Are "impervious" surgical gowns really liquid-proof?

by Nathan L. Belkin, PhD, Clearwater, FL

It was in 1952 that William C. Beck, MD, FACS, first alerted the medical community that there was a need for the materials used in surgical gowns to have a liquid-repellent capability.1

In response to that need, both the "woven" and "non-woven" segments of the industry began to introduce a new generation of fabrics. To demonstrate their product's resistance to liquid penetration, the woven gown industry used a number of tests that had been designed for rainwear fabrics. On the other hand, the non-woven segment used what was known as a "Mason jar" test that their trade association had developed for that specific purpose.

Because of what proved to be the poor performance of many of the new materials and the obvious lack of an appropriate test method, the American College of Surgeons' Committee on the Operating Room Environment (CORE) took a position on the matter in 1975.2 Under the leadership of Harvey R. Bernard, MD, FACS, and Dr. Beck, the entire industry was formally charged with the responsibility of developing test methods demonstrating the desirable liquid-repellent attribute and to do so under what they so astutely described as "usual conditions of use."

It was about this time that a group headed by the distinguished surgical researcher, Harold Laufman, MD, published the results of their comprehensive investigation of an array of allegedly barrier materials.3 Identifying the phenomena of liquid penetration as "strike-through" and using his relatively simple, inexpensive hammock-like device, Dr. Laufman reported that some of the non-woven materials that had passed the Mason jar test proved to be totally ineffective, some were moderately effective, and a number performed quite well.

Several years later, another team of researchers Schwartz and Saunders, reported on the results of their study.4 Of the four materials they examined, two that had reportedly passed the Mason jar test were non-woven. However, under the conditions of their simple test, these were similarly found to be ineffective.

In the interim, the U.S. Food and Drug Administration (FDA) had classified surgical gowns as Class II Medical Devices, and thereby required them to have performance standards. As a result of Dr. Laufman presenting his data to the FDA device panel, the FDA rated the matter one of high priority. This action prompted the formation of an ad hoc interdisciplinary committee that included members of the CORE.

The group was organized under the auspices of the Association for the Advancement of Medical Instrumentation (AAMI). Although the five test methods considered by AAMI Aseptic Barrier Committee were quite different, they each were similar in that they: (1) assessed the ability of a material to resist liquid penetration on a comparative basis, (2) could be performed inexpensively in any hospital laboratory with existing equipment and supplies, (3) were not time-consuming, and (4) did not require extensive training of personnel. Unfortunately, because of a lack of consensus among its members, the committee was disbanded in May 1983.5

A new era

With the emergence of the era of the hazards associated with the transmission of blood-borne pathogens, the primary purpose of the surgical gown suddenly changed from that of protecting the patient from the members of the surgical team to that of protecting the members of the surgical team from the patient. Notwithstanding the need for a universally accepted test method, this also meant that whatever degree of strike-through may have been experienced in the past could no longer be tolerated.

It was during this period that clinical researchers (Shadduck6 and Nichols7) reported on the results of their examination of a variety of products that were on the market. What exemplified the need for a standard test method was the fact that some of the materials that had been found to be satisfactory under the conditions of Shadduck's test would have failed when subjected to the challenge of the device used by Nichols. Noteworthy was the fact that Shadduck reported detecting penetration of human immunodeficiency virus (HIV) through plastic-reinforced materials in which strike-through was not visible. This has recently been reported again by another group who experienced the phenomena in their in vivo study in which they used a unique method to detect the presence of HIV.8

At this point, it was reasonable to believe that whatever test method was to be adopted wold be one that expressed a material's ability to resist strike-through based on its level of resistance. Rating the materials in this manner would be in accord with the findings reported by Quebbeman and Telford in their in vivo study,9 and would furthermore be in compliance with the mandate of the Occupational Safety and Health Administration (OSHA) that the garment selected should be appropriate for the "task and degree of exposure anticipated."10

A noble mission

With the pressing need for a test method, the American Society for Testing Materials (ASTM) announced the development of a new mechanical device to fill the void. In addition to being expensive, the device required the use of specific supplies, the training of personnel, and was time-consuming (one hour). The methodology was incorporated for use in two tests that the society initially introduced in 1991 on an "emergency status" basis and officially adopted in 1995.11,12

Under the provision of the tests, if a material passed the first test for liquid penetration, it qualified to be tested for viral penetration with the second test. However, rather than expressing the results on a comparative basis, they were reported as pass/fail with a pass predicated on a fabric's ability to withstand penetration at a challenge of 2 psi. This methodology characterizes a material to be "impervious" or liquid-proof, but is contrary to the results of an in vivo study taht revealed a number of instances in which the level of pressure reached 2.9 psi.13 This may also account for the in vivo findings reported by Telford and Quebbeman in which all gowns that were worn permitted varying amounts of liquid penetration—including those made of materials that were known to have passed both of the ASTM's pseudo tests.14 What is even more noteworthy are the results of a recent study in which a material known as having passed both of the ASTM's tests was found to fail the Mason jar test.15

Despite the ASTM's noble mission to help reduce the risks associated with the exposure to blood-borne pathogens, the fact of the matter is that our health care delivery system is being scrutinized to further reduce, let alone contain, its costs. Under the circumstances, to indiscriminately provide all surgeons with what the industry-driven ASTM maintains to be the maximum level of protection would certainly not be fiscally prudent and can only be viewed as self-serving and irresponsible.

