Description of the Public Safety Medical Response and Patient Encounters Within and During the Indianapolis (USA) Spring 2020 Civil Unrest.

OBJECTIVE: This study describes the local Emergency Medical Services (EMS) response and patient encounters corresponding to the civil unrest occurring over a four-day period in Spring 2020 in Indianapolis, Indiana (USA). METHODS: This study describes the non-conventional EMS response to civil unrest. The study included patients encountered by EMS in the area of the civil unrest occurring in Indianapolis, Indiana from May 29 through June 1, 2020. The area of civil unrest defined by Indianapolis Metropolitan Police Department covered 15 blocks by 12 blocks (roughly 4.0 square miles) and included central Indianapolis. The study analyzed records and collected demographics, scene times, interventions, dispositions, EMS clinician narratives, transport destinations, and hospital course with outcomes from receiving hospitals for patients extracted from the area of civil unrest by EMS. RESULTS: Twenty-nine patients were included with ages ranging from two to sixty-eight years. In total, EMS transported 72.4% (21 of 29) of the patients, with the remainder declining transport. Ballistic injuries from gun violence accounted for 10.3% (3 of 29) of injuries. Two additional fatalities from penetrating trauma occurred among patients without EMS contact within and during the civil unrest. Conditions not involving trauma occurred in 37.9% (11 of 29). Among transported patients, 33.3% (7 of 21) were admitted to the hospital and there was one fatality. CONCLUSIONS: While most EMS transports did not result in hospitalization, it is important to note that the majority of EMS calls did result in a transport. There was a substantial amount of non-traumatic patient encounters. Trauma in many of the encounters was relatively severe, and the findings imply the need for rapid extraction methods from dangerous areas to facilitate timely in-hospital stabilization.

Results of a Quality Improvement Initiative to Increase the Completion Rate of Electronic Health Records for Patient Encounters at a Large Urban Fire-Based Non-Transporting EMS Agency.

INTRODUCTION: Documentation of patient care is essential for both out-of-hospital and in-hospital clinical management. Secondarily, documentation is key for monitoring and improving quality; however, in some EMS systems initial care is often provided by non-transporting agencies whose personnel may not routinely complete patient care reports. Limited data exist describing effective methods for increasing complete patient care documentation among non-transporting agencies. The aim of this quality improvement project was to increase electronic health record (EHR) documentation compliance in a large urban fire-based non-transporting EMS agency. METHODS: The improvement project began in May 2020. Our primary outcome was the proportion of completed EHR records for EMS responses. Primary drivers were determined from informal interviews with front-line firefighters. Interventions were implemented following a Plan-Do-Study-Act (PDSA) approach first at a single station, then battalion, and ultimately at the entire department. Interventions included performance reports, modifications of chart requirements, localized directive requiring EHR completion for all EMS runs, directive to officers that EHRs are required, documentation training, and a department-wide directive. We used statistical process control charts (p-chart) to identify special cause variation following interventions. RESULTS: The baseline of EHR completion for the entire fire department was 5% (373/7423 records) for the month of January 2020. Front-line interviews with 58 firefighters revealed drivers including lack of accountability and unfamiliarity with the software. After implementing a station performance report at one fire station, the station's EHR rate climbed from 0.9% (3/337 records) to 26.7% (179/671) after 9 weeks. This test was expanded to a battalion of six stations with similar results. After multiple PDSA cycles focused on agency policy and training, overall department wide EHR compliance per month improved to 89% (4,816/5,439 records) for the month of February 2021 and sustained in following months. CONCLUSIONS: Within this large urban fire department, EHR documentation compliance improved significantly through a series of tests of change. Informal interviews with front-line personnel were instrumental in determining primary drivers to develop change ideas. Performance reports, training and facilitation of the reporting process, and department-wide directives led to acceptance and improvement with EHR compliance.

Patient Demographics Are Associated with Differences in Prehospital Pain Management among Trauma Patients.

