Scrubbing the Hub, How Long Is Enough?

Background Patients undergoing hematopoietic stem cell transplant (HSCT) require a central venous catheter (CVC) for their care. The presence of a CVC increases the risk of bloodstream infections (BSI). Central line associated bloodstream infections (CLABSI) are associated with increase morbidity, mortality and healthcare costs. Substantial effort is placed in the maintenance and disinfection of needless connectors (NC) with the goal to prevent CLABSI. Current guidelines don't specify the duration of mechanical friction that should be applied to NC prior to accessing a CVC. Our current practice is 30 seconds of scrubbing and 30 seconds of dry time with nurses collectively spending approximately a total of 120 hours/day scrubbing. The objective of this study was to evaluate the impact that length of mechanical friction has on NC disinfection. Methods Sixty sterile NC were used, divided in groups of ten. McFarland solution composed of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa was used to inoculate the NC for 30 minutes. One millimeter of sterile saline was used to flush the NC into a sterile tube and ten microliter loops were used to inoculate blood agar plates followed by use of spreaders for quantification. The first group was negative controls which were flushed after being removed from the package, the second group was positive controls with no scrubbing done prior to the flush. For the remaining 4 groups 2% chlorhexidine gluconate plus 70% alcohol pads were used to scrub the NC per routine practice for 15 seconds, 30 seconds, 45 seconds and 60 seconds. All the groups had the same drying time of 30 seconds. After 24 hours of incubation at 38 degrees Celsius positive cultures were identified and number of colonies on each plate were recorded. Ten nurses participated in the study scrubbing the hubs. Results All the negative controls were negative, 7/10 positive controls were positive with a mean of 127 CFU/ml. For the 3 rd group 8/10 were positive with a mean of 171 CFU/ml. For the 4 th group 6/10 were positive with a mean of 122 CFU/ml. For the 5 th group 4/10 were positive with a mean of 55 CFU/ml and for the 6 th group 3/10 were positive with a total of 15 CFU/ml. There was a statistically significant difference between positive and negative cultures in the 15 second group versus 60 second group (p = 0.02) but not between the 30 second versus the 60 second group (p=0.2). Three cultures were too numerous to count and were given a value of 1000 CFU/ml. Results do not appear to be dependent on who was scrubbing the NC. Conclusions Longer scrubbing time appears to decrease line contamination which can be translated into clinical practice. Results from a larger study with a total of 120 NC assessing different disinfecting solutions as well as drying time will be available by December 2018.