Study on infection risk in a negative pressure ward under different fresh airflow patterns based on a radiation air conditioning system.

COVID-19 and other respiratory infectious viruses are highly contagious, and patients need to be treated in negative pressure wards. At present, many negative pressure wards use independent air conditioning equipment, but independent air conditioning equipment has problems such as indoor air circulation flow, condensate water accumulation, and improper filter maintenance, which increase the risk of infection for healthcare workers and patients. The radiation air conditioning system relies on the radiation ceiling to control the indoor temperature and uses new air to control the indoor humidity and air quality. The problems caused by the use of independent air conditioning equipment should be avoided. This paper studies the thermal comfort, contaminant distribution characteristics, contaminant removal efficiency, and accessibility of supply air in a negative pressure ward with a radiation air conditioning system under three airflow patterns. In addition, the negative pressure ward was divided into 12 areas, and the infection probability of healthcare workers in different areas was analyzed. The results show that the application of radiation air conditioning systems in negative pressure wards can ensure the thermal comfort of patients. Stratum ventilation and ceiling-attached jets have similar effects in protecting healthcare workers; both can effectively reduce the contaminant concentrations and the risk of infection of healthcare workers. Ceiling-attached jets decreases the contaminant concentrations by 10.73%, increases the contaminant removal efficiency by 12.50%, and decreases the infection probability of healthcare workers staying indoors for 10 min by 23.18%, compared with downward ventilation.

Association between negative-pressure room utilization and hospital-acquired Aspergillus rates in patients with coronavirus disease 2019 (COVID-19) in two academic hospitals.

Hospital-acquired Aspergillus rates among coronavirus disease 2019 (COVID-19) patients were initially higher at a hospital with high negative-pressure room utilization compared to a similar hospital with low utilization but with otherwise identical infection control policies. After the index hospital decreased negative-pressure utilization, hospital-acquired Aspergillus case rates at the 2 hospitals converged.

Aerosol Concentrations During Otolaryngology Procedures in a Negative Pressure Isolation Room.

OBJECTIVE: To evaluate the role of a negative pressure room with a high-efficiency particulate air (HEPA) filtration system on reducing aerosol exposure in common otolaryngology procedures. STUDY DESIGN: Prospective quantification of aerosol generation. SETTINGS: Tertiary care. METHODS: The particle concentrations were measured at various times during tracheostomy tube changes with tracheostomy suctioning, nasal endoscopy with suctioning, and fiberoptic laryngoscopy (FOL), which included 5 times per procedure in a negative pressure isolation room with a HEPA filter and additional 5 times in a nonpressure-controlled room without a HEPA filter. The particle concentrations were measured from the baseline, during the procedure, and continued until 30 minutes after the procedure ended. The particle concentrations were compared to the baseline concentrations. RESULTS: The particle concentration significantly increased from the baseline during tracheostomy tube changes (mean difference [MD] 0.80 × 106 p/m3 , p = .01), tracheostomy suctioning (MD 0.78 × 106 p/m3 , p = .004), at 2 minutes (MD 1.29 × 106 p/m3 , p = .01), and 3 minutes (MD 1.3 × 106 p/m3 , p = .004) after suctioning. There were no significant differences in the mean particle concentrations among various time points during nasal endoscopy with suctioning and FOL neither in isolation nor nonpressure-controlled rooms. CONCLUSION: A negative pressure isolation room with a HEPA filter was revealed to be safe for medical personnel inside and outside the room. Tracheostomy tube change with tracheostomy suctioning required an isolation room because this procedure generated aerosol, while nasal endoscopy with suctioning and FOL did not. Aerosol generated in an isolation room was diminished to the baseline after 4 minutes.

Visualization of the infection risk assessment of SARS-CoV-2 through aerosol and surface transmission in a negative-pressure ward.

Since December 2019, coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a great challenge to the world's public health system. Nosocomial infections have occurred frequently in medical institutions worldwide during this pandemic. Thus, there is an urgent need to construct an effective surveillance and early warning system for pathogen exposure and infection to prevent nosocomial infections in negative-pressure wards. In this study, visualization and construction of an infection risk assessment of SARS-CoV-2 through aerosol and surface transmission in a negative-pressure ward were performed to describe the distribution regularity and infection risk of SARS-CoV-2, the critical factors of infection, the air changes per hour (ACHs) and the viral variation that affect infection risk. The SARS-CoV-2 distribution data from this model were verified by field test data from the Wuhan Huoshenshan Hospital ICU ward. ACHs have a great impact on the infection risk from airborne exposure, while they have little effect on the infection risk from surface exposure. The variant strains demonstrated significantly increased viral loads and risks of infection. The level of protection for nurses and surgeons should be increased when treating patients infected with variant strains, and new disinfection methods, electrostatic adsorption and other air purification methods should be used in all human environments. The results of this study may provide a theoretical reference and technical support for reducing the occurrence of nosocomial infections.

