COVID-19: smoke testing of surgical mask and respirators

Surgical smoke: a matter of hygiene, toxicology, and occupational health

The use of devices for tissue dissection and hemostasis during surgery is almost unavoidable. Electrically powered devices such as electrocautery, ultrasonic and laser units produce surgical smoke containing more than a thousand different products of combustion. These include large amounts of carcinogenic, mutagenic and potentially teratogenic noxae. The smoke contains particles that range widely in size, even as small as 0.007 µm. Most of the particles (90%) in electrocautery smoke are ≤6.27 µm in size, but surgical masks cannot filter particles smaller than 5 µm. In this situation, 95% of the smoke particles which pass through the mask reach deep into the respiratory tract and frequently cause various symptoms, such as headache, dizziness, nausea, eye and respiratory tract irritation, weakness, and abdominal pain in the acute period. The smoke can transport bacteria and viruses that are mostly between 0.02 µm and 3 µm in size and there is a risk of contamination. Among these viruses, SARS-CoV-2, influenza virus, HIV, HPV, HBV must be considered. The smoke may also carry malignant cells. The long-term effects of the surgical smoke are always ignored, because causality can hardly be clarified in individual cases. The quantity of the smoke changes with the technique of the surgeon, the room ventilation system, the characteristics of the power device used, the energy level at which it is set, and the characteristics of the tissue processed. The surgical team is highly exposed to the smoke, with the surgeon experiencing the highest exposure. However, the severity of exposure differs according to certain factors, e.g., ventilation by laminar or turbulent mixed airflow or smoke evacuation system. In any case, the surgical smoke must be removed from the operation area. The most effective method is to collect the smoke from the source through an aspiration system and to evacuate it outside. Awareness and legal regulations in terms of hygiene, toxicology, as well as occupational health and safety should increase.

Surgical smoke and the orthopedic surgeon: a non-systematic review of the hazards and strategies for mitigating risk

INTRODUCTION

Surgical smoke generated through the use of electrical surgical devices poses a risk to the surgeon, medical personnel in the operating room, and the patient by exposing them to environmentally hazardous particulate matter. Previous investigation has shown that surgical smoke leads to an increased risk of pulmonary conditions, circulatory disorders, and irritation of the eyes, nose, and throat. Transmission of infectious disease can occur through inhalation of viral particles, and the presence of carcinogens are also of major concern. The deleterious effects of surgical smoke are well documented in several subspecialties, namely dermatology and general surgery, but there has been little discussion on the topic amongst orthopedic surgeons.

METHODS

A non-systematic review of the literature was completed with the aim of identifying the major categories of adverse health effects associated with surgical smoke inhalation and offering recommendations to reduce these hazards in the orthopedic surgical community.

RESULTS

Three primary categories of risk associated with surgical smoke inhalation were identified: inflammation, viral/bacterial transmission, and carcinogenicity. In addition, strategies for mitigating risk and best practice recommendations were explored.

CONCLUSION

Surgical smoke is an under-recognized occupational hazard within the orthopedic surgery literature. There are several strategies which can be employed to reduce risk. Further investigation is needed to understand the long-term impact of these risks, as well as what can be done to improve the practicality and compliance with protective measures.

Non-Pharmaceutical Interventions against COVID-19 Causing a Lower Trend in Age of LHON Onset

Leber hereditary optic neuropathy (LHON) is a monogenic but multifactorial disease vulnerable to environmental triggers. Little is known about how LHON onset changed during the COVID-19 pandemic and how non-pharmaceutical interventions (NPHIs) against COVID-19 impact LHON onset. One hundred and forty-seven LHON patients with the m.11778G>A mutation complaining of vision loss were involved between January 2017 and July 2022. The onset time points, age of onset, and possible risk factors were evaluated. Analyses were conducted among 96 LHON patients in the Pre-COVID-19 group and 51 in the COVID-19 group. The median (IQR) age of onset decreased significantly from 16.65 (13.739, 23.02) in pre-COVID-19 to 14.17 (8.87, 20.29) during COVID-19. Compared with the Pre-COVID-19 group, the COVID-19 group exhibited bimodal distribution with an additional peak at six; the first quarter of 2020 also witnessed a relatively denser onset, with no subsequent second spike. NPHIs against COVID-19 significantly changed patients' lifestyles, including higher secondhand smoke exposure (p < 0.001), adherence to masks (p < 0.001), reduction in time spent outdoors for leisure (p = 0.001), and prolonged screen time (p = 0.007). Multivariate logistic regression revealed that secondhand smoke exposure and mask-wearing were independent risk factors of younger LHON onset. Lower age of onset of LHON appeared after the breakout of the COVID-19 pandemic, and novel risk factors were detected, including secondhand exposure and long mask-wearing. Carriers of LHON mtDNA mutations, especially teenagers or children, should be advised to avoid secondhand smoke exposure and there are possible adverse outcomes of longer mask-wearing.

