James V. Dunford

Integration of pre-hospital electrocardiograms and ST-elevation myocardial infarction receiving center (SRC) networks: impact on Door-to-Balloon times across 10 independent regions.

OBJECTIVES The aim of this study was to evaluate the rate of timely reperfusion for ST-elevation myocardial infarction (STEMI) with primary percutaneous coronary intervention (PPCI) in regional STEMI Receiving Center (SRC) networks. BACKGROUND The American College of Cardiology Door-to-Balloon (D2B) Alliance target is a >75% rate of D2B <or=90 min. Independent initiatives nationwide have organized regional SRC networks that coordinate universal access to 9-1-1 with the pre-hospital electrocardiogram (PH-ECG) diagnosis of STEMI and immediate transport to a SRC (designated PPCI-capable hospital). METHODS A pooled analysis of 10 independent, prospective, observational registries involving 72 hospitals was performed. Data were collected on all consecutive patients with a PH-ECG diagnosis of STEMI. The D2B and emergency medical services (EMS)-to-balloon (E2B) times were recorded. RESULTS Paramedics transported 2,712 patients with a PH-ECG diagnosis of STEMI directly to the nearest SRC. A PPCI was performed in 2,053 patients (76%) with an 86% rate of D2B <or=90 min (95% confidence interval: 84.4% to 87.4%). Secondary analyses of this cohort demonstrated a 50% rate of D2B <or=60 min (n = 1,031), 25% rate of D2B <or=45 min (n = 517), and an 8% rate of D2B <or=30 min (n = 155). A tertiary analysis restricted to 762 of 2,053 (37%) cases demonstrated a 68% rate of E2B <or=90 min. CONCLUSIONS Ten independent regional SRC networks demonstrated a combined 86% rate of D2B <or=90 min, and each region individually surpassed the American College of Cardiology D2B Alliance benchmark. In areas with regional SRC networks, 9-1-1 provides entire communities with timely access to quality STEMI care.

A Trial of an Impedance Threshold Device in Out-of-Hospital Cardiac Arrest

BACKGROUND The impedance threshold device (ITD) is designed to enhance venous return and cardiac output during cardiopulmonary resuscitation (CPR) by increasing the degree of negative intrathoracic pressure. Previous studies have suggested that the use of an ITD during CPR may improve survival rates after cardiac arrest. METHODS We compared the use of an active ITD with that of a sham ITD in patients with out-of-hospital cardiac arrest who underwent standard CPR at 10 sites in the United States and Canada. Patients, investigators, study coordinators, and all care providers were unaware of the treatment assignments. The primary outcome was survival to hospital discharge with satisfactory function (i.e., a score of ≤3 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating greater disability). RESULTS Of 8718 patients included in the analysis, 4345 were randomly assigned to treatment with a sham ITD and 4373 to treatment with an active device. A total of 260 patients (6.0%) in the sham-ITD group and 254 patients (5.8%) in the active-ITD group met the primary outcome (risk difference adjusted for sequential monitoring, -0.1 percentage points; 95% confidence interval, -1.1 to 0.8; P=0.71). There were also no significant differences in the secondary outcomes, including rates of return of spontaneous circulation on arrival at the emergency department, survival to hospital admission, and survival to hospital discharge. CONCLUSIONS Use of the ITD did not significantly improve survival with satisfactory function among patients with out-of-hospital cardiac arrest receiving standard CPR. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).

Effect of prehospital 12-lead electrocardiogram on activation of the cardiac catheterization laboratory and door-to-balloon time in ST-segment elevation acute myocardial infarction.

Reducing door-to-balloon (D + B) time during primary percutaneous coronary intervention for patients with ST-segment elevation myocardial infarction (STEMI) reduces mortality. Prehospital 12-lead electrocadiography (ECG) with cardiac catheterization laboratory (CCL) activation may reduce D + B time. Paramedic-performed ECG was initiated in the city of San Diego in January 2005 with STEMI diagnosis based on an automated computer algorithm. We undertook this study to determine the effect of prehospital CCL activation on D + B time for patients with acute STEMI brought to our institution. All data were prospectively collected for patients with STEMI including times to treatment and clinical outcomes. We evaluated 78 consecutive patients with STEMI from January 2005 to June 2006, and the study group consisted of all patients with prehospital activation of the CCL (field STEMI; n = 20). The control groups included concurrently-treated patients with STEMI during the same period who presented to the emergency department (nonfield STEMI; n = 28), and all patients with STEMI treated in the preceding year (2004) (historical STEMI; n = 30). Prehospital CCL activation significantly reduced D + B time (73 +/- 19 minutes field STEMI, 130 +/- 66 minutes nonfield STEMI, 141 +/- 49 minutes historical STEMI; p <0.001) with significant reductions in door-to-CCL and CCL-to-balloon times as well. The majority of patients with field STEMI achieved D + B times of <90 minutes (80% field STEMI, 25% nonfield STEMI, 10% historical STEMI; p <0.001). In conclusion, this study demonstrates that prehospital electrocardiographic diagnosis of STEMI with activation of the CCL markedly reduces D + B time.

