Preventing spread of aerosolized infectious particles during medical procedures: A lab-based analysis of an inexpensive plastic enclosure.

Severe viral respiratory diseases, such as SARS-CoV-2, are transmitted through aerosol particles produced by coughing, talking, and breathing. Medical procedures including tracheal intubation, extubation, dental work, and any procedure involving close contact with a patient's airways can increase exposure to infectious aerosol particles. This presents a significant risk for viral exposure of nearby healthcare workers during and following patient care. Previous studies have examined the effectiveness of plastic enclosures for trapping aerosol particles and protecting health-care workers. However, many of these enclosures are expensive or are burdensome for healthcare workers to work with. In this study, a low-cost plastic enclosure was designed to reduce aerosol spread and viral transmission during medical procedures, while also alleviating issues found in the design and use of other medical enclosures to contain aerosols. This enclosure is fabricated from clear polycarbonate for maximum visibility. A large single-side cutout provides health care providers with ease of access to the patient with a separate cutout for equipment access. A survey of medical providers in a local hospital network demonstrated their approval of the enclosure's ease of use and design. The enclosure with appropriate plastic covers reduced total escaped particle number concentrations (diameter > 0.01 µm) by over 93% at 8 cm away from all openings. Concentration decay experiments indicated that the enclosure without active suction should be left on the patient for 15-20 minutes following a tracheal manipulation to allow sufficient time for >90% of aerosol particles to settle upon interior surfaces. This decreases to 5 minutes when 30 LPM suction is applied. This enclosure is an inexpensive, easily implemented additional layer of protection that can be used to help contain infectious or otherwise potentially hazardous aerosol particles while providing access into the enclosure.

The association between preinduction arterial blood pressure and postoperative cardiovascular, renal, and neurologic morbidity, and in-hospital mortality in elective noncardiac surgery: an observational study.

BACKGROUND: The association between preinduction blood pressure (BP) and postoperative outcomes after noncardiac surgery is poorly understood. Whether this association depends on the presence of risk factors for poor cardiovascular outcomes remains unclear. Accordingly, we evaluated the association between preinduction BP and its different components; isolated systolic hypertension (ISH) and wide pulse pressure (WPP), and postoperative complications in patients with and without revised cardiac risk index (RCRI) components. METHODS: We analysed consecutive patients undergoing elective noncardiac surgery at Cleveland Clinic. Separate analyses were undertaken for patients with and without any RCRI components. Preinduction BP was assessed both continuously and according to hypertension stages. Logistic regression was used to assess the association between the BP values and composite of in-hospital mortality as well as cardiovascular, renal, and neurologic morbidity. We considered the following potential confounding factors in our analysis; year of surgery, age, sex, race, BMI, and American College of Cardiology/American Heart Association surgical procedure risk classification. RESULTS: Of 58 276 patients, 10 512 had one or more RCRI components. For those with no RCRI, no significant relationship was found between preinduction BP and outcome after adjustment for confounders. For patients with RCRI, the adjusted incidence was the greatest among those with normal preinduction SBP and DBP of less than 70 mmHg. Among patients with preinduction DBP greater than 75 mmHg, risk rose slightly with increasing SBP. However, we found no association between preinduction hypertension stages, ISH, or WPP and the composite outcome in patients with and without RCRI. CONCLUSION: Preinduction low DBP less than 70 mmHg or SBP greater than 160 mmHg and not ISH, nor WPP were associated with an increased risk of postoperative complications in noncardiac surgery patients with one or more RCRI components.

Are American Surgical Residents Prepared for Humanitarian Deployment?: A Comparative Analysis of Resident and Humanitarian Case Logs.

