Aerosol-generating Procedures Research Articles

1574 Does Use of Intra-Operative PPE Affect Post-Operative Infection Rates in Hip Fracture Patients?

AimCOVID-19 has required significant change to theatre protocol. Regional guidelines dictate full PPE must be donned for all procedures where aerosol generating procedures (AGP) occur. Additionally, no one may enter or leave theatre whilst an operation is in progress, or until 20 minutes after an AGP. We hypothesized that adopting these protocols may lead to a reduction in post-operative infection in hip fracture patients.MethodMulticentre retrospective cohort study comparing post-operative infection and return to theatre rates (<30-days post-op) from 18/03/20 to 27/04/20 with respective period in 2019. COVID-19 was considered endemic in Northern Ireland from 18/03/20. Patients were identified from the Fracture Outcomes Research Department database and relevant inpatient episode reviewed via Electronic Care Record.Results464 patients were included– 261(2020) and 203(2019). In 2019, 4 patients (1.5%) returned to theatre within 30-days, however only one was due to wound dehiscence. In 2020, 1 patient (0.5%) returned to theatre for traumatic wound dehiscence, however they had no documented infection.ConclusionsThere was no difference in post-operative complication rate requiring return to theatre within 30 days between cohorts. Whilst PPE can be considered important for protection of patients and staff against COVID-19, it may not have significant effect on post-operative infection rates.

352 Did the Discontinuation of Pulse-Lavage Have A Detrimental Effect on The Quality of Hip Hemiarthroplasties Performed During the First COVID-19 Wave?

IntroductionThe standard of practice for performing hip hemiarthroplasty is to thoroughly wash and dry the femur with pulse-lavage. With the COVID-19 pandemic we were issued with guidance to minimise Aerosol Generating Procedures (AGPs) and discontinued the use of pulse lavage. Instead, we used a bladder syringe to wash the femoral canal.MethodWe retrospectively assessed 100 post-operative radiographs following hemiarthroplasties for neck of femur fractures. We used the Barrack classification to assess the bone cement mantle which is an indicator of aseptic loosening. We assessed 50 radiographs pre-covid (using pulse lavage) and 50 radiographs during covid (without pulse lavage).ResultsPre-COVID-19, 30% of hemiarthroplasties were deemed as being ‘at risk’. During COVID-19, 64% of hips were deemed as being ‘at risk’. This represents an absolute increase of 34%.ConclusionsThis forced service change had a detrimental effect on the quality of the bone cement mantle following hip hemiarthroplasty. We recommend following these patients up at 2 years to assess for signs of aseptic loosening. In future pandemics, we recommend carefully weighing up the dangers of using AGPs against the detriment in patient outcomes likely to be experienced.

Microdebrider is less aerosol-generating than CO2 laser and cold instruments in microlaryngoscopy

ObjectiveCOVID-19 spreads through aerosols produced in coughing, talking, exhalation, and also in some surgical procedures. Use of CO2 laser in laryngeal surgery has been observed to generate aerosols, however, other techniques, such cold dissection and microdebrider, have not been sufficiently investigated. We aimed to assess whether aerosol generation occurs during laryngeal operations and the effect of different instruments on aerosol production.MethodsWe measured particle concentration generated during surgeries with an Optical Particle Sizer. Cough data collected from volunteers and aerosol concentration of an empty operating room served as references. Aerosol concentrations when using different techniques and equipment were compared with references as well as with each other.ResultsThirteen laryngological surgeries were evaluated. The highest total aerosol concentrations were observed when using CO2 laser and these were significantly higher than the concentrations when using microdebrider or cold dissection (p < 0.0001, p < 0.0001) or in the background or during coughing (p < 0.0001, p < 0.0001). In contrast, neither microdebrider nor cold dissection produced significant concentrations of aerosol compared with coughing (p = 0.146, p = 0.753). In comparing all three techniques, microdebrider produced the least aerosol particles.ConclusionsMicrodebrider and cold dissection can be regarded as aerosol-generating relative to background reference concentrations, but they should not be considered as high-risk aerosol-generating procedures, as the concentrations are low and do not exceed those of coughing. A step-down algorithm from CO2 laser to cold instruments and microdebrider is recommended to lower the risk of airborne infections among medical staff.

