From ZERO- to HERO! The Lowly and Taken For-Granted… Surgical Mask…

Editor’s Note:

I have put people on bypass at 54 hospitals. I have worked as a surgical first assistant in another 10 hospitals – and in the operating room theater of at least five military hospitals.

I won’t even begin to try to count the days, hours, or the number of operations that this implies, but I’m pretty sure it adds up to an incredible number of disposable surgical masks.

By my estimate, during routine day in the operating room involving a single uncomplicated open heart operation, I would say I go through at minimum 5 to 10 masks in roughly an eight hour period. Typically one for setting up, changing masks if I leave the OR to go to the cafeteria, changing masks if I have gone to the staff lounge for coffee, changing masks simply because they tore or didn’t feel/fit right, the occasional sneeze in the mask or cough, is definitely a mask change out event, because both situations are gross, your mask is wet thus compromised, and did I say it’s gross?  Or tearing it off when I leave the OR- just because it feels good to be released from wearing it for a few minutes.

So when I showed up this morning to find no masks at the scrub sinks outside our room, I looked to the next operating room and noticed that there were no masks anywhere to be found. I had been in this same OR until 4 PM the day before, and every single scrub sink had boxes of at least eight different styles of masks to choose from. All masks had  been removed sometime in the PM or during the night.

At approximately 7 o’clock in the morning, in a central area outside of the operating rooms, the director of perioperative services was handing out masks with very serious look of concern and worry on his face. He’s usually a stern man to begin with, but there was a look there that clearly implied that we were in uncharted waters. He was almost hesitant as he told me that I would only have one mask for the entire day, and if possible keep it in my locker for use on the next day.  It was pretty clear from the way he presented this new mandate- that he in his heart-of-hearts (no pun) knew- that this was just NOT the right way to go about this.

So I wore that mask from 7 AM to 3:30 PM, during which we performed very complex combined open-heart procedure. Since I don’t have a locker at this hospital, as I am a locums here, I put that tired overused mask into a drawer in our office, on the off chance that I would be able to find one in the middle of the night for an emergency heart.

I was shocked we were so low on masks- because I cover 5 hospitals in this region- and there really wasn’t any surge or uptick in our surgical caseload at any of those hospitals- so that implies that  increased demand was not the issue.  Employee hording or theft?  NOT A CHANCE.  These are good people that are too strong willed and straight up to degrade themselves like that.  Professional pride supersedes silly tunnel visioned panic.

I’m assuming there is a supply chain disruption closer to the manufacturing side of things- where either a delivery issue- or a materials shortage issue.  It’s possible a portion of the manufactured masks were being siphoned off to other vendors- but not enough to so immediately and abruptly affect our availability so quickly.

I included a few articles below- the most significant is the study suggesting that:

after 150 minutes of wearing the same mask-

you might as well not be wearing one at all-

based on it effectiveness in subverting bacterial communication past the mask!

Let’s Get Past This  🙂

Pump Strong (bcf)

Frank

Bottom Line:  After 150 minutes- Fabric Face Masks are useless in terms of containing bacteria.

=

Bottom Line:  After 150 minutes- Disposable Face Masks are useless in terms of containing bacteria.

Click on Image Above to Read Source Article

Abstract

This study was conducted to check the efficacy of face masks in limiting bacterial dispersal when worn continuously in Operation Theater. A comparison was done to find out difference between fabric and two ply disposable masks. The first sample was collected prior to wearing the mask, using cough plate method holding a blood agar plate approximately 10 -12 centimeters away from the mouth. the personnel were asked to produce “ahh” phonation. Participants were then asked to don the face mask, continue routine work and report to the study center located inside the theater for further sample collections at designated intervals of 30, 60, 90, 120 and 150 minutes after wearing the fabric mask made of cotton. the study was replicated on immediate next day using two ply disposable mask keeping all the other conditions and personnel exactly the same. Bacterial counts before wearing the mask were 5.36±4.38 and 5.7±2.99 on day 1 and day 2 of study. Bacterial counts were 0.96±1.06 (P<0.001) and 0.7±0.87 (P<0.001) at 30 min; 2.33±1.42 (P<0.001) and  2.36±1.03

(P<0.001) at 60 min;   3.23±1.54 (P=0.007) and 4.16±1.78 (P=0.011) at 90 min; 5.63±4.02 (P=0.67) and

4.9±1.98 (P=0.161) at 120 min and 7.03±4.45 (P=0.019) and 5.6±2.21 (P=0.951) at 150min respectively for fabric and two ply disposable mask. Counts were near pre-wear level in about two hours irrespective of the type of mask. There was no significant difference between cotton fabric and two ply disposable masks.

