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Armijo et al.2525. Armijo PR, Markin NW, Nguyen S, et al. 3D printing of face shields to meet the immediate need for PPE in an anesthesiology department during the COVID-19 pandemic. Am J Infect Control. 2021;49(3):302-8. PMID: 32763350; https://doi.org/10.1016/j.ajic.2020.07.037. https://doi.org/https://doi.org/10.1016/...
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United States
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Laboratory. |
The experiments were repeated five times on the face shield (headband, headpiece, facial shield) and organism (Escherichia coli, Staphylococcus aureus), thus making a total of 30 experiments, not including positive and negative controls. |
In total, 112 face shields (the solid headband and the chin protector part of the face shield) were printed in 3D on the FDM platform because they were more accessible and easier to use for non-industrial applications. Diluted bleach solution was used for decontamination. Escherichia coli and Staphylococcus aureus were selected as Gram-negative and Gram-positive model organisms. |
Face shields were useful and inexpensive. The efficacy of the decontamination protocol against Escherichia coli was greater than that of Staphylococcus aureus. E. coli was observed on facial protection, Staphylococcus aureus was detected on facial protection and on the chin. No organisms were recovered from the head bands. The decontamination protocol was highly effective against Escherichia coli and Staphylococcus aureus, achieving a reduction ≥ 4 log 10 (99.99%) in colony counts for each repeat. Face shields formed a barrier against soiling of N95 face masks and were more effective for eye protection from respiratory droplets than standard eye shields. Implementation of decontamination protocols successfully allowed face shield and N95 mask reuse, thus enabling a higher level of protection for anesthesiology providers at the onset of the COVID-19 pandemic. |
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Arumuru et al.2424. Arumuru V, Pasa J, Samantaray SS. Experimental visualization of sneezing and efficacy of face masks and shields. Phys Fluids (1994). 2020;32(11):115129. PMID: 33244217; https://doi.org/10.1063/5.0030101. https://doi.org/https://doi.org/10.1063/...
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India
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Laboratory, using a standard mannequin in a controlled environment. |
Homemade cotton mask, surgical mask, N95 mask and a nostril of a mannequin. |
Homemade masks, N95 masks and surgical masks, and a 30,000 Reynolds pulsed jet sneeze simulator. Trace particles were introduced into the stream to capture the emulated turbulent jet formed due to a sneeze. Compressed air and a solenoid valve were also used. A laser camera and lighting were set up. |
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A homemade three-layer mask was suitable for preventing penetration of fine-sized particles, but in a sneeze, these can travel up to 45.7 cm.
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With a surgical mask, the sneeze particles can travel up to approximately 76.2 cm and with a surgical mask plus a face shield the spread of the particles become greater, by traveling 12.2 cm.
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An N95 mask blocks sneezing in the forward direction; however, leakage from the sides and top spreads the sneeze backwards over a distance of up to approximately 60.9 cm. None of the measures adopted, such as homemade two- and three-layer masks, standard three-layer surgical masks and face shields effectively blocked the escape of particles ejected during sneezing. Protective measures effectively reduced leakage and diminished the sneeze range to between 30 and 90 cm.
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Chaturvedi et al.77. Chaturvedi S, Gupta A, Krishnan SV, Bhat AK. Design, usage and review of a cost effective and innovative face shield in a tertiary care teaching hospital during COVID-19 pandemic. J Orthop. 2020;24(21):331-6. PMID: 32753794; https://doi.org/10.1016/j.jor.2020.07.003. https://doi.org/https://doi.org/10.1016/...
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India
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Cross-sectional study analyzing the characteristics of 3D printed face shields. |
227 healthcare professionals. |
Face shield produced by 3D printer. |
Orthopedic surgeons reported that the face shield was useful during screening tasks, in which the interactions with patients involved wound care, immobilization and application of traction. In the wards and in the ICU, all groups of healthcare professionals found that face shields with soft PVC film were effective during airway management and other aerosol-generating procedures, as they could insert the PVC film visor into the PPE gown to provide complete closure of the facial region, although with an opening at the top for ventilation. Development of face shields with participation by healthcare professionals increased their acceptability and effectiveness. Use of face shields was effective in screening and treatment situations, with the ability to vary the configuration of the device. Cost-efficacy, ergonomics, reuse and acceptance were evaluated among orthopedic surgeons and emergency medicine personnel and positive feedback was obtained in relation to all variables considered. |
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Chow et al.2323. Chow VLY, Chan JYW, Ho VWY, et al. Tracheostomy during COVID-19 pandemic-Novel approach. Head Neck. 2020;42(7):1367-73. PMID: 32358855; https://doi.org/10.1002/hed.26234. https://doi.org/https://doi.org/10.1002/...
