Blood volume and distribution

[Ref: KB2: p92; WG21:p580]

Blood volume

Neonate blood volume = 80-100mL/kg

Adult blood volume = 70mL/kg
* Reached by age of 12 months
* = 7% of body weight (c.f. 8% per WG21)

Blood volume distribution per KB

[KB2:p92]

Distribution in erect position

• Vein = 65%
• Arteries = 13%
• Arterioles = 2%
• Capillaries = 5%
• Central blood volume = 15%
  * Pulmonary circulation included

Distribution in supine position

• Less blood in peripheral veins
  * e.g. 65--> 55%
• More blood in central volume
  * e.g. 15 --> 25%

NB:

• Figures of distribution in BL8:p5 are based on dog

Blood volume distribution per WG

Figures in WG21:p580 Table 30-1 are quite different

Distribution in ??supine position

• Vein = 54%
• Arteries = 10%
  * Aorta = 2%
  * Artery = 8%
• Arterioles = 1%
• Capillaries = 5%
• Central volume = 30%
  * 12% in heart
  * 18% in lung

Blood volume measurement

(See Measurement of compartments)

Blood reservoir

• Venous system
• Lungs
• Liver
  * 7.5% can be released on sympathetic stimulation
  * See Hepatic
• Skin
• Splanchnic
• Spleen (not as important in human)