Strokes Averted by Intravenous Thrombolysis: A Secondary Analysis of a Prospective, Multicenter, Controlled Trial of Mobile Stroke Units.

OBJECTIVE: This study was undertaken to examine averted stroke in optimized stroke systems. METHODS: This secondary analysis of a multicenter trial from 2014 to 2020 compared patients treated by mobile stroke unit (MSU) versus standard management. The analytical cohort consisted of participants with suspected stroke treated with intravenous thrombolysis. The main outcome was a tissue-defined averted stroke, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours attributed to thrombolysis and no acute infarction/hemorrhage on imaging. An additional outcome was stroke with early symptom resolution, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours attributed to thrombolysis. RESULTS: Among 1,009 patients with a median last known well to thrombolysis time of 87 minutes, 159 (16%) had tissue-defined averted stroke and 276 (27%) had stroke with early symptom resolution. Compared with standard management, MSU care was associated with more tissue-defined averted stroke (18% vs 11%, adjusted odds ratio [aOR] = 1.82, 95% confidence interval [CI] = 1.13-2.98) and stroke with early symptom resolution (31% vs 21%, aOR = 1.74, 95% CI = 1.12-2.61). The relationships between thrombolysis treatment time and averted/early recovered stroke appeared nonlinear. Most models indicated increased odds for stroke with early symptom resolution but not tissue-defined averted stroke with earlier treatment. Additionally, younger age, female gender, hyperlipidemia, lower National Institutes of Health Stroke Scale, lower blood pressure, and no large vessel occlusion were associated with both tissue-defined averted stroke and stroke with early symptom resolution. INTERPRETATION: In optimized stroke systems, 1 in 4 patients treated with thrombolysis recovered within 24 hours and 1 in 6 had no demonstrable brain injury on imaging. ANN NEUROL 2024;95:347-361.

Prospective, Multicenter, Controlled Trial of Mobile Stroke Units.

BACKGROUND: Mobile stroke units (MSUs) are ambulances with staff and a computed tomographic scanner that may enable faster treatment with tissue plasminogen activator (t-PA) than standard management by emergency medical services (EMS). Whether and how much MSUs alter outcomes has not been extensively studied. METHODS: In an observational, prospective, multicenter, alternating-week trial, we assessed outcomes from MSU or EMS management within 4.5 hours after onset of acute stroke symptoms. The primary outcome was the score on the utility-weighted modified Rankin scale (range, 0 to 1, with higher scores indicating better outcomes according to a patient value system, derived from scores on the modified Rankin scale of 0 to 6, with higher scores indicating more disability). The main analysis involved dichotomized scores on the utility-weighted modified Rankin scale (≥0.91 or <0.91, approximating scores on the modified Rankin scale of ≤1 or >1) at 90 days in patients eligible for t-PA. Analyses were also performed in all enrolled patients. RESULTS: We enrolled 1515 patients, of whom 1047 were eligible to receive t-PA; 617 received care by MSU and 430 by EMS. The median time from onset of stroke to administration of t-PA was 72 minutes in the MSU group and 108 minutes in the EMS group. Of patients eligible for t-PA, 97.1% in the MSU group received t-PA, as compared with 79.5% in the EMS group. The mean score on the utility-weighted modified Rankin scale at 90 days in patients eligible for t-PA was 0.72 in the MSU group and 0.66 in the EMS group (adjusted odds ratio for a score of ≥0.91, 2.43; 95% confidence interval [CI], 1.75 to 3.36; P<0.001). Among the patients eligible for t-PA, 55.0% in the MSU group and 44.4% in the EMS group had a score of 0 or 1 on the modified Rankin scale at 90 days. Among all enrolled patients, the mean score on the utility-weighted modified Rankin scale at discharge was 0.57 in the MSU group and 0.51 in the EMS group (adjusted odds ratio for a score of ≥0.91, 1.82; 95% CI, 1.39 to 2.37; P<0.001). Secondary clinical outcomes generally favored MSUs. Mortality at 90 days was 8.9% in the MSU group and 11.9% in the EMS group. CONCLUSIONS: In patients with acute stroke who were eligible for t-PA, utility-weighted disability outcomes at 90 days were better with MSUs than with EMS. (Funded by the Patient-Centered Outcomes Research Institute; BEST-MSU ClinicalTrials.gov number, NCT02190500.).

