Level of Risk - Different Mask

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https://healthcentricadvisors.org/wp-content/uploads/2017/04/3_MaskEnomics_Poster_2012.pdf

Ever Wondered Why Surgeons Wear Only Green or Blue Overalls During a Surgery?

Here is the Answer

Every time there’s a surgery, however colorful attire the surgeons may have donned, the moment he or she enters an operation theatre, he wears that same green or blue overalls and the same cap. Wonder why he does that? Well, there are scientific reasons for it.

History Speaks

First, let’s go back to the year 1914.

White overalls of the surgeons during the 1900s

Before the blue or green dress code the surgeons used to wear white clothes during a surgery. However, according to an article published in 1998’s Today’s Surgical Nurse, in 1914 this trend came to an end with the help of a reputed doctor who introduced the green and blue overalls.

Blinding White Overalls

One of the scientific reasons behind the use of green or blue overalls is that surgeons may get blinded by the completely spotless white overalls once they shift their gaze from the dark red color of the blood to the white clothing of his or her colleagues.

One also experiences the same thing when he or she goes outside in winter and sees the sun’s reflection on the snow.  

Surgeons now wear green or blue overalls

Seeing Illusions During a Surgery is a Big 'NO'

The surgeons may also experience certain green illusions after gazing at blood for so long a time. Now, this tends to intensify if his or her co-surgeons wear white overalls as he or she may see distracting green illusions on the white surfaces (quite similar to the after effects of a camera flash). Whereas if it’s a color that is a complete opposite to red then, the illusions are greatly reduced.

Because Green and Blue are the Opposites of Red

While performing a surgery the surgeon mostly sees the color of the blood, tissues and muscles that are red and pink. After a point he is not able to sense the difference between the two as both the colors are associated. But looking at contrasting colors like blue or green helps the doctor to differentiate colors and concentrate on the patient and his or her anatomy.

Visibly Accurate

The green and blue overall, therefore, provides the surgeons with a visual accuracy enhancing their sensitivity to the different shades of red present in the patient’s blood. This not only helps the surgeons to prevent mistakes during surgery but also to pay more attention to their patient’s anatomy. 

thankx. https://www.vaidam.com/ 

Evaluation of surgical masks

Evaluation of surgical masks

In Europe, surgical masks must wear a CE-mark and comply with the requirements defined in EN 14683: Medical face masks - Requirements and test methods.

The standard defines surgical masks as: medical devices, covering the mouth, nose and chin ensuring a barrier that limits the transition of an infectious agent between the hospital staff and the patient.

In respect of the performances, the mask is tested as a final product and has to comply with different requirements.

The classification of the masks is based on the results from the following tests:

• bacterial filtration efficiency (BFE)
• breathability (delta P)
• splash resistance (synthetic blood)
• microbial cleanliness
• biocompatibility

Because surgical masks are considered medical devices of class I, the manufacturer has to run a risk analysis and additional tests if needed to respond to the European Medical Device Regulation 2017/745.

There are no requirements regarding barrier against inert particles.

Evaluation of surgical masks in the US

The FDA (US Food and Drug Administration) is the organism that regulates medical devices on the USA market. Surgical masks are considered medical devices class 2.

The FDA has drafted standards to which manufacturers have to comply in order to receive a licence to sell the products on the market. The same standards apply to surgical masks, procedures, isolation, dental interventions and laser treatments.

The FDA strongly recommends that the manufacturer clearly indicates the use of the product on the package.

The masks are submitted to the same tests as the ones described in the European standard EN14683, except that the FDA also prescribes the measurement of filtration efficiency regaring inert particles (latex) and fire tests.

The US standard ASTM F2100-11 Standard specification for performance of material used in medical face masks describes the tests and requirements with which the materials have to comply that are used to produce the masks. Several tests are not run on the final product, but on the different materials have to be tested together in the way they will be used in the final mask.

The performances of the materials composing the mask are evaluated by five tests :

• bacterial fitlration efficiency
• breathability (delta P)
• splash resistance
• particle filtration efficiency
• fire test

According to the results, the masks are classified in three levels.

Centexbel equipment

Bacterial filtration efficiency (BEF)

Bacterial filtration efficiency (BEF)

The EN 14683 standard method measures the effectiveness of a surgical mask in capturing aerosol droplets containing bacteria. The filtration efficiency depends on the particles or bacteria size, the air flow passing through the mask and the surface properties of the particles.

Principle

A specimen of the mask is inserted between an impactor and the chamber where the bacterial aerosol is produced. The bacterial aerosol (Staphylococcus aureus) arrives in the chamber "aerosol", goes through the specimen and is recuperated on Petri dishes placed in the impactor.
The efficiency of filtration of the mask is given by the percentage of bacteria that are stopped by the mask specimen, compared to a trial performed without specimen.

Depending on the type of facial mask, the required filtering levels are ≥ 95 % or 98%.

Breathability (Delta P)

Breathability (Delta P)

This method measures the pressure drop across a surgical mask under specific conditions of airflow, temperature and humidity. The differential pressure is an indicator of the breathability of the mask, expressed in a differential pressure (∆P) in mm H2O/cm2 or Pascal/cm2.

the differential pressure is an indicator of the breathability of the mask

A differential pressure of viz. < 29,4 or < 49,0 Pascal/cm² is required for surgical masks of Type I and Type II.

The breathability of a surgical mask or its properties to let air through depends on a series of parameters such as the nature of the textile, the applied finish, the number of layers or its thickness.

Splash resistance

Splash resistance

EN 14683 refers to the standard ASTM F1862 9 ‘Resistance of medical face mask to penetration by synthetic blood’.

This test method is used to evaluate the resistance of medical face masks to penetration by the impact of a small volume (~2 ml) of a high velocity stream of synthetic blood. The impact speeds and volumes of synthetic blood are chosen to simulate different scenarios in the operating theatre.

The masks are evaluated at speeds of 450, 500 and 635 cm/s. These speeds correspond to the puncturing of a small blood vessel at a vessel pressure of viz. 10.6, 16 and 21.3 kPa (80, 120 and 160 mmHg).

medical facemask pass/fail determinations are based on visual detection of synthetic blood penetration

Prior to the test, the masks are conditioned over a period of four hours in a very humid environment (85% ± 5% at 21°C ± 5° C) to simulate the conditions of use corresponding to the humidity created by the respiration of the wearer of the mask. Medical facemasks pass/fail determinations are based on visual detection of synthetic blood penetration.

Thankx : Centexbel