Self-contamination following removal of two personal protective equipment suits: a randomized, controlled, crossover simulation trial

Healthcare personnel are often at high risk of contamination when participating in airway management and other aerosol-generating procedures. To explore the differences in self-contamination after removal of gown and coverall personal protective equipment (PPE) using an ultraviolet-fluorescent solution. This prospective, randomized, controlled crossover trial was set in a third-level university health centre in Buenos Aires, Argentina between August and October 2020. The study included 60 anaesthesia personnel volunteers, and no participants were excluded from the study. A two-period/two-intervention design was chosen; each intervention comprised audio-guided placement of PPE, full-body spraying of fluorescent solution, audio-guided removal of PPE, and self-contamination assessment through ultraviolet light scanning. The primary outcome was the mean within-participant difference (any traces) between PPE suits. Statistical significance was tested using t-tests for paired data. The allocation ratio was 25/35 (gown followed by coverall/coverall followed by gown). Self-contamination after removal of coveralls was greater than that after removal of gowns, with a mean within-participant difference of 11.45 traces (95% confidence interval 8.26-14.635; P<0.001). Significant differences were found for the number of self-contaminated body zones, small fluorescent traces and large fluorescent traces. Removal of a gown was associated with a markedly lower risk of self-contamination. Quick one-step removal of a gown and gloves may reduce self-contamination in the arm/hand area. Fluorescent solutions can help to identify self-contamination and compare outcomes between available PPE suits. Repeated training sessions and enhanced knowledge on self-contamination following removal of PPE are paramount. NCT04763304 (on ClinicalTrials.gov).

Dental care during COVID-19 pandemic: Follow-up survey of experts' opinion.

ObjectivesThe purpose of the present survey is to give an update of European experts' opinion on infection control and prevention in dentistry during second wave of pandemic. The secondary aim was to analyze how experts' opinion changed in the light of the new scientific evidence since the first wave.Material & MethodsAn anonymous online 14‐item questionnaire was sent to a total of 27 leading academic experts in Oral (and Maxillofacial) Surgery from different European countries, who had completed a previous survey in April‐May 2020. The questionnaire covered the topics of dental setting safety, personal protective equipment (PPE), and patient‐related measures to minimize transmission risk. Data collection took place in November‐February 2020/21.Results26 experts participated in the follow‐up survey. The overall transmission risk in dental settings was scored significantly lower compared to the initial survey (p < .05), though the risk associated with aerosol‐generating procedures (AGP) was still considered to be high. Maximum PPE was less frequently recommended for non‐AGP (p < .05), whereas the majority of experts still recommended FFP2/FFP3 masks (80.8%), face shields or goggles (88.5%), gowns (61.5%), and caps (57.7%) for AGP. Most of the experts also found mouth rinse relevant (73.1%) and reported to be using it prior to treatment (76.9%). No uniform opinion was found regarding the relevance of COVID‐19 testing of staff and patients.ConclusionWith the continuation of dental care provision, transmission risk has been scored lower compared to the first wave of pandemic. However, high risk is still assumed for AGP, and maximum PPE remained advised for the respective treatments.

Leak-Testing of an Endoscopic Aerosol Box for Preventing SARS-CoV-2 Infection during Upper Gastrointestinal Endoscopy

Objective: The SARS-CoV-2 virus has infected many healthcare professionals. Endoscopy is an aerosol-generating procedure and the endoscopy team is at risk of exposure and infection. We describe the leak-testing of an aerosol box that uses a glove-covering for the endoscope.Materials and Methods: An endoscopic aerosol box with a glove-covering over the endoscope was made for gastroscopy, EUS and ERCP procedures and was tested for leakage of aerosol/airborne particles. Fine particulate matter (PM) from burnt incense sticks was used as a model for viral aerosol. The leakage from the box was measured by comparing readings from 2 PM light-scattering sensors, one placed inside the box and the other just outside the glove opening in a sealed container. Negative pressure conditions were also used to see if this had any effect on the leakage.Results: The concentration levels of the particulate matter differed with different negative pressure conditions and movement of the endoscope through the glove. Very little leakage was seen with the endoscope stationary even with no negative pressure, at 2.4%, 0.17% and 0.07% for PM1, PM2.5 and PM10, respectively. The maximum leakage was 14% for PM1, 8.7% for PM2.5 and 2.6% for PM10 in the moving-endoscope condition and no negative pressure. This reduced to 6.2%, 1.3%and 0.37% respectively when suction was applied at full strength (negative pressure of -0.05 bar). Conclusion: The glove covering significantly reduced the passage of particles. The particulate leak was seen most with the smallest particles and reached 14% for PM1 without negative pressure. This reduced to 6.2% with maximum negative pressure using the wall suction.

