TPP - Blunt/penetrating trauma

What is the pathophysiology of blunt abdominal trauma?

• Compression of internal organs against posterior structures e.g. spine.

• Deceleration injury where organs continue moving whilst body stops, causing tearing/vascular tears.

• Burst injury from sudden increase in intra-abdominal pressure.

• Internal bleeding —>Contusions

• Peritonitis

• Inflammatory response from tissue damage

What is the pathophysiology of blunt limb trauma?

• Compression of soft tissues against bones causes contusions, muscle crush injury (rhabdo & AKI), haematoma.

• Prolonged compression can cause muscle ischaemia and increase risk of compartment syndrome.

• Bending/torsional forces cause fractures, soft tissue and vascular injury.

• Vascular injury —> distal tissue hypoxia/ischaemia & haemorrhage.

• Nerve damage

• Inflammatory response from tissue damage

What is the pathophysiology of penetrating abdominal trauma?

• Laceration/transection of organs

• Perforation of hollow organs

  • Peritonitis —> sepsis

• Vascular injury causing haemorrhage

• Inflammatory response from tissue damage

What is the pathophysiology of penetrating limb trauma?

• Vascular injury —> distal tissue hypoxia/ischaemia & haemorrhage

• Compartment syndrome: increased pressure in closed muscle fascial compartments from fluid/blood, causing ischaemia and necrosis

• Neurological deficits: nerve injury causing loss of sensation/motor function

• Inflammatory response

What is the pathophysiology of hypovolaemic shock?

• Reduction in circulatory volume decreases venous return to the heart, which decreases preload which decreases stroke volume, reducing cardiac output and causing hypotension.

• Low blood pressure causes decreased stretch in vascular walls which triggers baroreceptors, activating sympathetic nervous system, causing release of catecholamines. This stimulates tachycardia + myocardial contractility to maintain cardiac output.

• Catecholamines also trigger peripheral vasoconstriction which causes shunting of blood to vital organs to maintain perfusion, causing pallor.

• There is a shift to anaerobic metabolism due to tissue hypoperfusion causing build-up of lactic acid and metabolic acidosis.

• The change in blood pH triggers chemoreceptors, stimulating increased ventilation

• Triad of Death – coagulopathy, metabolic acidosis, hypothermia

  o   Impaired function of clotting factors

What is the treatment of blunt trauma?

• High flow oxygen

• [bilateral cannulas] orange - 45-55 seconds 250ml bolus

• [raise legs]

• Fluid bolus

• Pain relief: Entonox/IVP

• TXA

What is the treatment of penetrating trauma?

• High flow oxygen

• [bilateral cannulas] orange - 45-55 seconds 250ml bolus

• [raise legs]

• [if external haemorrhage, apply large non-adherent wound pad and bandage and direct pressure]

• Fluid bolus

• Pain relief: Entonox/IVP

• TXA

What are the benefits of high flow oxygen in blunt/penetrating trauma?

• Prevents/treat hypoxia

• Improves tissue oxygen delivery

• Prevents ischaemia

• Helps maintain cellular metabolism

• Prevent shock.

What is the benefit of raising legs in blunt/penetrating trauma?

• Increases BP: shift of blood from lower limbs to central circulation increases venous return, preload, stroke volume and thus cardiac output

What are the risks of raising legs in blunt/penetrating trauma?

• Pain/discomfort

• Exacerbate lower limb injuries

• Temporary solution - fluids are important

What are the benefits of fluid bolus in blunt/penetrating trauma?

• Increases BP: temporary restores circulatory volume which increases venous return, preload, stroke volume and thus cardiac output

• Reduces risk of ischaemic injury: increases oxygen delivery to vital organs

What are the risks of fluid bolus in blunt/penetrating trauma?

• Excess fluid can increase haemorrhage:

  • Dislodges clots

  • Dilutes clotting factors

  • Worsens coagulopathy

• Compartment syndrome

What are the benefits of entonox in blunt/penetrating trauma?

• Rapid onset analgesia

• Less patient harm/distress: does not require IV access

• Prevents hypoxia: contains 50% oxygen

What are the risks of entonox in blunt/penetrating trauma?

• Dizziness: mild CNS depression

• Nausea & vomiting: stimulates chemoreceptor trigger zone in medulla

• Euphoria: release of dopamine which bind to dopamine receptors in the brain

What are the benefits of IVP in blunt/penetrating trauma?

• Rapid onset pain relief: faster acting than oral paracetamol

What are the risks of IVP in blunt/penetrating trauma?

• Hypotension if administered too quickly: peripheral vasodilation reduces systemic vascular resistance - highlights importance of running over 15 mins

What are the benefits of TXA in blunt/penetrating trauma?

• Reduces blood loss: antifibrinolytic that inhibits conversion of plasminogen to plasmin, preventing plasmin interacting with fibrin, preventing breakdown of clots (fibrinolysis)

What are the risks of TXA in blunt/penetrating trauma?

• Nausea/vomiting by stimulating chemoreceptor trigger zone

• Diarrhoea: irritation of intestinal mucosa

• Hypotension & dizziness if injected too rapidly as causes transient vasodilation, reducing systemic vascular resistance

• Arterial/venous embolism by preventing breakdown of pathological clots