Intra-Arrest Induction of Hypothermia via Large-Volume Ice-Cold Saline for Sudden Cardiac Arrest: The New York City Project Hypothermia Experience.

Therapeutic hypothermia, the standard for post-resuscitation care of out-of-hospital sudden cardiac arrest (SCA), is an area that the most recent resuscitation guidelines note "has not been studied adequately." We conducted a two-phase study examining the role of intra-arrest hypothermia for out-of-hospital SCA, first standardizing the resuscitation and transport of patients to resuscitation centers where post-resuscitation hypothermia was required and then initiating hypothermia during out-of-hospital resuscitation efforts. The primary end points were return of spontaneous circulation (ROSC), sustained ROSC, survival to hospital admission, and survival to discharge. Comparing the cohort of standard hospital-initiated hypothermia (Phase I) with the prehospital-initiated hypothermia via large-volume ice-cold saline (LVICS) infusion (Phase II), no difference was noted for any end point: ROSC (56.4% vs. 53.4%, p = 0.51; 95% confidence interval [CI]: -5.7 to 11.4), sustained ROSC (46.9% vs. 42.8%, p = 0.38; 95% CI: -4.7 to 12.4), hospital admission (44.7% vs. 37.7%, p = 0.13; 95% CI: -1.9 to 15.4), hospital discharge among those surviving to admission (40.0% vs. 28.0%, p = 0.08; 95% CI: -1.5 to 27.8), or neurological outcome among those surviving to discharge (76.0% vs. 71.4%, p = 0.73; 95% CI: -26.9 to 38.7). Patients presenting in ventricular fibrillation were more likely to survive to hospital discharge in both phases, although a trend toward worsened early outcomes (ROSC, sustained ROSC, and survival to admission) with intra-arrest hypothermia was noted in this subgroup. Multivariable regression analyses failed to demonstrate any survival benefit associated with the intra-arrest initiation of hypothermia via LVICS. Our study, the largest study of intra-arrest initiation of hypothermia published to date, failed to demonstrate any effect on survival for out-of-hospital SCA patients, confirming findings of previously published smaller studies. We therefore do not recommend the use of intra-arrest cooling via LVICS infusion as part of routine out-of-hospital SCA resuscitative efforts.

A modified simple triage and rapid treatment algorithm from the New York City (USA) Fire Department.

INTRODUCTION: The objective of this study was to determine if modification of the Simple Triage and Rapid Treatment (START) system by the addition of an Orange category, intermediate between the most critically injured (Red) and the non-critical, non-ambulatory injured (Yellow), would reduce over- and under-triage rates in a simulated mass-casualty incident (MCI) exercise. METHODS: A computer-simulation exercise of identical presentations of an MCI scenario involving a 2-train collision, with 28 case scenarios, was provided for triaging to two groups: the Fire Department of the City of New York (FDNY; n=1,347) using modified START, and the Emergency Medical Services (EMS) providers from the Eagles 2012 EMS conference (Lafayette, Louisiana USA; n=110) using unmodified START. Percent correct by triage category was calculated for each group. Performance was then compared between the two EMS groups on the five cases where Orange was the correct answer under the modified START system. RESULTS: Overall, FDNY-EMS providers correctly triaged 91.2% of cases using FDNY-START whereas non-FDNY-Eagles providers correctly triaged 87.1% of cases using unmodified START. In analysis of the five Orange cases (chest pain or dyspnea without obvious trauma), FDNY-EMS performed significantly better using FDNY-START, correctly triaging 86.3% of cases (over-triage 1.5%; under-triage 12.2%), whereas the non-FDNY-Eagles group using unmodified START correctly triaged 81.5% of cases (over-triage 17.3%; under-triage 1.3%), a difference of 4.9% (95% CI, 1.5-8.2). CONCLUSIONS: The FDNY-START system may allow providers to prioritize casualties using an intermediate category (Orange) more properly aligned to meet patient needs, and as such, may reduce the rates of over-triage compared with START. The FDNY-START system decreases the variability in patient sorting while maintaining high field utility without needing computer assistance or extensive retraining. Comparison of triage algorithms at actual MCIs is needed; however, initial feedback is promising, suggesting that FDNY-START can improve triage with minimal additional training and cost.

From door-to-balloon time to contact-to-device time: predictors of achieving target times in patients with ST-elevation myocardial infarction.

