Use of separate venipunctures for IV access and laboratory studies decreases hemolysis rates

Emergency department (ED) patients routinely undergo placement of a saline lock device (SLD) with the aspiration of blood for laboratory testing. Drawing blood through a SLD may result in hemolysis of sample, repeated venipuncture and increased ED length of stay (LOS). The objective of this study was to examine if separate venipunctures for intravenous (IV) access and laboratory studies decrease the rate of hemolysis and ED LOS. The study was conducted at an urban university level 1 trauma center with an ED volume of 55,000. We compared the rate of hemolysis and ED LOS before and after mandating the use of separate venipunctures for IV access and laboratory studies over 1 month. Venipuncture was performed utilizing either a 21 ga needle or an IV catheter (BD Insight Autoguard) with a needless vacutainer. The incidence of hemolysis was calculated and a Student's t test was used to compare groups. The potassium sample redraw and processing time was observed. Blood was aspirated from 315 patients using the SLD. A baseline hemolysis rate of 23.0% (16.7-29.1) was obtained, corrected to 6.7% after factoring a 29.2% redraw rate for critical potassium levels. In the following month, 2,564 samples were obtained using the butterfly needle with a hemolysis rate of 6.6% (5.5-7.5), corrected to 2.0% after applying the 29.2% redraw rate. Avoiding hemolysis, we saved 4.7% of our patients' 56 min of ED stay, and avoided 185 retests over the month. In conclusion, venipuncture from a butterfly needle decreases the rate of hemolysis and may decrease the overall ED LOS.