Bronchoscopy during COVID-19 pandemic, ventilatory strategies and procedure measures.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has changed bronchoscopy practices worldwide. Bronchoscopy is a high-risk aerosol-generating procedure with a potential for direct SARS-CoV-2 exposure and hospital-acquired infection. Current guidelines about personal protective equipment and environment considerations represent key competencies to minimize droplets dispersion and reduce the risk of transmission. Different measures should be put in field based on setting, patient's clinical characteristics, urgency and indications of bronchoscopy. The use of this technique in SARS-CoV-2 patients is reported primarily for removal of airway plugs and for obtaining microbiological culture samples. In mechanically ventilated patients with SARS-CoV-2, bronchoscopy is commonly used to manage complications such as hemoptysis, atelectasis or lung collapse when prone positioning, physiotherapy or recruitment maneuvers have failed. Further indications are represented by assistance during percutaneous tracheostomy. Continuous positive airway pressure, non-invasive ventilation support and high flow nasal cannula oxygen are frequently used in patient affected by Coronavirus disease 2019 (COVID-19): management of patients' airways and ventilation strategies differs from bronchoscopy indications, patient's clinical status and in course or required ventilatory support. Sedation is usually administered by the pulmonologist (performing the bronchoscopy) or by the anesthetist depending on the complexity of the procedure and the level of sedation required. Lastly, elective bronchoscopy for diagnostic indications during COVID-19 pandemic should be carried on respecting rigid standards which allow to minimize potential viral transmission, independently from patient's COVID-19 status. This narrative review aims to evaluate the indications, procedural measures and ventilatory strategies of bronchoscopy performed in different settings during COVID-19 pandemic.

A Cross-Sectional Survey of the Workplace Factors Contributing to Symptoms of Anxiety and Depression Among Nurses and Physicians During the First Wave of COVID-19 Pandemic in Two US Healthcare Systems.

BackgroundAnxiety and depression among physicians and nurses during the COVID-19 pandemic in the USA are not well described and their modifiable causes are poorly understood.MethodsWe conducted a cross-sectional survey of symptoms of anxiety and depression (Hospital Anxiety and Depression Scale) among physicians and nurses in two US healthcare systems in June through September 2020; participation rate was 5–10%. We described features of work as well as their perceptions and associated concerns in relation to the risk of anxiety and depression, while controlling for health history via regression and path analyses.ResultsAbout a third of 684 nurses and 185 physicians surveyed showed symptoms of anxiety or depression, and the excess of symptoms of mood disorders was particularly prominent in nurses. The belief that one was infected was a dominant correlate of both anxiety and depression. This belief was more associated with history of symptoms of pneumonia than the contact with COVID-19 diagnosed patients. Factors found to be associated with reduced anxiety and depression in this working environment were having confidence in the competent use of and access to personal protective equipment, maintaining usual working hours, being surrounded by colleagues who were both sufficient in numbers and not stressed, and the support of immediate family and religious communities. Involvement in aerosol-generating procedures with infected patients was linked with lower depression in nurses but higher among physicians. Likewise, the setting of recent patient encounters affected risk of anxiety and depression differently for physicians and nurses.ConclusionsOur findings may help develop mitigation measures and underscore the need to help nurses and physicians bear the psychological burden of the COVID-19 pandemic and similar events in the future.

In Vivo Study of Aerosol, Droplets and Splatter Reduction in Dentistry.

