Shock In Trauma

Question 1

What is shock defined as?

Answer 1

The inadequate delivery of oxygen and nutrients necessary for normal tissue and cellular function

Question 2

Is the initial cellular injury that occurs during shock reversible?

Answer 2

Yes

Question 3

What causes the initial cellular injury during shock to become irreversible?

Answer 3

Prolonged or sever tissue hypoperfusion leading to cellular compensation no longer being possible

Question 4

What are the different types of shock?

Answer 4

Hypocolaemic
Cardiogenic
Neurogenic
Inflammatory (septic)
Obstructive
Traumatic

Question 5

What is hypovolaemic shock?

Answer 5

Sever blood or fluid loos that causes the heart to be unable to pump enough volume around the body

Question 6

What is cardiogenic shock?

Answer 6

The heart suddenly can’t pump enough blood to meet the body’s needs

Question 7

What is neurogenic shock?

Answer 7

Damage to the nervous system after spinal cord injury that causes the nervous system to have trouble keeping HR, BP and temp stable

Question 8

What is inflammatory (septic) shock?

Answer 8

Infection causing problems in how cells work leading to a drop in BP

Question 9

What is obstructive shock?

Answer 9

A physical obstruction reducing blood flow, causing a reduced cardiac output e.g PE, tamponade

Question 10

What is traumatic shock?

Answer 10

Body’s response to trauma, think hateful 8

Question 11

What is the pathophysiology of shock?

Answer 11

Delivery of O2 and metabolic substrates to tissue and cells is insufficient to maintain aerobic metabolism. Tissue hypoperfusion is designed to compensate and reverse inadequate tissue perfusion. Shock can lead to minimal physiological dysfunction to end organ dysfunction to death

Question 12

What do afferent impulses transmitted from the periphery and then processed within the central nervous system activate?

Answer 12

Reflexive effector responses or efferent impulses designed to expand plasma volume, maintain peripheral perfusion and tissue oxygen delivery and re-establish homeostasis

Question 13

What are the initial events that lead to shock?

Answer 13

Loss of circulating blood volume
Tissue trauma
Pain
Hypoxemia
Hypercarbia
Hypoglycaemia

Question 14

What receptors are important pathway in initiating adaptive or corrective responses to shock?

Answer 14

Barrow receptors

Question 15

What do volume receptors present in the atria get effected by?

Answer 15

Low volume haemorrhage or mild reductions in right arterial pressure

Question 16

What do chemoreceptors on the aorta and carotid bodies provide?

Answer 16

Afferent stimulation when the circulatory system is distributed and active effector response mechanisms

Question 17

What is the cardiovascular response to shock?

Answer 17

Activation of B1-adrenergic receptors that increase heart rate and cardiac contractility in an attempt to increase cardiac output. Also increases vasoconstriction and causes compensatory increase in systemic vascular resistance and blood pressure. Blood is shunted away from organs such as intestines, kidneys and skin. The brain and heart have auto regulatory mechanisms that attempt to prevent reserve blood flow despite a decreased cardiac output

Question 18

What is the Neuro endocrine response to shock?

Answer 18

Activation of hypothalamic-pituitary-adrenal axis that function as an integral component of the bodies adaptive response to shock. Hypothalamus is stimulated to release corticotrophin-releasing hormone which leads to the release of ACTH by the pituitary. This causes the adrenal cortex to release cortisol which acts in combination with adrenaline and glucagon to induce a catabolic state. This stimulates glycogen edits and insulin resistance resulting in hyperglycaemia. Cortisol causes retention of sodium and water in the kidneys that aids in restoration of the circulating volume. Pituitary releases vasopressin or ADH in response to hypovolemia

Question 19

How might a patient with advance stages of shock present?

Answer 19

• Unconscious and lack the ability to protect their airway
• high RR as the respiratory system attempts to correct the metabolic acidosis associated with tissue hypoperfusion
• cool clammy skin
• altered sensorium
• tachycardia
• hypotension

Question 20

What are the 3 distinct groups that trauma shock patients are categorised by dependent on their response to resuscitative manoeuvres?

Answer 20

Responders, transient responders and non responders

Question 21

What is meant by a responder patient in relation to trauma shock?

Answer 21

A patient who rapidly correct their shocked state with minimal intravascular replacement. These patients do not have ongoing bleeding, or bleeding that has been tamponaded.

Question 22

What is meant by a transient responder patient in relation to trauma shock?

