Abstract

Textiles are no more restricted for apparel use only. Due to the growing awareness of, and demand for, secured protection against clinical hazards coupled with comfort characters, the traditional apparel market is moving towards high value added product segments, e.g., in medical uses.

Today's healthcare worker (HCW) is faced with potential exposure to a growing number of increasingly dangerous pathogens on a daily basis. Among available variants of medical textiles, reusable surgical gowns are experiencing phenomenal growth. Apart from absolute reliability and comfort characteristics, the improved bioclimatic and physiological properties are also of increasing demands, such as durability, breathability, thermoregulatory characteristics, ease of laundering, sterilization and antistatic behavior, low level of textile chemicals and dyes with high mechanical stability.

Loosely woven cotton fabric had been used universally as bacteriological barrier in earlier days. After a decade of trial and error, a plastic surgical material was developed that made an ideal bacteriological barrier, but it was deemed unsuitable because of heat retention. Then the industry responded by introducing a variety of laminated materials made of combination of polyethylene film and the non-woven, single-use fabric. At the beginning of the seventies surgical gown made of better quality cotton, cotton-polyester mixtures were introduced. But the unsatisfactory fulfillment of the hygienic requirements led to an addition or a change of classical OR textiles by so-called barrier articles in the form of tightly woven fabrics with hydrophobic surface modification. The latest technology medical garments are having base fabric as synthetic material like polyester/nylon etc. with appropriate finishing to impede water droplets from penetrating ensuring an initial barrier effect but allow water vapors to permeate, resulting in increased comfort, especially for the long surgical procedures.

Introduction & Background

Medical textiles will probably be the field of new millennium. Due to constant improvements and innovations in both medical procedures and textile technology the annual growth of medical textile products during the last two decades occurred at a compound annual rate of 10 - 15 %.

Textiles in the health service, frequently also designated as medicine or clinical textiles, represent a various and extensive segment within the sphere of technical textiles.

Dedicated surgical apparel did not see regular usage until the very late 1800s. Surgical gowns and aprons in those days were primarily used to keep the surgeon's clothes clean of blood and other fluids. In the early 1900s the first surgical gowns were made out of two sterilized pieces of lightweight fabric [1]. These garments reached the floor and had elbow length sleeves. In the 1920s, gowns began to be constructed of muslin, which was viewed as a barrier material. In 1939, there was concern about fluid penetration with muslin. So, rubber was applied to increase the barrier and sleeves were extended to length. Protection enhanced with decrease in comfort [2]. During 1950s, not only were surgical gown fabrications evaluated, new designs were explored. Non-wovens were introduced in different grades and weights leading to development of a range of gown types for different levels of protection [3]. With the emergence of the era of the hazards associated with the transmission of bloodborne pathogens, the primary purpose of the surgical gown suddenly changed from third person to first person to protect the surgeon from the patient. So, whatever degree of strikethrough may have been tolerated in the past was no longer acceptable. Today, different gowns are designed to handle different surgeries. To perform a surgery with several risks and a high blood count, a higher barrier, and frequently reusable, gown will be chosen. For less risky surgeries, a lower barrier disposable gown is used [4]. It was the 1980s, though, that saw the biggest increase in surgical apparel usage in modern times. Today, it is virtually unheard of that a surgical procedure is performed without a full arsenal of protective apparel to keep both the patient and surgical team safe from infection. Fortunately, maintaining and increasing that level of safety has become a main concern for a number of companies serving the surgical apparel market. As a result, advancement in protective apparel continues to be made.

Though protection is of critical importance, surgeons are still unwilling to sacrifice comfort and fit [2, 4]. Gowns of proper fit more effectively repel dangerous infections and fluids providing improved protection for both medical personnel and the patient [2].

There is an abundance of scientific studies addressing various aspects of medical fabric effectiveness [5, 6, 7]. Researchers studied and found that fabric construction, repellency and pore size contributed to gown performance. Liquid strike-through was not always accompanied by bacterial transmission. Higher fabric repellency ratings and smaller pore size generally corresponded with higher barrier properties.

