Blood culture contamination, a common problem in emergency departments (ED), leads to further testing and treatments and adds costs to care. Concerned about blood culture contamination rates in the ED, researchers at Vanderbilt University School of Medicine in Nashville conducted a quality improvement (QI) study, and their interventions and findings are the subject of this issue of Strategies.
CLSI recommends that healthcare institutions maintain a blood culture contamination rate <3%, but achieving this level, particularly in the ED, can be challenging. “There are a lot of things going on all at once in the ED. Patients who are having blood cultures taken are often quite ill and could be receiving antibiotics, fluids, and blood products at the same time. In the middle of all of that, the technique of collecting a specimen for culture might be thought more mundane and perhaps not as important as some of the other things going on,” said Wesley Self, MD, MPH, an assistant professor of emergency medicine and lead author of the report describing Vanderbilt’s study of blood culture contamination in the ED (Acad Emerg Med 2013;20:89–97).
Self and his colleagues were concerned that improvements were needed in the contamination rate of blood cultures drawn in the Vanderbilt ED, something borne out by a baseline analysis of 7,389 cultures taken over 48 weeks, which had a 4.3% rate of contamination. This prompted the researchers to embark on a two-part QI study, consisting of developing and implementing an intervention followed by evaluating the effectiveness of the intervention.
The authors started by observing ED processes around blood culture collection, which ED nurses and paramedics were performing. “We took a couple of months and just watched what they did. We also interviewed them and got a really good idea of where the holes in the process were and where contaminants were sneaking into our specimens,” said Self. “Once we had a good handle on the standard process we targeted some very specific ways to improve it.”
The researchers made a fishbone diagram to outline factors that were contributing to the higher-than-desired blood culture contamination rate. They identified 17 factors in five broad categories, including collection and education processes, and patient, ED, and hospital factors. One key issue was that there wasn’t a standard technique for culture collection. In addition, no staff member was using a fully sterile technique.
“The way blood was being collected typically was to put a small amount of alcohol on the patient’s skin to disinfect the skin, and then use non-sterile techniques. This involved grabbing gloves off the wall and equipment at the bedside table, inserting a needle, drawing blood, sending it off to the lab,” Self recalled. “We found that in order to consistently perform venipuncture, staff were repeatedly palpating the skin over the vein where they were going to insert the needle. That step was producing a lot of contamination, so we really focused on disinfecting the skin very thoroughly and then using sterile technique and equipment, including a sterile drape and sterile gloves.”
The QI team developed a sterile blood culture kit, a 10-point checklist for use at the time of culture collection, and a policy change outlining a standard collection technique and requiring use of the sterile kits. They also devoted a considerable amount of time to gaining input from and educating staff. “Just introducing a new technique has not worked here before. The extra effort and time to really focus on getting everyone involved and understanding why this is important really helped prime the change,” said Self.
After implementation of the new protocol, the researchers assessed the ED’s blood culture contamination rate for 48 weeks, and found that it had declined significantly, to 1.7% of 6,590 samples. In the 2 years since the study ended, the rates have fluctuated somewhat, usually associated with staffing changes in the ED, but have been brought down readily to the desired level <3%, according to Self. “We tried to make the intervention as simple as possible and as much a part of routine practice as possible so that it wasn’t a new or different process, but something embedded into patient care. That has helped get the contamination rate down quickly after we see any blips,” he said.
The Vanderbilt team is to be commended for the thoroughness and success of their efforts, according to Frederick Nolte, PhD, D(ABMM), F(AAM). “They took a number of interventions simultaneously to change the process, and did a good job of analyzing the entire process and identifying the contributing factors. So they put together an intervention that addressed those problems, and this is a very nicely done QI study,” he said. Nolte, who was not involved in the study, is a professor of pathology and laboratory medicine and director of clinical laboratories at the Medical University of South Carolina in Charleston.
Nolte, who previously reported on a similar effort at Emory University to improve blood culture contamination rates, explained that initiating and sustaining QI initiatives in the ED often proves tricky. “We’ve done a good job here at the Medical University of South Carolina with keeping the hospital institution-wide contamination rate at or below two percent but the ED contamination rate remains at about four-to-five percent despite repeated efforts to help them bring it down,” he observed.
Nolte’s study at Emory University, which focused on improving blood culture contamination rates, ED length-of-stay, and turnaround time for certain lab results, reduced blood culture contamination rates to 1.1% from 5.5%. One strategy involved stationing a phlebotomist in ED, something Vanderbilt did not do. However, Self emphasized how important laboratorians were to Vanderbilt’s overall QI initiative. “They were not involved in the direct collection of blood, but they were heavily involved in designing the technique changes we implemented—including the antiseptic we chose—and reinforcing the volume of blood needed in each specimen and why that’s important. So they were involved in all the discussions and training throughout the project.”
Nolte encouraged laboratorians to engage with their EDs about improving blood culture contamination rates, and to use this study as a guide for setting goals around this important QI parameter.