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China
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Cross-sectional study in a real environment. |
Five patients without clinical evidence of COVID-19 underwent tracheostomy. Two horizontal anesthetic screens and a transparent sterile plastic sheet (plastic curtain) over a tracheostomy operative field were used. |
Presence or absence of droplet contamination on the five plastic sheets used (plastic curtain) during the procedures and on the surgeon’s face shield and instrumentation. |
All five sheets were contaminated with droplets of 0.2 to 2.8 mm. Droplet contamination was most severe on the central surface at 91.5% (range: 86.7%-100.0%) followed by the left and right-side surfaces at 5.2% (6.7%-10.0%) and 3.3% (6.7%-10.0%), respectively. No droplet contamination was observed on the face shield. The droplet contamination count was greater in the upper central half of the plastic sheet that covered the surgical site in the lower part of the neck. Use of two horizontal anesthetic screens and a sterile plastic sheet over a tracheostomy operative field can effectively prevent droplet contamination, thus eliminating the need for a face shield with adequate eye protection and respirator. No droplet contamination was observed on the surgeon’s face shield or on the instruments, thus showing that the plastic sheets (plastic curtain) were effective in preventing droplet and aerosol spillage. |
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Fischer et al.2222. Fischer RJ, Morris DH, van Doremalen N, et al. Effectiveness of N95 Respirator Decontamination and Reuse against SARS-CoV-2 Virus. Emerging Infect Dis. 2020;26(9). PMID: 32491983; https://doi.org/10.3201/eid2609.201524. https://doi.org/https://doi.org/10.3201/...
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United States
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Research letter citing a cross-sectional laboratory study. |
N95 mask. |
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The decontamination method against SARS-CoV-2 on N95 masks considered the time needed to reduce the virus viability within 1000 minutes. With ethanol, 99.56% was eliminated; with dry heat (70 °C), 93.89%; with UV light (260-285 nm), 91.84%; and with vaporized VHP, 99.36%.
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All the substances analyzed decontaminated the N95 masks.
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Decontamination by means of vaporization with hydrogen peroxide or ultraviolet light allowed N95 masks to be reused three times, while doing this with dry heat at 70 °C allowed it twice. Decontamination with 70% alcohol reduced the integrity of N95 masks and was not recommended.
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Noguera et al.2020. Noguera SV, Espinoza EPS, Côrtes MF, et al. Disinfection of 3D-printed protective face shield during COVID-19 pandemic. Am J Infect Control. 2021;49(4):512-5. PMID: 33080363; https://doi.org/10.1016/j.ajic.2020.10.008. https://doi.org/https://doi.org/10.1016/...
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Brazil
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Cross-sectional study with evaluation questionnaire applied to users of the face shields that were developed. |
3D printing face shield: the total number evaluated was not reported. |
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Face shield after chemical disinfection: [70% ethanol, H2O2-quaternary ammonium salt mixture, 0.1% sodium hypochlorite or water (negative control)] with different thicknesses and materials were tested: 0.5 mm and 0 mm polyethylene glycol, 75 mm, 0.75 mm polycarbonate, 0.5 mm PET and 0.5 mm glycol modified PETG.
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Headbands for face shield after chemical disinfection and autoclaving (121 °C for 15 minutes): Different materials (Tritan HT, PLA EasyFill, ASA WP, ABS PT and PETG XT) and different layer thicknesses (0.15 mm, 0.30 mm, 0.60 mm) were used.
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3D printing questionnaire: Online about the comfort, visual integrity and viability of the 3D face shield.
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3,343 hospitalized COVID-19 patients, 2,778 trained health workers and 30,000 face shields were used.
