Infusate contamination in regional anesthesia: what every anesthesiologist should know.

Infection can be a devastating complication of regional anesthesia. Contaminated infusate as a cause of infection in neuraxial anesthesia or peripheral nerve blockade has rarely been reported in the literature. However, it may be an important source of morbidity, especially as increasing numbers of patients are being discharged with perineural catheters and portable pumps of local anesthetic, which may infuse for several days at home. Two important issues related to infusate contamination in regional anesthesia are that of "hang-time" and sterile compounding practices. Hang-time can be defined as the maximum length of time during which an admixture preparation (infusate) can be safely administered without risk of microbiological or chemical instability. In the United States, there are currently no national guidelines on the hang-times of regional anesthesia infusates. On the other hand, guidelines for the sterile compounding of infusions used in regional anesthesia are now established by United States Pharmacopeia and The National Formulary Chapter 797, entitled "Pharmaceutical Compounding, Sterile Preparations." These guidelines have significant implications for the anesthesiologist. In this review, we examined the available literature regarding contaminated infusate as a cause of infection in regional anesthesia, to discuss strategies for the prevention of such contamination including the appropriate hang-time for infusates, and to discuss the implications of United States Pharmacopeia and The National Formulary Chapter 797 for anesthesiologists.