In a study [6] the researcher evaluated the liquid and microbial barrier properties of reusable and disposable gowns and investigated the cumulative effects of laundering and sterilizing on the barrier efficacy of reusable gowns by means of the impact penetration (splash) test, the synthetic blood resistance test, the viral resistance test, and the elbow lean (demonstration) test.4 The study showed that single-layer regular gowns and double-layer fabric reinforced gowns offer different degrees of resistance to splashes and pooling of liquids on the surface. Gowns reinforced with films, membranes and coatings are generally liquid-proof, meaning that they resist visible penetration of synthetic blood under pressure. Some of the gowns were also resistant to viral penetration. The researcher concluded that healthcare facilities should provide liquid-proof gowns that also offer microbial resistance to their medical personnel for use in high-risk situations in which optimum safety is required. Other gowns may be used when the risk of exposure to body fluids is low. Hospital personnel should determine the type of gown that should be worn in different operating room situations. Any incidents of penetration would indicate that a higher level of protection is required.

According to Leonas [7] a combination of fabric characteristics are associated with the barrier properties of the surgical gown fabrics. Repellency and pore size contribute to gown performance. Laundering reduces the ability of the fabric to prevent the transmission of bacteria through the fabrics. However, fabric with greater thickness as in case of gowns with a second fabric layer, retains greatest degree of repellency with no transmission of bacteria after laundering. Higher repellency ratings generally corresponded with higher barrier properties.

Thus, best practices for selecting medical gowns can be summarized as follows:

▪ Materials used in surgical gowns should be safe, meet identified needs and promote the safety of patients and HCWs.

▪ The selection of gown - both single-use and reusable - should be based on criteria specific to the products' function and use.

▪ Materials used for surgical gowns should be resistant to penetration by blood and other body fluids, particulates and microorganisms.

▪ Surgical gowns should be 100% lint free, anti-static (optional), have an acceptable quality level and be resistant to tears, punctures and abrasions.

▪ Materials used for surgical gowns should be appropriate to the methods of sterilization, and reusable surgical products' barrier properties must be monitored after repeated processing.

▪ Surgical gowns drape should resist combustion.

▪ Surgical gowns should be comfortable and contribute to maintaining the wearer's desired body temperature

▪ These surgical products should have a desirable cost-to-benefit ratio.

In view of the supra, different typical case studies were reviewed on the characteristics and performance of typical medical gowns and the future prospect of such medical garments are discussed in this paper.

Experimental Case Studies

A typical surgical gown of following specifications has been investigated in the study.

The Plate 1 depicts a typical style in OPERATING/SURGICAL GOWNS. Basically the garment is made of 2 parts (a) Front Part and (b) Back Part. Two different types of medical fabrics are used. Typical specifications of those two types of fabrics are mentioned as below:

(a) Front Part Fabric: (This part of the garment is facing the patient and hence need Teflon coating)

Composition : 99% Polyester Filament Yarn + 1% Conductive Yarn with Teflon coated Finish
Weave         : Plain
Weight         : 100 GSM

(b) Back Part Fabric:

Composition : 99% Polyester Filament Yarn + 1% Conductive Yarn
Weave         : Plain
Weight         : 120 GSM



Table 1 describes the measurements taken on a typical surgical gown to form a sizing analysis. Selected physical measurements provided an objective measure of fit. The reported fit measurement has been averaged out by taking into consideration of actual performances such as standing in a relaxed posture, and then following performance of a minimal range of motions that mimicked those of operating room personnel.

Front and back of the surgical gowns were evaluated for Air permeability, Water repellency and Water resistance and values are reported in Table 2. It is corroborated from the Table that front part of the surgical gown has superior barrier properties in comparison with back. Lower value in Air permeability and higher water repellency and water resistance properties do reflect the suitability of the front part in surgical operation. But such a property will definitely make the front part of the gown uncomfortable in comparison to back.