BACKGROUND: The 2013 American College of Cardiology Foundation/American Heart Association ST-segment elevation myocardial infarction (STEMI) guidelines have shifted focus from door-to-balloon (D2B) time to the time from first medical contact to device activation (contact-to-device time [C2D] ). HYPOTHESIS: This study investigates the impact of prehospital wireless electrocardiogram transmission (PHT) on reperfusion times to assess the impact of the new guidelines. METHODS: From January 2009 to December 2012, data were collected on STEMI patients who received percutaneous coronary interventions; 245 patients were included for analysis. The primary outcome was median C2D time in the PHT group and the secondary outcome was D2B time. RESULTS: Prehospital wireless electrocardiogram transmission was associated with reduced C2D times vs no PHT: 80 minutes (interquartile range [IQR], 64-94) vs 96 minutes (IQR, 79-118), respectively, P < 0.0001. The median D2B time was lower in the PHT group vs the no-PHT group: 45 minutes (IQR, 34-56) vs 63 minutes (IQR, 49-81), respectively, P < 0.0001. Multivariate analysis showed PHT to be the strongest predictor of a C2D time of <90 minutes (odds ratio: 3.73, 95% confidence interval: 1.65-8.39, P = 0.002). Female sex was negatively predictive of achieving a C2D time <90 minutes (odds ratio: 0.23, 95% confidence interval: 0.07-0.73, P = 0.01). CONCLUSIONS: In STEMI patients, PHT was associated with significantly reduced C2D and D2B times and was an independent predictor of achieving a target C2D time. As centers adapt to the new guidelines emphasizing C2D time, targeting a shorter D2B time (<50 minutes) is ideal to achieve a C2D time of <90 minutes.

Waveform analysis-guided treatment versus a standard shock-first protocol for the treatment of out-of-hospital cardiac arrest presenting in ventricular fibrillation: results of an international randomized, controlled trial.

BACKGROUND: Ventricular fibrillation (VF) waveform properties have been shown to predict defibrillation success and outcomes among patients treated with immediate defibrillation. We postulated that a waveform analysis algorithm could be used to identify VF unlikely to respond to immediate defibrillation, allowing selective initial treatment with cardiopulmonary resuscitation in an effort to improve overall survival. METHODS AND RESULTS: In a multicenter, double-blind, randomized study, out-of-hospital cardiac arrest patients in 2 urban emergency medical services systems were treated with automated external defibrillators using either a VF waveform analysis algorithm or the standard shock-first protocol. The VF waveform analysis used a predefined threshold value below which return of spontaneous circulation (ROSC) was unlikely with immediate defibrillation, allowing selective treatment with a 2-minute interval of cardiopulmonary resuscitation before initial defibrillation. The primary end point was survival to hospital discharge. Secondary end points included ROSC, sustained ROSC, and survival to hospital admission. Of 6738 patients enrolled, 987 patients with VF of primary cardiac origin were included in the primary analysis. No immediate or long-term survival benefit was noted for either treatment algorithm (ROSC, 42.5% versus 41.2%, P=0.70; sustained ROSC, 32.4% versus 33.4%, P=0.79; survival to admission, 34.1% versus 36.4%, P=0.46; survival to hospital discharge, 15.6% versus 17.2%, P=0.55, respectively). CONCLUSIONS: Use of a waveform analysis algorithm to guide the initial treatment of out-of-hospital cardiac arrest patients presenting in VF did not improve overall survival compared with a standard shock-first protocol. Further study is recommended to examine the role of waveform analysis for the guided management of VF.

Utilization of emergency medical services in a large urban area: description of call types and temporal trends.

BACKGROUND: Emergency medical services (EMS) systems are used by the public for a range of medically related problems. OBJECTIVE: To understand and analyze the patterns of EMS utilization and trends over time in a large urban EMS system so that we may better direct efforts toward improving those services. METHODS: The 63 call type designations from all New York City (NYC) 9-1-1 EMS calls between 1999 and 2007 were obtained and grouped into 10 broad and 30 specific medical categories. Aggregated numbers of total EMS calls and individual categories were divided by NYC resident population estimates to determine utilization rates. Temporal trends were evaluated for statistical significance with Spearman's rho (ρ). RESULTS: There were 9,916,904 EMS calls between 1999 and 2007, with an average of 1,101,878 calls/year. Utilization rates increased from 129.5 to 141.9 calls/1,000 residents/year over the study period (average annual rise of 1.16%). Among all medical/surgical call types (excluding trauma), there was an average annual increase of 1.8%/year. The most substantial increases were among "psychiatric/drug related" (+5.6%/year), "generalized illness" (+3.2%/year), and "environmental related" calls (+2.9%/year). The largest decrease was among "respiratory" calls (-1.2%/year), specifically for "asthma" (-5.0%/year). For trauma call types, there was an annual average decrease of 0.4%/year, with the category of "violence related" calls having the greatest decline (-3.3%/year). CONCLUSION: There was an increase in overall EMS utilization rates, though not all call types rose uniformly. Rather, a number of significant trends were identified reflecting either changing medical needs or changing patterns of EMS utilization in NYC's population.

