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.

The effectiveness of antibacterial curtains in comparison with standard privacy curtains against transmission of microorganisms in a hospital setting

Studies have shown a correlation between a cleaner patient environment and lower infection rates and reduced risk of transmission. Privacy curtains are potentially important sites of bacterial contamination in hospitals. Privacy curtains integrated with antimicrobial properties have been shown to increase the time to first contamination compared with standard privacy curtains. In this study, we examined the difference in bacterial colonization of different curtains. We experimentally contaminated antibacterial Fantex protective curtains and compared the bacterial counts to natural contamination of privacy curtains. There was a significant reduction in the CFU/cm2 on antibacterial Fantex protective privacy curtains after 24 hours of experimental contamination with Pseudomonas aeruginosa, Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus (MRSA) or extended-spectrum-producing organisms (Escherichia coli or Klebsiella pneumoniae), compared to standard privacy curtains. Levels of environmental contamination with S. epidermis, Streptococcus viridians, E. coli, S. haemolyticus, S. aureus, S. capitis, non-fermenting Gram-negative bacteria, and Bacillus species were also significantly less on the Fantex curtains after two months hanging in the emergency department. Healthcare facilities may find that addressing surfaces, including use of antibacterial privacy curtains, is an effective horizontal strategy for addressing healthcare-associated infections across the board.

Aeromedical Transfer of Patients with Viral Hemorrhagic Fever

For >40 years, the British Royal Air Force has maintained an aeromedical evacuation facility, the Deployable Air Isolator Team (DAIT), to transport patients with possible or confirmed highly infectious diseases to the United Kingdom. Since 2012, the DAIT, a joint Department of Health and Ministry of Defence asset, has successfully transferred 1 case-patient with Crimean-Congo hemorrhagic fever, 5 case-patients with Ebola virus disease, and 5 case-patients with high-risk Ebola virus exposure. Currently, no UK-published guidelines exist on how to transfer such patients. Here we describe the DAIT procedures from collection at point of illness or exposure to delivery into a dedicated specialist center. We provide illustrations of the challenges faced and, where appropriate, the enhancements made to the process over time.

Initial test of emergency procedure performance in temporary negative pressure isolation by using simulation technologies

Study objective

The potential of infectious disease spread in diseases such as tuberculosis, infectious disease epidemic such as avian flu and the threat of terrorism with agents capable of airborne transmission have focused attention on the need for increased surge capacity for patient isolation. Total negative pressure isolation using portable bioisolation tents may provide a solution. The study assesses the ability of health care workers to perform emergency procedures in this environment.

Methods

Physician performance in completing predetermined critical actions in 5 emergency care scenarios inside and outside of a bioisolation tent (“setting”) was studied in an advanced medical simulation laboratory. By design, no pretraining of subjects about total negative pressure isolation use occurred. Impact of setting on time to completion of predetermined critical actions was the primary outcome measured. Secondary variables studied included impact of study groups, scenarios, and run order (inside or outside of the tent first). Subjective assessments were obtained through questionnaires.

Results

Four teams of 3 physicians completed 5 emergency patient care scenarios during 2 4-hour sessions. Mean time to completion of critical actions was for tent/no tent 298 seconds/284 seconds (P=.69, one way ANOVA), respectively. Mean time to completion for first versus second performance of a scenario in the crossover design was 338 versus 243 (P=.01). The mean score for self-assessed performance did not differ according to setting.

Conclusion

The ability of physicians naive to the total negative pressure isolation environment to perform emergency medical critical actions was not significantly degraded by a simulated bioisolation tent patient care environment.

Development of an empirical model to aid in designing airborne infection isolation rooms

Airborne infection isolation rooms (AIIRs) house patients with tuberculosis, severe acute respiratory syndrome (SARS), and many other airborne infectious diseases. Currently, facility engineers and designers of heating, ventilation, and air-conditioning (HVAC) systems have few analytical tools to estimate a room's leakage area and establish an appropriate flow differential (DeltaQ) in hospitals, shelters, and other facilities where communicable diseases are present. An accurate estimate of leakage area and selection of DeltaQ is essential for ensuring that there is negative pressure (i.e., pressure differential [DeltaP]) between an AIIR and adjoining areas. National Institute for Occupational Safety and Health (NIOSH) researchers evaluated the relationship between DeltaQ and DeltaP in 67 AIIRs across the United States and in simulated AIIR. Data gathered in the simulated AIIR was used to develop an empirical model describing the relationship between DeltaQ, DeltaP, and leakage area. Data collected in health care facilities showed that the model accurately predicted the leakage area 44 of 48 times. Statistical analysis of the model and experimental validation showed that the model effectively estimated the actual leakage area from -39% to +22% with 90% confidence. The NIOSH model is an effective, cost-cutting tool that can be used by HVAC engineers and designers to estimate leakage area and select an appropriate DeltaQ in AIIRs to reduce the airborne transmission of disease.

Modified N95 mask delivers high inspired oxygen concentrations while effectively filtering aerosolized microparticles

STUDY OBJECTIVE

In a pandemic, hypoxic patients will require an effective oxygen (O2) delivery mask that protects them from inhaling aerosolized particles produced by others, as well as protecting the health care provider from exposure from the patient. We modified an existing N95 mask to optimize O2 supplementation while maintaining respiratory isolation.