Face masks significantly decreased bacterial dispersal initially but became almost ineffective after two hours of use.

OSHA Issues Guidance for Stockpiling Masks and Respirators

By Eric Toner, M.D., May 30, 2008

The Occupational Safety and Health Administration (OSHA) recently proposed guidance for employers to use in determining the numbers of masks and respirators to stockpile for an influenza pandemic.1 OSHA’s guidance addresses the various levels of respiratory risk that employees may face and the type of protection needed at each level. The guidance also addresses methods for calculating the required numbers and costs to stockpile masks and respirators. While not obligatory, this guidance should prove useful to hospital pandemic planners in making informed decisions about stockpiling.

Respirators for High Exposure Risk Groups; Face Masks for Medium Exposure Risk Groups

OSHA’s proposed guidance describes the types of masks or respirators needed by various healthcare workers (HCW) based on their exposure risk. Most HCWs are at high or very high risk of exposure and should use a respirator instead of a mask for protection. Respirators should be rated N95 or higher and can be any one of several types, including a common disposable N95 filtering face piece, a surgical respirator, a reusable elastomeric (flexible rubber) respirator, or a powered air purifying respirator (PAPR). HCWs with limited exposure to patients may fall in the medium risk category; for this group, a surgical mask is appropriate protection. Also noted is the need to provide masks for essential visitors, such as parents of small children and patients with flu-like illnesses in the emergency department and waiting rooms. A comparison of the advantages, disadvantages, and relative costs of the various types of respirators and masks is included.

OSHA Provides Methods for Estimating Stockpile Numbers and Costs

The guidelines provide estimates of the number of respirators or masks needed per HCW, expressed as masks per shift. With these estimates, along with assumptions about the duration, attack rate, and severity of an epidemic, a planner can calculate the number and cost of masks and respirators needed to protect HCWs.

Interestingly, the analysis of the cost to protect one HCW at high risk of exposure reveals that it may be far less expensive in the long run to stockpile more expensive reusable elastomeric respirators than it would be to stockpile inexpensive disposable N95 filtering face pieces. And both of these options are less expensive than PAPRs. The calculation assumes two 12-week pandemic waves, during which time the HCW could be expected to use:

  • 1 PAPR with spare hoods, batteries, and filters for $330 total;
  • 480 N95 filtering face pieces @ $.50/each for $240 total; or
  • 1 reusable elastomeric respirator every day with periodic filter changes for $40 total.
OSHA Guidelines and Hospital Data Will Support Informed Decisions about Stockpiling

Since re-supply during a pandemic may be difficult or impossible, stockpiling critical supplies such as masks and respirators is important. This guidance, used in conjunction with a hospital’s actual data on cost of respirators and masks and numbers of staff, along with credible assumptions about numbers of pandemic patients, will allow hospital pandemic planners to make informed decisions about stockpiling.

Reference

U.S. Department of Labor, OSHA. Proposed Guidance on Workplace Stockpiling of Respirators and Facemasks for Pandemic Influenza. May 12, 2008. https://www.osha.gov/dsg/guidance/proposedGuidanceStockpilingRespirator.pdf. Accessed May 28, 2008.

Introduction

In the era of cost constraints, shrinking hospital budgets and evidence-based medicine, many health-care professionals have begun re-examining traditional infection control practices. There has been much debate about whether the wearing of surgical facemasks (SFMs) in the operation theatre (OT), distinct from respiratory protective devices (RPDs), is an effective practice to prevent surgical site infections (SSI) or is just a habit that has no basis in fact.

SFMs vs. RPDs

RPDs are masks which are certified as personal protective equipments (PPE) under the European Directive 89/686/EEC (PPE Regulation 2002 SI 2002 No. 1144). These provide a high level of filtering capability and face-fit and are recommended particularly for people in the healthcare sector dealing with symptomatic patients where aerosols are likely to be generated (e.g. at times of influenza epidemic) [].

