Objective: The purpose of this study was to determine (1) the rate of contamination for a normal saline solution prepared with distilled water and salt when stored at room temperature and (2) when stored under refrigerated conditions; and (3) to compare the rate of contamination for solutions prepared and stored under controlled conditions with those prepared and stored in patients' homes.
Design: This quasi-experimental study examined the bacterial content of saline made with distilled water and stored at room temperature and that of saline stored in a refrigerator.
Setting: A large urban home health agency was the setting for the study.
Methods: Eight teaspoons of table salt were added to 1-gallon jugs of distilled water purchased from a grocery store to produce a normal saline solution. Two gallons of the prepared solution were stored at room temperature (80 degrees F) and 2 were stored in a refrigerator (48 degrees F). Cultures were taken from each of the 4 bottles of prepared solution immediately following preparation and at weekly intervals until bacterial growth occurred, or 4 weeks after preparation.
Results: All tested solutions were negative for bacterial growth at baseline. Cultures of the solution stored at room temperature were positive for bacterial growth 2 weeks after preparation, whereas those stored under refrigerated conditions remained free of bacterial contamination 4 weeks after preparation. Two "patient-prepared" solutions were tested at 3 weeks, and both were negative for bacteria at that time. Three patient-prepared solutions were tested at 4 weeks, of which 2 showed no bacterial growth in 48 hours, whereas 1 revealed 600 cfu/mL of Pseudomonas species.
Conclusions: The results of this small study suggest that saline solutions produced by adding table salt to distilled water will remain bacteria-free for 1 month if refrigerated. Additional studies are needed to confirm these findings.