[Nurses' Experience with Caring for COVID-19 Patients in a Negative Pressure Room Amid the Pandemic Situation].

PURPOSE: The purpose of this study was to explore nurses' experience with caring for COVID-19 patients in a negative pressure room amid the spread of the pandemic. METHODS: This study was a qualitative research, and focus group interviews were used to collect data. Three focus groups comprising 19 nurses were interviewed from February 17 to 25, 2021. All interviews were recorded and transcribed verbatim with the consent of the participants. The verbatim transcripts were scrutinized using thematic analysis. RESULTS: Two main themes emerged from the analysis: 'Struggling in an isolated space' and 'Limitations of nursing infrastructure and system'. The nurses caring for COVID-19 patients experienced anxiety and fear about the infection, physical exhaustion, emotional burnout, and a sense of duty as a nurse. They also acknowledged the lack of guidelines, increased task and burden, limitations of nursing care, and the demand for improving the limitations of the nursing system. CONCLUSION: The results of this study demonstrate that nurses caring for COVID-19 patients encounter physical and emotional problems within the limited healthcare system. The study suggests that comprehensive interventions are needed for nurses. Furthermore, detailed guidelines, strengthening of nursing personnel, and improvements to the nursing system are vital to effectively cope with the pandemic. The government and medical institutions should be aware of the needs of nurses and what they are going through, and make efforts to improve the quality of life of healthcare workers and create a safe healthcare environment.

Projecting COVID-19 isolation bed requirements for people experiencing homelessness.

As COVID-19 spreads across the United States, people experiencing homelessness (PEH) are among the most vulnerable to the virus. To mitigate transmission, municipal governments are procuring isolation facilities for PEH to utilize following possible exposure to the virus. Here we describe the framework for anticipating isolation bed demand in PEH communities that we developed to support public health planning in Austin, Texas during March 2020. Using a mathematical model of COVID-19 transmission, we projected that, under no social distancing orders, a maximum of 299 (95% Confidence Interval: 223, 321) PEH may require isolation rooms in the same week. Based on these analyses, Austin Public Health finalized a lease agreement for 205 isolation rooms on March 27th 2020. As of October 7th 2020, a maximum of 130 rooms have been used on a single day, and a total of 602 PEH have used the facility. As a general rule of thumb, we expect the peak proportion of the PEH population that will require isolation to be roughly triple the projected peak daily incidence in the city. This framework can guide the provisioning of COVID-19 isolation and post-acute care facilities for high risk communities throughout the United States.

Planning and Design of a Full-Outer-Air-Intake Natural Air-Conditioning System for Medical Negative Pressure Isolation Wards.

In the beginning of 2020, the coronavirus (COVID-19) pandemic started to spread globally, causing panic to the lives of people around the world; many countries executed lockdown of cities or even total lockdown of the entire countries. The coronavirus disease (COVID-19) is transmitted via air droplets. In medical environments that use traditional hermetic ventilation systems, medical personnel who come in contact with patients are more susceptible to infection compared to regular staff; therefore, the air flow and air quality of hermetic negative pressure isolation wards are highly critical. For this purpose, the study proposes a full-outer-air-intake natural air-conditioning system for negative pressure isolation wards. This innovative system draws in large amounts of fresh external air to greatly improve the air exchange rate in wards; negative pressure environments can be implemented depending on requirements to solve the issue of nosocomial infections in traditional negative pressure isolation wards that draw air from within the hospital. This greatly reduces the probability of nosocomial infection and infection via air droplets; furthermore, the system's intake and exhaust paths are completely isolated, solving the issue of air cross-contamination. Based on the results from the experiment site, this innovative system was designed and implemented based on the guidelines of hospital facilities and achieved air exchange per hour in excess of 12 times/hour, reaching a maximum of 54.5 times/hour. Indoor CO2 concentration was 576 ppm, negative pressure was -14 Pa, indoor temperature was 23.3°C, indoor humidity was 54.1%, and sensible heat exchange efficiency (ηs) was 105.88% which effectively reduced ventilation load. Therefore, this innovative full-outer-air-intake natural air-conditioning system can provide medical staff and patients with a safe and healthy environment that prevents cross-infection.

Prevention and control measures of the coronavirus disease 2019 (COVID-19) in low-risk departments: The spine surgery department example.

