The Leaflet Article
An Alternative to the N-95 Face Mask
The Texas Center for Infectious Disease (TCID), the last specialty tuberculosis (TB) hospital left in the nation, has been receiving worldwide attention these days. Staff currently use elastomeric masks as part of its PPE when treating and caring for TB patients. Back in February TCID was part of the operation which helped house patients from multiple cruise ships that landed in San Antonio for care. A combination of the CDC, US Public Health Officials, and the Texas Infectious Disease Response Unit managed the operation while TCID provided the negative air pressure rooms. Since then the word has spread about
TCID’s practices and processes regarding PPE. TCID, part of the Regional Local Health Operations of the Department of State Health Services, is a hospital for patients with TB who are unable to get treatment in the outpatient setting. Some of the reasons for admission include non-compliance with directly observed therapy, side effects to the first line of TB drugs, and drug-resistant TB. TCID admitted 1,212 TB patients from January 2000 to January 2015. One hundred of these patients were multi-drug (MDR) resistant TB patients and 5 were extremely drug-resistant (XDR) TB patients. Infection control measures which included environmental and administrative controls were put in place after it was found that a patient with drug-resistant TB had infected another patient admitted at the hospital. Only surgical masks were used before 1995 but once the respiratory protection program was implemented in 1996 as part of the infection control plan, TCID selected elastomeric masks over N95 masks based on durability and comfort, better respiratory protection, cost-effectiveness and less time consumption for fit testing.
The specific masks used are the North 7700 half-face respirators made of 100% silicone which is durable and has a comfortable cradle suspension system that sits securely on the head to provide an even seal. There is an exhalation valve that reduces excessive dampness and warmth in the mask from exhaled breath. According to the National Institute for Occupational Safety and Health (NIOSH), the North 7700 respirator used with a P100 filter provides better respiratory protection (99.97%) than an N95 mask (95%) against airborne particles. The protection provided by a mask depends on other factors such as the filter type, face seal fit, the velocity and number of particles that reach the mask, the charges on the filter, and the conditions in which a particular mask is used. Employees can also check if the elastomeric mask fits properly each time it is put on by performing a simple test called a positive or negative pressure seal test. Just to give you an idea of how well the masks work, no employee has converted from a negative to a positive TST since the use of elastomeric masks was instituted at TCID.
Elastomeric masks could offer one solution to hospitals to help fill the worker-protection gap left by the N95 shortage during the current pandemic. There are both advantages and disadvantages to the use of elastomeric masks vs. N95 masks. TCID’s experience with the elastomeric mask in TB patients has been excellent; however, the route of spread of TB is primarily airborne. As TCID’s Medical Director, Dr. Annie Kizilbash, states, “The SARS- COV2 may also spread partly through the airborne route in addition to droplets. Spread through droplets in all likelihood plays a more important role, other than in certain situations which increase the risk of aerosolization such as intubation and sputum induction. It is also important to note that NIOSH testing of respirators is based on 0.3 um particles and M.tuberculosis varies in length from 2-4 um in length and 0.2-0.5um in width while a coronavirus is on average 0.1 um in size.” In the absence of adequate disinfection, the elastomeric masks could become a fomite and a source for the spread of infection from one patient to another and a provider. It is recommended that the mask be disinfected between each patient interaction. When properly used, the elastomeric respirator can prove to be useful during a pandemic and the advantages in terms of respiratory protection and cost-effectiveness exceed the disadvantages. An elastomeric respirator, if cared for properly, can last for years and filters only changed out once a year unless wet or soiled. The average cost for an elastomeric respirator and filter is now $46. An N95 mask is now as high as $7 per mask and must be discarded after one use. This is much more cost-effective than using N95s. One important factor to keep in mind though is that an elastomeric mask does not protect a patient from asymptomatic spread from a healthcare worker due to the exhalation valve that exists on the mask. One way to correct this is to place a surgical mask underneath or over the elastomeric mask.
TCID’s lead respiratory technician, Salena DeAnda, has been overwhelmed with national and international inquiries regarding the use of elastomeric masks. She gracefully takes time to respond to each inquiry by providing a detailed letter and attachments which includes an operating and maintenance instruction manual on the North 7700 respirator; cleaning procedures; a medical evaluation questionnaire; recommendations for maintaining an employee database; step by step instructions with visuals included on how to fit the respirator; and even an approved list of facial hair as per OSHA, NIOSH, and CDC.
The Department of State Health Services hopes that this information is useful to you and your clients. Architects, engineers, and designers part of the Healthcare Facilities Symposium Community, can share this information with its hospital owners through the TCID website at https://www.dshs.texas.gov/tcid/Respiratory-Protection-FAQs/