BACKGROUND: Effective humanitarian surgeons require skills in general surgery, OB/GYN, orthopedics, and urology. With increasing specialization, it is unclear whether US general surgery residents are receiving exposure to these disparate fields. We sought to assess the preparedness of graduating American surgical residents for humanitarian deployment. METHODS: We retrospectively analyzed cases performed by American College of Graduate Medical Education general surgery graduates from 2009 to 2015 and cases performed at select Médecins Sans Frontières (MSF) facilities from 2008 to 2012. Cases were categorized by specialty (general surgery, orthopedics, OB/GYN, urology) and compared with Chi-squared testing. Non-operative care including basic wound and drain care was excluded from both data sets. RESULTS: US general surgery residents performed 41.3% MSF relevant general surgery cases, 1.9% orthopedic cases, 0.1% OB/GYN cases, and 0.3% urology cases; the remaining 56.4% of cases exceeded the standard MSF scope of care. In comparison, MSF cases were 30.1% general surgery, 21.2% orthopedics, 46.8% OB/GYN, and 1.9% urology. US residents performed fewer OB/GYN cases (p < 0.01) and fewer orthopedic cases (p < 0.01). Differences in general surgery and urology caseloads were not statistically significant. Key procedures in which residents lacked experience included cesarean sections, hysterectomies, and external bony fixation. CONCLUSION: Current US surgical training is poorly aligned with typical MSF surgical caseloads, particularly in OB/GYN and orthopedics. New mechanisms for obtaining relevant surgical skills should be developed to better prepare American surgical trainees interested in humanitarian work.

Titanium Oxide Crystallization and Interface Defect Passivation for High Performance Insulator-Protected Schottky Junction MIS Photoanodes.

Atomic layer deposited (ALD) TiO2 protection layers may allow for the development of both highly efficient and stable photoanodes for solar fuel synthesis; however, the very different conductivities and photovoltages reported for TiO2-protected silicon anodes prepared using similar ALD conditions indicate that mechanisms that set these key properties are, as yet, poorly understood. In this report, we study hydrogen-containing annealing treatments and find that postcatalyst-deposition anneals at intermediate temperatures reproducibly yield decreased oxide/silicon interface trap densities and high photovoltage. A previously reported insulator thickness-dependent photovoltage loss in metal-insulator-semiconductor Schottky junction photoanodes is suppressed. This occurs simultaneously with TiO2 crystallization and an increase in its dielectric constant. At small insulator thickness, a record for a Schottky junction photoanode of 623 mV photovoltage is achieved, yielding a photocurrent turn-on at 0.92 V vs NHE or -0.303 V with respect to the thermodynamic potential for water oxidation.

Design principles for maximizing photovoltage in metal-oxide-protected water-splitting photoanodes.

Metal oxide protection layers for photoanodes may enable the development of large-scale solar fuel and solar chemical synthesis, but the poor photovoltages often reported so far will severely limit their performance. Here we report a novel observation of photovoltage loss associated with a charge extraction barrier imposed by the protection layer, and, by eliminating it, achieve photovoltages as high as 630 mV, the maximum reported so far for water-splitting silicon photoanodes. The loss mechanism is systematically probed in metal-insulator-semiconductor Schottky junction cells compared to buried junction p(+)n cells, revealing the need to maintain a characteristic hole density at the semiconductor/insulator interface. A leaky-capacitor model related to the dielectric properties of the protective oxide explains this loss, achieving excellent agreement with the data. From these findings, we formulate design principles for simultaneous optimization of built-in field, interface quality, and hole extraction to maximize the photovoltage of oxide-protected water-splitting anodes.

A systematic comparison of cockcroft-gault and modification of diet in renal disease equations for classification of kidney dysfunction and dosage adjustment.

BACKGROUND: The dosing of drugs in patients with kidney dysfunction is often based on the estimates of kidney function. OBJECTIVE: To systematically compare the performance of the Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (CG) equations for dosage adjustment. METHODS: We assessed agreement (concordance, kappa statistics [κ,κ(ω)]) between CG and MDRD using a Food and Drug Administration database to evaluate the effect of renal function on the pharmacokinetics of 36 approved drugs. Across the approved drugs, we compared the correlation between these 2 equations for renal drug clearance (Cl(ren)) and area under the concentration-time curve. For 26 approved drugs that require renal dose adjustment, we also compared dosing regimens and expected exposure using these equations. Sensitivity analyses were performed by adjusting the MDRD estimates for individualized body surface area and/or range of serum creatinine assay calibration errors. RESULTS: In the pharmacokinetic database with 973 subjects (age 18-95 years, weight 35-153 kg, female 33%), we found that the CG and the MDRD classification of renal function generally agreed (64.2%, κ = 0.54, κ(ω) = 0.73). Among the subjects studied for drugs requiring renal dose adjustment, dosages in 12% were changed to a higher or lower dosing category by the MDRD compared to the CG equation. In particular, using MDRD in place of CG for dosage modification yielded higher dosing recommendations for subjects with a combination of age >80 years, weight <55 kg, and serum creatinine >0.7 and ≤1.5 mg/dL; the coefficient of determination was also higher by CG than MDRD in trials that enrolled these or similar patients. CONCLUSIONS: For patients with advanced age, low weight, and modestly elevated serum creatinine, further work is needed before the MDRD equations can replace the CG equation for dose adjustment in the labeling.