OBJECTIVE: Disparities have been observed in the treatment of pain in emergency department patients. However, few studies have evaluated such disparities in emergency medical services (EMS). We describe pain medication administration for trauma indications in an urban EMS system and how it varies with patient demographics. METHODS: We performed a retrospective review of the electronic medical records of adult patients transported for isolated trauma (without accompanying medical complaint) from 1/1/18 to 6/30/2020 by a third service EMS agency in a major United States metropolitan area. We performed descriptive statistics on epidemiology, type of pain medications administered, and pain scores. Kruskall-Wallis and chi-square or Fisher's exact tests were used to compare continuous and categorical variables, respectively. We constructed a logistic regression model to estimate the odds of nontreatment of pain by age, race, sex, transport interval, pain score, and Glasgow Coma Scale (GCS) score for patients with pain scores of at least four on a one to ten scale, the threshold for pain treatment per the EMS protocol. RESULTS: Of 32,463 EMS patients with traumatic injuries included in the analysis, 40% (12,881/32,463) were African American, 50% (16,284/32,463) were female, the median age was 27 years (IQR 45-64), and the median initial pain score was 5 (IQR 2-8). Fifteen percent (4,989/32,463) received any analgesic. Initial pain scores were significantly higher for African American and female patients. African American patients were less likely to receive analgesia compared to White and Hispanic patients (19% versus 25% and 23%, respectively, p < 0.0001). Adjusting for age, pain score, transport interval, and GCS, African American compared to White, and female compared to male patients were less likely to be treated for pain, OR 1.59 (95% CI 1.47-1.72) and OR 1.20 (95% CI 1.11-1.28), respectively. CONCLUSION: Among patients with isolated traumatic injuries treated in a single, urban EMS system, African American and female patients were less likely to receive analgesia than White or male patients. Analgesics were given to a small percentage of patients who were eligible for treatment by protocol, and intravenous opioids were used in the vast majority patients who received treatment.

Increased weight in patients with time-sensitive diagnosis is associated with longer prehospital on-scene times.

BACKGROUND: Obesity is a growing epidemic associated with higher rates of metabolic disease, heart disease and all-cause mortality. Heavier patients may require more advanced resources and specialized equipment. We hypothesize that increasing patient weight will be associated with longer prehospital on-scene times. METHODS: We reviewed electronic patient care records for patients transported by two urban 9-1-1 emergency medical services (EMS) agencies. We collected age, sex, estimated patient weight, vital signs (systolic blood pressure, heart rate, pulse oximetry), provider impression, method of moving patient to ambulance, and on-scene times. We selected patients with time-sensitive diagnoses of stroke, ST-segment elevation myocardial infarction (STEMI), and trauma and compared on-scene times for patients who weighed above or below 300 pounds. We performed descriptive statistics, Mann-Whitney U tests for continuous variables and Chi-square tests for discrete variables. We constructed a generalized linear model to determine the effect of patient weight adjusted for covariates. RESULTS: For a three-year period (May 1, 2018 to April 30, 2021) 48,203 patients were transported with an EMS impression of stroke, ST-segment elevation myocardial infarction (STEMI), and trauma. 23,654 (49.1%) patients were female, and the median age was 52 (IQR 34-68) years. The median weight was 175.0 (IQR 150.0-205.0) pounds. Patients above a dichotomous weight categorization of 300 pounds experienced a longer median scene time with any time-sensitive diagnosis (12.6 versus 11.9 min p < 0.001), STEMI (16.0 versus 13.1 min, p = 0.014) and blunt trauma (12.6 versus 11.9 min, p < 0.001)). They were more likely to be hypoxic (p < 0.001) and more likely to experience cardiac arrest (p < 0.001). They were less likely to walk to the ambulance (22.1% versus 32.2%, p < 0.001). CONCLUSION: Patient weight above 300 pounds was associated with significantly longer on-scene time. These patients were more likely to be hypoxic, sustain a cardiac arrest, and less likely to walk to the ambulance.

Farewell editorial from the founding editors.

The retiring Editor-in-Chief and Deputy Editor provide a brief retrospective of the first six volumes of Biomedical Optics Express, thank the Editorial Board and OSA professional staff, and endorse the new journal leadership and the continued support of the journal by the biomedical optics community.

Prediction of Persistent Postconcussion Symptoms in Youth Using a Neuroimaging Decision Rule.