Answer 22

Patients who initially improve following resuscitative efforts but then subsequently deteriorate. They often have intracavity blood that will require operative management.

Question 23

What is meant by a non responder patient in relation to trauma shock?

Answer 23

Patients who have persistent state of shock despite resuscitative efforts. These are the sickest patients

Question 24

When does acute traumatic coagulopathy occur?

Answer 24

Immediately after massive trauma when shock, hypoperfusion and vascular damage are present

Question 25

What do the mechanisms of acute coagulopathy include?

Answer 25

Activation of protein C, endothelial glycocalyx disruption, depletion of fibrogen and platelet dysfunction. Hypothermia and academia worsen this endogenous coagulopathy which leads to decreased clot strength, autoheprinization and hyperfibrinolysis

Question 26

What is the triad of death?

Answer 26

Hypothermia, acidosis and coagulopathy

Question 27

What does the triad of death lead to?

Answer 27

Worsening haemorrhage and eventually death

Question 28

How does hypothermia have an impact on trauma patients?

Answer 28

As a patients body temp decreases so does their ability to clot effectively. This results in impaired platelet function, inhibition of clotting factors and inappropriate activation of clot breakdown

Question 29

What can effect the body’s ability to regulate temperature?

Answer 29

Haemorrhagic shock, traumatic brain injuries, exposure and drug and alcohol intoxication

Question 30

How is acidosis defined?

Answer 30

Arterial pH of less than 7.35 and in trauma is likely secondary to poor tissue perfusion

Question 31

How does a patient become acidotic?

Answer 31

Anaemia from massive haemorrhage, peripheral vasoconstriction, hypothermia and overall decreased cardiac output causes severe impairment of oxygen delivery to the tissues. The cells begin to utilise anaerobic metabolism resulting in the production of lactic acid. The accumulation of lactic acid causes pH to drop

Question 32

What can cause acidosis to worsen in a trauma patient?

Answer 32

Administration of large volumes of crystalloids

Question 33

When does dilutional coagulopathy occur?

Answer 33

When trauma patients are resuscitated using blood products that don’t contain the clotting factors lost during haemorrhage

Question 34

What can result in massive deficiency of clotting factors?

Answer 34

Packed red blood cells can dilute the clotting factors preeminent alongside acute traumatic coagulopathy

Question 35

What is damage control resuscitation?

Answer 35

A systemic approach to the management of trauma patients with sever injuries. It starts in ED and carries through to theatres and ITU

Question 36

What does damage control resuscitation involve?

Answer 36

Haemostatic resuscitation, permissive hypotension and damage control surgery

Question 37

What is the aim of damage control resuscitation?

Answer 37

Maintain circulating volume, control haemorrhage and correct the triad of death

Question 38

What is the aim of haemostatic resuscitation?

Answer 38

To resuscitate the patient with blood component ratios resembling whole blood, therefore, avoiding acute traumatic coagulopathy with the aim to maintain circulating volume, limit ongoing bleeding and prevent/reverse the triad of death

Question 39

When are massive haemorrhage protocols triggered?

Answer 39

When the patient is in haemorrhagic shock with ongoing instability following a transfusion of 4 units of RBC

Question 40

What are the ideal blood component ratios?

Answer 40

1 PRBC : 1 FFP : 1 Platelets

Question 41

What time scale should TXA be given?

Answer 41

Within 3 hours of injury

Question 42

What is permissive hypotension?

Answer 42

Low volume resuscitation/hypotension resuscitation that invokes allowing the systolic BP to fall low enough to avoid exsanguination but high enough to maintain perfusion

Question 43

What kind of patients is permissive hypotension used for?

Answer 43

Penetrating trauma

Question 44

What is the goal of permissive hypotension?

Answer 44

To avoid clot disruption and avoid cyclic over resuscitation

Question 45

What is damage control surgery?

Answer 45

Surgery involving using limited surgical interventions to control haemorrhage and minimise contamination until the patient has sufficient physiological reserve to undergo definitive interventions. Survival is given precedence over morality

Question 46

What is TXA?

Answer 46

An anti-fibrinolytic agent that helps to prevent haemorrhage

Question 47

What study showed the benefit of using TXA in trauma patients?

Answer 47

CRASH-2

Question 48

How does TXA work?

Answer 48

It interferes with the normal fibrinolysis process and inhibits the activation of plasminogen through interactions with lysine-binding sites on the enzyme. It inhibits the breakdown of fibrinogen leading to greater clot stabilisation