DATABITS: Bigger Isn't Always Better

Kentucky Nurse, Jul-Sep 2006 by Cronin, Sherill Nones

In today's busy health care world, it has become increasingly Important to maximize efficiency at every opportunity. The practice of obtaining blood samples through newly inserted IV catheters is one attempt by health care workers to improve efficiency in the clinical setting, while also decreasing patient discomfort from multiple needle sticks. However, there have been reports of increased hemolysis in blood samples obtained in this manner, often leading to a second blood draw and, as a result, negating the increased efficiency of the practice. Despite these findings, however, the practice continues. Therefore, nurses in the emergency department (ED) at Summa Health System's Akron City Hospital decided to see if an alternative technique of obtaining the blood from the IV catheter-via Vacutainer-could minimize hemolysis.

Since no clinical nursing studies had documented the effect of tube collection size on hemolysis of samples obtained via FV catheters, this study's purpose was to determine if there was a significant difference in rates of hemolysis in blood drawn from an IV catheter using a 5-mL vacuum tube or a 10-mL vacuum tube. The researchers recruited 12 ED nurses who represented all shifts to do the blood collection. The 268 patients selected for the study were randomized into four groups. As the nurses drew blood from the patients, the samples were collected into two Becton Dickson red-top Vacutainers fitted with Vacutainer Brand Luer adapters, using either two 10-mL tubes (Group D). two 5-mL tubes (Group C), or one of each (in Group B, the small tube was drawn first: in Group A, this was reversed). When drawing the blood, the nurses used only 18-20 gauge Johnson and Johnson ProtectIV*Plus IV catheters. These large bore catheters have been shown in a previous study to cause the least amount of hemolysis.

The study used a 2-period crossover design in which each patient served as his or her own control. Blood samples were drawn over a 2-month period. All of the samples were analyzed by the laboratory for the presence of hemolysis, determined by an automated Hitachi spectrophotometer as well as by visual inspection, which is the current standard. The findings revealed that there was significantly more hemolysis seen when 10-mL tubes were used compared to when 5-mL tubes were used. Therefore, hemolysis could be minimized by simply collecting blood in 5-ml, lower vacuum collection tubes. Furthermore, once the study facility implemented the use of the low vacuum collection tubes for all blood draws, they found that their overall hemolysis rate dropped from 2% to 1.1%. This resulted in substantial savings of both nursing and laboratory personnel time and quicker access to clinical information for patient diagnosis and treatment

Perhaps even more importantly, however, is that the decreased incidence of hemolysis by use of the smaller tube could, in turn, increase patient satisfaction because the patient does not have to be stuck by a needle more than once. Perhaps bigger isn't always better. If the use of a smaller tube has the potential to save valuable time and to prevent additional patient discomfort, maybe good things really do come in small packages!

Source: Cox, S.R., Dages, J.H., Jarjoura, D., Hazelett, S. (2004). Blood samples drawn from IV catheters have less hemolysis when 5-mL (vs 10-mL) collection tubes are used. Journal of Emergency Nursing, 30, 529-533.

Submitted by: Amy Miller, Shana Cassady. and Rebecca Lewis, BSN graduates from Bellarmine University Lansing School of Nursing and Health Science.

Data Bits is a regular feature of Kentucky Nurse. Sherill Nones Cronin, PhD, RN, BC is the editor of the Accent on Research column and welcomes manuscripts for publication consideration. Manuscripts for this column may be submitted directly to her at: Bellarmine University. 2001 Newburg Rd., Louisville, KY 40205.