Assessment of Shock

Question 1

What is shock?

Answer 1

A clinical syndrome rather than a disease entity. It is usually understood to mean a significant compromise in oxygen delivery to tissues.

Question 2

What are the 4 kinds of circulatory shock?

Answer 2

Hypovolaemic shock, cardiogenic shock, obstructive shock and maldistributive shock

Question 3

What CVS parameters do you need to evaluate to determine whether an animal is in shock?

Answer 3

MM colour, CRT, Heart rate, pulses (esp peripheral), auscultation

Question 4

What is hypovolaemic shock? Examples?

Answer 4

Tissue hypoperfusion occurs secondary to a lack of circulating blood volume e.g. haemorrhage, third spacing, loss into GIT/

Question 5

What is cardiogenic shock? Examples?

Answer 5

Failure of the heart as a pump. This occurs secondary to a number of cardiac diseases including advanced (late stage) cardiomyopathies and valvular disease and
severe arrhythmias.

Question 6

What is Obstructive shock? Examples?

Answer 6

Obstruction to blood flow. e.g. pericardial effusion and cardiac tamponade, GDV or PTE.

Question 7

What is Maldistributive shock? Examples?

Answer 7

The body displays generalised inappropriate vasodilation leading to alteration in distribution of blood flow between the tissues. e.g. sepsis, SIRS, anaphylaxis

Question 8

Why is hypovolaemia different from dehydration?

Answer 8

Hypovolaemia is loss of body water from the intravascular system, dehydration is loss of body water from all of the “compartments”.

Question 9

What clinical signs would you expect with hypovolaemia and dehydration?

Answer 9

Hypovolaemia - Increase CRT, MM colour, pulse quality.

Dehydration - skin tent, MM dryness, sunken eyes (CS mainly to do with loss interstitial fluids)

Question 10

How would you adminster fluids in hypovolaemia vs. dehydration?

Answer 10

Hypovolaemia administer quickly, Dehydration given slowly and allowed to resdistribute.

Question 11

If a dog has a HR of 130-150, normal-pinker than normal MM colour, rapid CRT, increased pulse amplitude, and easily palpable metatarsal pulses, what type of hypovolaemia do they have (mild, moderate or severe)?

Answer 11

Mild

Question 12

What parameters would you expect with Mild hypovolaemia?

Answer 12

HR of 130-150, normal-pinker than normal MM colour, rapid CRT, increased pulse amplitude, and easily palpable metatarsal pulses

Question 13

If a dog has a HR of 150-170, pale pink MM colour, approx normal CRT, mild to moderate decrease in pulse amplitude, and just palpable metatarsal pulses, what type of hypovolaemia do they have (mild, moderate or severe)?

Answer 13

Moderate

Question 14

What parameters would you expect with Moderate hypovolaemia?

Answer 14

HR of 150-170, pale pink MM colour, approx normal CRT, mild to moderate decrease in pulse amplitude, and just palpable metatarsal pulses

Question 15

If a dog has a HR of 170-220, grey, white or muddy MM colour, prolonged or absent CRT, severe decrease in pulse amplitude, and absent metatarsal pulses, what type of hypovolaemia do they have (mild, moderate or severe)?

Answer 15

Severe

Question 16

What parameters would you expect with Severe hypovolaemia?

Answer 16

HR of 170-220, grey, white or muddy MM colour, prolonged or absent CRT, severe decrease in pulse amplitude, and absent metatarsal pulses

Question 17

What type of tachycardia is seen in hypovolaemia? What is the maximum heart rate seen when hypovolaemia is the cause? Why is it not a cause above this?

Answer 17

Sinus tachycardia. Max HR for sinus tachycardia is 220bpm, as at heart rates above this their is decreased ventricular filling time and compromised cardiac output.

Question 18

What clinical signs would suggest maldistributive shock over any other type of shock?

Answer 18

Inappropriately red mucous membranes. Most other signs are the same as hypovolaemia, but may have increased temp due to infection.

Question 19

What is SIRS? What type of shock does it cause?

Answer 19

Systemic inflammatory response syndrome - it causes maldistributive shock

Question 20

What is Sepsis? What type of shock does it cause?

Answer 20

SIRS + documented infection site - it causes maldistributive shock

Question 21

What clinical signs may indicate cardiogenic shock rather than any other kind of shock?

Answer 21

Usually present with congestive heart failure and breathing difficulties, often have breathing problems as well.

Question 22

What are the main treatment aims for hypovolaemic shock? When would you use hypertonic crystalloids?

Answer 22

Very much dependent on the situation. Main treatment is isotonic crystalloids 10-40ml/kg given in 20 mins then reevaluate. May use hypertonic crystalloids in a large dog when can’t get a large amount of fluid in quickly. Oxygen administration.

Question 23

What are the main treatment aims for maldistributive shock?

Answer 23

Fluid therapy the same as hypovolaemic shock. Aim to treat the underlying condition. May use inotropes or vasopressors to improve BP. Oxygen administration.

Question 24

What are the main treatment aims for obstructive shock?

Answer 24

Remove vascular obstruction e.g. pericardiocentesis. Fluid therapy is not likely to make it any easier. Oxygen administration.

Question 25

What are the main treatment aims for cardiogenic shock?

Answer 25

Fluids are contraindicated. Aims are relieving the clinical signs and decreasing the load on the heart (may involve diruretics, inotropes, vasodilators. Oxygen administration.