Disposition Outcomes Following Prehospital Use of Naloxone in a large metropolitan city in the United States.

OBJECTIVES: During a drug overdose, research suggests individuals may not call 9-1-1 out of fear of criminal justice concerns. Of those that call, research is inconclusive about the disposition of the emergency transport. We evaluated transport outcomes for adults with opioid-related overdose in the Emergency Medical Services (EMS) of a large metropolitan city in the United States. METHODS: We reviewed the EMS incident report database from the patient care record system for years 2018 to 2022. We queried all records, searching for relevant terms, and two reviewers cross-checked the database to identify cases that did not result in death at the scene. Study outcome was defined as hospital transportation or no transportation. Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for hospital transport with patient age, sex, race and ethnicity as the independent variables. RESULTS: We identified 5,482 cases of nonfatal opioid-related overdose. Of these, 4,984 (90.9%) were transported to the hospital; 37 (0.7%) were placed in police custody; 304 (5.5%) were not transferred; and 157 (2.9%) had unknown outcomes. Among 5,288 with data on the transport outcome, the majority were male (65%), and the highest proportion were White (39%). Compared to those who were not transported, each 1-year increase in age was related to a 2% increase in the odds of transportation (OR: 1.02, 95% CI: 1.01-1.02). Compared to White patients, Black and Hispanic patients were 43% OR: 1.43, 95% CI: 1.07-1.90) and 44% (OR: 1.44, 95% CI: 1.03-2.00) more likely to be transported. CONCLUSIONS: Individuals with suspected opioid-related overdose who call 9-1-1 are most often transported to the hospital. Current EMS procedures are successful at on-scene treatment and transportation; however, data on the long-term impact of opioid-related overdoses are still needed.

Management and Control Issues Related to Two Mumps Outbreaks in Houston: Future Implications.

BACKGROUND: Mumps is a highly contagious disease spread by airborne droplets, making control especially difficult in congregate, crowded settings such as shelters and jails. A mumps outbreak in Honduras, starting in 2018 among adults who were unvaccinated, spread northward with Central Americans migrating to the United States. We describe 2 mumps outbreaks in Houston during 2019 among migrants at the Houston Contract Detention Facility (HCDF) and among inmates at the Harris County Jail (HCJ). METHODS: We investigated cases of acute onset parotitis. Three or more mumps cases in a facility was considered an outbreak. Confirmed cases had positive polymerase chain reactions (PCR). Probable cases were linked epidemiologically to a confirmed case in the same unit and a positive serology for serum anti-mumps immunoglobulin M (IgM) antibody. Outbreak control measures included enhanced surveillance, isolation of housing units, educational outreach, and immunization with Measles, Mumps, Rubella (MMR) vaccine. RESULTS: At HCDF, during a 10-month period, we investigated 42 possible cases. Of the possible cases, 28 were lab-confirmed with 9 probable, 4 ruled out, and 1 vaccine reaction. All were migrants. At HCJ, during a 3-month period, we investigated 60 suspect cases; 20 cases were lab-confirmed, 13 probable and 27 ruled out. All but 2 were inmates. Only about a third of those offered MMR vaccination accepted. CONCLUSIONS: Successful outbreak resolution required close cooperation with HCDF and HCJ with ongoing surveillance, isolation of units with cases and MMR vaccination. Such facilities will have outbreaks; regular communications with local public health could improve response.

First Responder CPR and Survival Differences in Texas Minority and Lower Socioeconomic Status Neighborhoods.

