder but there is not enough oxygen
to keep up with needs.
Ischaemia= reversible
Y1W1&2_ Blood on the Road
TRIGGERS
MED 1000
Necrosis= ireversible
6 hours to cause permanent damage through to the whole wall.
PE can be an explanation of irreversible shock- many different explanations of irreversible
shock.