The electrical properties of natural rubber latex (NRL) gloves have been of clinical interest since the concept of using an electrical device to monitor glove barrier integrity was introduced over thirty years ago by Beck. Beck's monitoring device, and other similar devices, function by treating the glove barrier as a resistor. The theory is that a hole will appear as a lower resistance than an intact glove. We conducted a series of tests designed to explore the validity of this theory.
We examined the electrical properties of gloves representing the product lines of most major U.S. and international manufacturers. Approximately 1200 gloves, representing a total of 60 glove types, were tested. Gloves were filled with isotonic saline solution (750ml of .9% NaCl) and immersed in a non-conductive plastic tank containing the same saline solution. Water temperature was varied between 25 and 40 degrees Celsius. Non-polarizing electrodes were placed in the tank and glove and resistance measurements were taken repeatedly using an instrument designed for that purpose.
Our principal result is that the conductivity of most NRL gloves decreases significantly over time, once the glove is wetted. All natural rubber gloves tested were observed to exhibit this tendency, but to dramatically different degrees. The electrically ``best'' gloves typically increased in conductivity by no more than a factor of ten over an hour of exposure. The electrically ``worst'' gloves showed increases in conductivity of several orders of magnitude in less than 10 minutes of exposure to saline solution. Synthetic rubber gloves did not appear to exhibit this phenomenon. The variability of conductivity over glove manufacturer and style correlated strongly with the rate of glove hydration. These data preclude the use of the simple resistor model for monitoring glove barrier effectiveness.
While it is difficult to establish with certainty whether a glove with high conductivity has failed, or is simply hydrated, the converse is easy to establish. Thus, a glove that exhibits low conductivity is necessarily a ``good'' biological barrier. For the health care professional, this suggests that gloves styles with low initial conductivity, and that hydrate slowly, may offer superior protection, particularly when these gloves are used in conjunction with an electrical barrier monitoring device that recognizes the difference between hydration and penetration.
We have also investigated the origin of the observed electrical behavior. Our results indicate that water-soluble proteins, found to varying degree in NRL gloves, strongly influence NRL glove hydration and conductivity. Since some number of these proteins are associated with latex product hypersensitivity in humans, an understanding of the electrical behavior of NRL gloves has both clinical and manufacturing implications beyond barrier integrity monitoring.
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J.R. Nelson, T.A. Roming and J.K. Bennett. A whole glove method for evaluation of surgical gloves as barrier to virus. American Journal of Contact Dermatology. 10(4):183-9. Dec. 1999. |
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J.K. Bennett. The Clinical Significance of Hydration in Natural Rubber Latex Gloves. In Surgical Services Management, 3(2), 29-33, Feb, 1997. |
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J.K. Bennett.
The feasibility of using electrical means for
monitoring barrier integrity in natural |
| J.K. Bennett. Hydration and conductivity in natural rubber latex gloves. In Source To Surgery 1(3), 1-4, October, 1993. |
| J.K. Bennett. Investigating the physical properties of latex gloves. In In Touch 2(2), 1-2, May 1993. |