The Utility of Prehospital ECG Transmission in a Large EMS System.

BACKGROUND: Prehospital identification of STEMI and activation of the catheterization lab can improve door-to-balloon (D2B) times but may lead to decreased specificity and unnecessary resource utilization. The purpose of this study was to examine the effect of electrocardiogram (ECG) transmission on false-positive (FP) cath lab activations and time to reperfusion. METHODS: This is a retrospective cohort from a registry in a large metropolitan area with regionalized cardiac care and emergency medical services (EMS) with ECG transmission capabilities. Thirty-four designated STEMI receiving centers (SRC) contribute to this registry, from which patients with a prehospital ECG software interpretation of myocardial infarction (MI) indicated by ****Acute MI****, or manufacturer equivalent, were identified between April 2011 and September 2013. Frequency of FP field activations (defined as not resulting in emergent percutaneous coronary intervention [PCI] or referral for CABG during hospital admission) for patients with ECG transmission received by the SRC was compared to a reference group without successful ECG transmission. FP field activations were compared to the baseline frequency of FP ED activations. We hypothesized that successful transmission would reduce FP field activation to ED activation levels. Door-to-balloon and first medical contact-to-balloon (FMC2B) times were compared. The protocol for field cath lab activation varied by institution. RESULTS: There were 7,768 patients presenting with a prehospital ECG indicating MI. The ECG was received by the SRC for 2,156 patients (28%). Regardless of transmission, the cath lab was activated 77% of the time; this activation occurred from the field in 73% and 74% of the activations in the transmission and reference group, respectively. The overall proportion of FP activation was 57%. Among field activations, successful ECG transmission reduced the FP activation rate compared to without ECG transmission, 55% vs. 61% (RD = -6%, 95%CI -9, -3%). This led to an overall system reduction in FP activations of 5% (95%CI 2, 8%). ECG transmission had no effect on D2B and FMC2B time. CONCLUSION: Prehospital ECG transmission is associated with a small reduction in false-positive field activations for STEMI and had no effect on time to reperfusion in this cohort.

Re-examining outcomes after unsuccessful out-of-hospital resuscitation in the era of field termination of resuscitation guidelines and regionalized post-resuscitation care.

BACKGROUND: Dismal prognosis after failed out-of-hospital resuscitation has previously been demonstrated. Changes in resuscitation and post-resuscitation care may affect patient outcomes. We describe characteristics and outcomes of patients with out-of-hospital cardiac arrest (OOHCA) transported to specialty cardiac centers after failure of out-of-hospital interventions. METHODS: In Los Angeles (LA) County, patients with non-traumatic OOHCA with return of spontaneous circulation (ROSC) are transported to specialized cardiac care centers. Outcomes are reported to a registry maintained by the LA County Emergency Medical Services (EMS) Agency. We report patient characteristics and outcomes for the subset of patients treated at these specialty centers in whom initial ROSC was achieved in the ED. The primary outcome was neurologically intact survival, defined by a cerebral performance category (CPC) score of 1 or 2. RESULTS: 105 patients transported to the SRC after failure to achieve ROSC with out-of-hospital resuscitation were successfully resuscitated in the ED. The median age was 68 years (IQR 57-78); 74 (70%) were male. The presenting rhythm was ventricular fibrillation or ventricular tachycardia in 40 patients (38%) and 86 (82%) were witnessed. Twenty-two patients (21%) survived to hospital discharge. Of the 103 patients with known CPC scores, 13 (13% [95% CI 7-21%]) survived to hospital discharge with a CPC score of 1 or 2. No patient who survived with good neurologic outcome met criteria for termination of resuscitation in the field. CONCLUSION: Failure of out-of-hospital resuscitation is not universally predictive of poor neurologic outcome.

Survival and neurologic outcome after out-of-hospital cardiac arrest: results one year after regionalization of post-cardiac arrest care in a large metropolitan area.

