A substitute for plasma in the treatment of shock ideally should increase the reduced blood volume without producing significant untoward effects. Only the presence of large molecules which retain the injected fluid within the circulation produces a sustained rise of the blood volume. Such hydrophilic colloidal solutions have been observed to produce undesirable side effects; therefore, these side effects should be evaluated before the solutions are used as plasma substitutes.
Increase of the blood volume with solutions devoid of red cells reduces the red cell concentration, as measured by the hemoglobin concentration or the hematocrit value. Hemodilution is easily recognized by simple laboratory methods, which are sufficiently accurate for clinical evaluation to substitute for the elaborate methods for determination of the blood volume. The production of hemodilution then can be used as a criterion for the efficiency of a plasma substitute in the treatment of shock.
Among the undesirable effects