Background Face coverings constitute an important strategy for containing pandemics, such as COVID-19. Infection from airborne respiratory viruses including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) can occur in at least three modes; tiny and/or dried aerosols (typically < 1.0 μm) generated through multiple mechanisms including talking, breathing, singing, large droplets (> 0.5 μm) generated during coughing and sneezing, and macro drops transmitted via fomites. While there is a growing number of studies looking at the performance of household materials against some of these situations, to date, there has not been any systematic characterization of household materials against all three modes. Methods A three-step methodology was developed and used to characterize the performance of 21 different household materials with various material compositions (e.g. cotton, polyester, polypropylene, cellulose and blends) using submicron sodium chloride aerosols, water droplets, and mucous mimicking macro droplets over an aerosol-droplet size range of ~ 20 nm to 0.6 cm. Results Except for one thousand-thread-count cotton, most single-layered materials had filtration efficiencies < 20% for sub-micron solid aerosols. However, several of these materials stopped > 80% of larger droplets, even at sneeze-velocities of up to 1700 cm/s. Three or four layers of the same material, or combination materials, would be required to stop macro droplets from permeating out or into the face covering. Such materials can also be boiled for reuse. Conclusion Four layers of loosely knit or woven fabrics independent of the composition (e.g. cotton, polyester, nylon or blends) are likely to be effective source controls. One layer of tightly woven fabrics combined with multiple layers of loosely knit or woven fabrics in addition to being source controls can have sub-micron filtration efficiencies > 40% and may offer some protection to the wearer. However, the pressure drop across such fabrics can be high (> 100 Pa).

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Background Gastrostomy tubes (G-tubes) are typically used when people cannot eat food by mouth. The connector section that allows G-tubes to connect to other devices, such as feeding sets or syringes, has been modified on some of the devices to reduce misconnections in hospital settings. The narrow internal diameter of the new connector, standardized under ISO 80369–3, has caused some users to express concern about a reduced flow rate. Previous studies performed on commercial devices determined that it was not conclusive how much the ISO 80369–3 connector contributed towards the reduced flow rate, because when manufacturers designed these new connector-based devices, they often changed other geometric variables (such as distal tube diameter, or length) at the same time. Thus, it became difficult isolating the effect of the connector from other geometric variables. Method The key objective of this study was to investigate how different design variables impacted the flow rate through the G-tubes. 3D-printed devices were used to assess the geometric parameters in a systematic manner. Commercial diets and Newtonian analog fluids with matched viscosities were used for testing. Results The flow path length of the “transition section” encompassing the standardized ISO 80369–3 connector in the new devices was found to cause reduced flow. Additionally, results showed that a shortened (≤ 10 mm) transition section, along with a 10% increase in the distal inner diameter of large bore devices (e.g., 24 Fr), can restore flow rates to levels consistent with the previous devices prior to the connector standardization. Conclusions The strategy for restoring flow rates to previous levels may help alleviate concerns raised by multiple stakeholders such as health care professionals, patients, caregivers and device manufacturers. In addition, the approach proposed here can be used as a tool for designing future G-tube devices.

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Misconnections between enteral devices and other medical devices have been associated with patient death and serious injuries. To minimize such misconnections, the design of connectors on enteral devices has been standardized. The most common adaptation of the standardized enteral connector is called ENFit. Gastrostomy tubes (G-tubes), which may or may not possess the ENFit connector, are increasingly used to deliver commercial and blenderized diets in home settings to enteral device users. To investigate and compare the performance of Gtubes with and without ENFit connectors, research investigations have recently been performed. However, synthesis of such investigations and quantitative discussion of the consequences of transitioning to ENFit-based G-tube devices has not yet occurred. Here we review the research findings from these studies, with data on patient practices from a Mayo Clinic survey, to estimate the impact on tube feeders in home settings of transitioning to ENFit-based G-tube devices. Extrapolating the findings from these studies to US enteral G-tube patients, 2.5%-8.6% of adult patients and 0.2%-1.9% of pediatric patients may experience perceptible slowing in their gravity feeds if using ENFit-based G-tube devices. About 2.5%-8.6% of adult patients and 0.5%-5.5% of pediatric patients (or their caregivers) may need to push with perceptibly more force for syringe push-based feeding using ENFit-based G-tube devices. Lastly, the article offers suggestions for patients and device manufacturers.