As the coronavirus disease 2019 (COVID-19) spreads globally, hospital departments will need take steps to manage their treatment procedures and wards. The preparations of high-risk departments (infection, respiratory, emergency, and intensive care unit) were relatively well within this pandemic, while low-risk departments may be unprepared. The spine surgery department in The First Affiliated Hospital of Anhui Medical University in Hefei, China, was used as an example in this study. The spine surgery department took measures to manage the patients, medical staff and wards to avoid the cross-infection within hospital. During the outbreak, no patients or healthcare workers were infected, and no treatment was delayed due to these measures. The prevention and control measures effectively reduced the risk of nosocomial transmission between health workers and patients while providing optimum care. It was a feasible management approach that was applicable to most low-risk and even high-risk departments.

Theatre ventilation.

INTRODUCTION: Owing to the COVID-19 pandemic, there has been significant disruption to all surgical specialties. In the UK, units have cancelled elective surgery and a decrease in aerosol generating procedures (AGPs) was favoured. Centres around the world advocate the use of negative pressure environments for AGPs in reducing the spread of infectious airborne particles. We present an overview of operating theatre ventilation systems and the respective evidence with relation to surgical site infection (SSI) and airborne pathogen transmission in light of COVID-19. METHODS: A literature search was conducted using the PubMed, Cochrane Library and MEDLINE databases. Search terms included "COVID-19", "theatre ventilation", "laminar", "turbulent" and "negative pressure". FINDINGS: Evidence for laminar flow ventilation in reducing the rate of SSI in orthopaedic surgery is widely documented. There is little evidence to support its use in general surgery. Following previous viral outbreaks, some centres have introduced negative pressure ventilation in an attempt to decrease exposure of airborne pathogens to staff and surrounding areas. This has again been suggested during the COVID-19 pandemic. A limited number of studies show some positive results for the use of negative pressure ventilation systems and reduction in spread of pathogens; however, cost, accessibility and duration of conversion remain an unexplored issue. Overall, there is insufficient evidence to advocate large scale conversion at this time. Nevertheless, it may be useful for each centre to have its own negative pressure room available for AGPs and high risk patients.

Early presentation of post-intubation tracheoesophageal fistula with severe tracheal stenosis in COVID-19 patient.

The current global COVID-19 pandemic is caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, acquired tracheoesophageal fistulas are mainly iatrogenic lesions produced by prolonged tracheal intubation. We present a case of tracheoesophageal fistula with severe tracheal stenosis following tracheal intubation in a patient with SARS-CoV-2 infection.

Normal breathing releases SARS-CoV-2 into the air.

This study tests the release of SARS-CoV-2 RNA into the air during normal breathing, without any sign of possible risk of contagion such as coughing, sneezing or talking. Five patients underwent oropharyngeal, nasopharyngeal and salivary swabs for real-time reverse transcriptase PCR (RT-PCR) detection of SARS-CoV-2 RNA. Direct SARS-CoV-2 release during normal breathing was also investigated by RT-PCR in air samples collected using a microbiological sampler. Viral RNA was detected in air at 1 cm from the mouth of patients whose oropharyngeal, nasopharyngeal and salivary swabs tested positive for SARS-CoV-2 RNA. In contrast, the viral RNA was not identified in the exhaled air from patients with oropharyngeal, nasopharyngeal and salivary swabs that tested negative. Contagion of SARS-CoV-2 is possible by being very close to the mouth of someone who is infected, asymptomatic and simply breathing.

Negative-Pressure Isolation Mask for Endoscopic Examination During the Coronavirus Disease 2019 Pandemic: A Randomized Controlled Trial.

INTRODUCTION: During the coronavirus disease 2019 (COVID-19) pandemic, endoscopists have high risks of exposure to exhaled air from patients during gastroscopy. To minimize this risk, we transformed the oxygen mask into a fully closed negative-pressure gastroscope isolation mask. This study aimed to evaluate the effectiveness, safety, and feasibility of use of this mask during gastroscopy. METHODS: From February 28, 2020, to March 10, 2020, 320 patients undergoing gastroscopy were randomly assigned into the mask group (n = 160) or conventional group (n = 160). Patients in the mask group wore the isolation mask during gastroscopy, whereas patients in the conventional group did not wear the mask. The adenosine triphosphate fluorescence and carbon dioxide (CO2) concentration in patients' exhaled air were measured to reflect the degree of environmental pollution by exhaled air. Patients' vital signs, operation time, and adverse events during endoscopy were also evaluated. RESULTS: Four patients were excluded because of noncooperation or incomplete data. A total of 316 patients were included in the final analysis. The difference between the highest CO2 concentration around patients' mouth and CO2 concentration in the environment was significantly decreased in the mask group compared with the conventional group. There was no significant difference in the adenosine triphosphate fluorescence, vital signs, and operation time between the 2 groups. No severe adverse events related to the isolation mask, endoscopy failure, or new coronavirus infection during follow-up were recorded. DISCUSSION: This new isolation mask showed excellent feasibility of use and safety compared with routine gastroscopy during the COVID-19 pandemic.