Association of ambient fine particles with out-of-hospital cardiac arrests in New York City.

Cardiovascular morbidity has been associated with particulate matter (PM) air pollution, although the relation between pollutants and sudden death from cardiac arrest has not been established. This study examined associations between out-of-hospital cardiac arrests and fine PM (of aerodynamic diameter ≤2.5 µm, or PM(2.5)), ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide in New York City. The authors analyzed 8,216 out-of-hospital cardiac arrests of primary cardiac etiology during the years 2002-2006. Time-series and case-crossover analyses were conducted, controlling for season, day-of-week, same-day, and delayed/apparent temperature. An increased risk of cardiac arrest in time-series (relative risk (RR) = 1.06, 95% confidence interval (CI): 1.02, 1.10) and case-crossover (RR = 1.04, 95% CI: 0.99, 1.08) analysis for a PM(2.5) increase of 10 µg/m³ in the average of 0- and 1-day lags was found. The association was significant in the warm season (RR = 1.09, 95% CI: 1.03, 1.15) but not the cold season (RR = 1.01, 95% CI: 0.95, 1.07). Associations of cardiac arrest with other pollutants were weaker. These findings, consistent with studies implicating acute cardiovascular effects of PM, support a link between PM(2.5) and out-of-hospital cardiac arrests. Since few individuals survive an arrest, air pollution control may help prevent future cardiovascular mortality.

The "vertical response time": barriers to ambulance response in an urban area.

BACKGROUND: Ambulance response time is typically reported as the time interval from call dispatch to arrival on-scene. However, the often unmeasured "vertical response time" from arrival on-scene to arrival at the patient's side may be substantial, particularly in urban areas with high-rise buildings or other barriers to access. OBJECTIVES: To measure the time interval from arrival on-scene to the patient in a large metropolitan area and to identify barriers to emergency medical services arrival. METHODS: This was a prospective observational study of response times for high-priority call types in the New York City 9-1-1 emergency medical services system. Research assistants riding with paramedics enrolled a convenience sample of calls between 2001 and 2003. RESULTS: A total of 449 paramedic calls were included, with a median time from call dispatch to arrival on-scene of 5.2 minutes. The median on-scene to patient arrival interval was 2.1 minutes, leading to an actual response interval (dispatch to patient) of 7.6 minutes. The median on-scene to patient interval was 2.8 minutes for residential buildings, 2.7 minutes for office complexes, 1.3 minutes for private homes (less than four stories), and 0.5 minutes for outdoor calls. Overall, for all calls, the on-scene to patient interval accounted for 28% of the actual response interval. When an on-scene escort provided assistance in locating and reaching the patient, the on-scene to patient interval decreased from 2.3 to 1.9 minutes. The total dispatch to patient arrival interval was less than 4 minutes in 8.7%, less than 6 minutes in 28.5%, and less than 8 minutes in 55.7% of calls. CONCLUSIONS: The time from arrival on-scene to the patient's side is an important component of overall response time in large urban areas, particularly in multistory buildings.

Impact of a citywide blackout on an urban emergency medical services system.

INTRODUCTION: On 14 August 2003, New York City and a large portion of the northeastern United States experienced the largest blackout in the history of the country. An analysis of such a widespread disaster on emergency medical service (EMS) operations may assist in planning for and managing such disasters in the future. METHODS: A retrospective review of all EMS activity within New York City's 9-1-1 emergency telephone system during the 29 hours during which all or parts of the city were without power (16:11 hours (h) on 14 August 2003 until 21:03 h on 15 August 2003) was performed. Control periods were established utilizing identical time periods during the five weeks preceding the blackout. RESULTS: Significant increases were identified in the overall EMS demand (7,844 incidents vs. 3,860 incidents; p < 0.001) as well as in 20 of the 62 call-types of the system, including cardiac arrests (119 vs. 76, p = 0.043). Significant decreases were found only among calls related to psychological emergencies (114 vs. 221; p = 0.006) and drug- or alcohol-related emergencies (78 vs. 146; p = 0.009). Though median response times increased by only 60 seconds, median call-processing times within the 9-1-1 emergency telephone system EMS dispatch center of the city increased from 1.1 to 5.5 minutes. CONCLUSIONS: The citywide blackout resulted in dramatic changes in the demands upon the EMS system of New York City, the types of patients for whom EMS providers were assigned to provide care, and the dispositions for those assignments. During this time of increased, system-wide demand, the use of cross-trained firefighter and first-responder engine companies resulted in improved response times to cardiac arrest patients. Finally, the ability of the EMS dispatch center to process the increased requests for EMS assistance proved to be the rate-limiting step in responding to these emergencies. These findings will prove useful in planning for future blackouts or any disaster that may broadly impact the infrastructure of a city.