In vitro test of different urine-meters in an experimental bladder-drainage model: prevention of ascending contamination depends on construction of the urine-meter

Abstract

Modern urine-meters are provided with the urine collection bag directly attached to the measuring device, thus providing a closed collection system. The systems vary, however, in respect to how the measuring devices are emptied into the urine collection bag. Using an in vitro ascending contamination model we compared three systems: the Unometer (Unomedical), the Bard Urinemeter and the Curity Urinemeter (Kendall), which all differ in the methods of emptying. The urine collection bags were inoculated with Pseudomonas aeruginosa , and subsequently sampled daily at six different sites for up to seven days in order to determine the degree and timing of ascending contamination of the systems. Unometer was significantly less contaminated at the urine-meter level at day seven than both Bard (0/8 vs. 4/4, P=0.002) and Curity (0/8 vs. 8/8, P=0.0002), respectively, as well as significantly less contaminated in the infusion-catheter above the urine-meter at day seven than Bard (0/8 vs. 4/4, P= 0.002), but not so as compared to Curity (0/8 vs. 1/8, P =1,0). The Bard and Curity systems empty the devices by tilting thereby probably contaminating the devices, while the Unometer is emptied via a non-return valve in the bottom of the device.