INTRODUCTION: First responder (FR) cardiopulmonary resuscitation (CPR) is an important component of out-of-hospital cardiac arrest (OHCA) care. However, little is known about FR CPR disparities. METHODS: We linked the 2014-2021 Texas Cardiac Arrest Registry to Enhance Survival (TX-CARES) database to census tract data. We included non-traumatic OHCAs that were not witnessed by 9-1-1 responders and did not receive bystander CPR. We defined census tracts as having >50% of a race/ethnicity: White, Black, or Hispanic/Latino. We also stratified patients into quartiles based on socioeconomic status (SES): household income, high school graduation, and unemployment. We also combined race/ethnicity and income to create a total of five mixed strata, comparing lower income and minority census tracts to high income White census tracts. We created mixed model logistic regression models, adjusting for confounders and modeling census tract as a random intercept. Using the models, we compared FR CPR rates for census race/ethnicity (Black and Hispanic/Latino compared to White), and SES quartiles (2nd, 3rd, and 4th quartiles compared to 1st quartiles). Secondarily, we evaluated the association between FR CPR and survival for all strata. RESULTS: We included 21,966 OHCAs, and 57.4% had FR CPR. Evaluating the association between census tract characteristic and FR CPR, majority Black (aOR 0.30, 95% CI 0.22-0.41) had a lower bystander CPR rate when compared to majority White. The lowest income quartile had a lower rate of bystander CPR (aOR 0.80, 95% CI 0.65-0.98). The worst unemployment quartile was also associated with a lower rate of FR CPR (aOR 0.75, 95% CI 0.61-0.92). Combining race/ethnicity and income, middle income majority Black (30.0%; aOR 0.27, 95% CI 0.17-0.46) and low income >80% Black (31.8%; aOR 0.27, 95% CI 0.10-0.68) had lower rates of FR CPR in comparison to high income majority White. There were no associations between Hispanic or lower high school graduation and lower rates of FR CPR. We found no association between FR CPR and survival for all three strata. CONCLUSION: While we identified disparities in FR CPR in low SES and majority Black census tracts, we identified no association between FR CPR and survival in Texas.

Community Variations in Out-of-Hospital Cardiac Arrest Care and Outcomes in Texas.

Background: Large and unacceptable variation exists in cardiac resuscitation care and outcomes across communities. Texas is the second most populous state in the US with wide variation in community and emergency response infrastructure. We utilized the Texas-CARES registry to perform the first Texas state analysis of out-of-hospital cardiac arrest (OHCA) in Texas, evaluating for variations in incidence, care, and outcomes.Methods: We analyzed the Texas-CARES registry, including all adult, non-traumatic OHCAs from 1/1/2014 through 12/31/2018. We analyzed the incidence and characteristics of OHCA care and outcome, overall and stratified by community. Utilizing mixed models accounting for clustering by community, we characterized variations in bystander CPR, bystander AED in public locations, and survival to hospital discharge across communities, adjusting for age, gender, race, location of arrest, and rate of witnessed arrest (bystander and 911 responder witnessed).Results: There were a total of 26,847 (5,369 per year) OHCAs from 13 communities; median 2,762 per community (IQR 444-2,767, min 136, max 9161). Texas care and outcome characteristics were: bystander CPR (43.3%), bystander AED use (9.1%), survival to discharge (9.1%), and survival with good neurological outcomes (4.0%). Bystander CPR rate ranged from 19.2% to 55.0%, and there were five communities above and five below the adjusted 95% confidence interval. Bystander AED use ranged from 0% to 19.5%, and there was one community below the adjusted 95% confidence interval. Survival to hospital discharge ranged from 6.7% to 14.0%, and there were three communities above and two below the adjusted 95% confidence interval.Conclusion: While overall OHCA care and outcomes were similar in Texas compared to national averages, bystander CPR, bystander AED use, and survival varied widely across communities in Texas. These variations signal opportunities to improve OHCA care and outcomes in Texas.

Population-Based Estimates of SARS-CoV-2 Seroprevalence in Houston, Texas as of September 2020.

BACKGROUND: In contrast to studies that relied on volunteers or convenience sampling, there are few population-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence investigations and most were conducted early in the pandemic. The health department of the fourth largest US city recognized that sound estimates of viral impact were needed to inform decision making. METHODS: Adapting standardized disaster research methodology, in September 2020 the city was divided into high and low strata based on reverse-transcriptase polymerase chain reaction (RT-PCR) positivity rates; census block groups within each stratum were randomly selected with probability proportional to size, followed by random selection of households within each group. Using 2 immunoassays, the proportion of infected individuals was estimated for the city, by positivity rate and sociodemographic and other characteristics. The degree of underascertainment of seroprevalence was estimated based on RT-PCR-positive cases. RESULTS: Seroprevalence was estimated to be 14% with near 2-fold difference in areas with high (18%) versus low (10%) RT-PCR positivity rates and was 4 times higher compared to case-based surveillance data. CONCLUSIONS: Seroprevalence was higher than previously reported and greater than estimated from RT-PCR data. Results will be used to inform public health decisions about testing, outreach, and vaccine rollout.