BACKGROUND: Post-resuscitation care of cardiac arrest patients at specialized centers may improve outcome after out-of-hospital cardiac arrest (OOHCA). This study describes experience with regionalized care of resuscitated patients. METHODS: Los Angeles (LA) County established regionalized cardiac care in 2006. Since 2010, protocols mandate transport of nontraumatic OOHCA patients with field return of spontaneous circulation (ROSC) to a STEMI Receiving Center (SRC) with a hypothermia protocol. All SRC report outcomes to a registry maintained by the LA County Emergency Medical Services (EMS) Agency. We report the first year's data. The primary outcome was survival with good neurologic outcome, defined by a Cerebral Performance Category (CPC) score of 1 or 2. RESULTS: The SRC treated 927 patients from April 2011 through March 2012 with median age 67; 38% were female. There were 342 patients (37%) who survived to hospital discharge. CPC scores were unknown in 47 patients. Of the 880 patients with known CPC scores, 197 (22%) survived to hospital discharge with a CPC score of 1 or 2. The initial rhythm was VF/VT in 311 (34%) patients, of whom 275 (88%) were witnessed. For patients with an initial shockable rhythm, 183 (59%) survived to hospital discharge and 120 (41%) had survival with good neurologic outcome. Excluding patients who were alert or died in the ED, 165 (71%) patients with shockable rhythms received therapeutic hypothermia (TH), of whom 67 (42%) had survival with good neurologic outcome. Overall, 387 patients (42%) received TH. In the TH group, the adjusted OR for CPC 1 or 2 was 2.0 (95%CI 1.2-3.5, p = 0.01), compared with no TH. In contrast, the proportion of survival with good neurologic outcome in the City of LA in 2001 for all witnessed arrests (irrespective of field ROSC) with a shockable rhythm was 6%. CONCLUSION: We found higher rates of neurologically intact survival from OOHCA in our system after regionalization of post-resuscitation care as compared to historical data.

Effect of prehospital cardiac catheterization lab activation on door-to-balloon time, mortality, and false-positive activation.

BACKGROUND: Reperfusion of ST elevation myocardial infarction (STEMI) is most effective when performed early. Notification of the cardiac catheterization laboratory (cath lab) prior to hospital arrival based on paramedic-performed ECGs has been proposed as a strategy to decrease time to reperfusion and mortality. The purpose of this study was to compare the effects of cath lab activation prior to patient arrival versus activation after arrival at the emergency department (ED). METHODS: We performed a retrospective cohort study (n = 1933 cases) using Los Angeles County STEMI database from May 1, 2008 through August 31, 2009. The database includes patients arriving at a STEMI Receiving Center (SRC) by ambulance who were diagnosed with STEMI either before or after hospital arrival. We compared the cohort of patients with prehospital cath lab activation to those activated from the ED within 5 minutes of first ED ECG. Outcomes measured were mortality, door-to-balloon time, percent door-to-balloon time <90 min, and percentage of false-positive activations. RESULTS: Prehospital cath lab activations had mean door-to-balloon times 14 minutes shorter (95% CI 11-17), in-hospital mortality 1.5% higher (95% CI -1.0-5.2), and false-positive activation 7.8%, (95% CI 2.7-13.3) higher than ED activation. For prehospital activation, 93% (95% CI 91-94%) met a door-to-balloon target of 90 minutes versus 85% (95% CI 80-88%) for ED activations. CONCLUSION: Prehospital cath lab activation based on the prehospital ECG was associated with decreased door-to-balloon times but did not affect hospital mortality. False-positive activation was common and occurred more often with prehospital STEMI diagnosis.

Out-of-hospital unwitnessed cardiopulmonary collapse and no-bystander CPR: a practical addition to resuscitation termination guidelines.

Cardiopulmonary resuscitation (CPR) provides possible survival from otherwise fatal cardiopulmonary collapse. Termination guidelines have been developed for use when resuscitation has no potential benefit for a victim. The purpose of this prospective cohort study was to determine if unwitnessed collapse combined with no-bystander cardiopulmonary resuscitation would support a decision to terminate attempted resuscitation. There were 541 patients analyzed during 6 months, with functional neurological survival the outcome of interest. There were no functional neurological survivors at hospital discharge among the 180 victims in the unwitnessed, no-bystander CPR subgroup (95% confidence interval [CI] 0.0%-2.1%). Functional neurological survival for witnessed collapse, bystander CPR was 6.0% (95% CI 2.8%-12.5%), for witnessed collapse, no-bystander CPR was 3.8% (95% CI 1.9%-7.7%), and for unwitnessed collapse, bystander CPR 1.3% (95% CI 0.2%-6.9%). With confirmation by further studies, unwitnessed collapse and lack of bystander CPR may be a practical addition to resuscitation termination guidelines.