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Face shield visual integrity after chemical disinfection
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None of the materials of the face shields or the layer thickness were damaged after a maximum of 40 disinfections with 70% ethanol, a mixture of quaternary ammonium salts and 0.1% sodium hypochlorite. To reduce the potential damage from steam, it is recommended to wait 3-5 minutes after each disinfection, given that at one minute after disinfection with 70% alcohol, vapors can cause eye redness.
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Headbands for face shield after chemical disinfection and autoclaving
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After chemical disinfection 30 times, none of the headbands had changes to their visible physical structure, as occurred with the mask visors. After decontamination in an autoclave, the PETG XT and TRITAN HT supports were found to have suffered considerable damage. There were reductions in size and material conditioning, and some cracks appeared, through the effect of the temperature and pressure of the autoclave; which led to a reduction in resistance through triggering of microfiber buckling.
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3D printing questionnaire about face shields
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In the questionnaire, most answers were very good, with regard to mobility, visual integrity, mask removal and disinfection. All projects were considered adequate, with no major differences between them. The GRU and INSPER projects received higher marks from users.
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Ong et al.88. Ong SWX, Tan YK, Sutjipto S, et al. Absence of contamination of personal protective equipment (PPE) by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Infect Control Hosp Epidemiol. 2020;41(5):614-6. PMID: 32213231; https://doi.org/10.1017/ice.2020.91. https://doi.org/https://doi.org/10.1017/...
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Singapore
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Cross-sectional study using a standardized technique with pre-moistened sterile smears. |
Eyeglass protection, N95 respirators and shoe surfaces of 30 healthcare professionals who cared for 15 patients. |
Sampling study on PPE used for one day by healthcare professionals who were taking care of confirmed COVID-19 patients over the previous 48 hours. All patients were in isolation rooms for airborne infections with 12 air changes per hour. |
All 90 samples from 30 healthcare professionals (doctors, nurses and cleaning professionals) were negative. The average time spent in the patient’s room in general was 6 minutes (range: 5-10): 8 minutes for doctors, 7 minutes for nurses and 3 minutes for cleaning professionals. The activities ranged from casual contact (e.g. medication administration or cleaning) to closer contact (e.g. physical examination or collection of respiratory samples). Prolonged use of N95 masks and eyeglass protection with strict adherence to environmental and hand hygiene when handling patients with SARS-CoV-2 may be a safe option. These results may not be generalizable to other room configurations. |
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Saini et al.2626. Saini V, Sikri K, Batra SD, Kalra P, Gautam K. Development of a highly effective low-cost vaporized hydrogen peroxide-based method for disinfection of personal protective equipment for their selective reuse during pandemics. Gut Pathog. 2020;12:29. PMID: 32572338; https://doi.org/10.1186/s13099-020-00367-4. https://doi.org/https://doi.org/10.1186/...
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India
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Laboratory. |
Personal protective clothing, N95 masks and face shields obtained in a biosafety level 3 laboratory and in a hospital. |
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Biological indicators and culturing conditions Biological indicator strips with B. stearothermophilus were used as the gold standard to confirm the integrity of the sterilization process. Recombinant laboratory strains of E. coli and M. smegmatis were incorporated into the study to assess their suitability as a biological indicator for disinfecting personal protective equipment.
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Heat and alcohol treatment 70 °C and 80 °C for 5 and 10 minutes each, 75% and 85% ethanol for 0.5 and 1 min each and propan-2-ol (75% and 85% for 0.5 and 1 minute each.
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Disinfection using VHP
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Run time of around 10 minutes with 200 ml hydrogen peroxide solution for a 1000 cubic foot room.
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Biological indicators for disinfection of PPE for SARS-CoV-2
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E. coli was used as an indicator: it completely lost its viability at 70 °C and 85 °C. Mycobacterium smegmatis was more resistant to heat. Escherichia coli exhibited a low level of ethanol resistance, while Mycobacterium smegmatis was not viable. Use of propan-2-ol allowed viability of Escherichia coli and Mycobacterium smegmatis. Gold-standard Bacillus stearothermophilus spores exposed to aggressive treatments (heat 90 °C/30 minutes or alcohol 85%/1 minute) showed rebirth and growth. Only the Bacillus stearothermophilus standard remained viable under all conditions known to inactivate the SARS-CoV-2 virus, thus indicating its versatility as an ideal substitute or biological indicator for developing disinfection protocols for COVID-19.
