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Immediate control is usually achievable by direct pressure
over the site of injury. This pressure does not need
to be great (Systolic blood pressure is around 100mmHg),
but it does need to be directed over the site of haemorrhage.
Large bandages and pads applied overwounds, with more
and more bandaging applied as the bandages soak with
blood, is not controlling haemorrhage! It is better
to dedicaton one individual to manually compress the
site of haemorrhage.
Where haemorrhage is welling up from a deep knif or
gunshot track, control may be temporarily achieved by
passing a urinary catheter into the track as far as
possible, inflating the balloon, and then applying traction
to the catheter. The catheter can be sutured in place
if the patient is to be transferred to another department
or hospital.
If angiography is performed prior to surgery, it may
be possible to obtain proximal control by passing an
angioplasty balloon catheter into the proximal vessel
and inflating the balloon. This can also aid dissection
of the vessel at operation, as the angioplasty balloon
is easily palpable within the haematoma. The radiology
suite should not be used for proximal control alone
- this is more appropriately performed surgically in
the operating room.
Blind clamping in the depths of a wound is dangerous,
likely to fail, and likely to injure other structures.
There are two phases in the resuscitation of patients
with vascular injuries - before and after haemorrhage
control. Prior to haemorrhage control, minimal fluids
should be administered. Raising the blood pressure will
increase haemorrhage from the vessel injury and dislodge
any clot that has already formed. The patient cools
as more cold fluids are administered. Clotting factors
are used up and diluted, and the patients become coagulopathic.
Shock worsens, heat production is impaired and clotting
enzyme activity is attenuated.
The priority in this phase is operative control of
haemorrhage and there should be no delay in transferring
the patient. Systolic blood pressure can be maintained
at a level that is appropriate for perfusion of the
brain. If the patient is talking and orientated, the
blood pressure is adequate, regardless of actual value.
For unconscious patients, a sysolic of 60-70mmHg is
adequate in the absence of significant brain injury.
No inotropes should be given to the hypovolaemic patient
as this will effectively deplete myocardial tissue oxygen
and increase myocardial work in the absence of adequate
preload. These patients are already maximally vasoconstricted.
Large bore venous access is necessary however, and
there should be at least two sites of access to the
circulation, appropriate for giving warmed fluids rapidly.
Once haemorrhage control is achieved, there is a phase
of aggressive volume resuscitation to restore circulating
blood volume. Warmed fluids -crystalloid, blood or clotting
factors as necessary -are administered to correct acidosis,
hypothermia and coagulopathy, and to restore perfusion
rapidly to shut-down organ systems. This should help
to prevent the subsequent development of a systemic
inflammatory response and its consequences.
The patient is positioned on the operating table to
allow on-table angiography of the affected region and
distal perfusion. The entire affected limb is prepped
and draped, as well as proximal structures if control
has to be gained more proximally. The hand or foot is
prepped so that intra-operative assessment of distal
perfusion is possible. An entire uninjured limb should
also be prepped so that a vein graft can be harvested
as required. Often the person applying manual compression
at a bleeding site will have to be temporarily prepped
into the operative field until scrubbed personnel can
take over.
The basic principle of vascular repair is to gain
proximal and distal control of the relevant vessel before
investigating the site of injury. Direct exploration
of a wound that is actively bleeding will inevitably
lead to failure to control the haemorrhage and collateral
damage to neighbouring structures. Proximal control
is best achieved through a separate incision away from
the site of injury. Distal control similarly is best
achieved via a second incision. Once proximal and distal
control is achieved, the site of injury can be explored
and control made closer to the injury site. It may be
tempting to directly explore a wound that is not actively
bleeding. However, profuse haemorrhage can rapidly obscure
the operative field once clot is dislodged from around
the site of vascular injury.
Control is best achieved with slings passed twice
around the vessel. If vascular clamps are used they
should be applied with the minimum force necessary to
obstruct flow, not racked closed causing vessel wall
damage. Do not attempt to encircle the aorta or iliac
arteries for risk of damage to lumbar arteries or iliac
veins.
Once the vessel injury is identified, a decision on
repair technique must be made. This will depend on the
extent of damage to the vessel. The first step is therefore
debridement of devitalised tissue and definition of
the edges of the wound. Next an assessment of inflow
and outflow is made. If it is inadequate, a balloon
(Fogarty) catheter is passed proximally and distally
to extract any thrombus. Following extraction, heparinized
saline is instilled proximally and distally to locally
antcoagulate the vessel.
Small, clean, transverse wounds to vessels that involve
only part of the circumference can be repaired with
a direct suture technique. A vein (or synthetic) patch
may be required where there is a larger defect in the
vessel wall where direct sutuing may lead to narrowing
of the vessel lumen. While vein grafts probably have
a longer patency, the graft infection rates are the
same for both vein and synthetic grafts, regardless
of wound contamination.
 
