hypovolaemic horse

Question 1

Describe the relative compositions of Na, K, Cl and protein in ICF, ECF and plasma

Answer 1

Question 2

HR = <40
CRT = 2
Mucous membranes = normal/slightly tacky
Lactate = <2.0
USG = <1.030
What is the dehydration deficit as a % of BW?

Answer 2

6-8 (mild)

Question 3

HR = 40-60
CRT = 3
Mucous membranes = tacky
Lactate = >2.0
USG = >1.030
What is the dehydration deficit as a % of BW?

Answer 3

8-10 (moderate)

Question 4

HR = >60
CRT = 4
Mucous membranes = dry
Lactate = >6.0
USG = >1.030
What is the dehydration deficit as a % of BW?

Answer 4

10-12 (severe)

Question 5

How does hypotonic fluid loss affect the tonicity of remaining body fluid and blood volume?

Answer 5

increases tonicity of remaining body fluid
increases blood volume as water is drawn from cells into blood as blood is hypertonic so water is drawn from hypotonic cells

Question 6

How does isotonic fluid loss affect tonicity of remaining body fluid and blood volume?

Answer 6

No effect on tonicity
Decreases blood volume

Question 7

Describe the initial effect of water loss (hypotonic)

Answer 7

Loss of water from blood and interstitium increases ECF tonicity
=> osmosis and movement of water from ICF into ECF
=> cells lose fluid to plasma and interstitium
=> this compensates for volume loss in blood at the expense of cellular blood volume
LOSS OF HYPOTONIC FLUID LEADS TO DEHYDRATION INITIALLY

Question 8

Describe the initial effect of loss of water and electrolytes (isotonic)

Answer 8

No change in tonicity of remaining body fluids
No osmotic effect
No net fluid change between cells, interstitial space and blood
LOSS OF ISOTONIC FLUID LEADS TO HYPOVOLAEMIA INITIALLY

Question 9

What are the clinical signs of hypovolaemia?

Answer 9

prolonged CRT
Pale mucous membranes
Tachycardia
Weak peripheral pulses
Reduced mentation due to reduced cerebral blood flow

Question 10

What are the blood parameters found in hypovolaemia?

Answer 10

Increased PCV and total protein (haemoconcentration)
Increased lactate (tissue perfusion) and creatinine (kidney perfusion)

Question 11

What are the clinical signs of dehydration?

Answer 11

Dry/tacky mucous membranes
skin tenting
sunken eyes

Question 12

What are the blood parameters found in dehydration?

Answer 12

increased sodium due to hypotonic fluid loss of RAAS activation

Question 13

What is the effect of a hypertonic saline bolus on a hypovolaemic patient?

Answer 13

draws fluid from interstitial space and cells
acts in short term and cause temporary expansion of plasma volume
NaCl will redistribute over time reducing this effect so must be followed with isotonic fluid to restore total fluid deficit and maintain perfusion

Question 14

What is the effect of administering sterile water intravenously?

Answer 14

dangerously hypotonic
likely result in major electrolyte disturbances
can cause RBC swelling and bursting