In the interim, contrary to what has been cited in the literature, what is disconcerting is that even though terms such as "impervious" or "liquid-proof" do not appear in the text of the ASTM's tests, the FDA's Office of Device Evaluation is permitting the manufacturer to use the absolute connotation of those terms when promoting the sale of its products.16

More than a decade has passed since the emergence of the era associated with the transmission of blood-borne pathogens. What is incredible is that there is no data or evidence that indicates that anyone has ever acquired HIV as a result of blood having penetrated a protective type of garment. Also, it is more than likely that an overwhelming percentage of the garments in use would fail the ASTM's tests. However, under no circumstance should this observation be interpreted to mean or imply that there is no need for the surgeon to be provided with garments that afford both the level and extent of protection that he or she deems necessary.

As Dr. Beck once said, "If one uses something which he can anticipate to be a barrier, it should have the quality of being one."17 At the moment, it appears that a way and means for making that determination are still not available.

Dr. Belkin retired in 1991 after a 40-year career in research and development of surgical textiles. He was a charter member of the ad hoc interdisciplinary "barrier" committee (CORE, AORN, and industry) as well as its successor organized under AAMI's auspices.

References

1. Beck WC, Collette TA: False faith in the surgeon's gown and surgical drape. Am J Surg, 85:125-126, 1952.

2. Bernard HR, Beck WC: Operating room barriers: Idealism, practicality, and the future. Bull Am Coll Surg, 60(9):16, 1975.

3. Laufman HA, et al: Strike-through of moist contamination by woven and non-woven surgical materials. Ann Surg, 857-862, 1975.

4. Schwartz JT, Saunders DC: Microbial penetration of surgical gown material. Surg Gyn & Obst, 150:507-512, 1980.

5. Beck WC, Meeker MH: Demise of Aseptic Barrier Committee: Success and failure. AORN, 39:384-388, 1983.

6. Shadduck PD, Tyler DS, Lyerly HX, et al: Commercially availablesurgical gowns do not prevent penetration by HIV-1. Surg Forum,41:77-80, 1990.

7. Smith JC, Nichols RJ: Barrier efficacy of surgical gowns. Arch Surg, 26:756-761, 1991.

8. Ahmad FS, Sherman SJ, Hagglund KH: The use and failure rates of protective equipment to prevent blood and bodily fluid contamination in the obstetric health care worker. Obst & Gyn, 92:131-136, 1998.

9. Quebbeman EJ, Telford GL, Hubbard S, et al: In-use evaluation of surgical gowns. Surg, Gyn & Obst, 174:369-375, 1992.

10. Occupational Safety and Health Administration: Occupational exposure to blood-borne pathogens: Final rule 29CFR, Part 1910.1030. Fed Reg, 56 (Sec 6):64040-64182, 1991.

11. American Society for Testing Materials: Standard test method for resistance of materials used in protective clothing to penetration by synthetic blood. F1670-95. West Consnohocken, PA: ASTM, 1995.

12. American Society for Testing Materials: Standard test method for resistance of materials used in protective clothing to penetration by blood-borne pathogens using Phi-X174 bacteriophage penetration as a test system. F1671-95. West Consnohocken, PA: ASTM, 1995.

13. Smith JW, Tate WA, Yazhani S, et al: Determination of surgeon-generated pressures during various surgical procedures in the operating room. Am J Infect Con, 23:237-246, 1995.

14. Telford GL, Quebbeman EJ: Assessing the risk of blood exposure in the operating room. Am J Infect Con, 21:351-356, 1993.

15. Leonas KK: Effect of laundering on the barrier properties of reusable surgical gown fabrics. Am J Infect Con, 26:495-501, 1998.

16. FDA, Office of Device Evaluation, Center for Devices and Radiological Health: Interim guidance for substantiating liquid-proof or impervious claim using ASTM ES-21 and ASTM ES-22 standard test methods. FDA, March 19, 1995.

17. Personal communication with William Beck, May 21, 1987.

Readings on Operating Room Environment Issues

Committee on Perioperative Care