What Is Plasma Osmolarity?

Plasma osmotic pressure refers to a water absorption force of solute molecules through a semi-permeable membrane, and its size depends on the number of solute particles, and has nothing to do with the molecular weight and radius of the solute. Because the number of crystal solutes in plasma is much larger than the number of colloids, the plasma osmotic pressure is mainly composed of crystalline osmotic pressure. Plasma colloid osmotic pressure is mainly composed of protein molecules. Among them, plasma albumin has a small molecular weight and a large number (albumin> globin> fibrinogen), which determines the size of plasma colloid osmotic pressure.

Plasma osmotic pressure

Plasma osmotic pressure refers to a water absorption force of solute molecules through a semi-permeable membrane, and its size depends on the number of solute particles, and has nothing to do with the molecular weight and radius of the solute. Because the number of crystal solutes in plasma is much larger than the number of colloids, the plasma osmotic pressure is mainly composed of crystalline osmotic pressure.
Crystal
Crystals cannot pass freely through cell membranes, but can pass through porous capillaries freely. Therefore, crystals
Isotonic solution with
According to recent research data,
Calculation of plasma osmotic pressure (mmol / L)
for reference only
Cl- + HCO3- + 20 × 2 = mmol / L
Normal value 280 ~ 310mmol / L (average 300)
<280mmol / L is hypotonic,> 310mmol / L is hypertonic
Na ++ K + × 2 + BS + BUN = mmol / L
(Normal person: BS (blood sugar) is 3.9 ~ 6.1mmol / LBUN (blood urea nitrogen) is 1.78 ~ 7.14mmol / L)
Normal value 280 ~ 310mmol / L
<280mmol / L is hypotonic,> 310mmol / L is hypertonic
MCV (mean red blood cell volume m3) = hematocrit × 1000 divided by the number of red blood cells (N / L)
Normal value 82 ~ 96m3,> 96m3 is hypotonic, <82m3 is hypertonic
Normal serum sodium is 130 ~ 150mmol / L (average 140)
<130mmol / L is hypotonic,> 150mmol / L is hypertonic
(Na ++ 10) × 2, normal 280 ~ 310mmol / L (average 300)
<280mmol / L is hypotonic,> 310mmol / L is hypertonic
Cl- + HCO3- = 120-140mmol / L
<120mmol / L is hypotonic,> 140mmol / L is hypertonic
Related formulas for plasma colloid osmotic pressure:
Total plasma protein g / L × 2.41 × 2 = 289.2 ~ 385.6mmol / L
<289.2mmol / L is hypotonic,> 385.6mmol / L is hypertonic
74 × Ag / L + 1.205 × Gg / L = 85 ~ 131.85mmol / L
For example, albumin 50g / L, then 1.74 × 50 + 220 = 307mmol / L
(Albumin 50g / L, molecular weight 69000, osmotic pressure =
50 × 1000/69000
= 0.725mmol / L)
5 × (A + G / L) divided by 7.5 = 18.99kPa
<18.99kPa is hypotonic
Supplementary plasma ml = plasma protein (normal value-patient value) × 8 × body weight (kg)
Input at 8ml / kg can increase plasma protein by 10g / L. Generally 10 ~ 25g / d, can be continuously replenished
COP (plasma colloid osmotic pressure) = 3A + 0.2A2 + 0.01A3 + 2G + 0.2G2 + 0.01G3A: albumin; G globulin
Normal value: 25 + -2mmHg, with <20mmHg as low osmotic pressure
In the case of low colloid osmotic pressure caused by low protein, the normal maintenance of total osmotic pressure often needs to be accompanied by an increase in sodium ion concentration, and high sodium will cause peripheral tissues to resist insulin and cause blood glucose to rise, damaging liver glycogenogenesis Function and reduce the elimination of lactic acid.

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