Effects of Target Variables on Interpersonal Distance Perception for Young Taiwanese during the COVID-19 Pandemic

The COVID-19 pandemic has affected not only public health but also people's daily lives. Among various strategies to prevent infection, mask wearing and vaccination are considered to be the most effective methods; however, they may affect the comfortable interpersonal distance (IPD) for social interactions. In 2023, although the COVID-19 epidemic is considered to be similar to influenza, the public health sector of Taiwan still plans to give each person at least one dose per year, and even two does for special cases such as the elderly; and more than 90% of Taiwanese are still accustomed to wearing masks in public areas. Compared with mask wearing, studies examining the effects of vaccination on IPD are lacking. Therefore, an online survey was conducted in this study to collect the IPD data of 50 male and 50 female participants to elucidate the effects of mask wearing, vaccination, and target sex variables on IPD. The results showed that all variables significantly affected IPD (all p < 0.001). The effect of masks on IPD (49.1 cm) was slightly greater than that of vaccination (43.5 cm). The IPDs reported for wearing and not wearing masks were 145.7 and 194.8 cm, respectively, and those for vaccinated and unvaccinated were 148.5 and 192.0 cm, respectively. Regardless of participant sex, the IPDs for the female targets were significantly shorter than those for the male targets, which was consistent with the results of previous studies. Although mask wearing and vaccination are functionally different in nature, the findings indicate that the effects of both on IPD are nearly identical, jointly shortening IPD to approximately 93 cm. This implies that not only masks but also vaccination could lead to the shortening of IPD and may cause challenges in the prevention and control of COVID-19 transmission.

Microstructural evaluation and recommendations for face masks in community use to reduce the transmission of respiratory infectious diseases

BACKGROUND AND OBJECTIVE

Recommendations for the use of face masks to prevent and protect against the aerosols (≤5µm) and respiratory droplet particles (≥5µm), which can carry and transmit respiratory infections including severe acute respiratory syndrome coronavirus (SARS-CoV-2), have been in effect since the early stages of the coronavirus disease 2019 (COVID-19). The particle filtration efficiency (PFE) and air permeability are the most crucial factors affecting the level of pathogen transmission and breathability, i.e. wearer comfort, which should be investigated in detail.

METHODS

In this context, this article presents a novel assessment framework for face masks combining X-ray microtomography and computational fluid dynamics simulations. In consideration to their widespread public use, two types of face masks were assessed: (I) two layer non-woven face masks and (II) the surgical masks (made out of a melt-blown fabric layer covered with two non-woven fabric layers).

RESULTS

The results demonstrate that the surgical masks provide PFEs over 75% for particles with diameter over 0.1µm while two layer face masks are found out to have insufficient PFEs, even for the particles with diameter over 2µm (corresponding PFE is computed as 47.2%). Thus, existence of both the non-woven fabric layers for mechanical filtration and insertion of melt-blown fabric layer(s) for electrostatic filtration in the face masks were found to be highly critical to prevent the airborne pathogen transmission.

CONCLUSIONS

The present framework would assist in computational assessment of commonly used face mask types based on their microstructural characteristics including fiber diameter, orientation distributions and fiber network density. Therefore, it would be also possible to provide new yet feasible design routes for face masks to ensure reliable personal protection and optimal breathability.

A simple surgical mask modification to pass N95 respirator-equivalent fit testing standards during the COVID-19 pandemic

Background

The COVID-19 pandemic has infected hundreds of millions of people resulting in millions of deaths worldwide. While N95 respirators remain the gold standard as personal protective equipment, they are resource-intensive to produce and obtain. Surgical masks, easier to produce and obtain, filter ≥95% submicron particles but are less protective due to a lack of seal around a user’s face. This study tested the ability of a simple surgical mask modification using rubber bands to create a seal against particle exposure that would pass N95 standards.

Methods and findings

Forty healthcare workers underwent TSI PortaCount mask fit testing using an ASTM Level 1 surgical mask modified with rubber bands. Fit Factor was determined after testing four standard OSHA N95 fit testing scenarios. Performance of the properly-modified surgical mask was compared to that of a poorly-modified surgical mask, an unmodified standard surgical mask, and an N95 respirator. Thirty-one of forty (78%) healthcare workers passed Fit Factor testing using a properly-modified mask. The Fit Factor success rate significantly improved by subsequent test date (p = 0.043), but was not associated with any other participant characteristics. The average Fit Factor score for the properly-modified mask was 151 (SD 65.2), a significantly better fit than the unmodified mask score of 3.8 (SD 3.1, p<0.001) and the poorly-modified mask score of 24.6 (SD 48.4, p<0.001) but significantly lower than a properly fitted N95 score of 199 (SD 4.5, p<0.001).do.

