Estimation of sweat rates during cycling exercise by means of the closed chamber condenser technology

Comparing test methods for moisture-vapor transmission rate (MVTR) for vascular access transparent semipermeable dressings

BACKGROUND

Catheter insertion sites are commonly covered by transparent film dressings, offering protection of the insertion site from external contaminants and securement of the catheter while allowing site observation through a clear window. Currently, there is considerable focus on creating IV film dressings with ever-increasing moisture vapor transmission rates (MVTR) to prevent the accumulation of moisture under the film and reduce the risk of infection. These increasingly high MVTR IV dressings are often promoted as superior to IV dressings with lesser MVTR values.

METHODS

Since there are different methods to determine MVTR, we chose to test a series of commercially available dressings with two standard methods to compare the results and better understand the information provided by this measurement. We used European Standard EN 13726 to test the MVTR of seven different IV dressings with two different methods (upright and inverted).

RESULTS

We measured a range of MVTR values from 773 to 2838 g/m2/day for the upright method and from 845 to 30,530 g/m2/day for the inverted method for the seven IV dressings tested. Three dressings showed statistically different MVTR values with the two test methods.

CONCLUSIONS

The MVTR test method (upright or inverted) used and considered for IV dressing product selection matters because the results obtained can be very different. We suggest that the upright method is better suited for IV dressings because they are not in constant contact with fluid. We conclude that the inverted method alone is not adequate to compare IV dressings.

The proteomic and metabolomic characterization of exercise-induced sweat for human performance monitoring: A pilot investigation

Sweat is a biofluid with several attractive attributes. However, investigation into sweat for biomarker discovery applications is still in its infancy. To add support for the use of sweat as a non-invasive media for human performance monitoring, volunteer participants were subjected to a physical exertion model using a treadmill. Following exercise, sweat was collected, aliquotted, and analyzed for metabolite and protein content via high-resolution mass spectrometry. Overall, the proteomic analysis illustrates significant enrichment steps will be required for proteomic biomarker discovery from single sweat samples as protein abundance is low in this medium. Furthermore, the results indicate a potential for protein degradation, or a large number of low molecular weight protein/peptides, in these samples. Metabolomic analysis shows a strong correlation in the overall abundance among sweat metabolites. Finally, hierarchical clustering of participant metabolite abundances show trends emerging, although no significant trends were observed (alpha = 0.8, lambda = 1 standard error via cross validation). However, these data suggest with a greater number of biological replicates, stronger, statistically significant results, can be obtained. Collectively, this study represents the first to simultaneously use both proteomic and metabolomic analysis to investigate sweat. These data highlight several pitfalls of sweat analysis for biomarker discovery applications.