A novel technique to evaluate the precision of multiple pump systems infusing into a single site

Abstract

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Objectives: Many critically ill children require concurrent delivery of intravenous medication into a single site, sometimes with multiple infusion pumps. This study uses a novel apparatus to evaluate the variability in the delivery of a solution of Tc-99 infused with 2, 3, 4 or 5 pump infusion systems. Methods: A solution of Tc-99m was flushed through two 1.5ml fluid capacity lines (FCL) connected by a 4-way stopcock and attached to an Alaris 3000 syringe pump. A total of 4 independent trials were run, where, additional syringe pumps containing saline only, were added, one at a time, to a total of 5 pumps. In each of the 4 trials, the pump containing the radioactive solution ran, independently, at 1ml/hr for 30 minutes. At 30 minutes, 1, 2, 3 or 4 additional pumps containing saline were activated and left to run at 1ml/hr for 5.5 hours and imaged with a GE STAR3000 camera. A steady state line with the same radioactive solution was imaged concomitantly to evaluate statistical counting fluctuations. Regions of interest were drawn on the FCL where all solutions merged as well as the control line. An F-test was performed to compare the variance in counts between a single pump versus multiple pumps. Results: The largest fluctuation in counts for the control line was 1.8%, for 1 pump 4.5%, for 2 pumps was 16%, for 3 pumps 17%, for 4 pumps 16% and for 5 pumps 17%. The variance in the counts (F test) of one pump versus 2, 3, and 5 pumps was statistically significant where p= 0.04, 0.02, and 0.03, respectively. Conclusions: Multiple pumps infusing into a single site results in large delivery fluctuations above the limit accepted for a single pump system.