A Framework for EMS Outreach for Drug Overdose Survivors: A Case Report of the Houston Emergency Opioid Engagement System.

OBJECTIVE: Fatalities from drug-induced overdoses in the United States have taken greater than 292,000 lives in the last five years, and nearly two-thirds of these are opioid-related. The burden on prehospital emergency medical services (EMS) to respond to these incidents is growing. The standard of care typically involves overdose reversal and rapid transport, although a few agencies have begun to use community paramedicine to more proactively follow-up, initiate treatment, and refer patients to addiction medicine providers. Methods: In this manuscript we share the details of an outreach case study to serve as a blueprint for other agencies and municipalities to adopt and refine. The University of Texas Health Science Center, in partnership with the Houston Fire Department and other local first responder agencies, developed a program in Houston, Texas based on rapid response to post-overdose survivors using available incident data from the primary municipal agencies. Results: The Houston Emergency Opioid Engagement System (HEROES) was created to more comprehensively address the opioid epidemic. By utilizing data extracted from the patient care record system, a team comprised of a peer recovery coach and a paramedic is dispatched to the home location of a recent overdose (OD) incident to provide outreach. Conclusions: Outreach dialog and motivational interviewing techniques are used to provide awareness of treatment options and to engage individuals into a treatment program. A case report of this program and recommendations for broader adoption are presented.

Establishing a Regional Trauma Preventable/Potentially Preventable Death Rate.

OBJECTIVE: To establish a trauma preventable/potentially preventable death rate (PPPDR) within a heavily populated county in Texas. SUMMARY: The National Academies of Sciences estimated the trauma preventable death rate in the United States to be 20%, issued a call for zero preventable deaths, while acknowledging that an accurate preventable death rate was lacking. In this absence, effective strategies to improve quality of care across trauma systems will remain difficult. METHODS: A retrospective review of death-related records that occurred during 2014 in Harris County, TX, a diverse population of 4.4 million. Patient demographics, mechanism of injury, cause, timing, and location of deaths were assessed. Deaths were categorized using uniform criteria and recorded as preventable, potentially preventable or nonpreventable. RESULTS: Of 1848 deaths, 85% had an autopsy and 99.7% were assigned a level of preventability, resulting in a trauma PPPDR of 36.2%. Sex, age, and race/ethnicity varied across preventability categories (P < 0.01). Of 847 prehospital deaths, 758 (89.5%) were nonpreventable. Among 89 prehospital preventable/potentially preventable (P/PP) deaths, hemorrhage accounted for 55.1%. Of the 657 initial acute care setting deaths, 292 (44.4%) were P/PP; of these, hemorrhage, sepsis, and traumatic brain injury accounted for 73.3%. Of 339 deaths occurring after initial hospitalization, 287 (84.7%) were P/PP, of these 117 resulted from sepsis and 31 from pulmonary thromboembolism, accounted for 51.6%. CONCLUSIONS: The trauma PPPDR was almost double that estimated by the National Academies of Sciences. Data regarding P/PP deaths offers opportunity to target research, prevention, intervention, and treatment corresponding to all phases of the trauma system.

Establishing a regional pediatric trauma preventable/potentially preventable death rate.

PURPOSE: Although trauma is the leading cause of death for the pediatric population, few studies have addressed the preventable/potentially preventable death rate (PPPDR) attributable to trauma. METHODS: This is a retrospective study of trauma-related death records occurring in Harris County, Texas in 2014. Descriptive and Chi-squared tests were conducted for two groups, pediatric and adult trauma deaths in relation to demographic characteristics, mechanism of injury, death location and survival time. RESULTS: There were 105 pediatric (age < 18 years) and 1738 adult patients. The PPPDR for the pediatric group was 21.0%, whereas the PPPDR for the adult group was 37.2% (p = 0.001). Analysis showed fewer preventable/potentially preventable (P/PP) deaths resulting from any blunt trauma mechanism in the pediatric population than in the adult population (19.6% vs. 48.4%, p < 0.001). Amongst the pediatric population, P/PP traumatic brain injury (TBI) were more common in the youngest age range (age 0-5) vs. the older (6-12 years) pediatric and adolescent (13-17 years) patients. CONCLUSION: Our results identify areas of opportunities for improving pediatric trauma care. Although the overall P/PP death rate is lower in the pediatric population than the adult, opportunities for improving initial acute care, particularly TBI, exist.

