On average, patients lose about 20 to 25% of their body weight with surgery
Crystalloids: These are aqueous electrolyte solutions. Common examples are sodium chloride (saline) and balanced solutions (which include buffers/minerals). They are further classified by osmolarity/tonicity: Isotonic solutions: e.g. 0.9% Normal Saline (NS) and Lactated Ringers (LR) or Plasma-Lyte. These have an osmolarity close to blood (~275310 mOsm/L) and tend to stay in the extracellular space (blood + interstitial fluid). NS contains ~154 mEq/L of Na and Cl (308 mOsm), whereas LR contains Na~130, Cl~109, K~4, Ca1.5, and lactate28 mEq/L (osm ~273). The lactate in LR is metabolized to bicarbonate, making LR more buffered (less acidifying) than NS. Isotonic crystalloids are preferred for fluid resuscitation (e.g. rapid IV boluses in shock). Mixed isotonic solutions that include dextrose (see below) are often used for maintenance fluids. Hypotonic solutions: e.g. 5% dextrose in water (D5W) and half-normal saline (0.45% NaCl). D5W starts out isotonic (252 mOsm) but, once the glucose is taken up by cells, it effectively behaves like free water, distributing equally throughout total body water (including intracellular fluid). Half-normal saline (77 mEq/L Na/Cl, 154 mOsm) provides both water and some salt; it slowly shifts fluid into cells. These hypotonic fluids are used to correct free-water deficits (e.g. hypernatremia) or for gentle maintenance hydration. They must be used cautiously to avoid hyponatremia or cellular swelling. Hypertonic solutions: e.g. 3% or 5% NaCl. These very high-sodium fluids draw water from cells into the bloodstream. They are used only in critical situations (severe hyponatremia or cerebral edema). Such fluids require extreme caution and frequent monitoring (rapid shifts in serum sodium can cause osmotic demyelination). Dextrose (sugar) solutions: e.g. D5W, D10W (5% or 10% dextrose in water) or mixed fluids like D5NSS (5% dextrose in NS). D5W serves as an isotonic volume expander initially but quickly becomes hypotonic after glucose is metabolized, providing calories (~170 kcal/L) and free water. Higher dextrose percentages (e.g. D50W) are used for acute hypoglycemia boluses, not routine fluid maintenance. Other crystalloids: Specialized balanced fluids include Plasma-Lyte and Normosol (contain acetate or gluconate buffers), and Ringers acetate. These are similar to LR but use different buffers; all aim to approximate plasma electrolyte composition. (E.g. Plasma-Lyte A has Na 140, K 5, Cl 98, Mg 1.5, acetate/gluconate buffer)
Neutralise les radicaux libres la source, limitant le vieillissement cellulaire prmatur
[Google Scholar] 29.Han TK, Everett RS, Proctor WR, Ng CM, Costales CL, Brouwer KL, Thakker DR