Safe and Efficient Practice of Bronchoscopic Sampling from Mechanically Ventilated Patients: A Structured Evaluation of the Ambu Bronchosampler-Ascope 4 Integrated System.

BACKGROUND: Bronchoscopic sampling of bronchoalveolar fluid (BAL) should be safe and effective. Current sampling practice risks loss of sample to the attached negative flow, aerosolisation, or spillage, due to repeated circuit breaks, when replacing sample containers. Such concerns were highlighted during the recent coronavirus pandemic. OBJECTIVES: Evaluation of an alternative integrated sampling solution, with the Ambu Bronchosampler with aScope 4, by an experienced bronchoscopist in ICU. METHODS: An observational study of 20 sequential bronchoscopic diagnostic sampling procedures was performed on mechanically ventilated patients with suspected ventilator-associated pneumonia. Mixed methods assessment was done. The predefined outcome measures were (1) ease of set up, (2) ease of specimen collection, (3) ease of protecting specimen from loss or spillage, and (4) overall workflow. The duration of the procedure and the % volume of sample retrieved were recorded. RESULTS: The mean (±standard deviation [SD]) time for collecting 1 sample was 2.5 ± 0.8 min. The mean (±SD) specimen yield for instilled miniBAL was 54.2 ± 17.9%. Compared with standard sampling, the set-up was much easier in 18 (90%), or easier in 2 (10%) of procedures, reducing the connection steps. It was much more intuitive to use in 14 (70%), more intuitive in 4 (20%), and no more intuitive to use in 2 (10%). The overall set-up and workflow was much easier in 69% of the 13 intraprocedural connections and easier or as easy in the remaining 31% procedures. All procedures where pre connection was established were much easier (7, 100%). The Ambu Bronchosampler remained upright in all procedures with no loss or spillage of sample. Obtaining a sample was much easier in 60%, easier in 10%, no different in 20%, and worse in 10%. The ability to protect a sample from start to finish compared to standard procedures was much easier in 80%, easier in 15%, and no different in 5% of procedures. Overall workflow was much easier in 14 (70%), easier in 4 (20%), and no different in 2 (10%) of procedures. CONCLUSIONS: The Ambu Bronchosampler unit was a reliable, effective, and possibly safer technique for diagnostic sampling in ICU. It may improve safety standards during the coronavirus pandemic. A randomized control trial against the standard sampling technique is warranted.

Management of tracheostomy in COVID-19 patients: The Japanese experience.

OBJECTIVE: Involvement in the tracheostomy procedure for COVID-19 patients can lead to a feeling of fear in medical staff. To address concerns over infection, we gathered and analyzed experiences with tracheostomy in the COVID-19 patient population from all over Japan. METHODS: The data for health-care workers involved in tracheostomies for COVID-19-infected patients were gathered from academic medical centers or their affiliated hospitals from all over Japan. RESULTS: Tracheostomies have been performed in 35 COVID-19 patients with a total of 91 surgeons, 49 anesthesiologists, and 49 surgical staff members involved. Twenty-eight (80%) patients underwent surgery more than 22 days after the development of COVID-19-related symptoms (11: 22-28 days and 17: ≥29 days). Thirty (85.7%) patients underwent surgery ≥ 15 days after intubation (14: 15-21 days, 6: 22-28 days, and 10: ≥29 days). Among the total of 189 health-care workers involved in the tracheostomy procedures, 25 used a powered air-purifying respirator (PAPR) and 164 used a N95 mask and eye protection. As a result, no transmission to staff occurred during the 2 weeks of follow-up after surgery. CONCLUSION: No one involved in tracheostomy procedures were found to have been infected with COVID-19 in this Japanese study. The reason is thought to be that the timing of the surgery was quite late after the infections, and the surgery was performed using appropriate PPE and surgical procedure. The indications for and timing of tracheostomy for severe COVID-19 patients should be decided through multidisciplinary discussion.

Masks and closed-loop ventilators prevent environmental contamination by COVID-19 patients in negative-pressure environments.

Herein, we report that nosocomial infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be mitigated by using surgical masks and closed looped ventilation for both non-critical and critical patients. These preventive measures resulted in no viral contamination of surfaces in negative pressure environments.