Scalable in-hospital decontamination of N95 filtering face-piece respirator with a peracetic acid room disinfection system

BACKGROUND

Critical shortages of personal protective equipment, especially N95 respirators, during the coronavirus disease 2019 (COVID-19) pandemic continues to be a source of concern. Novel methods of N95 filtering face-piece respirator decontamination that can be scaled-up for in-hospital use can help address this concern and keep healthcare workers (HCWs) safe.

METHODS

A multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≥6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency. PAA and hydrogen peroxide off-gassing from treated masks were also assessed.

RESULTS

The PAA room HLDS was effective for disinfection of bacteriophage MS2 and G. stearothermophilus spores on respirators in a 2,447 cubic-foot (69.6 cubic-meter) room with an aerosol deployment time of 16 minutes and a dwell time of 32 minutes. The total cycle time was 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA and hydrogen peroxide from the treated masks at 20 and 60 minutes after the disinfection cycle, respectively.

CONCLUSION

The PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators during the COVID-19 pandemic.

Scalable in-hospital decontamination of N95 filtering face-piece respirator with a peracetic acid room disinfection system

BACKGROUND

Critical shortages of personal protective equipment, especially N95 respirators, during the coronavirus disease 2019 (COVID-19) pandemic continues to be a source of concern. Novel methods of N95 filtering face-piece respirator decontamination that can be scaled-up for in-hospital use can help address this concern and keep healthcare workers (HCWs) safe.

METHODS

A multidisciplinary pragmatic study was conducted to evaluate the use of an ultrasonic room high-level disinfection system (HLDS) that generates aerosolized peracetic acid (PAA) and hydrogen peroxide for decontamination of large numbers of N95 respirators. A cycle duration that consistently achieved disinfection of N95 respirators (defined as ≥6 log10 reductions in bacteriophage MS2 and Geobacillus stearothermophilus spores inoculated onto respirators) was identified. The treated masks were assessed for changes to their hydrophobicity, material structure, strap elasticity, and filtration efficiency. PAA and hydrogen peroxide off-gassing from treated masks were also assessed.

RESULTS

The PAA room HLDS was effective for disinfection of bacteriophage MS2 and G. stearothermophilus spores on respirators in a 2,447 cubic-foot (69.6 cubic-meter) room with an aerosol deployment time of 16 minutes and a dwell time of 32 minutes. The total cycle time was 1 hour and 16 minutes. After 5 treatment cycles, no adverse effects were detected on filtration efficiency, structural integrity, or strap elasticity. There was no detectable off-gassing of PAA and hydrogen peroxide from the treated masks at 20 and 60 minutes after the disinfection cycle, respectively.

CONCLUSION

The PAA room disinfection system provides a rapidly scalable solution for in-hospital decontamination of large numbers of N95 respirators during the COVID-19 pandemic.

Antimicrobial Activity of Silver Containing Crosslinked Poly(Acrylic Acid) Fibers

Bacterial and fungal pathogens have caused serious problems to the human health. This is particularly true for untreatable infectious diseases and clinical situations where there is no reliable treatment for infected patients. To increase the antimicrobial activity of materials, we introduce silver nanoparticle (NP) patches in which the NPs are incorporated to the surface of smooth and uniform poly(acrylic acid) (PAA) nanofibers. The PAA nanofibers were thermally crosslinked with ethylene glycol via heat treatment through a mild method. The characterization of the resulting PAA-silver NP patches was done using scanning electron microscopy (SEM), UV spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). To demonstrate the antimicrobial activity of PAA, we incorporated the patches containing the silver NPs into strains of fungi such as Candida albicans (C. albican) and bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA). The PAA-silver fibers achieved zones of inhibition against C. albicans and MRSA indicating their antimicrobial activity against both fungi and bacteria. We conclude that silver NP patches exhibited multiple inhibitory actions for the interruption and blockage of activity fungal and bacterial strains, which has the potential as an antimicrobial agent in infectious diseases. Moreover, the proposed material has the potential to be used in antimicrobial textile fabrics, food packaging films, and wound dressings.

A comparison of a new two-layer anatomic repair to the traditional shouldice herniorrhaphy

Since 1976, the Shouldice repair has been the herniorrhaphy of choice at the Veterans Administration Medical Center, Augusta, Georgia. The authors previously reported their experience with this technique, and their recurrence rate of 1.8 per cent was consistent with the experience of the Shouldice clinic. It is often difficult to obtain adequate tissue for a four-layer repair in patients with recurrent hernias or in those patients with large direct or indirect inguinal hernias. In these instances, a two-layer running closure similar to the Shouldice was performed, but the shelving edge of the inguinal ligament was sewn to the conjoined area in one layer and then the fascia of the internal oblique to the inguinal ligament in the second layer. To obtain an estimate of the recurrence rate with this modification, the authors reviewed their herniorrhaphy experience from 1984 to 1988. During this period, 420 herniorrhaphies were performed. Two hundred twenty-six patients were available for follow-up. Of this group, 154 patients had a traditional four-layer Shouldice repair; there were two recurrences in this group (1.2%). Seventy-two patients underwent the described two-layer repair; there were no documented recurrences in this group. Based on this experience, the authors believe that the described running two-layer herniorrhaphy is a valuable alternative when the tissue is inadequate to allow a traditional Shouldice repair. This procedure has now become the authors' method of choice for the majority of repairs.

Shouldice hernia repair: results at a teaching institution

Authors with wide experience report that the Shouldice technique for repair of inguinal hernia is very effective. The technique has not gained widespread acceptance or notoriety. For example, the 13th edition of Textbook of Surgery, edited by Sabiston, devotes only one paragraph to this type of herniorrhaphy. Because of the excellent results reported by the Shouldice Clinic, this technique was adopted at the Augusta Veterans Administration Hospital, a teaching hospital of the Medical College of Georgia. Since 1976, a total of 604 Shouldice repairs have been performed by supervised house staff; 468 patients have been followed for up to 8 years and a recurrence rate of 1.3 per cent is reported. Although the follow-up is brief, the Shouldice hernia repair is widely applicable and good results are not dependent on wide experience alone.

Relative frequency of ultrasound diagnoses in patients referred for ophthalmic ultrasound

An ultrasound diagnostic coding system was developed that permitted entry of diagnoses into a programmable calculator, thus permitting rapid information retrieval of patients with a specific diagnosis or diagnoses as well as the number of patients with a specific diagnosis. Cataract, vitreous opacity, trauma, choroidal disease, and retinal detachment were the most common diagnoses made. Only 7.2% of the patients had a normal ultrasound, indicating that ultrasound examination is a test probably underutilized by ophthalmologists.

Pacinian corpuscle neuroma of digital nerves

Symptoms and incapacitation due to abnormal aggregations of pacinian corpuscles are uncommon. Indeed, only three reports have been found in the scientific literature. A case is presented in which the patient's chief complaint was pain and localized tenderness in the hand which interfered with normal activity. Surgical exploration of the palm showed abnormalities of pacinian corpuscles attached to the median digital nerve in the form of a grape-like cluster and a single enlarged corpuscle beneath the epineurium; the abnormality attached to the ulnar digital nerve appeared as an offshoot of hyperplastic corpuscles lying in tandem. The abnormal corpuscles were excised. The symptoms have not recurred to date. These abnormalities in size, position, and number of pacinian corpuscles are compared to the findings of the few other reports in the literature. The neuroma formation found attached to this ulnar nerve has not been cited previously.