Surgical clothing and drapes EN 13795

EN 13795-1: Surgical clothing and drapes - Requirements and test methods - Part 1: Surgical drapes and gowns (2019)

General

Surgical drapes, including the intended use as a sterile field, and surgical gowns are used to minimize the spread of infective agents to and from patients’ operating wounds, thereby helping to prevent postoperative wound infections.

The performance required of coverings for patients, clinical staff and equipment varies with, for example, the type and duration of the procedure, the degree of wetness of the operation field, the degree of mechanical stress on the materials and the susceptibility of the patient to infection.

The use of surgical gowns with resistance to the penetration of liquids can also diminish the risk to the operating staff from infective agents carried in blood or body fluids.

Critical – less critical areas

Performance requirements are specified depending on product area and performance level.

Critical product area: area with a greater probability to be involved in the transfer of infective agents to or from the wound, e.g. front and sleeves of surgical gowns. The other areas are called “less critical product area”. EN 13795 does not include provisions for the size and position of critical and less critical areas. The user has to decide whether these are suitable to meet the anticipated challenges of a certain surgical procedure.

The American standard ANSI/AAMI PB70 provides more specifications: the critical zone of a surgical gown shall, at a minimum, comprise the front area of the gown from chest to knees and the sleeves from the cuff to above the elbow.

For drapes the identification of critical product area is not mentioned in the standards, but in literature it is mentioned: “The critical zone is usually the centre of the drape, around any fenestrations or openings. This area is often reinforced with additional fabric, which may be fluid absorbent”

If the manufacturer does not differentiate product areas, all areas shall meet the requirements for critical product areas. If there is such differentiation, the manufacturer must supply the information to allow identification of these areas by the user.

The manufacturer must provide information on the performance level to the user.

Characteristics to be evaluated and performance requirements for surgical gowns & drapes

• The biocompatibility of the product shall be evaluated and approved for acceptable risk
• Information on the flammability of the product and fire risks must be provided by the manufacturer on request.
• testing according to EN 13795: Summary see table below
• CA = critical product area
• LCA = less critical product area
• IB = Barrier index

Microbial penetration - dry:

• determine the ability of dry fabric to resist penetration of particles carrying micro-organisms.
• Measure: CFU = number of colonies formed after incubation
• Result: only required for the less critical areas: ≤ 300

Microbial penetration – wet

• Determine a fabric’s resistance to penetration of bacteria in liquid while being subjected to mechanical rubbing
• Measure: number of colonies formed after incubation, expressed in barrier index (BI) 6,0 = no penetration (maximum achievable value)
• Result: only required for the critical areas: ≥ 2.8 (standard performance) or ≥ 6.0 (high performance)

Cleanliness microbial / bioburden

• Estimate the bioburden or number of viable micro-organisms on the fabric prior to sterilization.
• Measure: CFU = number of colonies formed / dm²
• Result : ≤ 300 / dm² for all areas, gowns & drapes (based on the experience of manufacturers and what is routinely available)

Particle release

• = release of fiber fragments and other particles during mechanical stress simulating handling and use. Estimate linting of the fabric in a dry state. Particle release is a concern during surgery: foreign body contamination can cause an increased frequency of postoperative complications. An indirect effect is also observed: fibres and particles can deposit on surfaces in the operating room providing a potential vector for microorganisms to be carried into wounds. Particles smaller than 3µm are too small to carry microorganisms and particles larger than 25µm are too large to remain airborne because of gravity.
• Measure: number of particles 3 – 25 µm generated after twisting ad compressing, expressed as log10 of the count value.
• Result: ≤ 4 for all areas, gowns & drapes

Liquid penetration

• = hydrostatic head test: estimate the resistance of fabrics to liquid penetration by water under constantly increasing hydrostatic pressure
• Measure: the head height results are recorded in centimetres of water pressure on the fabric sample.
• Result:
• less critical areas: ≥ 10 cm H₂O
• critical area standard performance: gowns: ≥ 20 cm H₂O, drapes: ≥ 30 cm H₂O
• critical area high performance: ≥ 100 cm H₂O for gowns & drapes

Bursting strength - dry / wet

• Determine the resistance of a fabric to puncture under dry & wet conditions
• Measure: strength at burst, in kPa
• Results: gowns & drapes: ≥ 40 kPa, not required for the less critical area in wet state

Tensile strength - dry / wet

• Determine the ability of a product to withstand fabric tearing under dry and wet conditions
• Measure: amount of force applied to break the strip, in Newton
• Results (not required for the wet less critical areas)
• gowns: ≥ 20 N
• drapes: ≥ 15 N (standard performance) or ≥ 20 N (high performance)

Guidance for selecting products

Comfort is based on several factors: thermal resistance, air permeability, drapeability, stretchability, weight, size, fit, tactile comfort (softness = highly dependent on fibre smoothness and finish technologies), fibres and manufacture. Discomfort properties such as rustling tendency and skin irritation are difficult to measure.

The standard does not provide further essential requirements regarding flammability. However, manufacturers are required to supply information regarding fire risks in relation to the use of their products.

Specific tests for electrostatic discharge (ESD) re not required as no reports were made of patient safety incidents related to ESD.

EN 13795 does not specify requirements for the functional design of surgical gowns & drapes.

The products should be tested practically in clinical situations where the end-user is going to apply them, to ensure that they are suitable from all important aspects including functionality and comfort. The practical trials should be evaluated before choice of products.