Vein patch to carotid artery
The ends of a transected artery usually retract. If
the ends can be approximated without tension, a direct
end-to-end anastomosis repair can be employed. Mobilisation
of the two ends may be necessary, and aided by division
of minor arterial branches.
 
End-to-end anastomosis of
transected popliteal artery.
Where approximation of the vessels is not possible,
a reversed vein graft, or synthetic graft is used to
repair the defect. If there is a concomitant vein injury,
this should usually be repaired first, if possible to
avoid low-flow thrombosis of the arterial repair.
 
Reversed vein graft to transected
common femoral artery.
Intra-operative angiography is indicated if the location
of the vascular injury is unknown, if distal perfusion
is inadequate after a vascular repair is completed,
or at the end of a procedure for completion angiography.
To perform an angiogram, proximal control is attained.
This prevents flushing away of contrast and makes timing
of injection much easier. A small arteriotomy is made
to allow the introduction of an 18 guage catheter. A
50/50 dilution of intravenous contrast is used. An initial
scout film can be taken, and then 20 to 50 mls of contrast
solution injected rapidly, and the arteriogram film
obtained. A delay of 10 to 15 seconds should be used
where distal vessels are being imaged. If there is any
doubt about the timing of the image, a second film can
be taken. Fluoroscopy and digital subtraction angiography
avoid many of the pitfalls associated with plain film
radiographjy in the operating room.
The principles of damage
control surgery can be applied to vascular trauma.
The basic damage control techniques are ligation and
shunting.
Ligation
There are very few vessels that cannot be ligated in
extremis, at varying risk to life and limb. The common
and external carotid, subclavian, axillary, internal
iliac can be ligated with few consequences. Ligation
of the internal carotid artery carries a 10-20% risk
of stroke. Ligation of the exteral iliac artery, common
femoral or superficial femoral have a signficant risk
of critical limb ischaemia following ligation. Ischaemia
is more likely if there is significant soft tissue injury
and distruction of supporting collateral circulation.
Arteries of the celiac axis can be ligated but ligation
of the superior or inferior mesenteric artery will almost
inevitably lead to gut necrosis in the young trauma
patient.
Almost all veins, including the inferior vena cava,
can be ligated where necessary, with the consequence
of lower limb oedema. Ligation of the portal vein is
possible but bowel oedema with massive 'third-space'
fluid losses will ensue..
Shunting
Where there is a significant risk of limb loss, stroke,
gut ischaemia or other serios consequence of ligation,
intraluminal shunts may be employed to temporarily restore
flow. While specific vascular shunts are available,
shunts can be rapidly constructed out of sterile intravenous
tubing or chest tubes for larger calibre vessels. Ensure
that shunts are secured in place so that they do not
become dislodged during transfer to the intensive care
unit or during nursing procedures.
Where there is a vascular injury associated with a
fracture, and there is a risk of orthopaedic manoeuvers
disrupting an arterial repair, shunts may be employed
to temporarily restore flow to an injured limb. Definitive
repair is then carried out after fracture fixation.
Shunts may also be used while assessing an amputated
limb for its viability for reimplantation.
Superficial Femoral Artery injury following impalement
(Classic Case 013)
Prolonged interruprion of blood flow to a limb leads
to cellular ischaemia, actibvation of cellular and humoral
inflammatory responses and alterations in vascular permeability.
Subsequent reperfusion of the limb leads to generalised
tissue oedema. When this occurs in a limited, enclosed
space - such as the fascial compartments of the lower
limb, the pressure in the compartment may rise above
capillary and venous pressure and cause vascular stasis,
cellular ischaemia and death.
The pressure in the compartments is rarely above arterial
pressure and distal pulses are preserved. If the patient
is awake, there is intense, disporoportionate pain in
the limb, worsened by passive flexion of the muscle
groups. Many patients are unconscious, have spinal cord
injury or epidural anaesthesia. In this case the early,
reversible signs of compartment syndrome may be lost
and diagnosis relies on a high index of suspicion and
measurement of compartment pressures. Values over 30mmHg
are diagnostic of compartment syndrome.
Prevention is better than cure and the aphorism 'If
you think about doing a fasciotomy, you should do one'
probably still holds true. Fasciotomy is best performed
at the time of initial surgery, rather than as a subsequent
procedure for a second episode of limb ischaemia. Compartment
syndrome is not confined to the distal lower extremity
and can occur in the thigh, buttock and forearm.
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