Aryicle # 9

Evidence-Based Practice for Obtaining Blood Specimens from a Central Venous Access Device 

Sarah J. Mendez, MA, RN, AOCNS 

 

As part of a scheduled policy and procedure review, the department of nursing education at a large urban academic medical center conducted a literature review to determine the most up-to-date evidence for central venous access device (CVAD) blood draws. The literature review revealed that the dead space blood draw was the best practice methodology because the dead space methodology, defined as the point at which blood is in the attached syringe when aspirating without flushing, reduced the potential for infection with minimal blood loss from blood discard. 

 

Background: 

Laboratory tests such as complete blood count (CBC) and basic metabolic panel (BMP) are an essential part of monitoring eligibility for, and response to, the treatment of patients with cancer 

The best methods for blood collection reduce the risk of infections, occlusions, thrombus formation, and blood loss that require therapeutic interventions. 

Blood draw methods identified in the literature include the discard method, the push/pullmethod, the reinfusion method, and the dead space method. 

 

 

Methods : 

The project took place at NYU Langone Medical Center, a Magnet®-designated hospital located in the New York metropolitan area. The QPI project seeks to understand the error rate for the dead outlining the steps to follow for obtaining CVAD blood specimens. Data collection occurred throughout December 2009 and was performed by any nurse (n = 30) caring for a patient who required a blood draw. The nurses completed a form that requested medical record number, type of CVAD, and, if there were any fluids infusing, what type for each specimen collected. The majority of the blood specimens were obtained by the night shift nurses for required morn ing laboratory tests. Nurses would monitor results and mark if they were normal or skewed. Skewed results led to repeat blood draws by day-shift nurses. Repeat specimens were obtained using the standardized flush method procedure. Then, results were marked in the normal range or as remaining skewed 

 

Results : 

The collaborative group determined that an acceptable rate of error would be 5%. The percentage of error using the dead space method was 2%; the level of accuracy was 98%, showing that the dead space method is effective for the adult oncology unit patient popula tion with CVADs. The extremely low percentage of error with the dead space method supports its use in adult patients with cancer. Only 5 of 254 results were skewed, and repeated tests via the standardized flush method were in normal limits, a true percentage of error. A secondary aim of this study was to determine the length of time required for holding any infusing fluids. One minute proved sufficient because results were not skewed from lumens that had fluid infusing prior to collection. No literature was found regarding the length of time infusing fluid should be held prior to drawing blood specimens; had the time frame increased the number of skewed results, it would have been re addressed. A shorter time frame may be adequate but was not tested at this time. 

 

Implications for Nursing : 

The oncology nurse caring for patients with CVADs can impact nursing sensitive outcomes such as infection rate, decreased blood volume loss from laboratory specimen blood draws, less blood draw-induced hypovolemia and anemia, fewer blood transfusions, and fewer repeated blood draws. Bedside nurses access and use CVADs on a daily basis, therefore, their input is most valuable regarding the use and care of these lines. Keller (1994) stated that nurses are essential in the management of CVADs and that it is in their realm of practice to determine evidence-based practices. This project addressed a gap in the literature regarding the oncology and hematology patient populations, who are at higher risk of negative outcomes related to blood draw methods.  

Discussion Starting Points: 

Please choose two for your response:

How does this research article compare to our practice, policy and or procedure?

What are the advantages and disadvantages to the proposed recommendations in the article?

What are the advantages and disadvantages of implementing the article recommendations on your unit and/or hospital?

Was the correct method used? Why or why not?