OBJECTIVE: To evaluate the ability of risk strata generated by a neuroimaging rule, developed to assess risk of clinically important traumatic brain injury (ciTBI), to predict postconcussive symptoms in youth with an acute mild traumatic brain injury. METHODS: We performed a prospective cohort study of youth aged 5 to 17 years presenting to an emergency department (ED) within 24 hours of mild traumatic brain injury. Risk strata (very low, intermediate, and at risk) of ciTBI were determined in ED by criteria set forth by the neuroimaging rule. Postconcussive symptoms were assessed using the Health and Behavior Inventory (HBI) in the ED and at 1, 2, and 4 weeks after injury. General linear models were used to examine the relationship between the HBI score at 1 week and risk strata. Repeated measures analysis was used to measure change in HBI over time. RESULTS: Of the 120 participants, 46 were categorized by the Pediatric Emergency Care Applied Research Network (PECARN) rule as very low risk, 39 as intermediate risk, and 35 as at risk for ciTBI. Adjusted mean HBI scores (95% confidence intervals) at 1 week were 18.0 (13.9, 22.2) for at risk, 13.8 (9.9, 17.6) for intermediate risk, and 17.1 (13.4, 20.8) for very low risk. Risk strata were not significantly associated with the adjusted HBI score at 1 week (P = .17). While adjusted HBI scores declined significantly over time (P < .0001), the trajectories of the HBI score over time did not differ significantly by risk strata (P = .68). CONCLUSIONS: Risk of ciTBI as determined by factors within a neuroimaging rule alone is insufficient to predict children with persistent postconcussive symptoms.

Two-tone frequency-modulation stimulated Rayleigh spectroscopy.

We have demonstrated two-tone frequency-modulation (FM) stimulated Rayleigh spectroscopy. This method can provide high spectral resolution (∼1 MHz), excellent pump/probe detuning accuracy, and near-shot-noise-limited signal-to-noise ratios using a single narrowband laser as the master oscillator. Pump/probe detuning and FM sideband generation are produced with an electro-optic modulator. A double-pass two-rod Nd:YAG amplifier provides peak powers near 1 kW for the pump beam. Unlike with two-tone FM absorption spectroscopy, the phase signal is retained for two-tone FM Rayleigh spectroscopy. Measurements confirm that the shape of the phase component of the stimulated thermal Rayleigh peak agrees with theory.

Microdroplet temperature calibration via thermal dissociation of quenched DNA oligomers.

The development of microscale analytical techniques has created an increasing demand for reliable and accurate heating at the microscale. Here, we present a novel method for calibrating the temperature of microdroplets using quenched, fluorescently labeled DNA oligomers. Upon melting, the 3' fluorophore of the reporter oligomer separates from the 5' quencher of its reverse complement, creating a fluorescent signal recorded as a melting curve. The melting temperature for a given oligomer is determined with a conventional quantitative polymerase chain reaction (qPCR) instrument and used to calibrate the temperature within a microdroplet, with identical buffer concentrations, heated with an infrared laser. Since significant premelt fluorescence prevents the use of a conventional (single-term) sigmoid or logistic function to describe the melting curve, we present a three-term sigmoid model that provides a very good match to the asymmetric fluorescence melting curve with premelting. Using mixtures of three oligomers of different lengths, we fit multiple three-term sigmoids to obtain precise comparison of the microscale and macroscale fluorescence melting curves using "extrapolated two-state" melting temperatures.

Droplet shape analysis and permeability studies in droplet lipid bilayers.

We apply optical manipulation to prepare lipid bilayers between pairs of water droplets immersed in an oil matrix. These droplet pairs have a well-defined geometry allowing the use of droplet shape analysis to perform quantitative studies of the dynamics during bilayer formation and to determine time-dependent values for the droplet volumes, bilayer radius, bilayer contact angle, and droplet center-line approach velocity. During bilayer formation, the contact angle rises steadily to an equilibrium value determined by the bilayer adhesion energy. When there is a salt concentration imbalance between droplets, there is a measurable change in the droplet volume. We present an analytical expression for this volume change and use this expression to calculate the bilayer permeability to water.