In another study, five typical medical gowns (65% polyester and 35% cotton) were evaluated for properties related to its performance and are depicted in Table 3.

No. 1 test measures the resistance of fabrics to the penetration of water under static pressure as encountered during a storm. The fabric is considered storm-proof since 1 g of water is absorbed by blotter paper with shower head pressure of 3 ft for 5 min.

No.2 test demonstrates how well the fabric stands up to wetness less than 200 pounds of continuous pressure such as kneeling on wet ground or sitting in a wet chair lift for a period of 30 min.

No.3 test measures surface wetting.

No.4 test measures the high range resistance of a fabric when subjected to water under high pressure over a short period of time. The hydrostatic testing machine steadily increases water pressure on a single point of the fabric until it bursts. This bursting point is well beyond any normal rainstorm.

No.5 test is the upright cup method uses water placed in a cup with fabric stretched over the top in a controlled environment. Moisture vapour passes through the fabric and is measured in terms of weight loss over a period of 24 hour.

No.6 test measures cubic feet per minute of air able to penetrate the weave. Air permeability has a direct correlation to windproofness.

Discussions

There has been always an endeavour to impart unique properties in fabrics used for surgical gown so that the comfort and protection gets combined, and it does give that optimum balance of performance in terms of the overall tactile feel, but also the breathability as measured by moisture vapor transmission.

Providing excellent comfort becomes more challenging with higher levels of protection. The more impervious we make a product, by default the less breathable the product is going to become, and thus higher is the risk that it will be a hot garment and is uncomfortable to wear. One of the innovations is to have breathable impervious gown that utilizes a breathable film structure that, combined with spunbond/meltblown/spunbond (SMS) nonwoven fabric, really combines the best of both worlds - it has the barrier performance that exceeds the level required for an impervious product, but still provides the breathability necessary to provide the comfort needs of a healthcare worker."

One of the aspects that make this combination difficult is ensuring abrasion resistance. If material does not have good abrasion resistance, then fabric particles or problem of linting may occur. It can be a wound contaminant in a surgical setting that results in procedural complications or could be a vehicle for transmission of microorganisms. If microorganisms happen to be on the surface of that garment and it abrades and fibers are coming off, then we are creating another avenue for those microorganisms to be transferred from one location to another.

The most critical element of protection is the fabric's barrier characteristic. Manufacturers continue to explore new avenues of protection like understanding how to take antimicrobial technology and combine it with superior fabric performance to bring forward a higher performing product that has not only barrier characteristics, but also an active ingredient that would kill or control the spread of microorganism that might contribute to healthcare-acquired infections.

The effort to combine antimicrobial technology with high-performing barrier fabrics is no easy task. Some people have talked about the possibility of embedding antimicrobials into fabric, and there are two views on that - one is that may be a good thing, and the other is that it may be a bad thing, because treating a microorganism with a sub-lethal dose of an antimicrobial, may encourage developing resistance in that population. It's all part of the general precautions.

In the atmosphere of challenging medical environment of surgery, flame and electrostatic resistance is also needed especially for laser applications and oxygen administration, because of the danger of explosion [8].

New technical requirements

Designing of surgical gown as per the performance requirement is important and agreed upon by both the US and EU communities. A mandatory European standard EN 13795 was been developed to establish basic requirements and test methods for disposable and reusable materials used for surgical gowns and drapes to take care of safety and health of patients and healthcare professionals. As per the European standard, the protocol of basic performance tests for surgical gowns includes the following parameters:

Resistance to microbial penetration - dry (ISO 22612)
Resistance to microbial penetration - wet (ISO 22610)
Cleanliness - microbial (EN 1174)
Cleanliness - particulate matter (ISO / FDIS 9073 - 10)
Linting (ISO / FDIS 9073 - 10)
Resistance to liquid penetration (EN 20811)
Bursting strength - dry (EN ISO 13938)
Bursting strength - wet (EN ISO 13938)
Tensile strength - dry (EN 29073 - 3)
Tensile strength - wet (EN 29073 - 3)

In US standard, two such test methods were developed by the American Society for Testing and Materials (ASTM) to provide standard test methods to evaluate protective barriers. The two test methods are ASTM F1671-95 and F1670-95. Both test methods use a penetration test cell apparatus.

