Impact of air-handling system exhaust failure on dissemination pattern of simulant pathogen particles in a clinical biocontainment unit.

Biocontainment units (BCUs) are facilities used to care for patients with highly infectious diseases. However, there is limited guidance on BCU protocols and design. This study presents the first investigation of how HVAC (heating, ventilation, air-conditioning) operating conditions influence the dissemination of fluorescent tracer particles released in a BCU. Test conditions included normal HVAC operation and exhaust failure resulting in loss of negative pressure. A suspension of optical brightener powder and water was nebulized to produce fluorescent particles simulating droplet nuclei (0.5-5 µm). Airborne particle number concentrations were monitored by Instantaneous Biological Analyzers and Collectors (FLIR Systems). During normal HVAC operation, fluorescent tracer particles were contained in the isolation room (average concentration = 1 × 104 ± 3 × 103 /Lair ). Under exhaust failure, the automated HVAC system maximizes airflow into areas adjacent to isolation rooms to attempt to maintain negative pressure differential. However, 6% of the fluorescent particles were transported through cracks around doors/door handles out of the isolation room via airflow alone and not by movement of personnel or doors. Overall, this study provides a systematic method for evaluating capabilities to contain aerosolized particles during various HVAC scenarios. Recommendations are provided to improve situation-specific BCU safety.

Validation of Autoclave Protocols for Successful Decontamination of Category A Medical Waste Generated from Care of Patients with Serious Communicable Diseases.

In response to the Ebola outbreak in 2014, many hospitals designated specific areas to care for patients with Ebola and other highly infectious diseases. The safe handling of category A infectious substances is a unique challenge in this environment. One solution is on-site waste treatment with a steam sterilizer or autoclave. The Johns Hopkins Hospital (JHH) installed two pass-through autoclaves in its biocontainment unit (BCU). The JHH BCU and The Johns Hopkins biosafety level 3 (BSL-3) clinical microbiology laboratory designed and validated waste-handling protocols with simulated patient trash to ensure adequate sterilization. The results of the validation process revealed that autoclave factory default settings are potentially ineffective for certain types of medical waste and highlighted the critical role of waste packaging in successful sterilization. The lessons learned from the JHH validation process can inform the design of waste management protocols to ensure effective treatment of highly infectious medical waste.

From Alpha to Omicron: A Radiation Oncology Network's Biocontainment-Based COVID-19 Experience.

Purpose: To develop the safest possible environment for treating urgent patients with COVID-19 requiring radiation, we describe the unique construction of negative air pressure computed tomography simulator and linear accelerator treatment vaults in addition to screening, delay, and treatment protocols and their evolution over the course of the COVID-19 pandemic. Methods and Materials: Construction of large high-efficiency particulate air filter air-flow systems into existing ductwork in computed tomography simulator rooms and photon and proton treatment vaults was completed to create negative-pressure rooms. An asymptomatic COVID-19 screening protocol was implemented for all patients before initiation of treatment. Patients could undergo simulation and/or treatment in the biocontainment environments according to a predefined priority scale and protocol. Patients treated under the COVID-19 protocol from June 2020 to January 2022 were retrospectively reviewed. Results: Negative air-flow environments were created across a regional network, including a multi-gantry proton therapy unit. In total, 6525 patients were treated from June 2020 through January 2022 across 5 separate centers. The majority of patients with COVID-19 had radiation treatment deferred when deemed safe. A total of 42 patients with COVID-19, who were at highest risk of an adverse outcome should there be a radiation delay, were treated under the COVID-19 biocontainment protocol in contrast to those who were placed on treatment break. For 61.9% of patients, these safety measures mitigated an extended break during treatment. The majority of patients (64.3%) were treated with curative intent. The median number of biocontainment sessions required by each patient was 6 (range, 1-15) before COVID-19 clearance and resumption of treatment in a normal air-flow environment. Conclusions: Constructing negative-pressure environments and developing a COVID-19 biocontainment treatment protocol allowed for the safe treatment of urgent radiation oncology patients with COVID-19 within our department and strengthens future biopreparedness. These biocontainment units set a high standard of safety in radiation oncology during the current or for any future infectious outbreak.

Adapting the modified barium swallow: modifications to improve safety in the setting of airborne respiratory illnesses like COVID-19.

No guidance exists on how to safely perform modified barium swallows (MBS) in the midst of the COVID-19 pandemic or other communicable airborne respiratory infections (C-ARI). MBS has the potential to become an aerosol generating procedure (AGP) as it may trigger a cough or necessitate suctioning which may result in transmission of C-ARI putting patients and health care workers at risk. Regulations and best practices from international and US governmental and commercial agencies were reviewed. This review led to the multidisciplinary development of best practices of the safety measures and structural requirements to avoid transmission of SARS-CoV-2 or other C-ARIs when performing MBS. Implementation of these best practices resulted in structural changes to the fluoroscopy suite and protocol workflows. This enabled patients with COVID-19 to undergo MBS while maintaining patient and staff safety including mitigation of potential risk of onward transmission of SARS-CoV-2 to other patients. With proper modifications, MBS can be safely performed on patients with C-ARI such as COVID-19 while maintaining patient and health care worker (HCW) safety.

