Hypertonic Salt Solutions

Hypertonic salt solutions are less commonly used, and their sodium concentrations range from 250 to 1200 mEq/L. The greater the sodium concentration, the less the total volume is required for satisfactory resuscitation. This difference reflects the movement due to osmotic forces of water from the intracellular space into the extracellular space. The reduced volume of water injected may reduce edema formation. This could be crucial in patients predisposed to tissue edema (e.g., prolonged bowel surgery, burns, brain injuries). Clinical studies have confirmed that a moderately hypertonic solution (250 mEq/L of sodium) can be associated with lower muscle interstitial pressure than lactated Ringer's solution. Bowel function returned earlier, although the pulmonary shunt fraction was no different.^[111] Experimental studies have demonstrated lower intracranial pressures in animals receiving hypertonic solutions. However, the intravascular half-life of hypertonic solutions is no longer than isotonic solutions of an equivalent sodium load. In most studies, sustained plasma volume expansion was achieved only when colloid was present in the resuscitation solution. Moreover, the osmolality of these solutions can cause hemolysis at the point of injection.^[112]

Hypertonic saline has been used for almost a century in clinical practice for a variety of reasons. Interest in its use in hemorrhagic shock was rekindled in 1980 in an experiment in dogs suffering from severe hemorrhagic shock. These dogs were resuscitated solely with 7.5% NaCl or

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