The impact of a regionalized trauma system on trauma care in San Diego County

A review of autopsy reports on traumatic deaths in 1986 was conducted to determine the impact on trauma mortality of the regionalized trauma system instituted in San Diego County in 1984. Determination of preventable death was made by a panel of experts and compared with an identical review of traumatic deaths in 1979, five years before the institution of regionalized trauma care. Of 211 traumatic deaths reviewed from 1986, two (1%) were classified as preventable, compared with 20 of 177 (11.4%) deaths in 1979 (P less than .001). A breakdown of trauma deaths into central nervous system and noncentral nervous system categories revealed the overall decline was in large part a consequence of the decline in non-central nervous system deaths from 16 of 83 in 1979 to one of 62 in 1986 (P less than .005). The decrease in central nervous system-related preventable deaths from four of 94 in 1979 to one of 149 in 1986 (P less than .10) was not statistically significant. Although it is likely the trauma system introduced in 1984 contributed to the decline in preventable death, it is not possible to isolate this variable from other changes that occurred during the interval between studies. A review of trauma deaths over the same time interval in a community with similar demographics but without a trauma system might help determine the relative contribution of the trauma system.

Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest

BACKGROUND Antiarrhythmic drugs are used commonly in out-of-hospital cardiac arrest for shock-refractory ventricular fibrillation or pulseless ventricular tachycardia, but without proven survival benefit. METHODS In this randomized, double-blind trial, we compared parenteral amiodarone, lidocaine, and saline placebo, along with standard care, in adults who had nontraumatic out-of-hospital cardiac arrest, shock-refractory ventricular fibrillation or pulseless ventricular tachycardia after at least one shock, and vascular access. Paramedics enrolled patients at 10 North American sites. The primary outcome was survival to hospital discharge; the secondary outcome was favorable neurologic function at discharge. The per-protocol (primary analysis) population included all randomly assigned participants who met eligibility criteria and received any dose of a trial drug and whose initial cardiac-arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia was refractory to shock. RESULTS In the per-protocol population, 3026 patients were randomly assigned to amiodarone (974), lidocaine (993), or placebo (1059); of those, 24.4%, 23.7%, and 21.0%, respectively, survived to hospital discharge. The difference in survival rate for amiodarone versus placebo was 3.2 percentage points (95% confidence interval [CI], -0.4 to 7.0; P=0.08); for lidocaine versus placebo, 2.6 percentage points (95% CI, -1.0 to 6.3; P=0.16); and for amiodarone versus lidocaine, 0.7 percentage points (95% CI, -3.2 to 4.7; P=0.70). Neurologic outcome at discharge was similar in the three groups. There was heterogeneity of treatment effect with respect to whether the arrest was witnessed (P=0.05); active drugs were associated with a survival rate that was significantly higher than the rate with placebo among patients with bystander-witnessed arrest but not among those with unwitnessed arrest. More amiodarone recipients required temporary cardiac pacing than did recipients of lidocaine or placebo. CONCLUSIONS Overall, neither amiodarone nor lidocaine resulted in a significantly higher rate of survival or favorable neurologic outcome than the rate with placebo among patients with out-of-hospital cardiac arrest due to initial shock-refractory ventricular fibrillation or pulseless ventricular tachycardia. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT01401647.).

Rate of decline in oxygen saturation at various pulse oximetry values with prehospital rapid sequence intubation.

Background. A high incidence of desaturations has been observed during prehospital rapid sequence intubation (RSI). The rate of decline in oxygen saturation (SpO2) at various pulse oximetry values has not been defined with emergency RSI. Objective. To define the rate of SpO2 decline at various pulse oximetry values andidentify a threshold below which active BVM should be performed during prehospital RSI. Methods. Traumatic brain injury (TBI) patients undergoing RSI by prehospital providers were included in this analysis. The time period from the highest to the lowest preintubation SpO2 value was selected for review. The mean rate of SpO2 decline was calculated for each SpO2 value andthen used to define a theoretical SpO2 desaturation curve. The rate of desaturation to hypoxemia (SpO2 ≤ 90%) was defined for intubation attempts initiated at each SpO2 value. Results. A total of 684 SpO2 values from 87 patients were included. Lower SpO2 values were associated with a faster rate of SpO2 decline, with an inflection point occurring at 93%. The rate of desaturation to hypoxemia with intubation attempts initiated with SpO2 ≤ 93% was much higher than with SpO2 above 93% (100% vs. 6%, p < 0.01). In patients undergoing multiple attempts, SpO2 values with BVM between attempts was consistently higher than the preintubation SpO2 value. Conclusions. The rate of SpO2 decline increases as SpO2 decreases, with an inflection point occurring around 93%. Intubation attempts below this value are almost always associated with subsequent desaturation, suggesting that BVM should be used prior to laryngoscopy in these patients.