Face masks, on the other hand, can be labelled as surgical, laser, isolation, dental or medical procedure masks. SFMs are plain masks that cover the nose and mouth and are held in place by fabric ties or with elastic straps around the ears. These are available in two configurations, molded cup shape with an elastic cord around the head and non-molded which may be further available as a pleated or a flat-paper shield with two ties or ear loops. There may or may not be a flexible nose bridge. Furthermore, pleats can be either two ply or three ply. General purpose SFMs are usually two ply, designed mainly to capture respiratory secretions (including bacteria and viruses) in exhaled breath rather than to protect operators from airborne infections. These are not designed to prevent inhalation of airborne particles and their ability to prevent disease acquisition varies. The three ply SFMs usually have > 99% bacterial filtration efficacy and are one step short of respirators on this account [].

Specifications of SFMs

The material used by disposable SFMs has to be adequate to hold back air-borne contaminates which include, but are not limited to, biological contaminates, such as bacteria, viruses, fungal spores, lint, mineral fines, dust, skin squames and respiratory droplets expelled from the mouth and nose. It also should minimize condensation of moisture within the mask. Specifications developed by the American Society of Testing and Materials (ASTM) are generally accepted as the industry standard and include the following:

  • a.  Bacterial Filtration Efficiency (BFE) which specifies the percentage of 3.0 microns sized aerosols containing Staphylococcus aureus sized 0.8 microns which are filtered out.
  • b.  Particulate Filtration Efficiency which specifies the percentage of aerosols of particle size 0.1-5.0 microns which are filtered out.
  • c.  ‘Separating’ Efficiency tested for both solid (sodium chloride) and liquid particles (paraffin oil) which is denoted by either of the two letters, ‘P’ or ‘N’. Swedish and European standards (SS-EN) use the letter ‘P’ – P3 separating 99.95% and P2 94.0% of both solid particles and oil mist. American standards use the designation ‘N’ which indicates that these have not been tested for liquid particles – N95 is presumed to separate 95% of solid particles only.

Collectively, these three tests measure the filtering capacity for bacteria, viruses and other sub-micron particles [].

Other tests which have a bearing on the acceptability of SFMs include the Pressure Differential (Delta-P) which measures the air flow resistance of masks and is an objective measure of ‘breathability’. A Delta-P over 5.0 is uncomfortable for general use, whereas a masks with a Delta-P under 2.0 allows air movement across but is less effective. The Fluid Resistance (FR) reflects the mask’s ability to transfer fluids from the outer layers to the inner layer as the result of a splash or spray. ASTM specifies testing with synthetic blood at pressures of 80, 120 or 160 mm of Hg to qualify for low, medium or high fluid resistance [].

The general recommended wearing time for an ASTM-certified SFM is four hours []. SFMs become less effective over time. A fresh face mask almost completely prevented bacterial contamination of an agar plate 30 cms from the mouth, but after 15 minutes there was a measurable increase in the level of contamination []. This time is further reduced if SFMs are poorly fitted, placed below the nose or wet with blood or body fluids [].

Disposable SFMs can inherently contribute to contamination of the surgical wound by increasing OT germ concentration and wound contamination by ‘venting’ (air leaks from the side of the mask due to insufficient tension on the strings) and wicking(conveying liquid, via capillary action, from behind the mask). In addition, skin scales also frequently rub off the face due to friction (‘wiggling’). The quantity of germ concentration is altered by both facial hair and recent shaving [].

SFMs however, do protect the wearer from splashes. Masks with face shields and/or protective eyewear are recommended whenever splash, spray or aerosol of blood or other potentially infectious materials may be generated []. When SFMs were placed on the patients’ mouths while undergoing surgery, a lower incidence of SSI have been variously reported. However, this practice is disadvantageous for patients undergoing regional anaesthesia where deficient assessment of lip cyanosis, anxiety, retention of carbon-dioxide and increase in cost restricts the use. It may also be difficult to obtain a good fit with SFMs with an endotracheal tube in situ []. Eitherway, during general anaesthesia, higher airborne germ concentration has been detected but this has been attributed to higher activity and number of staff involved causing more air turbulence.

A recent Cochrane review did not report any difference in SSI rates on wearing SFMs or not, whether disposable or cloth. But the limited number of trials in the review makes it unsafe to draw definitive conclusions []. It is very difficult to perform controlled research on the effects of wearing surgical masks on wound infections as investigators may be hesitant due to the potential harm to patients if a mask is not worn.

Centre for disease control (CDC) guidelines for isolation precaution in hospitals recommend the concomitant use of a mask and respirator as a two tier precaution to help prevent two way transmission of infections between patients and staff in the OT from both recognized and unrecognized sources []. There is little evidence however that the current generation synthetic SFMs, when used alone, protect the staff either from airborne bacteria or Hepatitis B virus or reduce SSI [].