Oral health care workers (OHCW) are exposed to pathogenic microorganisms during dental aerosol-generating procedures. Technologies aimed at the reduction of aerosol, droplets and splatter are essential. This in vivo study assessed aerosol, droplet and splatter contamination in a simulated clinical scenario. The coolant of the high-speed air turbine was colored with red concentrate. The red aerosol, droplets and splatter contamination on the wrists of the OHCW and chests of the OHCW/volunteer protective gowns, were assessed and quantified in cm2. The efficacy of various evacuation strategies was assessed: low-volume saliva ejector (LV) alone, high-volume evacuator (HV) plus LV and an extra-oral dental aerosol suction device (DASD) plus LV. The Kruskal–Wallis rank-sum test for multiple independent samples with a post-hoc test was used. No significant difference between the LV alone compared to the HV plus LV was demonstrated (p = 0.372059). The DASD combined with LV resulted in a 62% reduction of contamination of the OHCW. The HV plus LV reduced contamination by 53% compared to LV alone (p = 0.019945). The DASD demonstrated a 50% reduction in the contamination of the OHCWs wrists and a 30% reduction in chest contamination compared to HV plus LV. The DASD in conjunction with LV was more effective in reducing aerosol, droplets and splatter than HV plus LV.

Recommendations for Safe Dental Care: A Systematic Review of Clinical Practice Guidelines in the First Year of the COVID-19 Pandemic.

In the context of a pandemic, the rapid development of clinical practice guidelines (CPGs) is critical to guide dental staff towards the safe provision of dental care; detailed knowledge of the recommendations will help to achieve the intended results. We carried out a systematic review of the recommendations in clinical practice guidelines (CPGs) on the provision of dental care issued during the first year of the COVID-19 pandemic. A systematic database search was performed in MEDLINE, EMBASE, LILACS, Epistemonikos, and Trip databases to identify documents with recommendations intended to minimize the risk of COVID-19 transmission during dental care. The selection process and data extraction were carried out by two researchers independently. The majority of CPGs recommended the use of rubber dam, high-volume evacuator, mouthwash prior to dental care, four-handed work, and mechanical barriers. The use of aerosol-generating equipment should be avoided whenever possible. In aerosol-generating procedures, the use of a N95 respirator (or similar) is recommended, in addition to a face protector, an impermeable disposable apron/gown, a cap, and gloves. The CPGs developed during the first year of the pandemic offer recommendations which guide dental staff in providing safe dental care, minimizing exposure to SARS-CoV-2 and reducing the risk of COVID-19 infection in the clinical environment. Such recommendations must, however, be updated as new evidence arises.

Quantification of aerosol dispersal from suspected aerosol-generating procedures.

BackgroundOxygen-delivering modalities like humidified high-flow nasal cannula (HFNC) and noninvasive positive-pressure ventilation (NIV) are suspected of generating aerosols that may contribute to transmission of disease such as coronavirus disease 2019. We sought to assess if these modalities lead to increased aerosol dispersal compared to the use of non-humidified low-flow nasal cannula oxygen treatment (LFNC).MethodsAerosol dispersal from 20 healthy volunteers using HFNC, LFNC and NIV oxygen treatment was measured in a controlled chamber. We investigated effects related to coughing and using a surgical face mask in combination with the oxygen delivering modalities. An aerodynamic particle sizer measured aerosol particles (APS3321, 0.3–20 µm) directly in front of the subjects, while a mesh of smaller particle sensors (SPS30, 0.3–10 µm) was distributed in the test chamber.ResultsNon-productive coughing led to significant increases in particle dispersal close to the face when using LFNC and HFNC but not when using NIV. HFNC or NIV did not lead to a statistically significant increase in aerosol dispersal compared to LFNC. With non-productive cough in a room without air changes, there was a significant drop in particle levels between 100 cm and 180 cm from the subjects.ConclusionsOur results indicate that using HFNC and NIV does not lead to increased aerosol dispersal compared to low-flow oxygen treatment, except in rare cases. For a subject with non-productive cough, NIV with double-limb circuit and non-vented mask may be a favourable choice to reduce the risk for aerosol spread.

Serological Testing Reveals the Hidden COVID-19 Burden among Health Care Workers Experiencing a SARS-CoV-2 Nosocomial Outbreak.

