The various types of parenteral fluids and their indications

Assessment of hydration and perfusion is essential in patient evaluation. The acid-base and electrolyte disturbances that accompany many illnesses should also be considered. The duration of illness and body systems involved are also of major importance in patient evaluation. Fluid therapy is an important and potentially life-saving treatment of many and varied problems. The clinician must be able to assess the patient and determine whether the intravascular or extravascular compartments, or both, are deficient. Of primary concern is the status of the intravascular volume, then restoration of total body water and electrolytes. Fluid therapy is divided into three phases; the emergency phase, the rehydration phase, and the maintenance phase; not all patients require the three-phase therapy. The clinician must also be able to select (1) the appropriate solution to treat the volume deficit and correct the acid-base and electrolyte abnormalities and (2) the rate of administration to optimize outcome. Therefore, knowledge of electrolyte composition in plasma and of the various types of commercially available fluids is essential in order to select the appropriate therapy for the individual animal. In addition to the therapeutic aspects of fluid therapy, a knowledge of the side effects and complications of inappropriate fluid selection and rate of delivery is also important. With the individual requirements of each patient seen in a practice, the prescription approach to parenteral fluid therapy will optimize patient response to this extremely important aspect of overall patient management as well as make the practice of fluid therapy intellectually stimulating. This article has introduced the clinician to the parenteral fluids available and their indications in veterinary patients; it also contains a discussion of how to utilize preferred solutions for treatment of specific diseased states. Although there are definite "right" and "wrong" fluids to select for specific problems, there also remains individual preference in fluid choice, which is based on appropriate laboratory data and the practitioner's clinical judgment of the status of the individual patient vis-à-vis the spectrum of its disease. Recommendations for selection of different fluid types to treat similar conditions are usually based on these variables.