Ventilation patterns in patients with severe traumatic brain injury following paramedic rapid sequence intubation

Introduction: Inadvertent hyperventilation has been documented during aeromedical transports but has not been studied following paramedic rapid sequence intubation (RSI). The San Diego Paramedic RSI Trial was designed to study the impact of paramedic RSI on outcome in patients with severe head injury. This analysis explores ventilation patterns in a cohort of trial patients undergoing end-tidal CO2 (ETCO2) monitoring.Methods: Adult patients with severe head injury (Glasgow Coma Score: 3–8) unable to be intubated without RSI were prospectively enrolled in the trial. Midazolam and succinylcholine were used for RSI; rocuronium was administered following tube confirmation. Standardized ventilation protocols were used by most paramedics; however, one agency instituted ETCO2 monitoring during the second trial year, with paramedics instructed to target ETCO2 values of 30 to 35 mmHg. The incidence and duration of inadvertent hyperventilation (ETCO2:<30 mmHg) and severe hyperventilation (ETCO2:<25 mmHg) were explored for patients undergoing ETCO2 monitoring. The initial, final, minimum, and maximum values for ETCO2 and the maximum and minimum ventilatory rate values were also calculated using descriptive statistics (95% confidence interval). The pattern of ETCO2 values over time and distribution of recorded ventilatory rate values were explored graphically.Results: A total of 76 trial patients had adequate ETCO2 data for this analysis. The mean values for initial, final, maximum, and minimum ETCO2 were 40.8 (range: 37.5–44.2), 28.4 (range: 25.4–31.4), 45.1 (range: 41.4–48.8), and 23.5 mmHg (range: 21.4–25.5), respectively. The mean maximum and minimum ventilatory rate values were 36.0/minute (range: 33.5–38.5) and 12.8/minute (range: 11.9–13.7), respectively. ETCO2 values less than 30 and 25 mmHg were documented in 79% and 59% of patients, respectively, with mean durations of 485 (range: 378–592) and 390 seconds (range: 285–494).Conclusion: Inadvertent hyperventilation is common following paramedic RSI, despite ETCO2 monitoring and target parameters.

Serum Troponin I Measurement of Subjects Exposed to the Taser X-26®

The Taser is a high-voltage, low-amperage conducted energy device used by many law enforcement agencies as a less lethal force weapon. The objective of this study was to evaluate for a rise in serum troponin I level after deployment of the Taser on law enforcement training volunteers. A prospective, observational cohort study was performed evaluating serum troponin I levels in human subjects 6 h after an exposure to the Taser X-26. Outcome measures included abnormal elevation in serum troponin I level (> 0.2 ng/mL). There were 66 subjects evaluated. The mean shock duration was 4.36 s (range 1.2-5 s). None of the subjects had a positive troponin I level 6 h after exposure. It was concluded that human volunteers exposed to a single shock from the Taser did not develop an abnormal serum troponin I level 6 h after shock, suggesting that there was no myocardial necrosis or infarction.

Emergency medical dispatch

EMD will always remain somewhat of an imprecise science by nature. 911 is, after all, the access point for lifesaving assistance, and citizens must have absolute freedom to this service. The consequence of having the freedom to request help from any location at any time is that some individuals will use it for the wrong reasons. Present-day dispatchers must serve ever-broadening communities with multiple languages, cultural diversity, and unique health needs. Along with other essential personnel that make up the fabric of the public safety net, emergency medical dispatchers have now become essential to the provision of time-critical skills and compassion for perceived medical emergency.

An autopsy study of traumatic deaths: San Diego County, 1979☆

All traumatic deaths in San Diego County were analyzed for the year of 1979. Death certificates, coroners reports, and autopsy data served as the basis for this review. A total of 177 deaths were studied, of which 94 were associated with CNS injury and 83 were not. Sixteen (20 percent) of the deaths not CNS-associated and four (5 percent) of the CNS-associated deaths were classified as preventable. One hundred seventeen deaths were due to motor vehicle accidents, of which 11 of 35 (31 percent; all not CNS-associated) were deemed preventable. Preventable causes of death included hemorrhage, unrecognized hemopneumothorax, and unrecognized epidural hematoma.