ABSTRACTWe describe the results of testing health care workers, from a tertiary care hospital in Japan that had experienced a coronavirus disease 2019 (COVID-19) outbreak during the first peak of the pandemic, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody seroconversion. Using two chemiluminescent immunoassays and a confirmatory surrogate virus neutralization test, serological testing revealed that a surprising 42% of overlooked COVID-19 diagnoses (27/64 cases) occurred when case detection relied solely on SARS-CoV-2 nucleic acid amplification testing (NAAT). Our results suggest that the NAAT-positive population is only the tip of the iceberg and the portion left undetected might potentially have led to silent transmissions and triggered the spread. A questionnaire-based risk assessment was further indicative of exposures to specific aerosol-generating procedures (i.e., noninvasive ventilation and airway suctioning) having mediated transmission and served as the origins of the outbreak. Our observations are supportive of a multitiered testing approach, including the use of serological diagnostics, in order to accomplish exhaustive case detection along the whole COVID-19 spectrum.IMPORTANCE We describe the results of testing frontline health care workers, from a hospital in Japan that had experienced a COVID-19 outbreak, for SARS-CoV-2-specific antibodies. Antibody testing revealed that a surprising 42% of overlooked COVID-19 diagnoses occurred when case detection relied solely on PCR-based viral detection. COVID-19 clusters have been continuously striking the health care system around the globe. Our findings illustrate that such clusters are lined with hidden infections eluding detection with diagnostic PCR and that the cluster burden in total is more immense than actually recognized. The mainstays of diagnosing infectious diseases, including COVID-19, generally consist of two approaches, one aiming to detect molecular fragments of the invading pathogen and the other to measure immune responses of the host. Considering antibody testing as one trustworthy option to test our way through the pandemic can aid in the exhaustive case detection of COVID-19 patients with variable presentations.

Regional Anaesthetic Techniques and Their Implications During the COVID Pandemic.

The current pandemic has highlighted the need to protect both patients and medical staff. The increased use of regional anaesthesia as a primary anaesthetic modality for operations and other invasive procedures has limited the number of aerosol-generating procedures performed during general anaesthesia. Its use is further characterized by decreases in postoperative pain and length of hospitalization. This article provides an overview of regional anaesthetic techniques (peripheral nerve locks, epidural and spinal anaesthesia) and their uses during the COVID pandemic.

A case-control study of airborne dissemination of bacteria during CT colonography.

The COVID-19 pandemic has highlighted the importance of aerosol spread of infection. We have conducted a study to detect bacterial contamination of room surfaces and room air during CT colonography and confirm the efficacy of room disinfection procedures carried out between examinations. Systematic sampling of the CT examination couch and horizontal surfaces 1 m and 3 m from the couch was performed before and after patient examinations. A 1 m3 sample of room air was obtained during patient examinations. Samples were processed using routine laboratory methods. A case-control study design was used (30 CT colonography and 30 routine body CT scans). Evidence of airborne dissemination of bacteria was detected in >30% of CT colonography examinations and <10% of control examinations (p = 0.01). No pathogenic bacteria were detected in surface samples taken before patient examinations. The room disinfection policy in use in our CT department is effective in eliminating pathogenic bacteria from surfaces in the patient environment. CT colonography causes contamination of room air with enteric bacteria in a significant proportion of cases. CT colonography may possibly be an aerosol-generating procedure. Larger-scale investigation is needed to fully evaluate this potential infection risk.

Positive impact of the Covid-19 pandemic on dental education.

This letter describes some positive effects of the Covid-19 pandemic on dental education in India. The apex body of dental education, the Dental Council of India (DCI) has formulated some universal guidelines based on those of the US Center for Disease Control and Prevention, about the use of personal protection and following sterilisation protocols adapted for use in dental clinics, hospitals and academic institutions of dental education in India(1). All individual dental clinics, hospitals and academic institutions have to follow stringent and mandatory sterilisation protocols, hence with the Covid-19 outbreak, some unethical practices of the dental profession such as inadequate sterilisation and improper waste management may be reversed (1,2). Emergency dental procedures also have to follow stringent sterilisation guidelines, to avoid aerosol-generating procedures (1). Dental professionals have been utilising teledentistry facilities during the pandemic which focus on emergency relief of dental pain and infection, and elective planning and scheduling of dental treatment (3).