Enhanced dispatch and rendezvous doubles the catchment area and number of patients treated on a mobile stroke unit.

INTRODUCTION: Mobile Stroke Units (MSUs) deliver acute stroke treatment on-scene in coordination with Emergency Medical Services (EMS). One criticism of the MSU approach is the limited range of a single MSU. The Houston MSU is evaluating MSU implementation, and we developed a rendezvous approach as an innovative solution to expand the range and number of patients treated. METHODS: In addition to direct 911 dispatch of our MSU to the scene within our 7-mile catchment area, we empowered more distant EMS units to activate the MSU. We also monitored EMS radio communications to identify possible patients. For these distant patients, the MSU met the EMS unit en route to the stroke center and treated the patient at that intermediate location. The distribution of the distance from MSU base station to site of stroke and time from 911 alert to tissue plasminogen activator (tPA) bolus were compared between patients treated on-scene and by rendezvous using Wilcoxon rank sum test. RESULTS: Over 4 years, 338 acute ischemic stroke patients were treated with tPA on our MSU. Of these, 169 (50%) were treated on-scene after MSU dispatch at a median of 6.4 miles (IQR 6.4 miles) from MSU base station. 169 (50%) were treated by 'rendezvous' pathway with assessment and treatment of stroke a median of 12.4 miles from base (IQR 5.5 miles) (p< 0.0001). Time (min) from MSU alert to tPA bolus did not differ: 36.0 ± 10.0 for on-scene vs 37.0 ± 10.0 with rendezvous (p=0.65). 13% of patients alerted via direct 911 dispatch were treated vs 44% of rendezvous patients. CONCLUSION: Adding a rendezvous approach to an MSU dispatch pathway doubles the range of operations and the number of patients treated by an MSU in an urban area, without incurring delay.

Telehealth Impact on Primary Care Related Ambulance Transports.

Introduction: Telehealth has been used nominally for trauma, neurological, and cardiovascular incidents in prehospital emergency medical services (EMS). Yet, much less is known about the use of telehealth for low-acuity primary care. We examine the development of one telehealth program and its impact on unnecessary ambulance transports. Objective: The objective of this study is to describe the development and impact of a large-scale telehealth program on ambulance transports. Methods: We describe the patient characteristics and results from a cohort of patients in Houston, Texas who received a prehospital telehealth consultation from an emergency medicine physician. Inclusion criteria were adults and pediatric patients with complaints considered to be non-urgent, primary care related. Data were analyzed for 36 months, from January 2015 through December 2017. Our primary dependent variable was the percentage of patients transported by ambulance. We used descriptive statistics to describe patient demographics, chi-square to examine differences between groups, and logistic regression to explore the effects with multivariate controls including age, gender, race, and chief complaint. Results: A total of 15,067 patients were enrolled (53% female; average age 44 years ± 19 years) over the three-year period. The 3 primary chief complaints were based on abdominal pains (13% of cases), nausea/vomiting/diarrhea (NVD) (9.4%), and back pain (9.3%). Ambulance transports represented 11.2% of all transports in the program, while alternative taxi transportation was used in 75.6%, and the remainder were self- or no-transports. Taxi transportation to an alternate, affiliated clinic (versus ED) was utilized in 5% of incidents. After multivariate controls, older age patients presenting with low-risk, non-acute chest pain, shortness of breath, and dizziness were much more likely to use ambulance transport. Race and gender were not significant predictors of ambulance transport. Conclusions: We found telehealth offers a technology strategy to address potentially unnecessary ambulance transports. Based on prior cost-effectiveness analyses, the reduction of unnecessary ambulance transports translates to an overall reduction in EMS agency costs. Telehealth programs offer a viable solution to support alternate destination and alternate transport programs.

Effectiveness of the Dual Dispatch to Cardiac Arrest Policy in Houston, Texas.

