David Persse

Houston Paramedic and Emergency Stroke Treatment and Outcomes Study (HoPSTO)

Background and Purpose— Establishment of stroke centers, combined with accurate paramedic diagnosis and rapid transport, is essential to deliver acute stroke therapy. We wanted to measure and improve paramedic and hospital performance through implementation of the Brain Attack Coalition and American Stroke Association guidelines. Methods— Pre-intervention and active-intervention phases with parallel data measurement points were used. The study involved six hospitals comprising the majority of acute-stroke admissions in Houston, Tex. Hospital, paramedic, and patient data were collected prospectively pre-intervention and during the active-intervention phase on all suspected acute-stroke patients admitted by Houston Fire Department-Emergency Medical Services. A multilevel educational intervention included paramedic, hospital, and community education. Paramedic diagnostic accuracy, hospital-performance efficiency, and thrombolytic treatment rates were the main outcome measures of the study. Results— Four hundred forty-six patients (74 per month) were transported in the pre-intervention phase to participating hospitals (59.8% of all suspected stroke patients transported city wide by Houston Fire Department—Emergency Medical Services), compared with 1072 patients (89 per month, or 68.7%) transported in the active-intervention phase (P<0.001). Accuracy of paramedic diagnosis of stroke increased from 61% to 79%. Admission within 2 hours of symptom onset increased from 58% to 62% (P=0.002). Thrombolysis rates increased in 4 of 6 centers, with 1 post- tissue plasminogen activator hemorrhage (3.7%) reported. Conclusions— A multilevel educational program improves rapid hospitalization and paramedic diagnostic accuracy and increases the number of patients presenting for evaluation within the 3-hour tissue plasminogen activator window. Stroke center development supports safe thrombolytic practice in community settings.

Manual vs. integrated automatic load-distributing band CPR with equal survival after out of hospital cardiac arrest. The randomized CIRC trial

OBJECTIVE To compare integrated automated load distributing band CPR (iA-CPR) with high-quality manual CPR (M-CPR) to determine equivalence, superiority, or inferiority in survival to hospital discharge. METHODS Between March 5, 2009 and January 11, 2011 a randomized, unblinded, controlled group sequential trial of adult out-of-hospital cardiac arrests of presumed cardiac origin was conducted at three US and two European sites. After EMS providers initiated manual compressions patients were randomized to receive either iA-CPR or M-CPR. Patient follow-up was until all patients were discharged alive or died. The primary outcome, survival to hospital discharge, was analyzed adjusting for covariates, (age, witnessed arrest, initial cardiac rhythm, enrollment site) and interim analyses. CPR quality and protocol adherence were monitored (CPR fraction) electronically throughout the trial. RESULTS Of 4753 randomized patients, 522 (11.0%) met post enrollment exclusion criteria. Therefore, 2099 (49.6%) received iA-CPR and 2132 (50.4%) M-CPR. Sustained ROSC (emergency department admittance), 24h survival and hospital discharge (unknown for 12 cases) for iA-CPR compared to M-CPR were 600 (28.6%) vs. 689 (32.3%), 456 (21.8%) vs. 532 (25.0%), 196 (9.4%) vs. 233 (11.0%) patients, respectively. The adjusted odds ratio of survival to hospital discharge for iA-CPR compared to M-CPR, was 1.06 (95% CI 0.83-1.37), meeting the criteria for equivalence. The 20 min CPR fraction was 80.4% for iA-CPR and 80.2% for M-CPR. CONCLUSION Compared to high-quality M-CPR, iA-CPR resulted in statistically equivalent survival to hospital discharge.

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/m3 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.

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.

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 &kgr;-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.

Cardiac arrest survival as a function of ambulance deployment strategy in a large urban emergency medical services system

INTRODUCTION This study examines the effect of paramedic deployment strategy on witnessed ventricular fibrillation (VF) cardiac arrest outcomes. Our null hypothesis was that there is no difference in survival between an EMS system using targeted response (TR) and one using a uniform or all advanced life support (ALS) response (UR) model. We define targeted response as a system where paramedics are sent to critical incidents while ambulances staffed with basic EMTs are sent to less critical incidents. A secondary outcome measure was paramedic skill proficiency between the systems. METHODS We conducted a retrospective review of all 1997 VF arrests in a large urban EMS system. The majority of the city is a busy, urban area that uses TR. Outlying areas of the city are suburban and are served by a UR model. All areas have first responders equipped with automated external defibrillators. Outcomes are compared using Utstein criteria. RESULTS Patient populations were well matched. There were 181 patients in the TR group and 24 in the UR group. Units in the TR area were able to demonstrate shorter response and time to defibrillation intervals than in the UR area. Rates for return of spontaneous circulation (ROSC), admission to the ward/intensive care unit (ICU), survival to discharge and survival to 1 year were all better in the cohort of patients cared for in the TR area than those in the UR area. Rates for successful intubation and IV initiation were also better in the TR areas than in the UR areas. CONCLUSION This study shows improved outcomes for a subset of patients with cardiac arrest when they are cared for in an area that uses TR compared to an area that uses a UR EMS system.

