Development of a Telemedicine Screening Program During the COVID-19 Pandemic.

Background: Telemedicine use increased during the COVID-19 pandemic due to concerns for patient and provider safety. Given the lack of testing resources initially and the large geographical range served by Augusta University (AU), a telemedicine platform with up-to-date screening guidelines was implemented for COVID-19 testing in March 2020. Our objective was to understand the level of adherence to telemedicine screening guidelines for COVID-19. Methods: The study population included health care providers and population who participated in an encounter in the AU Health Express Care virtual care program from March 22 to May 21, 2020. All encounters were intended to be for COVID-19 screening, free, and available 24 h per day, 7 days per week. Screening guidelines were developed by AU based on information from the Centers for Disease Control and Prevention and the Georgia Department of Public Health. Results: Among 17,801 total encounters, 13,600 were included in the final analysis. Overall adherence to screening guidelines was 71% in the adult population and 57% in the pediatric population. When providers did not follow guidelines, 72% determined that the patient should have a positive screen. Guidelines themselves determined that only 52% of encounters should have a positive screen. Providers' specialty significantly correlated with guideline adherence (p = 0.002). Departments with the highest adherence were psychiatry, neurology, and ophthalmology. No significant correlation was found between guideline adherence and provider degree/position. Conclusions: This study provides proof of concept of a free telehealth screening platform during an ongoing pandemic. Our screening experience was effective and different specialties participated. Our patient population lived in lower than average income zip codes, suggesting that our free telemedicine screening program successfully reached populations with higher financial barriers to health care. Early training and a posteriori knowledge of telemedicine was likely key to screening guideline adherence.

In Vivo Bioluminescence Imaging in a Rabbit Model of Orthopaedic Implant-Associated Infection to Monitor Efficacy of an Antibiotic-Releasing Coating.

BACKGROUND: In vivo bioluminescence imaging (BLI) provides noninvasive monitoring of bacterial burden in animal models of orthopaedic implant-associated infection (OIAI). However, technical limitations have limited its use to mouse and rat models of OIAI. The goal of this study was to develop a larger, rabbit model of OIAI using in vivo BLI to evaluate the efficacy of an antibiotic-releasing implant coating. METHODS: A nanofiber coating loaded with or without linezolid-rifampin was electrospun onto a surgical-grade locking peg. To model OIAI in rabbits, a medial parapatellar arthrotomy was performed to ream the femoral canal, and a bright bioluminescent methicillin-resistant Staphylococcus aureus (MRSA) strain was inoculated into the canal, followed by retrograde insertion of the coated implant flush with the articular surface. In vivo BLI signals were confirmed by ex vivo colony-forming units (CFUs) from tissue, bone, and implant specimens. RESULTS: In this rabbit model of OIAI (n = 6 rabbits per group), implants coated without antibiotics were associated with significantly increased knee width and in vivo BLI signals compared with implants coated with linezolid-rifampin (p < 0.001 and p < 0.05, respectively). On day 7, the implants without antibiotics were associated with significantly increased CFUs from tissue (mean [and standard error of the mean], 1.4 × 10 ± 2.1 × 10 CFUs; p < 0.001), bone (6.9 × 10 ± 3.1 × 10 CFUs; p < 0.05), and implant (5.1 × 10 ± 2.2 × 10 CFUs; p < 0.05) specimens compared with implants with linezolid-rifampin, which demonstrated no detectable CFUs from any source. CONCLUSIONS: By combining a bright bioluminescent MRSA strain with modified techniques, in vivo BLI in a rabbit model of OIAI demonstrated the efficacy of an antibiotic-releasing coating. CLINICAL RELEVANCE: The new capability of in vivo BLI for noninvasive monitoring of bacterial burden in larger-animal models of OIAI may have important preclinical relevance.

Polymeric nanofiber coating with tunable combinatorial antibiotic delivery prevents biofilm-associated infection in vivo.

Bacterial biofilm formation is a major complication of implantable medical devices that results in therapeutically challenging chronic infections, especially in cases involving antibiotic-resistant bacteria. As an approach to prevent these infections, an electrospun composite coating comprised of poly(lactic-coglycolic acid) (PLGA) nanofibers embedded in a poly(ε-caprolactone) (PCL) film was developed to locally codeliver combinatorial antibiotics from the implant surface. The release of each antibiotic could be adjusted by loading each drug into the different polymers or by varying PLGA:PCL polymer ratios. In a mouse model of biofilm-associated orthopedic-implant infection, three different combinations of antibiotic-loaded coatings were highly effective in preventing infection of the bone/joint tissue and implant biofilm formation and were biocompatible with enhanced osseointegration. This nanofiber composite-coating technology could be used to tailor the delivery of combinatorial antimicrobial agents from various metallic implantable devices or prostheses to effectively decrease biofilm-associated infections in patients.

Triple-sensor multiplexed frequency-modulated continuous-wave interferometric fiber-optic displacement sensor.

A triple-sensor multiplexed fiber-optic displacement sensor, which can measure the displacements of three different objects or the three-dimensional displacement of a single object, is introduced. The sensor is based on the principles of optical frequency-modulated continuous-wave interference and frequency-division multiplexing. The beat signals from the individual sensors are assigned in the frequency domain and separated with different electrical bandpass filters. The displacements of objects can be determined simultaneously by detecting the phase shifts of the corresponding signals. The cross talk between the individual sensors is evaluated, and an accuracy of 0.08 microm in a dynamic range of 1000 microm is achieved.

Coherence analysis of optical frequency-modulated continuous-wave interference.

I analyze the coherence of optical frequency-modulated continuous-wave (FMCW) interference. With a simple model modified from the classical coherence theory, I successfully derive the relationships among the frequency bandwidth, coherence length, and coherence time of the practical optical source, and the contrast of the beat signal in optical FMCW interference.

Optical frequency-modulated continuous-wave interferometers.

I discuss optical frequency-modulated continuous-wave (FMCW) interferometers, including their principles, characteristics, specific requirements, procedure for their construction, optical configurations, primary applications, optical sources, resolution, measurement range, and stability.

Continued analysis of optical frequency-modulated continuous-wave interference.

I continue to analyze systematically the theory of optical frequency-modulated continuous-wave (FMCW) interference. Two special cases, multiple-beam optical FMCW interference and multiple-wavelength optical FMCW interference, are discussed in detail. Multiple-beam optical FMCW interference generates a signal with multiple frequencies because of mutual interference among the waves. Multiple-wavelength optical FMCW interference produces a signal whose amplitude is modulated by a synthetic wave. The applications of both types of optical FMCW interference are also discussed.

All-fiber single-mode fiber frequency-modulated continuous-wave Sagnac gyroscope.

An all-fiber single-mode fiber unbalanced Sagnac gyroscope is described. The gyroscope is based on optical frequency-modulated continuous-wave interference and consists primarily of four Y-type single-mode fiber directional couplers and a single-mode fiber coil. The rotational velocity of the fiber coil is determined simultaneously by detection of the phase shift of the beat signal. The advantages and limitations of the gyroscope are discussed.

Analysis of optical frequency-modulated continuous-wave interference.

I systematically analyze the theory of optical frequency-modulated continuous-wave (FMCW) interference. There are three different versions of optical FMCW interference, discussed in detail: sawtooth-wave optical FMCW interference, triangular-wave optical FMCW interference, and sinusoidal-wave optical FMCW interference. The essential concepts and technical terms are clearly defined, the necessary simplifications are introduced according to the characteristics of optical waves, and the formulas used to calculate the signal intensities under two different situations (static and dynamic) are properly derived. Advantages and limitations of each version of optical FMCW interference are also discussed.