The Creation of a Biocontainment Unit at a Tertiary Care Hospital. The Johns Hopkins Medicine Experience.

In response to the 2014-2015 Ebola virus disease outbreak in West Africa, Johns Hopkins Medicine created a biocontainment unit to care for patients infected with Ebola virus and other high-consequence pathogens. The unit team examined published literature and guidelines, visited two existing U.S. biocontainment units, and contacted national and international experts to inform the design of the physical structure and patient care activities of the unit. The resulting four-bed unit allows for unidirectional flow of providers and materials and has ample space for donning and doffing personal protective equipment. The air-handling system allows treatment of diseases spread by contact, droplet, or airborne routes of transmission. An onsite laboratory and an autoclave waste management system minimize the transport of infectious materials out of the unit. The unit is staffed by self-selected nurses, providers, and support staff with pediatric and adult capabilities. A telecommunications system allows other providers and family members to interact with patients and staff remotely. A full-time nurse educator is responsible for staff training, including quarterly exercises and competency assessment in the donning and doffing of personal protective equipment. The creation of the Johns Hopkins Biocontainment Unit required the highest level of multidisciplinary collaboration. When not used for clinical care and training, the unit will be a site for research and innovation in highly infectious diseases. The lessons learned from the design process can inform a new research agenda focused on the care of patients in a biocontainment environment.

A 17-month evaluation of a chlorine dioxide water treatment system to control Legionella species in a hospital water supply.

OBJECTIVE: To assess the safety and efficacy of a chlorine dioxide water treatment system in controlling Legionella in a hospital water supply. DESIGN: For 17 months following installation of the system, we performed regular water cultures throughout the building, assessed chlorine dioxide and chlorite levels, and monitored metal corrosion. RESULTS: Sites that grew Legionella species decreased from 41% at baseline to 4% (P = .001). L. anisa was the only species recovered and it was found in samples of both hot and cold water. Levels of chlorine dioxide and chlorite were below Environmental Protection Agency (EPA) limits for these chemicals in potable water. Further, enhanced carbon filtration effectively removed the chemicals, even at chlorine dioxide levels of more than twice what was used to treat the water. After 9 months, corrosion of copper test strips exposed to the chlorine dioxide was not higher than that of control strips. During the evaluation period, there were no cases of nosocomial Legionella in the building with the system, whereas there was one case in another building. CONCLUSIONS: Our results indicate that operation of a chlorine dioxide system effectively removed Legionella species from a hospital water supply. Furthermore, we found that the system was safe, as levels of chlorine dioxide and chlorite were below EPA limits. The system did not appear to cause increased corrosion of copper pipes. Our results indicate that chlorine dioxide may hold promise as a solution to the problem of Legionella contamination of hospital water supplies.

Electronic-eye faucets: Legionella species contamination in healthcare settings.

OBJECTIVE: To compare heterotrophic plate counts (HPCs) and Legionella species growth from electronic and manual faucet water samples. DESIGN: Proportions of water samples with growth and colony-forming units were compared using Fisher's exact test and the Wilcoxon rank-sum test, respectively. SETTING: Two psychiatric units and 1 medical unit in a 1,000-bed university hospital. METHODS: Water samples were collected from 20 newly installed electronic faucets and 20 existing manual faucets in 3 hospital units. Manual faucets were located in rooms adjacent to the electronic faucets and received water from the same source. Water samples were collected between December 15, 2008, and January 29, 2009. Four electronic faucets were dismantled, and faucet components were cultured. Legionella species and HPC cultures were performed using standard methods. RESULTS: Nearly all electronic faucets (19/20 [95%]) grew Legionella species from at least 1 water sample, compared with less than half (9/20 [45%]) of manual faucets ([Formula: see text]). Fifty-four (50%) of 108 electronic faucet water cultures grew Legionella species, compared with 11 (15%) of 75 manual faucet water cultures ([Formula: see text]). After chlorine dioxide remediation, 4 (14%) of 28 electronic faucet and 1 (3%) of 30 manual faucet water cultures grew Legionella species ([Formula: see text]), and 8 (29%) electronic faucet and 2 (7%) manual faucet cultures had significant HPC growth ([Formula: see text]). All 12 (100%) of the internal faucet components from 2 electronic faucets grew Legionella species. CONCLUSIONS: Electronic faucets were more commonly contaminated with Legionella species and other bacteria and were less likely to be disinfected after chlorine dioxide remediation. Electronic faucet components may provide points of concentrated bacterial growth.