Pain Distraction During Awake Major Colorectal Surgery: Supporting Patients Beyond the COVID-19 Era. Preliminary Findings.

Introduction: During the coronavirus disease 2019 (COVID-19) pandemic, hospitals rapidly ran out of intensive care beds. Because minimally invasive surgery and general anaesthesia are both aerosol-generating procedures, their use has become controversial. We report a case series of awake undelayable colorectal surgeries which, innovatively, took advantage of intraoperative pain distraction. Moreover, we describe our frugal solution to social distancing in psychological support of inpatients.Methods: Between October 2020 and February 2021, five patients underwent acute-care colorectal surgery under locoregional anaesthesia in our department. A 3D mobile theatre (3DMT) was used during the operation to distract the patients from pain. Vital signs, pain intensity, ergonomic comfort/discomfort, sense of presence and distress were intraoperatively monitored. A postoperative “cuddle delivery” service was instituted: video messages from relatives and close friends were delivered daily to the patient through the 3DMT. Emotional effects were investigated through clinical interviews conducted by a psychologist at our hospital.Results: Both intraoperative and postoperative pain were always well controlled. Conversion to general anaesthesia and postoperative intensive support/monitoring were never necessary. The “cuddle delivery” initiative helped patients fill the emotional gap created by the strict containment measures implemented inside the hospital, distracting them from emotional anxiety and physical pain.Conclusions: During the next phase of the COVID-19 pandemic and even after the COVID-19 era, awake laparotomy under locoregional anaesthesia may be a crucial option for delivering acute-care surgery to selected patients when intensive care beds are unavailable and postponing surgery is unacceptable. We also introduce a new modality for the provision of emotional support during postoperative inpatient care as a countermeasure to the restrictions imposed by social distancing measures.

Case-control study evaluating risk factors for SARS-CoV-2 outbreak amongst healthcare personnel at a tertiary care center

BackgroundDespite several outbreaks of SARS-CoV-2 amongst healthcare personnel (HCP) exposed to COVID-19 patients globally, risk factors for transmission remain poorly understood. MethodsWe conducted an outbreak investigation and case-control study to evaluate SARS-CoV-2 transmission risk in an outbreak among HCP at an academic medical center in California that was confirmed by whole genome sequencing. ResultsA total of 7/9 cases and 93/182 controls completed a voluntary survey about risk factors. Compared to controls, cases reported significantly more patient contact time. Cases were also significantly more likely to have performed airway procedures on the index patient, particularly placing the patient on high flow nasal cannula, continuous positive airway pressure (CPAP), or bilevel positive airway pressure (BiPAP) (OR = 11.6; 95% CI = 1.7 –132.1). DiscussionThis study highlights the risk of nosocomial infection of SARS-CoV-2 from patients who become infectious midway into their hospitalization. Our findings also reinforce the importance of patient contact time and aerosol-generating procedures as key risk factors for HCP infection with SARS-CoV-2. ConclusionsRe-testing patients for SARS-CoV-2 after admission in suspicious cases and using N95 masks for all aerosol-generating procedures regardless of initial patient SARS-CoV-2 test results can help reduce the risk of SARS-COV-2 transmission to HCP.

The value of tracheostomy of critically ill COVID-19 patients - A multicentral study