Conclusions

Rubber bands, a low-cost and easily-accessible modification, can improve the seal and protective ability of a standard surgical mask to the level of an N95 respirator. This could mitigate N95 respirator shortages worldwide and provide individuals in under-resourced regions a practical means for increased personal respiratory protection.

Reducing the risk of viral contamination during the coronavirus pandemic by using a protective curtain in the operating room

Background

Airborne transmission diseases can transfer long and short distances via sneezing, coughing, and breathing. These airborne repertory particles can convert to aerosol particles and travel with airflow. During the Coronavirus disease 2019 (COVID-19) pandemic, many surgeries have been delayed, increasing the demand for establishing a clean environment for both patient and surgical team in the operating room.

Methods

This study aims to investigate the hypothesis of implementing a protective curtain to reduce the transmission of infectious contamination in the surgical microenvironment of an operating room. In this regard, the spread of an airborne transmission disease from the patient was evaluated, consequently, the exposure level of the surgical team. In the first part of this study, a mock surgical experiment was established in the operating room of an academic medical center in Norway. In the second part, the computational fluid dynamic technique was performed to investigate the spread of airborne infectious diseases. Furthermore, the field measurement was used to validate the numerical model and guarantee the accuracy of the applied numerical models.

Results

The results showed that the airborne infectious agents reached the breathing zone of the surgeons. However, using a protective curtain to separate the microenvironment between the head and lower body of the patient resulted in a 75% reduction in the spread of the virus to the breathing zone of the surgeons. The experimental results showed a surface temperature of 40 ˚C, which was about a 20 ˚C increase in temperature, at the wound area using a high intensity of the LED surgical lamps. Consequently, this temperature increase can raise the patient's thermal injury risk.

Conclusion

The novel method of using a protective curtain can increase the safety of the surgical team during the surgery with a COVID-19 patient in the operating room.

One year of surgical mask testing at the University of Bologna labs: Lessons learned from data analysis

The outbreak of SARS-CoV-2 pandemic highlighted the worldwide lack of surgical masks and personal protective equipment, which represent the main defense available against respiratory diseases as COVID-19. At the time, masks shortage was dramatic in Italy, the first European country seriously hit by the pandemic: aiming to address the emergency and to support the Italian industrial reconversion to the production of surgical masks, a multidisciplinary team of the University of Bologna organized a laboratory to test surgical masks according to European regulations. The group, driven by the expertise of chemical engineers, microbiologists, and occupational physicians, set-up the test lines to perform all the functional tests required. The laboratory started its activity on late March 2020, and as of the end of December of the same year 435 surgical mask prototypes were tested, with only 42 masks compliant to the European standard. From the analysis of the materials used, as well as of the production methods, it was found that a compliant surgical mask is most likely composed of three layers, a central meltblown filtration layer and two external spunbond comfort layers. An increase in the material thickness (grammage), or in the number of layers, does not improve the filtration efficiency, but leads to poor breathability, indicating that filtration depends not only on pure size exclusion, but other mechanisms are taking place (driven by electrostatic charge). The study critically reviewed the European standard procedures, identifying the weak aspects; among the others, the control of aerosol droplet size during the bacterial filtration test results to be crucial, since it can change the classification of a mask when its performance lies near to the limiting values of 95 or 98%.

COVID-19 infection risk by open and laparoscopic surgical smoke: A systematic review of the literature

BACKGROUND

The current COVID-19 pandemic has greatly changed the way surgery is delivered. In particular, current guidelines and policies have highlighted the need to use high level Personal Protective Equipment to reduce the risk of viral infection during open and laparoscopic surgical procedures. In particular, it was felt that the laparoscopic approach was at higher risk of viral transmission due to the chimney effect of the smoke escape from the trocars during and after the procedure. However, with this being a new and largely unknown viral agent, guidelines have been based on speculation and extrapolation from previous studies conducted in completely different situations, and led to anxiety amongst surgeons and theatre staff. We decided to conduct a systematic review of the Literature to try to clarify whether inhalation of surgical smoke can increase the risk of COVID-19 infection.

METHODS

A thorough search of the relevant Literature was performed following the PRISMA guidelines and the most relevant papers on this topic were selected for qualitative analysis. Duplicates, review, personal opinions and guidelines have been excluded. Quantitative analysis has not been performed due to the lack of homogeneous high-quality studies.

RESULTS

Literature search identified 740 papers but only 34 of them were suitable for qualitative analysis. The quality of those studies is generally quite low. We were not able to find any evidence directly linking surgical smoke with viral transmission, other than in patients with active HPV infection.

