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
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- 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.