A SYSTEMATIC REVIEW OF THE EVIDENCE FOR HYPODERMOCLYSIS TO TREAT DEHYDRATION IN OLDER-PEOPLE

Background. The purpose of the study was to evaluate the evidence supp orting the use of hypodermoclysis (i.e., subcutaneous infusion of flui ds) to treat dehydrated elderly patients, and to discuss clinical appl ications of this mode of therapy in the long-term care setting. Method . Articles reporting the use of hypodermoclysis were identified using a systematic MEDLINE search between January 1966 and May 1996. Article s were included in our sample if they contained original patient data that evaluated either the efficacy or adverse effects associated with the use of subcutaneous infusions to treat dehydration in adults, whet her hyaluronidase was required to facilitate the absorption of subcuta neous fluid, or if potassium could be added to the solution. Results. Eighteen articles met the inclusion criteria. Since we hypothesized th at adverse effects associated with hypodermoclysis may have been relat ed largely to the use of nonelectrolyte or hypertonic solutions, the s tudies were evaluated according to the type of fluid administered. Six hundred and eighty-five patients were described in 13 studies evaluat ing the efficacy and toxicity of subcutaneously administered fluid. Fo ur studies evaluated hypodermoclysis using electrolyte-containing solu tions in 25 patients. Two of these were randomized control trials (RCT ) that compared hypodermoclysis to intravenous therapy. Both reported similar absorption of fluids. In the single RCT that evaluated adverse effects, 4 of 17 patients receiving hypodermoclysis reported minor si de effects similar to those reported with intravenous therapy. Adverse effects were more severe when electrolyte-free or hypertonic solution s were evaluated. Of the 639 patients who may have received electrolyt e-free solutions, 16 patients (2.5%) reported adverse effects, 8 of wh ich were severe. Both patients reported to have received hypertonic so lutions noted adverse effects, one of which was severe. The use of hya luronidase to facilitate absorption was evaluated in 74 patients. Thes e studies suggest that hyaluronidase improves the speed of fluid absor ption but may not change the patient's comfort level. A single case re port of 350 subcutaneous infusions in 67 patients investigated the adm inistration of up to 34 mmol/L of potassium chloride (KCl) by hypoderm oclysis. The only adverse reaction observed was discomfort at the infu sion site. Conclusions. Hypodermoclysis can be used to most safely pro vide fluids when electrolyte-containing fluids are administered. Hypod ermoclysis may have fallen into disuse because of reports of severe ad verse reactions related to infusions of electrolyte-free or hypertonic solutions that would likely be considered inappropriate today. Whethe r or not hyaluronidase is required to promote subcutaneous fluid absor ption remains unresolved. Limited evidence suggests that potassium chl oride may, with caution, be safely added to subcutaneous infusions. Th e majority of the available studies evaluating hypodermoclysis are of poor quality. Because of the tremendous potential benefits of administ ering fluid subcutaneously, there is a need for good quality studies t o evaluate the efficacy of hypodermoclysis.