CONTEXT: Houston policy is to dual dispatch medically trained firefighters, in addition to emergency medical services (EMS) units to out-of-hospital cardiac arrest (OHCA) cases. While believed to improve public health outcomes, no research exists supporting the policy that when firefighters respond before a better-equipped EMS unit, they increase the probability of survival. OBJECTIVE: To inform EMS policy decisions regarding the effectiveness of dual dispatch by determining the impact of medically trained firefighter dispatch on return of spontaneous circulation (ROSC), a measure of survivability, in OHCA 911 calls while controlling for the subsequent arrival of an EMS unit. DESIGN: This retrospective study uses logistic regression to determine the association between ROSC and response time for fire apparatus first responders controlling for arrival of the EMS unit. SETTING: Out-of-hospital cardiac arrest cases in Houston between May 2008 and April 2013 when dual dispatch was used. PARTICIPANTS: A total of 6961 OHCA cases with the complete data needed for the analysis. MAIN OUTCOME MEASURES: Logistic regression of the dependence of OHCA survival using the indicator ROSC, as related to the fire first responder response times controlling for subsequent arrival of the EMS. RESULTS: Fire apparatus arrived first in 46.7% of cases, a median value of 1.5 minutes before an EMS unit. Controlling for subsequent arrival time of EMS has no effect on ROSC achieved by the fire first responder. If the firefighters had not responded, the resulting 1.5-minute increase in response time equates to a decrease in probability of attaining ROSC of 20.1% for cases regardless of presenting heart rhythm and a 47.7% decrease for ventricular fibrillation cases in which bystander cardiopulmonary resuscitation was initiated. CONCLUSIONS: The firefighter first responder not only improved response time but also greatly increased survivability independent of the arrival time of the better-equipped EMS unit, validating the public health benefit of the dual dispatch policy in Houston.

Observed survival benefit of mild therapeutic hypothermia reanalysing the Circulation Improving Resuscitation Care trial.

BACKGROUND: Mild therapeutic hypothermia is argued being beneficial for outcome after cardiac arrest. MATERIALS AND METHODS: Retrospective analysis of Circulation Improving Resuscitation Care (CIRC) trial data to assess if therapeutic cooling to 33 ± 1 °C core temperature had an association with survival. Of 4231 adult, out-of-hospital cardiac arrests of presumed cardiac origin initially enrolled, eligibility criteria for therapeutic hypothermia were met by 1812. Logistic regression was undertaken in a stepwise fashion to account for the impact on outcome of each significant difference and for the variable of interest between the groups. RESULTS: Out-of- and in-hospital cooled were 263 (15%), only after admission cooled were 230 (13%) and not cooled were 357 (20%) patients. The group cooled out of- and in hospital had 98 (37%) survivors as compared to the groups cooled in hospital only [80 (35%)] and of those not cooled [68 (19%)]. After adjusting for known covariates (sex, age, witnessed cardiac arrest, no- and low-flow time, shockable initial rhythm, random allocation, bystander cardiopulmonary resuscitation and percutaneous coronary intervention), the odds ratio for survival comparing no cooling to out-of- plus in-hospital cooling was 0·53 [95% confidence interval (CI): 0·46-0·61, P < 0·001], and comparing to in-hospital cooling only was 0·67 (95% CI: 0·50-0·89, P = 0·006). CONCLUSION: Mild therapeutic hypothermia initiated out of hospital and/or in hospital was associated with improved survival within this secondary analysis of the CIRC cohort compared to no therapeutic hypothermia.

Benefits of Stroke Treatment Using a Mobile Stroke Unit Compared With Standard Management: The BEST-MSU Study Run-In Phase.

BACKGROUND AND PURPOSE: Faster treatment with intravenous tissue-type plasminogen activator (tPA) is likely to improve outcomes. Optimizing prehospital triage by mobile stroke units (MSUs) may speed treatment times. The Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit (BEST-MSU) study was launched in May 2014 using the first MSU in the United States to compare stroke management using an MSU versus standard management (SM). Herein, we describe the results of the prespecified, nonrandomized run-in phase designed to obtain preliminary data on study logistics. METHODS: The run-in phase consisted of 8 MSU weeks when all-patient care occurred on the MSU and 2 SM weeks when the MSU nurse met personnel on scene or at the emergency department to ensure comparability with MSU patients. Telemedicine was independently performed in 9 MSU cases. RESULTS: Of 130 alerts, 24 MSU and 2 SM patients were enrolled. Twelve of 24 MSU patients received tPA on board; 4 were treated within 60 minutes of last seen normal, and 4 went on to endovascular treatment. There were no hemorrhagic complications. Four had primary intracerebral hemorrhage. Agreement on tPA eligibility between the onsite and telemedicine physician was 90%. CONCLUSIONS: The run-in phase provided a tPA treatment rate of 1.5 patients per week, assured us that treatment within 60 minutes of onset is possible, and enabled enrollment of patients on SM weeks. We also recognized the opportunity to assess the effect of the MSU on endovascular treatment and intracerebral hemorrhage. Challenges include the need to control biased patient selection on MSU versus SM weeks and establish inter-rater agreement for tPA treatment using telemedicine.

