Surgical gowns are specialized pieces of protective apparel worn by healthcare professionals in operating rooms and other sterile environments. The primary function of a surgical gown is to establish a barrier, preventing the transfer of microorganisms, bodily fluids, and particulate matter between the patient and the surgical team. This barrier protection helps maintain the sterility of the surgical field and reduces the risk of surgical site infections. The material composition balances this necessary barrier function with comfort and breathability for the wearer during long procedures.
The Dominance of Disposable Synthetic Materials
Most modern surgical gowns are designed for single-use and are constructed from synthetic, non-woven fabrics, primarily using polymers like polypropylene. These materials are formed by bonding fibers together using heat, chemicals, or pressure, rather than traditional weaving. This manufacturing method allows for precise control over the material’s barrier properties and breathability.
The most commonly used structure is known as SMS (Spunbond/Meltblown/Spunbond), composed of three distinct layers of polypropylene. The outer spunbond layers provide strength and tear resistance. The inner meltblown layer creates a dense, fine-fibered mesh that functions as the fluid and microbial barrier. This layered construction provides a high level of fluid resistance, often described as having hydrophobic properties.
Variations like SMMMS (Spunbond-Meltblown-Meltblown-Meltblown-Spunbond) incorporate additional meltblown layers to increase barrier protection and thickness. Some lower-level gowns use a simpler construction, such as polypropylene with an added polyethylene (PE) film coating. This coating provides high waterproofing but makes the gown less breathable. The single-use nature of these synthetic gowns ensures consistent barrier performance and eliminates the logistical demands of sterilization.
Reusable Gowns and Traditional Fabrics
While disposable gowns dominate high-risk settings, reusable surgical gowns continue to be used and typically feature traditional woven fabrics. These multi-use gowns are usually made from tightly woven cotton or a blend of polyester and cotton. Woven materials inherently offer comfort and better breathability compared to many synthetic non-wovens.
For a reusable gown to provide adequate protection, the woven fabric must be treated with a chemical finish to enhance its fluid-repellent characteristics. The thread count and density of the weave are important factors in determining the gown’s initial barrier performance. However, the fluid resistance of woven gowns can diminish over time due to repeated cycles of laundering and high-temperature sterilization.
Reusable gowns constructed with a high percentage of polyester often incorporate a small amount of carbon filament to dissipate static electricity. These textiles can maintain their protective properties for a specified number of reprocessing cycles, sometimes up to 75 washings. Modern reusable options utilize specialized dense weaves, such as taffeta, to create a durable, fluid-resistant barrier that allows the fabric to be washed and re-sterilized.
Defining Protective Performance Levels
The barrier performance of any surgical gown is classified using a standardized system developed by the Association for the Advancement of Medical Instrumentation (AAMI). This classification, known as ANSI/AAMI PB70, categorizes gowns into four levels based on their ability to resist liquid penetration in the gown’s critical zones. These critical zones include the entire front of the gown and the sleeves, which are the areas most likely to encounter infectious materials.
Level 1 gowns offer minimal barrier protection, suitable for basic patient care or minimal risk situations where fluid exposure is low. Level 2 gowns provide a low level of fluid barrier protection, often used for procedures involving a slight risk of fluid exposure. The barrier performance for these lower levels is measured using water impact and hydrostatic pressure tests.
Level 3 gowns are necessary for procedures with a moderate risk of fluid exposure, covering the widest range of surgical cases. Level 4 represents the highest level of fluid and microbial barrier protection, reserved for long, fluid-intensive, or high-risk surgeries. Gowns meeting Level 4 standards must pass rigorous testing against viral penetration and synthetic blood, often utilizing reinforced, laminated, or film-coated materials to achieve maximum impermeability.