Fig 1.
(a) labeled diagram of the Welch Allyn plastic speculum used in our experiments; (b,c,d) the physician’s view through the speculum at varying vaginal pressures as represented by our physical model during an experimental trial with a Skyn condom: (b) 0 mmHg with excellent visualization, (c) 40 mmHg (5.3 kPa) with adequate visualization, and (d) 120 (16.0 kPa) mmHg with poor visualization due to lateral wall collapse.
Fig 2.
Sample of photos collected during a glove trial (a) and a condom trial (b). The resulting calculations for decreased visualization at each pressure are drawn on the figure. The calculation for relative width is indicated as the percentage of baseline and is equal to the view width at that pressure divided by the view width at 0 mmHg (baseline).
Table 1.
Composite table of the mean and standard error for all the sets of trials performed.
Fig 3.
Comparison of speculum opening distance by the type of sheath applied.
Restriction of this value is the disadvantage of using a sheath. Because the condoms were looser than the gloves, opening the speculums to the same number of clicks leads to widely different speculum opening distances (distances between speculum blade apices) depending on the sheath used. To keep the speculum opening distances comparable, the speculums were opened to 3 clicks for condoms (a) and 5 clicks for gloves (b). However, when the speculums were opened to 5 clicks for the vinyl material gloves, the speculums often broke. To give a numeric value, the vinyl material gloves are shown at 3 clicks as well (a), which was the maximum amount of clicks that could be consistently attained without speculum breaking. All measurements shown are at baseline, before any external pressure was exerted (0 mmHg). The speculums can be inserted into the gloves via one of three methods: “middle finger” (1 finger), “two fingers”, and “palm” (see Fig 6). Trojan and LifeStyles condoms are composed of latex, and Durex and Skyn condoms are composed of synthetic polyisoprene.
Fig 4.
Comparison of small, medium, and large glove sizes in preventing lateral vaginal wall collapse during speculum examinations.
The data shown is for nitrile gloves using the “middle finger” placement method.
Fig 5.
Comparison of glove material type (nitrile vs vinyl) in preventing lateral vaginal wall collapse during speculum examinations.
Although the vinyl gloves seem better in this metric, they performed significantly worse overall because they restricted the speculum opening distance and occasionally even broke the speculum (see Fig 3). The data shown is for medium size gloves using the “middle finger” insertion method.
Fig 6.
Comparison of the different methods of applying the glove onto the speculum in preventing lateral vaginal wall collapse during speculum examinations.
The palm method (inserting the speculum into the palm of the glove only and using the palm as the sheath), is not shown as those trials were abandoned because of clear inferiority. (see Fig 3).
Fig 7.
Comparison of various condom brands and no condom in preventing lateral vaginal wall collapse during speculum examinations.
Table 2.
Summary of findings and recommendations.