METHODS

An N95 mask was modified to deliver O2 by inserting a plastic manifold consisting of a 1-way inspiratory valve, an O2 inlet and a gas reservoir. In a prospective repeated-measures study, we studied 10 healthy volunteers in each of 3 phases, investigating (1) the fractional inspiratory concentrations of O2 (F(I)O2) delivered by the N95 O2 mask, the Hi-Ox80 O2 mask, and the nonrebreathing mask during resting ventilation and hyperventilation, each at 3 O2 flow rates; (2) the ability of the N95 mask, the N95 O2 mask, and the nonrebreathing mask to filter microparticles from ambient air; and (3) to contain microparticles generated inside the mask.

RESULTS

The F(I)O2s (median [range]) delivered by the Hi-Ox80 O2 mask, the N95 O2 mask, and the nonrebreathing mask during resting ventilation, at 8 L/minute O2 flow, were 0.90 (0.79 to 0.96), 0.68 (0.60 to 0.85), and 0.59 (0.52 to 0.68), respectively. During hyperventilation, the FiO2s of all 3 masks were clinically equivalent. The N95 O2 mask, but not the nonrebreathing mask, provided the same efficiency of filtration of internal and external particles as the original N95, regardless of O2 flow into the mask.

CONCLUSION

An N95 mask can be modified to administer a clinically equivalent FiO2 to a nonrebreathing mask while maintaining its filtration and isolation capabilities.

An evaluation of portable high-efficiency particulate air filtration for expedient patient isolation in epidemic and emergency response

Extraordinary incidents resulting in airborne infectious disease outbreaks could produce patient isolation requirements that exceed most hospitals' capacity. This article investigates expedient methods to establish airborne infection isolation areas using a commercially available portable filtration unit and common hardware supplies. The study was conducted within a conventional, nonisolation hospital room, and researchers evaluated several airborne isolation configurations that did not require building ventilation or structural modifications. A portable high-efficiency particulate air filtration unit and full-length plastic curtains established a “zone-within-zone” protective environment using local capture and directional airflows. The cost of constructing the expedient configurations was less than US$2,300 and required fewer than 3 person-hours to construct. A medical nebulizer aerosolized polystyrene latex microspheres to generate respirable condensation nuclei. Aerosol spectrometers sized and counted respirable particles at the source patient and health care worker positions and in areas outside the inner zone. The best-performing designs showed no measurable source migration out of the inner isolation zone and mean respirable particle counts up to 87% lower at the health care worker position(s) than those observed directly near the source patient location. Investigators conclude that with careful implementation under emergency circumstances in which engineered isolation rooms are unavailable, expedient methods can provide affordable and effective patient isolation while reducing exposure risks and potential disease transmission to health care workers, other patients, and visitors.

Reduction of nosocomial infection during pediatric intensive care by protective isolation

To determine whether simple protective isolation reduces the incidence of nosocomial bacterial and fungal infection during pediatric intensive care, we randomly assigned 70 children who were not immuno-suppressed and who required mechanical ventilatory support and three or more days of intensive care to receive standard care (n = 38) or protective isolation (n = 32) with use of disposable, non-waven, polypropylene gowns and nonsterile latex gloves. Risk factors predisposing patients to infection were comparable in the two groups. Nosocomial colonization occurred later among isolated patients (median, vs. 7 days; P less than 0.01) and was associated with subsequent infection in 12 patients, as compared with 12 patients given standard care (P = 0.01). Among patients who were isolated, the interval before the first infection was significantly longer than (median, 20 vs. 8 days; P = 0.04), the daily infection rate was 2.2 times lower than (95 percent confidence interval, 1.2 to 4.0; P = 0.007), and there were fewer days with fewer (13 percent vs. 21 percent; P = 0.001). The benefit of isolation was most notable after seven days of intensive care. Isolation was well tolerated by patients and their families. Regular monitoring showed that the children in each group were touched and handled comparably often by hospital personnel and family members. We conclude that the use of disposable, high-barrier gowns and gloves for the care of selected, high-risk children who require prolonged intensive care significantly reduces the incidence of nosocomial infection, is well tolerated, and does not compromise the delivery of care.

Monitoring monitors

A centralized, remote alarm system was implemented to alert nursing personnel when patient monitors located in isolation rooms go into alarm. The design includes a method of confirming the ON/OFF status of individual monitors to avoid operator error. This system utilizes low-cost individual patient monitors and includes interface devices, an alarm panel, and indicator panels. The design logic is based on the need for nursing personnel to also be alerted in the event of any abnormality associated with the patient monitors, the alarm panel itself, or with the interconnections. The system will also accommodate infusion pumps, respirators, or any other devices equipped with a remote alarm (nurse call) output.

Cost-effective application of the Centers for Disease Control Guideline for Isolation Precautions in Hospitals

Isolation, as practiced in many hospitals today, is associated with ineffective, costly rituals. The isolation process can be monitored and critically examined to determine illogical practices. When these practices and their associated costs are known, specific strategies can be implemented to reduce the costs associated with isolation.

[Environment microbiological control in a department with patients at great risk (author's transl)]

Microbic flora has been studied in the Centro di Rianimazione of the Ospedali Riuniti in Chieti to control validity of the antibacterial systems and to verify efficacy of the filter systems that allow the admission into the isolation boxes, stopping great bacterial exogenous increases. These inspection have been executed by suction system Batteriological Air Pollution Detector.