Tissue containment systems (TCS) are medical devices that may be used during morcellation procedures during minimally invasive laparoscopic surgery. TCS are not new devices but their use as a potential mitigation for the spread of occult malignancy during laparoscopic power morcellation of fibroids and/or the uterus has been the subject of interest following reports of upstaging of previously undetected sarcoma in women who underwent a laparoscopic hysterectomy. Development of standardized test methods and acceptance criteria to evaluate the safety and performance of these devices will speed development, allowing for more devices to benefit patients. As a part of this study, a series of preclinical experimental bench test methods were developed to evaluate the mechanical and leakage performance of TCS that may be used in power morcellation procedures. Experimental tests were developed to evaluate mechanical integrity, e.g., tensile, burst, puncture, and penetration strengths for the TCS, and leakage integrity, e.g., dye and microbiological leakage (both acting as surrogates for blood and cancer cells) through the TCS. In addition, to evaluate both mechanical integrity and leakage integrity as a combined methodology, partial puncture and dye leakage was conducted on the TCS to evaluate the potential for leakage due to partial damage caused by surgical tools. Samples from 7 different TCSs were subjected to preclinical bench testing to evaluate leakage and mechanical performance. The performance of the TCSs varied significantly between different brands. The leakage pressure of the TCS varied between 26 and > 1293 mmHg for the 7 TCS brands. Similarly, the tensile force to failure, burst pressure, and puncture force varied between 14 and 80 MPa, 2 and 78 psi, and 2.5 N and 47 N, respectively. The mechanical failure and leakage performance of the TCS were different for homogeneous and composite TCSs. The test methods reported in this study may facilitate the development and regulatory review of these devices, may help compare TCS performance between devices, and increase provider and patient accessibility to improved tissue containment technologies.

Objective: Development of test methods used to determine the leakage factor for tissue containment systems during power morcellation. Design: Samples from six different legally marketed tissue containment bags were subjected to modified dye penetration tests (ASTM F1670 / F1671) at pressures ranging from 0.5 to 50 times the insufflation pressure. The minimum pressure required to cause bag leakage was measured. Subsequently, the leakage factor for each bag was determined as the ratio of the minimum leakage pressure to the total pressure combined from all forces acting on the bag during the power morcellation procedure, including the insufflation pressure. The total pressure includes the insufflation pressure plus additional pressures acting during the morcellation procedure. In vitro morcellation was performed using bovine tongue as a tissue surrogate to determine additional pressures acting on the bag. Settings: A Medical Device Testing Laboratory. Patients: Tissue containment bags. Interventions: Dye penetration tests and in vivo morcellation. Measurements/Results: The amount of pressure required to cause bag failure for the dye penetration testing was dependent on the bag material and thickness. The leakage pressures obtained ranged from 0.75 PSI to >25 PSI (n = 3 trials) for the six bag brands, and leakage factors ranged from 1 to 50 when only the insufflation pressure was considered. However, if all the morcellation forces considered were included in the calculation, the leakage factor dropped below one (i.e. indicating bag leakage for at least one of the six brands. Conclusions: Our results show that at least one of the tissue containment bags leaked when exposed to all forces (including insufflation pressure) experienced during power morcellation. Future experiments will determine how much of an effect the morcellation forces have on the bag and whether they are more significant than the insufflation forces. The results from these studies may aid in the development of pre-clinical testing methodologies for tissue containment bags used in power morcellation.

Background: Tissue containment systems (TCS) are medical devices that may be used during morcellation procedures during minimally invasive laparoscopic surgery. TCS are not new devices but their use as a potential mitigation for the spread of occult malignancy during laparoscopic power morcellation of fibroids and/or the uterus has been the subject of interest following reports of upstaging of previously undetected sarcoma in women who underwent a laparoscopic hysterectomy. Development of standardized test methods and acceptance criteria to evaluate the safety and performance of these devices will speed development, allowing for more devices to benefit patients. Methods: As a part of this study, a series of preclinical experimental bench test methods were developed to evaluate the mechanical and leakage performance of TCS that may be used in power morcellation procedures. Experimental tests were developed to evaluate mechanical integrity, e.g., tensile, burst, puncture, and penetration strengths for the TCS, and leakage integrity, e.g., dye and microbiological leakage (both acting as surrogates for blood and cancer cells) through the TCS. In addition, to evaluate both mechanical integrity and leakage integrity as a combined methodology, partial puncture and dye leakage was conducted on the TCS to evaluate the potential for leakage due to partial damage caused by surgical tools. Samples from 7 different TCSs) were subjected to preclinical bench testing to evaluate leakage and mechanical performance. Results: The performance of the TCSs varied significantly between different brands. The leakage pressure of the TCS varied between 26 mmHg and >1293 mmHg for the 7 TCS brands. Similarly, the tensile force to failure, burst pressure, and puncture force varied between 14 MPa and 80 MPa, 2.5 and 78 psi, and 2.5 N and 45 N, respectively. The mechanical failure and leakage performance of the TCS were different for homogeneous and composite TCSs. Conclusions: Test methods have been developed to evaluate the mechanical and leakage performance of TCS. These test methods may facilitate the development and regulatory review of these devices, may help compare TCS performance between devices, and increase provider and patient accessibility to improved tissue containment technologies.