Establishing the first mobile stroke unit in the United States.

BACKGROUND AND PURPOSE: Recently, the Mobile Stroke Unit (MSU) concept was introduced in Germany demonstrating prehospital treatment of more patients within the first hour of symptom onset. However, the details and complexities of establishing such a program in the United States are unknown. We describe the steps involved in setting up the first MSU in the United States. METHODS: Implementation included establishing leadership, fund-raising, purchase and build-out, knitting a collaborative consortium of community stakeholders, writing protocols to ensure accountability, radiation safety, purchasing supplies, licensing, insurance, establishing a base station, developing a communication plan with city Emergency Medical Services, Emergency Medical Service training, staffing, and designing a research protocol. RESULTS: The MSU was introduced after ≈1 year of preparation. Major obstacles to establishing the MSU were primarily obtaining funding, licensure, documenting radiation safety protocols, and establishing a smooth communication system with Emergency Medical Services. During an 8 week run-in phase, ≈2 patients were treated with recombinant tissue-type plasminogen activator per week, one-third within 60 minutes of symptom onset, with no complications. A randomized study to determine clinical outcomes, telemedicine reliability and accuracy, and cost effectiveness was formulated and has begun. CONCLUSION: The first MSU in the United States has been introduced in Houston, TX. The steps needed to accomplish this are described.

A case-crossover analysis of out-of-hospital cardiac arrest and air pollution.

BACKGROUND: Evidence of an association between the exposure to air pollution and overall cardiovascular morbidity and mortality is increasingly found in the literature. However, results from studies of the association between acute air pollution exposure and risk of out-of-hospital cardiac arrest (OHCA) are inconsistent for fine particulate matter, and, although pathophysiological evidence indicates a plausible link between OHCA and ozone, none has been reported. Approximately 300 000 persons in the United States experience an OHCA each year, of which >90% die. Understanding the association provides important information to protect public health. METHODS AND RESULTS: The association between OHCA and air pollution concentrations hours and days before onset was assessed by using a time-stratified case-crossover design using 11 677 emergency medical service-logged OHCA events between 2004 and 2011 in Houston, Texas. Air pollution concentrations were obtained from an extensive area monitor network. An average increase of 6 µg/m(3) in fine particulate matter 2 days before onset was associated with an increased risk of OHCA (1.046; 95% confidence interval, 1.012-1.082). A 20-ppb ozone increase for the 8-hour average daily maximum was associated with an increased risk of OHCA on the day of the event (1.039; 95% confidence interval, 1.005-1.073). Each 20-ppb increase in ozone in the previous 1 to 3 hours was associated with an increased risk of OHCA (1.044; 95% confidence interval, 1.004-1.085). Relative risk estimates were higher for men, blacks, or those aged >65 years. CONCLUSIONS: The findings confirm the link between OHCA and fine particulate matter and introduce evidence of a similar link with ozone.

Prehospital utility of rapid stroke evaluation using in-ambulance telemedicine: a pilot feasibility study.

BACKGROUND AND PURPOSE: Prehospital evaluation using telemedicine may accelerate acute stroke treatment with tissue-type plasminogen activator. We explored the feasibility and reliability of using telemedicine in the field and ambulance to help evaluate acute stroke patients. METHODS: Ten unique, scripted stroke scenarios, each conducted 4 times, were portrayed by trained actors retrieved and transported by Houston Fire Department emergency medical technicians to our stroke center. The vascular neurologists performed remote assessments in real time, obtaining clinical data points and National Institutes of Health (NIH) Stroke Scale, using the In-Touch RP-Xpress telemedicine device. Each scripted scenario was recorded for a subsequent evaluation by a second blinded vascular neurologist. Study feasibility was defined by the ability to conduct 80% of the sessions without major technological limitations. Reliability of video interpretation was defined by a 90% concordance between the data derived during the real-time sessions and those from the scripted scenarios. RESULTS: In 34 of 40 (85%) scenarios, the teleconsultation was conducted without major technical complication. The absolute agreement for intraclass correlation was 0.997 (95% confidence interval, 0.992-0.999) for the NIH Stroke Scale obtained during the real-time sessions and 0.993 (95% confidence interval, 0.975-0.999) for the recorded sessions. Inter-rater agreement using κ-statistics showed that for live-raters, 10 of 15 items on the NIH Stroke Scale showed excellent agreement and 5 of 15 showed moderate agreement. Matching of real-time assessments occurred for 88% (30/34) of NIH Stroke Scale scores by ±2 points and 96% of the clinical information. CONCLUSIONS: Mobile telemedicine is reliable and feasible in assessing actors simulating acute stroke in the prehospital setting.