Current recommendations

While guideline for prevention of surgical site infection (1999) [], strongly recommended the use of SFMs for prevention of SSI, the 2007 CDC guideline [] reiterated the use of different qualities of SFMs for sterile procedures and otherwise without adding any new scientific data for support of the recommendation. Most international guidelines acknowledge the controversy surrounding the use of disposable SFMs [] with no clear clinical and experiential evidence that wearing SFMs may decrease the incidence of SSI, which itself depends on several variables, especially patient’s immunological status and behavior of the surgical team in the operating field. SFMs with 95% BFE are efficient microbial barriers up to wearing time (4 hours) and therefore, should be made mandatory in the following circumstances:

  • Within 3 m of the sterile zone (Putsep Zone I), particularly when the face is in close proximity to the operative field and/or the need for speaking is anticipated.
  • If the patient has risk factors for a blood borne infection [].
  • By anaesthesiologists when carrying out sterile procedures under full aseptic conditions [].
  • While carrying out procedures that generate splashes or sprays of blood, body fluids, secretions, or excretions (e.g. endotracheal suctioning, bronchoscopy, invasive vascular procedures etc).

SFMs should also be standard wear for patients. Non-scrubbed staff need not wear SFMs in OTs with forced ventilation [].

Correct technique for use of SFMs

These should cover both the nose and mouth completely, assuring no tenting at the sides to allow dispersion of microbes. A mask should never be allowed to hang or dangle around the neck, nor should it be folded and placed in a pocket for later use. Masks should be either on or off. If the mask cannot be easily re-adjusted or becomes wet by overt breathing or fluid insult, it should be replaced immediately as the filtration efficiency and protective ability of SFMs is compromised when the mask becomes wet, torn or dislodged. Removal of the mask by grasping the filter-section (pleats) could result in contamination of the wearer’s hands. Disposal is recommended by handling the tapes only [].

Recommendations for procurements

Three ply SFMs with a small pliable strip at the nose area should be preferred. The mask material should have high separating/filtering efficiency (>99% and N95) with a Delta-P between 2.0-5.0 and a medium-high FR. Masks with different fluid resistant properties can be procured as per risk of exposure to blood, body fluids, excretions and other potential hazards as well as degree of sterility and isolation required.

All health care workers must be aware of the potential risk of exposure as well as protective capabilities of the mask being worn.

Conflicts of Interest

None identified

References
1. World Health Organization (WHO) Practical Guidelines for Infection Control in Health Care Facilities. 2005. []
2. Pratt RJ. National Evidenced-based guidelines for preventing healthcare-associated infections in NHS hospitals in England. J Hosp Infection. 2007;65:1–64. [PubMed[]
3. Standard specification for performance of materials used in medical face masks F2100-04. Standard test methods: F2299-03, F2101-01, F1862-00a. 2006. American society of testing and materials (ASTM) []
4. Lipp A, Edwards P. Vol. 1. 2002. Disposable surgical face masks for preventing surgical wound infection in clean surgery. (Cochrane Database of Systematic Reviews). CD002929. DOI: 10.1002/14651858.CD002929. [PubMed[]
5. Davis PJ, Spady D, Forgie SE. A survey of Alberta physicians’ use of and attitudes toward face masks and face shields in the operating room setting. Am J Infect Control. 2007;35:455–459. [PubMed[]
6. Romney MG. Surgical face masks in the operating theatre: reexamining the evidence. J Hosp Infect. 2001;47:251–256. [PubMed[]
7. The Association of Anaesthetists of Great Britain and Ireland Guidelines. Infection Control in Anaesthesia. 2008;63:1027–1036. [PMC free article] [PubMed[]
8. Hebl JR. The importance and implications of aseptic techniques during regional anaesthesia. Reg Anaesth Pain Med. 2006;31:311–323. [PubMed[]
9. Centres for Disease Control (CDC). Guideline for isolation precautions: preventing transmission of infectious agents in healthcare settings. Available at http://www.cdc.gov/ncidod/dhqp/pdf/isolation 2007; 52. [PubMed]
10. Vol. 20. 1999. Centres for Disease Control (CDC) p. 262. (Guideline for the prevention of surgical site infection). []

Articles from Medical Journal, Armed Forces India are provided here courtesy of Elsevier

 

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