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Disinfection using vaporized hydrogen peroxide (VHP)
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Escherichia coli was sterilized and there was a reduction greater than 7 log10 in Mycobacterium smegmatis. Bacillus stearothermophilus spores did not revive with VHP. A single VHP cycle (7%-8% hydrogen peroxide) was able to disinfect PPE in less than 10 min. Repetition of the procedure did not result in any physical break, deformity or other considerable change to the overalls and N95 masks.
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Sapoval et al.2121. Sapoval M, Gaultier AL, Del Giudice C, et al. 3D-printed face protective shield in interventional radiology: Evaluation of an immediate solution in the era of COVID-19 pandemic. Diagn Interv Imaging. 2020;101(6):413-5. PMID: 32354631; https://doi.org/10.1016/j.diii.2020.04.004. https://doi.org/https://doi.org/10.1016/...
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France
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Cross-sectional study. |
38 radiologists (21 attending physicians, 6 fellows and 11 residents) in 31 consecutive interventions, such as central venous access, percutaneous peripheral angioplasty, percutaneous urinary intervention, arterial embolization due to acute bleeding, radiofrequency ablation of lung tumor, transjugular liver biopsy and sampling of the adrenal vein. |
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Face shields consisting of a standard transparent polymerizable vinyl chloride sheet were built on a 3D printer. The 3D printed face shields were evaluated in 31 interventional procedures.
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The average duration of the interventions was 59 ± 58 (SD) minutes (range: 15-240 minutes). Each face shield was used 2 ± 1.7 (SD) times (range: 1-8 times).
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In total, the average duration of the interventions was 59 ± 58 (SD) minutes (range 15-240 minutes); each face shield was used 2 ± 0.8 (SD) times (range 1-8 times). The average rating for the ability to perform the intervention assigned as usual was 1.7 ± 0.8 (SD) (range: 1- 4). The average visual tolerance rating was 1.6 ± 0.7 (SD) (range: 1-4). The average tolerability rating was 1.4 ± 0.7 (SD) (range: 1-3). Visual tolerance was satisfactory and no discomfort was observed, even during lengthy interventions. The study showed that 3D printed face shields were well accepted in several interventions in interventional radiology. |
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Smith et al.2727. Smith CR, Gravenstein N, LeMaster TE, Borde CM, Fahy BG. A Flexible Enclosure to Protect Respiratory Therapists During Aerosol-Generating Procedures. Respir Care. 2020;65(12):1923-32. PMID: 33229369. https://doi.org/10.4187/respcare.08568. https://doi.org/https://doi.org/10.4187/...
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United States
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Simulation study in an ICU environment. |
A simulated patient in an ICU, with infection due to severe acute respiratory syndrome coronavirus-2 that involved endotracheal intubation, was used. A laryngoscopist, a nurse and a respiratory therapist assisted in laryngoscopy. Three different methods of intubation were used. Fluorescent marker was sprayed by means of an atomizer during the procedure. The three techniques included only PPE, a polycarbonate intubation box or a flexible coronavirus enclosure. Black light was used to evaluate the laryngoscopist and the respiratory therapist. |
Contamination of the professional and personal protective equipment (gloves, apron, shoes and face shield) The PPE consisted of two masks (an N95 that was covered with a conventional surgical mask to protect the N95), a face shield, a cap, a long-sleeved waterproof plastic apron and gloves. |
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One person can install the coronavirus flexible casing in about two minutes. The intubation box can be unfolded in about two minutes, but it needs two people to position it properly. Use of PPE alone seriously contaminated the laryngoscopist and respiratory therapist.
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With the use of the intubation box, contamination of the laryngoscopist occurred only on the gloves, while the apron and face shield were not contaminated. The respiratory therapist showed great contamination on the gloves, the apron and the neck and face shield. The laryngoscopist reported that the arm holes restricted movement a little, without compromising intubation.
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With the coronavirus flexible closure system, the laryngoscopists and respiratory therapists were more protected. Only the gloves of both were contaminated. With all the three types, neither the nurse nor the surroundings were contaminated. The coronavirus flexible enclosure contained the fluorescent marker more effectively during endotracheal intubation than did personal protective equipment alone or the intubation box, based on the exposure of the laryngoscopist and respiratory support therapist.
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