ASTM F1671-95
Standard test method for resistance of materials used in medical clothing to penetration by blood-borne pathogens using Phi-X174 bacteriophage penetration as a test system.
This test method is used to measure the resistance of materials used in medical clothing to penetration by blood-borne pathogens using a surrogate microbe under conditions of continuous liquid contact. Medical clothing material pass/fail determinations are based on the detection of viral penetration.

ASTM F1670-95
Standard test method for resistance of materials used in medical clothing to penetration by synthetic blood.
This test method is used to evaluate the resistance of materials used in medical clothing to penetration by synthetic blood under conditions of continuous liquid contact. Medical clothing pass/fail determinations are based on visual detection of synthetic blood penetration.

Concluding remarks

Medical regulations do not restrict the medical staff from using whatever type of medical gown they wish. But they do have the responsibility to take manufacturers claims into account and not to use such material for purposes for which they were never intended. Only if there is good collaboration between users, producers and hygienists, the utility of standards will succeed. From the medical perspective, neither reusable materials nor single-use products can generally be designated as suitable or unsuitable. Though the emphasis on standards varies from country to country, the essential requirement of any product is to provide a high level of protection.

The latest technology medical clothing is composed of 100% microfilament polyester. As spun yarns are source of lint, one can expect a possible source of micro contamination and fiber generated infections during surgery in case of using cotton material. Being a cellulosic base, it is also more prone to attract microbes and bacteria under moist condition. But compared to cotton garments, 100% filament made polyester garments are not comfortable to wear due to less breathability. Static charge generation on abrasion with any surface is also a common cause of concern for a synthetic material like polyester since charged dust particles and pathogens may be attracted due to this.

However, by using 100% Filament Polyester fabrics for medical garments, linting problem will be solved which is considered to be a major problem in medical sector. Special finishes like Anti-Microbial finish shall decrease the risk of infection transmission. Water repellent finish helps to repel blood from medical gowns during critical operations. Use of antistatic finish coating on the surface or the use of an antistatic material during production may solve the static generation problem.

It will take sometime for the hospitals, medical surgeons and the medical institutes to switch over to new technology medical garments and stop using old and conventional medical garments after getting convinced and satisfied with the product quality.

REFERENCES

▪ Traci May-Plumlee and Amanda Pittman, Surgical gown requirements capture: a design analysis case study, JTATM, Vol.2, Issue.2, Spring 2002, pp 2-3.
▪ N. Belkin, The challenge of defining the effectiveness of protective aseptic barrier, Technical Textiles International, 1993, pp 22-24.
▪ D. Lickfield, Non-wovens in medical textiles, International Fiber Journal, 2001, pp 42-48.
▪ L. Stanley, OSHA ruling still causing shifts in surgical gown marketplace, Health Industry Today, 1994.
▪ K K Leonas and R S Jinkins, The relationship of selected fabric characteristics and the barrier effectiveness of surgical gown fabrics, Am. J. Infect Control, Vol 25, No.25, 1997, pp 16-23.
▪ E A McCullough, Methods for determining the barrier efficacy of surgical gowns, Am. J. Infect Control, Vol. 21, No. 6, 1993, pp 368-374.
▪ K K Leonas, Effect of laundering on the barrier properties of reusable surgical gown fabrics, Am. J. Infect Control, Vol 26, 1998, pp 495-501.
▪ S. Adanur, Wellington Sears Handbook, Technomic Publishing, USA, 1995.