PurposeTracheostomy is an aerosol-generating procedure, thus performing it during the COVID-19 pandemic arises considerations such as the most appropriate timing and the patients to whom it is suitable. Medical teams lack sufficient data to assist determining whether or not to conduct tracheostomy, its short- and long-term implications are not fully understood. This study aims to shed light on the critically ill COVID-19 patients that require tracheostomy, and to investigate its value. MethodsA retrospective multicentral case-control study of 157 hospitalized critically ill COVID-19 patients, among whom 30 patients went through tracheostomy and consisted of our study group. ResultsThe mean age was similar between study and control groups (68.9 ± 12.7 years vs 70.5 ± 15.8 years, p = 0.57), as well as comorbidity prevalence (56.7% vs 67.7%, p = 0.25). Patients in the study group were hospitalized for longer duration until defined critically ill (5 ± 4.3 vs 3 ± 3.9 days; p = 0.01), until admitted to the intensive care unit (6 ± 6.6 vs 2.5 ± 3.7 days respectively; p = 0.005), and until discharged (24 ± 9.7 vs 10.7 ± 9.1 days, p < 0.001). Mortality rate was lower in the study group (30% vs 59.8%, p = 0.003). Kaplan Meier survival analysis revealed a statistically significant difference in survival time between groups (Log rank chi-sq = 20.91, p < 0.001) with mean survival time of 41 ± 3.1 days vs 21 ± 2.2 days. Survival was significantly longer in the study group (OR = 0.37, p = 0.004). ConclusionTracheostomy allows for more prolonged survival for gradually deteriorating critically ill COVID-19 patients. This should be integrated into the medical teams' considerations when debating whether or not to conduct tracheostomy.

Aerosol-generating dental procedures: a reappraisal of analysis methods and infection control measures

Dental aerosol-generating procedures (AGPs) have been associated with risk for transmitting infectious agents. However, existing infection control monitoring studies potentially underestimate the extent of contamination, due to methodological inadequacies. These studies employed settle plate methodology which only captures droplets that land on agar plates, but not those suspended in air. Furthermore, bacterial culture was used to determine the extent of contamination, without accounting for non-bacterial sources of contamination. This study sought to bridge these gaps by establishing a monitoring protocol involving active aerosol sampling and analysis of two dental AGPs, root canal treatment (RCT) and scaling. RCT and scaling were performed with standard aerosol mitigation precautions. Aerosols generated throughout each procedure were sampled using the air sampler device, while contamination of operatory fomites and personal protective equipment was sampled using surface swabs, before and post-treatment. The amount of contamination was quantified using bacterial culture and adenosine triphosphate (ATP) assay. RCT generated insignificant aerosol and splatter, supporting the infection control procedures' effectiveness. Conversely, scaling significantly increased the amount of aerosol and splatter. When comparing bacterial culture and ATP assay, the magnitude of contamination obtained with ATP assay was greater, suggesting that ATP assay may have detected additional contamination of human origin and bacteria that was not recovered by the culture conditions employed. This monitoring protocol is feasible in the dental setting and determines the extent of contamination generated during AGPs. This could be adopted in future studies to overcome the limitations of the existing literature.

Adapted full-face snorkel masks as an alternative for COVID-19 personal protection during aerosol generating procedures in South Africa: A multi-centre, non-blinded in-situ simulation study.

IntroductionSARS-CoV-2 has resulted in increased worldwide demand for personal protective equipment (PPE). With pressure from ongoing epidemic and endemic episodes, we assessed an adapted snorkel mask that provides full-face protection for healthcare workers (HCWs), particularly during aerosol-generating procedures. These masks have a custom-made adaptor which allows the fitment of standard medical respiratory filters. The aim of this study was to evaluate the fit, seal and clinical usability of these masks.MethodsThis multicentre, non-blinded in-situ simulation study recruited fifty-two HCWs to don and doff the adapted snorkel mask. Negative pressure seal checks and a qualitative fit test were performed. The HCWs completed intubation and extubation of a manikin in a university skills training laboratory, followed by a web-based questionnaire on the clinical usability of the masks.ResultsWhilst fit and usability data were generally satisfactory, two of the 52 participants (3.8%) felt that the mask did not span the correct distance from the nose to the chin, and 3 of 34 participants (8.8%) who underwent qualitative testing with a Bitrex test failed. The majority of users reported no fogging, humidity or irritation. It was reportedly easy to speak while wearing the mask, although some participants perceived that they were not always understood. Twenty-one participants (40%) experienced a subjective physiological effect from wearing the mask; most commonly a sensation of shortness of breath.DiscussionA fit-tested modified full-face snorkel mask may offer benefit as a substitute for N95 respirators and face shields. It is, however, important to properly select the correct mask based on size, fit testing, quality of the three-dimensional (3D) printed parts and respiratory filter to be used. Additionally, HCWs should be trained in the use of the mask, and each mask should be used by a single HCW and not shared.