DISCUSSION

Inhalation of surgical smoke can be generally hazardous, and therefore the use of PPE during surgical operations must be recommended in any case. However, the present systematic review of the existent Literature did not identify any significant evidence of the risk of viral transmission with the surgical smoke, therefore the current guidelines restricting the use of laparoscopy and/or diathermy during the current Covid-19 pandemic may be considered excessive and non-evidence based.

The seroprevalence of SARS-CoV-2 during the first wave in Europe 2020: A systematic review

BACKGROUND

A year following the onset of the COVID-19 pandemic, new infections and deaths continue to increase in Europe. Serological studies, through providing evidence of past infection, can aid understanding of the population dynamics of SARS-CoV-2 infection.

OBJECTIVES

This systematic review of SARS-CoV-2 seroprevalence studies in Europe was undertaken to inform public health strategies including vaccination, that aim to accelerate population immunity.

METHODS

We searched the databases Web of Science, MEDLINE, EMBASE, SCOPUS, Cochrane Database of Systematic Reviews and grey literature sources for studies reporting seroprevalence of SARS-CoV-2 antibodies in Europe published between 01/12/2019-30/09/20. We provide a narrative synthesis of included studies. Studies were categorized into subgroups including healthcare workers (HCWs), community, outbreaks, pregnancy and children/school. Due to heterogeneity in other subgroups, we only performed a random effects meta-analysis of the seroprevalence amongst HCWs stratified by their country.

RESULTS

115 studies were included spanning 17 European countries, that estimated the seroprevalence of SARS-CoV-2 from samples obtained between November 2019 -August 2020. A total of 54/115 studies included HCWs with a reported seroprevalence among HCWs ranging from 0.7% to 45.3%, which did not differ significantly by country. In community studies significant heterogeneity was reported in the seroprevalence between different age groups and the majority of studies reported there was no significant difference by gender.

CONCLUSION

This review demonstrates a wide heterogeneity in reported seroprevalence of SARS-CoV-2 antibodies between populations. Continued evaluation of seroprevalence is required to understand the impact of public health measures and inform interventions including vaccination programmes.

A simple and cheap aerosol penetrometer for filter testing using an electronic cigarette

Background: During the coronavirus disease 2019 (COVID-19) pandemic face masks grew in importance as their use by the general population was recommended by health officials in order to minimize the risk of infection and prevent further spread of the virus. To ensure health protection of medical personnel and other system relevant staff, it is of considerable interest to quickly test if a certain lot of filtering facepiece masks meets the requirements or if the penetration changes under different conditions. As certified penetrometers are rather expensive and were difficult to obtain during the COVID-19 pandemic, we describe two quite simple and cheap methods to quickly test the filter penetration based on an electronic cigarette. Methods: The first method uses a precision scale, the second method uses a light scattering detector to measure the filter penetration. To make sure these two methods yield reliable results, both were tested with freshly cut filter samples covering the range of approx. 2 % to 60 % filter penetration and compared to the results of a certified penetrometer. Results: The comparison of the two methods with the certified penetrometer showed a good correlation and therefore allow a quick and rather reliable estimation of the penetration. Conclusions: Several examples about the use of faulty masks and the resulting health risks show that simple, fast, cheap and broadly available methods for filter characterization might be useful in these days.

Dentists' Working Conditions during the First COVID-19 Pandemic Lockdown: An Online Survey

The aim of this study was to investigate the operating conditions of dentists in Central Europe during the first coronavirus disease 2019 (COVID-19) lockdown. A survey including 24 questions was emailed to dentists in Austria, Germany, Switzerland and South Tyrol (Italy). Questions regarding dentists’ field of work, working hours, treatments performed, personal protective equipment and protocols, and economic consequences were asked. 1731 participants were included. 30.4% of participants worked mainly in Austria, 60.8% in Germany, 6% in Switzerland and 2.1% in South Tyrol. A country-specific analysis for the situation of South Tyrol was not possible due to the low participation; 53.7% of German, 45.5% of Austrian, and 11.7% of Swiss respondents reduced their working hours; 42.8% of Austrian, 41.5% of Swiss, and 17.3% of German participants closed their offices temporarily; 52.2% of respondents provided emergency service including pain management, restorations/temporaries, and denture repairs. A lack of access to FFP2/FFP3 (filtering facepiece) respirators was indicated by 59.4% Austrian, 38.0% German, and 11.7% Swiss dentists (p < 0.001). FFP2/FFP3 respirators were, when available, most frequently used in Austria (86.9%), followed by Switzerland (61.2%) and Germany (56.7%) (p < 0.001). Financial consequences could not be conclusively quantified by 58.6% of the participants. Most respondents in all partaking countries made use of governmental support. A lack of blueprints/guidelines resulted in heterogeneous working conditions. In consideration of a potentially high risk of infection in the dental setting, non-emergency dental treatments were largely suspended in all participating countries.