charney material

Question 1

isotonic fluid

Answer 1

• A crystalloid fluid with a
tonicity equal to that of
plasma
– ≈ 280 mOsm/L

Question 2

• Diseases leading to isotonic body fluid loss?

Answer 2

*Blood loss
• Diarrhea
• 3rd space fluid sequestration
• Vomiting 
– NG reflux in horses
• Polyuria
• Burns
• Excessive sweat loss

Question 3

isotonic loss characteristics

Answer 3

• Loss of effective circulating volume
– primary ECF / vascular tree affected

• an ACUTE process → progress to shock

• Isotonic loss has no effect on ECF tonicity
– As result, no contribution of water from ICF
– Serum [Na+] may be normal / low

• Homeostatic response to ↓ ECV??

Question 4

consequence of isotonic body fluid loss

Answer 4

• decreased circulation blood volume
• decreased preload
• decreased CO

Question 5

hemostatic response to isotonic loss

Answer 5

activation of

• autonomic NS
• RAAS
• AVP

Question 6

sv

Answer 6

preload

after load

contractability

co= hr *sv

Question 7

Carotid sinus / aortic arch: baroreceptors response to water depletion

Answer 7

Stimulate sympathetic neurons (CN X)
• Increase HR & cardiac contractility
• Peripheral vasoconstriction
• Cortisol release from adrenal gland

Question 8

• Portal / mesenteric vasc & 3rd ventricle response to water depletion

Answer 8

Promotes renal water conservation (V2 R)

• Peripheral vasoconstriction (V1 R)

Question 9

• Atrial volume-receptor reflex response to water depletion

Answer 9

Specialized stretch R’s in atrial walls

– Degree of ―stretch‖ affects frequency of action
potentials to CNS (via CN X)

• Decrease stretch = decrease afferent activity
– decreased parasympathetic stimulus
– ↑ sympathetic activity

improve BP and blood volume

Question 10

kidney response to water depletion

Answer 10

glomerular afferent arteriole Senses ↓ renal blood flow / blood pressure

• Renin is released → activates RAAS

Question 11

dysoxia

Answer 11

shock

Question 12

define dysoxia

Answer 12

The condition in which metabolic energy
production is limited by the supply or
utilization of oxygen

—>Inadequate cellular energy production

Question 13

clinical expression of dysoxia

Answer 13

shock

Question 14

shock occurs due to

Answer 14

poor tissue perfusion

poor tissue perfusion–> decrease 02 delivery to tissues as compare to utilization

Question 15

decrease in DO2 leads to

Answer 15

> in lactate

Anaerobic metabolism of lactate
– Less efficient utilization of glucose for energy
production

Question 16

hypovolemic shock occurs at the point where

Answer 16

VO2 starts to decrease

Question 17

Causes of Shock:

Answer 17

• Loss of intravascular volume
– Hypovolemic shock

• Failure of the cardiac pump
– Cardiogenic shock

• Loss of oxygen-carrying capacity
– Hypoxemic shock

• Maldistribution of vascular volume
– Distributive shock

Question 18

Hypovolemic Shock

Answer 18

LOSS OF INTRAVASCULAR VOLUME

– Hemorrhage

_Severe loss of body fluids
• Vomiting, diarrhea, polyuria, burns
• 3rd space sequestration into body cavity (effusions)
• Severe dehydration

Question 19

DZ THAT MAY LEAD TO HYPOVOLEMIA IN VET MED

Answer 19

– Trauma / lacerations

– Parvovirus

– Equine colitis
• Potomac Horse Fever
• Salmonellosis

Question 20

Cardiogenic Shock

Answer 20

Failure of the cardiac pump:
• Leads to decrease in forward blood 
flow from the heart
– Heart failure
– Cardiac arrhythmia 
– Cardiac tamponade
– Drug overdose

Question 21

Hypoxemic Shock

Answer 21

A decrease in oxygen content (CaO2) in arterial

blood

Question 22

What determines oxygen content in the arterial

blood?

Answer 22

– RBC → Hemoglobin
– Saturation of hemoglobin
– Healthy lungs

Question 23

Causes of Hypoxemic Shock

Answer 23

Anemia
– Severe pulmonary disease
– Carbon monoxide poison
– Methemoglobinemia

Question 24

Distributive Shock

Answer 24

Maldistribution of blood flow
– Compartment syndrome

• Reduction in venous return to heart
– GDV {gastric dilatation volvulus} (dogs)
& LCV (horses)

• Maldistribution of blood volume
– A decrease in vascular tone leads to poor
distribution of blood in tissues

• Sepsis / Endotoxemia
Common cause of shock in veterinary medicine!

Question 25

Distributive / Endotoxemic / Septic Shock

Answer 25

Maldistribution of blood volume: diseases which upregulate the immune system

Question 26

diseases which upregulate the immune system

Answer 26

– Sepsis – Systemic Inflammatory Response System – Endotoxemia – Anaphylaxis

Question 27

Distributive Shock: Sepsis

Answer 27

* Loss of vascular tone leads to systemic hypotension * Inadequate perfusion of tissues → shock Detrimental consequences caused by the upregulation of the immune system and inflammatory response culminates in the clinical signs of cardiovascular instability, impaired hemostasis, organ failure (including laminitis in horses), shock and death.

Question 28

Early” hyperdynamic phase of septic shock

Answer 28

– Vasodilatory phase • Patient compensating for decreased tissue perfusion – Compensated shock

Question 29

Clinical signs of early hyperdynamic phase of septic shock

Answer 29

-Mild to mod tachycardia – Mild to mod tachypnea – Fever • Some forms – Bright pink/red mucous membranes • Hyperemic – Fast capillary refill time – Normal blood pressure – Normal mentation / urine

Question 30

“Late” hypodynamic phase of septic shock

Answer 30

– Vasoconstricted phase • Patient no longer able to compensate for loss of tissue perfusion – Non-compensated shock

Question 31

Clinical signs of hypodynamic phase of septic shock

Answer 31

-Tachycardia – Pale mucous membranes – Hypothermia – Prolonged CRT – Hypotension – Poor pulse quality – Depressed mentation