A tale of two cities: The role of neighborhood socioeconomic status in spatial clustering of bystander CPR in Austin and Houston ☆

BACKGROUND Despite evidence to suggest significant spatial variation in out-of-hospital cardiac arrest (OHCA) and bystander cardiopulmonary resuscitation (BCPR) rates, geographic information systems (GIS) and spatial analysis have not been widely used to understand the reasons behind this variation. This study employs spatial statistics to identify the location and extent of clusters of bystander CPR in Houston and Travis County, TX. METHODS Data were extracted from the Cardiac Arrest Registry to Enhance Survival for two U.S. sites - Austin-Travis County EMS and the Houston Fire Department - between October 1, 2006 and December 31, 2009. Hierarchical logistic regression models were used to assess the relationship between income and racial/ethnic composition of a neighborhood and BCPR for OHCA and to adjust expected counts of BCPR for spatial cluster analysis. The spatial scan statistic was used to find the geographic extent of clusters of high and low BCPR. RESULTS Results indicate spatial clusters of lower than expected BCPR rates in Houston. Compared to BCPR rates in the rest of the community, there was a circular area of 4.2km radius where BCPR rates were lower than expected (RR=0.62; p<0.0001 and RR=0.55; p=0.037) which persist when adjusted for individual-level patient characteristics (RR=0.34; p=0.027) and neighborhood-level race (RR=0.34; p=0.034) and household income (RR=0.34; p=0.046). We also find a spatial cluster of higher than expected BCPR in Austin. Compared to the rest of the community, there was a 23.8km radius area where BCPR rates were higher than expected (RR=1.75; p=0.07) which disappears after controlling for individual-level characteristics. CONCLUSIONS A geographically targeted CPR training strategy which is tailored to individual and neighborhood population characteristics may be effective in reducing existing disparities in the provision of bystander CPR for out-of-hospital cardiac arrest.

Pre-shock chest compression pause effects on termination of ventricular fibrillation/tachycardia and return of organized rhythm within mechanical and manual cardiopulmonary resuscitation☆

BACKGROUND Shorter manual chest compression pauses prior to defibrillation attempts is reported to improve the defibrillation success rate. Mechanical load-distributing band (LDB-) CPR enables shocks without compression pause. We studied pre-shock pause and termination of ventricular fibrillation/pulseless ventricular tachycardia 5s post-shock (TOF) and return of organized rhythm (ROOR) with LDB and manual (M-) CPR. METHODS In a secondary analysis from the Circulation Improving Resuscitation Care trial, patients with initial shockable rhythm and interpretable post-shock rhythms were included. Pre-shock rhythm, pause duration (if any), and post-shock rhythm were obtained for each shock. Associations between TOF/ROOR and pre-shock pause duration, including no pause shocks with LDB-CPR, were analyzed with Chi-square test. A p-value <0.05 was considered statistically significant. RESULTS For TOF and ROOR analyses we included 417 LDB-CPR patients with 1476 and 1438 shocks, and 495 M-CPR patients with 1839 and 1796 shocks, respectively. For first shocks with LDB-CPR, pre-shock pause was associated with TOF (p=0.049) with lowest TOF (77%) for shocks given without pre-shock compression pause. This association was not significant when all shocks were included (p=0.07) and not for ROOR. With M-CPR there were no significant associations between shock-related chest compression pause duration and TOF or ROOR. CONCLUSION For first shocks with LDB-CPR, termination of fibrillation was associated with pre-shock pause duration. There was no association for the rate of return of organized rhythm. For M-CPR, where no shocks were given during continuous chest compressions, there were no associations between pre-shock pause duration and TOF or ROOR.

Stroke Severity as Well as Time Should Determine Stroke Patient Triage

The National Institute of Neurological Disorders and Stroke studies,1 published in 1995, demonstrated for the first time that in patients selected by clinical and noncontrast computed tomography criteria, intravenous TPA (IV tissue plasminogen activator) resulted in improved outcomes compared with standard treatment. Since that time, safe and quick delivery of IV TPA has become the primary focus of acute stroke management and forever changed the way that acute stroke care is delivered. The most important variable that predicts response to treatment is time from symptom onset to treatment initiation.2,3 On the basis of European Cooperative Acute Stroke Study III (ECASS III),4 treatment with IV TPA in Europe is approved out to 4.5 hours, but the benefit of treatment if started >3 hours is marginal if any. IV TPA is not approved >3 hours in the United States and best results occur if treatment is started within 2 hours. The number needed to treat of 3.1 within 3 hours5 is probablyμ2 if treatment is started within 2 hours. Recently, this lesson has been reinforced by the International Stroke Trial (IST),6 which once again confirmed that time is the most important determination of IV TPA benefit, and that other criteria, such as advanced age and increased stroke severity, commonly used to exclude patients from treatment, do not in fact preclude benefit.7 Although such a narrow time window necessarily limits treatment to only a subset of stroke patients, such is the reality of reperfusion therapy at least with IV TPA as demonstrated now by abundant human clinical trial data. Because IV TPA was approved in 1996, this critical importance of time to treatment has generated a massive change in the way stroke is managed by prehospital emergency medical services (EMS) and emergency departments (EDs). Guidelines …