Shock & Systemic Response to Injury

Question 1

What is a simple definition of shock?

Answer 1

Cardiovascular collapse

Question 2

What are the main types of insult or injury?

Answer 2

Trauma, stress, sepsis, GA, Sx

Question 3

A stress response caused by insult or injury results in

Answer 3

Initiating the sympathoadrenal axis
Leads to release of catecholamines
leads to release of cortisol

Question 4

What is shock?

Answer 4

Failure of the cardiovascular system to deliver adequate oxygen & nutrients to tissues

Question 5

Tissue perfusion is dependent on:

Answer 5

circulating blood/fluids
heart pump ability
vagal motor tone
vascular musculature

Question 6

What are the main classifications of shock?

Answer 6

Cardiogenic
Hypovolaemic
Distributive/Vasogenic
(Obstructive)

Question 7

What is cardiogenic shock?

Answer 7

Failure of the heart, so unable to push blood around the body

Question 8

What is hypovolaemic shock?

Answer 8

Volume deficit preventing deliver of oxygen and nutrients to the body

Question 9

In hypovolaemic shock, a reduction of circulating volume is caused by…

Answer 9

whole blood loss
fluid loss (dehydration)
intestinal hypersecretion

Question 10

What is distributive/vasogenic shock?

Answer 10

Blood maldistribution where the volume is available within the body but cannot be distributed to the appropriate location (vascular tone issues)

Question 11

Describe the path of Vasogenic/Distributive shock.

Answer 11

Entotoxemia/sepsis/anaphylaxis –> release of vasoactive substances –> extensive dilation –> pooling of blood –> massive maldistribution of blood volume

Question 12

Septic causes of Vasogenic/distributive shock can lead to what syndrome?

Answer 12

Systemic inflammatory response syndrome (SIRS)

Question 13

What are the 3 main causes of vasogenic/distributive shock?

Answer 13

Sepsis, anaphylaxis, neurogenic

Question 14

What are the main characteristics of the early or acute phase of shock?

Answer 14

conservation of fluid volume
change in energy metabolism
accelerated metabolic rate

Question 15

What changes within the body will be seen during the early or acute phase of shock?

Answer 15

Increased HR
Increased SV
Increased peripheral pulses
Increased CRT

Question 16

How does the body respond to the early/acute phase of shock?

Answer 16

increases sympathetic tone to conserve and minimize any losses –> vasoconstriction peripherally; increase HR/SV so the heart works harder increasing cardiac output; chemoreceptors tell the body to reduce oxygen saturation so the kidney stops secretion to conserve

Question 17

What main organs/tissues are affected by the early/acute phase of shock?

Answer 17

kidneys, heart, blood vessels

Question 18

What occurs during the decompensatory phase of shock?

Answer 18

Insult to the body continues and the compensatory mechanisms are unable to keep up. This leads to breakdown of the gut wall, increasing toxins, and thus overwhelming the liver. The liver releases more inflammatory mediators causing autoregulatory escape. This leads to organ vasodilation, blood pooling, further maldistribution, release of more cytokines from hypoxic tissues, DIC initiated, multiple organ failure, then death.

Question 19

What clinical signs can be seen in the compensatory phase of shock?

Answer 19

tachycardia, tachypnoea, hyperaemic MM, fast CRT, increased peripheral pulses

Question 20

What clinical signs can be seen in early decompensatory phase?

Answer 20

progressive tachycardia, tachypnoea, prolonged CRT, cold extremities, weak peripheral pulses, anuria/oliguria, depression, lack of responsiveness

Question 21

What clinical signs can be seen in the late decompensatory phase?

Answer 21

Hypotension, bradycardia, circulatory collapse, pale MM, anuria, collapse, severe depression
Also possible: recumbency, loss of consciousness

Question 22

What are the main ways of treating shock?

Answer 22

Oxygen supplementation
Restoration of circulating volume through early aggressive fluid therapy
Glucocorticosteroids
Pain control
Cardiovascular support
Control of haemorrhage

Question 23

What are some things to ask yourself when thinking of fluid therapy?

Answer 23

Crystalloid vs colloid?
Isotonic vs hypertonic?
Plasma/whole blood?
Synthetic blood products?

Question 24

What is the shock dose rate of administration of crystalloid fluids?

Answer 24

90 ml/kg/hr

Question 25

what is the normal maintenance dose of crystalloid fluids?

Answer 25

2.5 ml/kg/hr

Question 26

When giving fluid therapy, if there is a lack of control of hypotension due to ongoing haemorrhage, what can happen in the body and how can it be prevented?

Answer 26

Excess amounts of fluid therapy can dislodge clots
Prevention by giving less fluids to maintain a lower BP to prevent dislodging clots

Question 27

What do you monitor to determine the effectiveness of your fluid therapy?

Answer 27

cardiac output and perfusion

Question 28

What are signs of improvement in a shock patient following fluid therapy?

Answer 28

increased HR
increased BP
Improved mentation
Warming of extremities
decreased CRT
increased urine production
return to normal serum lactate levels

Question 29

What are the phases of injury?

Answer 29

Acute phase
Flow/Catabolic Phase
Recovery/Anabolic Phase

Question 30

Describe your process when receiving a patient showing signs of the acute phase of injury.

Answer 30

1. evaluate the animal
2. recognize the signs of shock
3. Full clinical exam, catalogue all injuries

Question 31

How do you minimize the length and severity of the acute phase of injury?

Answer 31

minimize further tissue trauma
restore circulating volume
reduce bacterial contamination
maintain body temperature
careful hemostasis
adequate immobilization & analgesia
Provision of adequate dietary intake
minimize stress thru appropriate handling & husbandry
restrict exercise
control any infection

Question 32

The prolonged stress response of the acute phase of injury induces…

Answer 32

the hypermetabolic state

Question 33

During the Catabolic phase, what occurs?

Answer 33

Total body catabolism raises leading to increased nutritional demands. This leads to persistent hyperglycaemia and rapid muscle and fat breakdown leading to weight loss, thus prolonging tissue healing

Question 34

What is the third phase of injury called?

Answer 34

the Anabolic or recovery phase

Question 35

What occurs during the recovery/anabolic phase of injury?

Answer 35

Any losses from the acute phase are replaced. The systemic neurohormonal system returns to normal, thus stabilizing catecholamine and cortisol levels. Visceral and muscle protein is synthesized, organ function improves. Appetite increases, animal gains weight, strength and vitality improve.