Using community level strategies to reduce asthma attacks triggered by outdoor air pollution: a case crossover analysis.

BACKGROUND: Evidence indicates that asthma attacks can be triggered by exposure to ambient air pollutants, however, detailed pollution information is missing from asthma action plans. Asthma is commonly associated with four criteria pollutants with standards derived by the United States Environmental Protection Agency. Since multiple pollutants trigger attacks and risks depend upon city-specific mixtures of pollutants, there is lack of specific guidance to reduce exposure. Until multi-pollutant statistical modeling fully addresses this gap, some guidance on pollutant attack risk is required. This study examines the risks from exposure to the asthma-related pollutants in a large metropolitan city and defines the city-specific association between attacks and pollutant mixtures. Our goal is that city-specific pollution risks be incorporated into individual asthma action plans as additional guidance to prevent attacks. METHODS: Case-crossover analysis and conditional logistic regression were used to measure the association between ozone, fine particulate matter, nitrogen dioxide, sulfur dioxide and carbon monoxide pollution and 11,754 emergency medical service ambulance treated asthma attacks in Houston, Texas from 2004-2011. Both single and multi-pollutant models are presented. RESULTS: In Houston, ozone and nitrogen dioxide are important triggers (RR = 1.05; 95% CI: 1.00, 1.09), (RR = 1.10; 95% CI: 1.05, 1.15) with 20 and 8 ppb increase in ozone and nitrogen dioxide, respectively, in a multi-pollutant model. Both pollutants are simultaneously high at certain times of the year. The risk attributed to these pollutants differs when they are considered together, especially as concentrations increase. Cumulative exposure for ozone (0-2 day lag) is of concern, whereas for nitrogen dioxide the concern is with single day exposure. Persons at highest risk are aged 46-66, African Americans, and males. CONCLUSIONS: Accounting for cumulative and concomitant outdoor pollutant exposure is important to effectively attribute risk for triggering of an asthma attack, especially as concentrations increase. Improved asthma action plans for Houston individuals should warn of these pollutants, their trends, correlation and cumulative effects. Our Houston based study identifies nitrogen dioxide levels and the three-day exposure to ozone to be of concern whereas current single pollutant based national standards do not.

A Novel Framework for Internal Responses to Detection of Pathogens in Wastewater by Public Health Agencies.

OBJECTIVES: To build on the success of wastewater surveillance during the COVID-19 pandemic, jurisdictions funded under the Centers for Disease Control and Prevention National Wastewater Surveillance System are looking to expand their wastewater programs to detect more pathogens. However, many public health agencies do not know how to use the collected wastewater data to formulate public health responses, underscoring a need for guidance. To address this knowledge gap, the Houston Health Department (HHD) developed a novel response framework that outlines an internal action plan that is tailored by pathogen type after detection of various pathogens in wastewater. MATERIALS AND METHODS: In July 2023, HHD met with subject matter experts (eg, bureau chiefs, program managers) in internal departments, including epidemiology, immunization, and health education, to discuss the general outline of the response framework and each department's anticipated role after pathogen detection. RESULTS: The internal framework established a flow for notifications and the actions to be taken by departments in HHD, with the goals of (1) ensuring timely and efficient responses to pathogen detections, (2) creating accountability within departments for taking their assigned actions, and (3) making certain that HHD was prepared for intervention implementation when a new pathogen was detected. PRACTICE IMPLICATIONS: As more public health agencies expand their wastewater surveillance programs to target additional pathogens, development of internal action plans tailored to departmental capacity and programs is an important step for public health agencies. The information compiled in this response framework can be a model for other public health agencies to adopt when expanding the scope of their wastewater monitoring systems.