Haemorrhagic shock Flashcards
What is shock due to significant and rapid blood loss causing inadequate tissue perfusion?
Haemorrhagic shock
This is a subtype of hypovolaemic shock.
What are the four classes of hypovolaemic shock based on blood loss percentage?
15%, <30%, <40%, game over (>40%)
The numbers correspond to the percentage of blood loss in each class.
What confounding factors affect the classification of hypovolaemic shock?
- Age
- Severity of injury
- Type of injury
- Anatomical location of injury
- Time lapse between injury and treatment initiation
- Prehospital fluid therapy
- Medications
What occurs to blood volume during hypovolaemic shock?
Reduced circulating volume
This leads to decreased venous return and preload, reduced cardiac output, and systemic hypotension and reduced cellular perfusion
What compensatory mechanisms are activated in response to hypotension in hypovolaemic shock?
- hypotension causes Activation of baroreceptors
- Sympathetic nervous system activation
- Peripheral vasoconstriction (to preserve blood supply to vital organs)
- Tachycardia
- Increased cardiac contractility
What symptoms are associated with hypovolaemic shock?
- Thirst
- Feeling dizzy
- Confusion
- Lethargy
What are key signs of hypovolaemic shock?
- Tachycardia
- Hypotension
- Shock index (HR/systolic BP) >0.9
- Overt blood loss
What does a shock index greater than 0.9 indicate?
Haemorrhage needing transfusion
This is calculated as heart rate divided by systolic blood pressure.
What blood tests are used to determine the extent of bleeding?
- Arterial blood gas: acidosis is the best indicator of ongoing O2 imbalance in tissues
- U+Es: checking for electrolyte imbalance, kidney function, fluid loss
- Group and Hold/cross match: in case transfusion is required
What imaging techniques are used to identify the source of bleeding?
- FAST scan
- CT scan
What are the initial steps in treating hypovolaemic shock?
- Establish a patent airway
- Ensure adequate ventilation and oxygenation
- Insert 2x large bore IV cannulas
*control external bleeding by applying direct pressure
*early damage control surgery may be indicated in severe hemorrhagic shock
What is the massive transfusion protocol?
- Identify and treat underlying cause
- Replace like with like
- Use crystalloids cautiously
- Reversal of anticoagulation if necessary
- Administer anti-fibrinolytics
- Surgery to control the bleed
- Monitoring
What is permissive hypotension?
damage control resuscitation Maintaining lower than physiological BP while preserving organ perfusion and preventing haemorrhage, acidosis, hypothermia and organ dysfunction
NOT for traumatic brain injury or spinal cord injury
Systolic BP 80-100 mmHg.
What conditions contraindicate permissive hypotension?
- Traumatic head injury
- Spinal cord injury
What are potential complications of resuscitation in hypovolaemic shock?
- Pulmonary oedema
- Reaction to blood products
- Dilutional syndromes
- End-organ damage
What is the lethal triad of trauma?
- Metabolic acidosis
- Coagulopathy
- Hypothermia