Cell assay using a two-photon-excited europium chelate.

We report application of two-photon excitation of europium chelates to immunolabeling of epidermal growth factor receptor (EGFR) cell surface proteins on A431 cancer cells. The europium chelates are excited with two photons of infrared light and emit in the visible. Europium chelates are conjugated to antibodies for EGFR. A431 (human epidermoid carcinoma) cells are labeled with this conjugate and imaged using a multiphoton microscope. To minimize signal loss due to the relatively long-lived Eu(3+) emission, the multiphoton microscope is used with scanning laser two-photon excitation and non-scanning detection with a CCD. The chelate labels show very little photobleaching (less than 1% during continuous illumination in the microscope for 20 minutes) and low levels of autofluorescence (less than 1% of the signal from labeled cells). The detection limit of the europium label in the cell assay is better than 100 zeptomoles.

High-speed camera with real time processing for frequency domain imaging.

We describe a high-speed camera system for frequency domain imaging suitable for applications such as in vivo diffuse optical imaging and fluorescence lifetime imaging. 14-bit images are acquired at 2 gigapixels per second and analyzed with real-time pipeline processing using field programmable gate arrays (FPGAs). Performance of the camera system has been tested both for RF-modulated laser imaging in combination with a gain-modulated image intensifier and a simpler system based upon an LED light source. System amplitude and phase noise are measured and compared against theoretical expressions in the shot noise limit presented for different frequency domain configurations. We show the camera itself is capable of shot noise limited performance for amplitude and phase in as little as 3 ms, and when used in combination with the intensifier the noise levels are nearly shot noise limited. The best phase noise in a single pixel is 0.04 degrees for a 1 s integration time.

Light-driven formation and rupture of droplet bilayers.

We demonstrate the optical manipulation of nanoliter aqueous droplets containing surfactant or lipid molecules and immersed in an organic liquid using near-infrared light. The resulting emulsion droplets are manipulated using both the thermocapillary effect and convective fluid motion. Droplet-pair interactions induced in the emulsion upon optical initiation and control provide direct observations of the coalescence steps in intricate detail. Droplet-droplet adhesion (bilayer formation) is observed under several conditions. Selective bilayer rupture is also realized using the same infrared laser. The technique provides a novel approach to studying thin film drainage and interface stability in emulsion dynamics. The formation of stable lipid bilayers at the adhesion interface between interacting water droplets can provide an optical platform on which to build droplet-based lipid bilayer assays. The technique also has relevance to understanding and improving microfluidics applications by devising Petri dish-based droplet assays requiring no substrate fabrication.

Wound healing monitoring using near infrared fluorescent fibrinogen.

We demonstrate a method for imaging the wound healing process with near infrared fluorescent fibrinogen. Wound healing studies were performed on a rat punch biopsy model. Fibrinogen was conjugated with a near infrared fluorescent dye and injected into the tail vein. Fibrinogen is a useful protein for tracking wound healing because it is involved in fibrin clot formation and formation of new provisional matrix through transglutaminase's crosslinking activity. Strong fluorescence specific to the wound was observed and persisted for several days, indicating that the fibrinogen is converted to crosslinked fibrin. Administration of contrast agent simultaneously with wound creation led to primary labeling of the fibrin clot, indicating that the wound was in its early phase of healing. Administration on the following day showed labeling on the wound periphery, indicating location of formation of a new provisional matrix. This method may prove to be useful as a diagnostic for basic studies of the wound healing process, in drug development, or in clinical assessment of chronic wounds.

Near infrared transillumination imaging of breast cancer with vasoactive inhalation contrast.

Inhalation of vasoactive gases such as carbon dioxide and oxygen can provide strong changes in tissue hemodynamics. In this report, we present a preliminary clinical study aimed at assessing the feasibility of inhalation-based contrast with near infrared continuous wave transillumination for breast imaging. We describe a method for fitting the transient absorbance that provides the wavelength dependence of the optical pathlength as parametrized by tissue oxygenation and scatter power as well as the differential changes in oxy- and deoxy-hemoglobin. We also present a principal component analysis data reduction technique to assess the dynamic response from the tissue that uses coercion to provide single temporal eigenvalues associated with both oxy- and deoxy-hemoglobin changes.