Is pulmonary vascular resistance index predictive of exercise tolerance in adult patients with idiopathic pulmonary arterial hypertension.

BACKGROUND: Clinical trials for adults with pulmonary arterial hypertension use exercise capacity, as measured by walking distance, as the primary endpoint to measure symptomatic improvement. In this article, we look at the relationship between walking distance and a hemodynamic variable, pulmonary vascular resistance index (PVRI), from the available trials. METHODS: Patient-level data from 16 randomized controlled clinical trials were obtained. All idiopathic subjects with a baseline and study endpoint measurement of both hemodynamic and exercise endpoints were included. Changes from baseline in both endpoints and the relationship between the endpoints were summarized. Receiver operating characteristic curves were used to investigate the predictive ability. Measures of surrogacy were also calculated. RESULTS: There is a weak correlation between changes in PVRI and exercise capacity. Receiver operating characteristic analysis shows a high false positive rate of using one variable to predict the other. Measures of surrogacy show the proportion of variability in exercise capacity explained by PVRI is approximately 5%. CONCLUSIONS: PVRI should not be used as a surrogate marker to predict changes in exercise capacity.

Inherited germline TP53 mutation encodes a protein with an aberrant C-terminal motif in a case of pediatric adrenocortical tumor.

Childhood adrenocortical tumor (ACT), a very rare malignancy, has an annual worldwide incidence of about 0.3 per million children younger than 15 years. The association between inherited germline mutations of the TP53 gene and an increased predisposition to ACT was described in the context of the Li-Fraumeni syndrome. In fact, about two-thirds of children with ACT have a TP53 mutation. However, less than 10% of pediatric ACT cases occur in Li-Fraumeni syndrome, suggesting that inherited low-penetrance TP53 mutations play an important role in pediatric adrenal cortex tumorigenesis. We identified a novel inherited germline TP53 mutation affecting the acceptor splice site at intron 10 in a child with an ACT and no family history of cancer. The lack of family history of cancer and previous information about the carcinogenic potential of the mutation led us to further characterize it. Bioinformatics analysis showed that the non-natural and highly hydrophobic C-terminal segment of the frame-shifted mutant p53 protein may disrupt its tumor suppressor function by causing misfolding and aggregation. Our findings highlight the clinical and genetic counseling dilemmas that arise when an inherited TP53 mutation is found in a child with ACT without relatives with Li-Fraumeni-component tumors.

Physics and instrumentation of ultrasound.

A thorough understanding of the physics of ultrasound waves and the instrumentation will provide the user with a better understanding of the capabilities and limitations of ultrasound equipment. The ultrasound machine combines two technologies: image production (M-mode and 2-dimensional imaging) with Doppler assessment (continuous and pulse wave as well as color-flow mapping). These distinct technologies have been combined to provide the examiner with the ability to make accurate and comprehensive diagnoses and guide therapeutic intervention.

Surgical treatment of a gastric diverticulum in an adolescent.

Gastric diverticula are uncommonly seen in childhood. They typically emanate from the posterior wall of the stomach near the gastroesophageal junction. The authors report on a 15-year-old adolescent boy who presented with a symptomatic gastric diverticulum that was surgically resected. Potential pitfalls in diagnosis and treatment are discussed.

Advances and new insights in monitoring.

It cannot be overemphasized that a piece of electrical equipment is not capable of replacing a vigilant, well-trained clinician. As monitoring devices become more sophisticated, the potential for artifact or misinterpretation increases. When applied appropriately, operated properly, and interpreted correctly, however, the monitors afford the patient the best possible outcome.