SHOCK
Shock: Assessment and management priorities
Recognize presence of shock
Identify probable cause
Treatment of shock
Definition of shock
A fall in blood pressure such that the delivery of oxygen and energy to the organs by the blood falls below that which is required to maintain normal organ function.
Recognition of shock
Pulse rate
Skin circulation (capillary refill time)
Blood pressure
Conscious level
Respiratory rate
Circulating adrenaline may mask the signs of shock unless it is advanced
Causes of shock in trauma patients
Haemorrhage
Cardiogenic shock (tension pneumothorax, cardiac contusion, cardiac tamponade, air embolus, myocardial infarction)
Neurogenic shock Isolated head injuries do not cause shock. Likely to be hypovolaemic secondary to hemorrhage.
The normal response to shock
Increased heart rate
Constriction of blood vessels reducing their calibre and increasing blood pressure. This reduces blood flow to some organs (e.g. skin, gut, kidneys) whilst maintaining flow to others (e.g. brain)
Initial management of haemorrhagic shock
Airway
Breathing
Haemorrhage control (pressure dressings)
Wide bore vascular access (2 Ch14 cannulas)
Rapid fluid therapy
Continued reassessment
Fluid therapy
Types of intravenous fluid
- Crystalloids - Fluids comprised mainly of water, usually with some added electrolytes such as sodium chloride.
(0.9% Saline, Hartmans solution)
- Colloids - Fluids containing protein or starch molecules dissolved in water.
(Gelofusine, Voluven, Hespan)
Crystalloid or colloid?
Crystalloids - the water leaks out of the circulation into the tissues within 30mins.
Colloids - because of the large molecules of protein or starch, stay within the circulation for between 1 and 4 hours depending on the solution used.
For resuscitation following haemorrhage it doesn’t matter which is used initially, although a combination of a crystalloid and a colloid will be required in the medium term.
Blood
Neither crystalloid nor colloid solutions can carry oxygen.
The only available oxygen carrier is blood.
Therefore intravenous fluid therapy is not a definitive treatment for bleeding, but will buy time.
The only definitive treatment is to stop the bleeding and transfuse blood.
Fluid therapy
Hypovolaemic resuscitation
A low blood pressure will result in a reduction in rate of blood loss following trauma. If blood pressure is raised too rapidly or too high by aggressive fluid therapy, bleeding will increase. Where blood is not available for transfusion, non oxygen carrying fluids have to be used to replace blood loss and this may impair oxygen delivery to the tissues. In this situation, fluid therapy may be restricted, hypovolaemic resuscitation.
Monitoring progress in shock
Improvement is indicated by;
1. Slowing heart rate
2. Rising blood pressure
3. Improved skin blood flow
4. Normal conscious level
Likely outcome if shock is inadequately treated
Brain failure
Heart failure
Lung failure
Kidney failure
DEATH
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