Dehydration

Question 1

Total Body Fluid Distribution

Answer 1

• Intracellular = 67%

- Extracellular = 33% (Interstitial 25%, Intravascular 8%, Transcellular <1%)

Question 2

Interstitial Volume

Answer 2

• Usually used when discussing dehydration

- Can be shown with dry MM, sunken eyes, skin tent

Question 3

Intravascular Volume

Answer 3

• Usually used when discussing shock

- Can be shown with pale MM, slow CRT, tachycardia, tachypnoea, hypothermia and pulse changes

Question 4

5 %

Answer 4

• Dry MM
• Subtle loss of skin elasticity
• HR/pulses normal
• Eyes normal

Question 5

7 %

Answer 5

• Dry MM
• Mild skin tenting
• HR/pulses normal
• BP normal
• PCV/TP increased

Question 6

10 %

Answer 6

• Dry MM
• Skin tenting increased
• Eyes sunken
• HR increased, pulses weak
• CRT >2 sec

Question 7

12 %

Answer 7

• Dry MM
• Skin tenting persistent
• Eyes markedly sunken, dull corneas
• HR tachycardia or bradycardia
• Pulses weak or absent
• BP hypotensive
• Altered level of consciousness
• Hypothermic, cold extremities

Question 8

PCV/TP

Answer 8

• Isotonic fluid loss affects the volume of extracellular fluid, resulting in concentration of cells (PC) and protein (TP) in the blood.
• 7% dehydration = Both PCV and TP increased
• Changes in these could be due to other processes

Question 9

Shock vs Dehydration

Answer 9

• Shock is the physiological state in which O2 supply to the tissues becomes inadequate to meet the body needs
• A severely dehydrated patient will show signs of fluid loss from the intravascular compartment and will become hypovolaemic
• A patient may be hypovolaemic but not dehydrated when there was an acute loss of a large volume of fluid from the intravascular space