Frequency domain measurements on turbid media with strong absorption using the PN approximation.

We have applied the frequency-domain technique to measurement of the optical properties of turbid media with strong absorption in the infinite medium limit. Absorption coefficients up to 2.3 cm(-1) for a modified scattering coefficient of 4.3 cm(-1) are studied, which corresponds to a reduced scattering albedo of 0.65. Low phase noise and good phase stability are required for these low albedo conditions. As the degree of absorption increases, the phase changes are reduced while amplitude changes increase. For this reason, correction of amplitude-phase cross talk is essential to achieve accurate measurements with strong absorption. Careful control of stray reflections is required to properly measure amplitude-phase cross talk. Because the diffusion approximation becomes less accurate, measurements are compared to calculations performed in the PN approximation, which is essentially an exact solution for the infinite medium limit. Agreement between theory and experiment is only obtained when correction for amplitude-phase cross talk is performed. These measurements can provide a good method for testing amplitude-phase cross talk.

Development of a transillumination infrared modality for differential vasoactive optical imaging.

We present the development and implementation of a new near infrared transillumination imaging modality for tissue imaging. Exogenous inhaled hyperoxic and hypercarbic gases are used as "vasoactive contrast agents" via the production of changes in concentration of the endogenous HbO(2) and Hb in blood. This vasoactive differential imaging method is employed to acquire data and for subsequent image analysis. Spectroscopic changes obtained from transillumination measurements on the palms of healthy volunteers demonstrate the functionality of the imaging platform. This modality is being developed to monitor suspect breast lesions in a clinical setting based on the hypothesis that the atypical tumor vascular environment will yield sufficient contrast for differential optical imaging between diseased and healthy tissue.

Petri dish PCR: laser-heated reactions in nanoliter droplet arrays.

We report high-speed real-time PCR performed on an unmodified disposable polystyrene Petri dish. The reaction cycle relies solely on an infrared laser for heating; no conventional heater is required. Nanoliter droplets of PCR mixture as water-in-oil emulsions printed in an array format served as individual PCR microreactors. A simple contact printing technique was developed to generate a large array of uniform sized nanoliter droplets using disposable pipette tips. Printed droplets showed variation of less than 10% in volume and the oil/water/polystyrene interface formed a compact droplet microreactor approximately spherical in shape. The uniform droplet array was used to optimize the laser power required for the two heating steps of PCR, annealing/extension and melting, while the ambient conditions were at room temperature. The optical heating allows for an extremely fast heating rate due to the selective absorption of the infrared laser by PCR buffer only and not the oil or polystyrene Petri dish, allowing completion of 40 amplification cycles in approximately 6 minutes. The quantitative assay capability of the system is also presented and discussed.

Nanodroplet real-time PCR system with laser assisted heating.

We report the successful application of low-power (approximately 30 mW) laser radiation as an optical heating source for high-speed real-time polymerase chain reaction (PCR) amplification of DNA in nanoliter droplets dispersed in an oil phase. Light provides the heating, temperature measurement, and Taqman real-time readout in nanoliter droplets on a disposable plastic substrate. A selective heating scheme using an infrared laser appears ideal for driving PCR because it heats only the droplet, not the oil or plastic substrate, providing fast heating and completing the 40 cycles of PCR in 370 seconds. No microheaters or microfluidic circuitry were deposited on the substrate, and PCR was performed in one droplet without affecting neighboring droplets. The assay performance was quantitative and its amplification efficiency was comparable to that of a commercial instrument.

Inspiratory contrast for in vivo optical imaging.

We demonstrate the use of inspired oxygen and carbon dioxide as a possible route to increase contrast in optical imaging of cancerous tissue. Differential imaging in human xenograft rodent models of cancer exhibits significant variation in signal between normal and cancerous tissue. This differential cancer-specific contrast is stronger and more consistent than the conventional static contrast. This differential technique exploits the response of abnormal tumor vasculature to inhaled gases and could provide a promising alternative to supplement mainstream cancer imaging modalities such as x-rays and MRI.