Physico-chemical stability and sterility of previously prepared saline infusion solutions for use in out-of-hospital emergencies.

Objective: The topic of this research was to determine whether out-of-hospital emergency teams could make use of previously prepared saline solutions (SS). The objective was to discover the physical, chemical and sterility characteristics of previously prepared saline infusions stored in ambulances and ascertain how long they remained in optimum condition.

Method: Randomised clinical trial, triple blind, where study units consisted of saline solutions prepared with an infusion system and a three-way valve. The duration of the study was 12 months. Six intervention groups were designed on the basis of time of exposure and location. Samples consisted of 672 units. Twelve microbiological cultures were made and the pH, density, viscosity and CINa concentration were determined. We compared hypotheses with four models of linear regression for the variables and a model of logistic regression for the variables. A value of P < 0.05 was considered significant.

Results: We obtained results from 669 saline solutions (98.82%). Neither multivariant analysis nor ANOVA tests showed any significant association for a power greater than 99% with regard to the physical-chemical characteristics. The model of logistic regression also did not find any significant association for sterility. Colonisation was present in 1.7% of the 8,028 cultures made and more than 5 CFU per millilitre was found in only two cases.

Conclusion: There is no evidence to suggest that recently prepared saline infusion solutions are any different from a physical-chemical and sterility point of view than those exposed for 24, 48, or 72 h. It was concluded that use can be made of previously prepared saline solutions with a guarantee their stability and sterility.