Pre-hospital electrocardiography by emergency medical personnel: effects on scene and transport times for chest pain and ST-segment elevation myocardial infarction patients.

OBJECTIVES: This study sought to measure the impact of pre-hospital (PH) electrocardiography (ECG) on scene-to-hospital time for patients with chest pain of cardiac origin and those with ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Pre-hospital ECG decreases door-to balloon (D2B) time for STEMI patients. However, obtaining a PH ECG might prolong scene time. We investigated the impact of obtaining a PH ECG on both scene and transport times for patients with chest pain suspected of cardiac origin. METHODS: City of San Diego Emergency Medical System runsheets of patients with chest pain from January 2003 to April 2008 were analyzed. The scene times and transport times were compared before (from January 2003 to December 2005) and after (from January 2006 to April 2008) implementation of the PH ECG. Among patients with a PH ECG, median scene times and transport times were compared in patients with and without STEMI. RESULTS: There were 21,742 patients evaluated for chest pain during the study period. Implementation of PH ECG resulted in minimal increases in median scene time (19 min, 10 s vs. 19 min, 28 s, p = 0.002) and transport time (13 min, 16 s vs. 13 min, 28 s, p = 0.007). However, compared with chest pain patients, in STEMI patients (n = 303), shorter median scene time (17 min, 51 s vs. 19 min, 31 s, p < 0.001), transport time (12 min, 34 s vs. 13 min, 31 s, p = 0.006), and scene-to-hospital time was observed (30 min, 45 s vs. 33 min, 29 s, p < 0.001). CONCLUSIONS: Obtaining a PH ECG for patients with chest pain minimally prolongs scene and transport times. Further, for STEMI patients, both scene times and transport times are actually reduced leading to a potential reduction in total ischemic time.

Gender differences in scene time, transport time, and total scene to hospital arrival time determined by the use of a prehospital electrocardiogram in patients with complaint of chest pain.

BACKGROUND: Recent studies have described a gender bias against women in the setting of acute coronary syndrome (ACS). OBJECTIVES: We sought to measure the impact that a prehospital electrocardiogram (PH ECG) has on prehospital total scene time to hospital arrival time, comparing men and women with the complaint of chest pain (cCP). METHODS: This study retrospectively analyzed San Diego Emergency Medical Services (EMS) runsheets of patients with cCP before and after implementation of the PH ECG protocol. The average scene time (ST), transport time (TT), and total scene-to-arrival-at-hospital time (STH) were compared. After stratification by gender, times were compared in patients with ST-elevation myocardial infarction (STEMI) to those without STEMI. RESULTS: Of 21,742 EMS activations for patients with cCP, there were no significant differences overall. When stratified by gender, there was a significant reduction of ST (00:19:16 min vs. 00:20:48 min, p<0.001, 95% CI 00:01:17-00:01:48) and STH (00:33:22 min vs. 00:35:44 min, p<0.001, 95% CI 00:01:21-00:02:24) favoring men in cases without STEMI. In cases of STEMI, men had a significant reduction in ST (00:17:27 min vs. 00:20:29 min, p<0.001, 95% CI 00:01:24-00:04:40) and STH (00:30:30 min vs. 00:34:25 min, p<0.01, 95% CI 00:01:23-00:06:26) times compared to women. CONCLUSION: Prehospital ECG implementation led to no significant differences in pre- and post-implementation times. In cases of STEMI, men had significantly reduced scene time and scene-to-hospital time when compared to women. The precise reason for these disparities remains unknown.

The feasibility of a regional cardiac arrest receiving system.

BACKGROUND: Patients suffering out-of-hospital cardiac arrest (OOHCA) are generally transported to the closest ED, presumably to expedite a hospital level of care and improve the chances of return for spontaneous circulation (ROSC) or provide post-resuscitative care for patients with prehospital ROSC. As hospital-based therapies for survivors of OOHCA are identified, such as hypothermia and emergency primary coronary interventions (PCI), certain hospitals may be designated as cardiac arrest receiving facilities. The safety of bypassing non-designated facilities with such a regional system is not known. OBJECTIVES: To explore the potential ED contribution in OOHCA victims without prehospital ROSC and document the relationship between transport time and outcome in patients with prehospital ROSC. METHODS: This was a prospective, observational study conducted in a large, urban EMS system over an 18-month period. Data were collected using the Utstein template for OOHCA. The incidence of prehospital ROSC was calculated for patients who were declared dead on scene, transported but died in the ED, died in the hospital, and survived to hospital discharge. The relationship between transport time and survival was also explored for patients with prehospital ROSC. RESULTS: A total of 1141 cardiac arrest patients were enrolled over the 18-month period. A strong association between prehospital ROSC and final disposition was observed (chi-square test for trend p<0.001). Only two patients who survived to hospital discharge did not have prehospital ROSC. Mean transport times were not significantly different for patients with prehospital ROSC who were declared dead in the ED (8.3min), died following hospital admission (7.8min), and survived to hospital discharge (8.5min). Outcomes in patients with prehospital ROSC who had shorter (7min or less) versus longer transport times were similar, and receiver-operator curve analysis indicated no predictive ability of transport time with regard to survival to hospital admission (area under the curve=0.52). CONCLUSIONS: In this primarily urban EMS system, the vast majority of survivors from OOHCA are resuscitated in the field. A relationship between transport time and survival to hospital admission or discharge was not observed. This supports the feasibility of developing a regional cardiac arrest system with designated receiving facilities.

Predictors of intubation success and therapeutic value of paramedic airway management in a large, urban EMS system.

BACKGROUND: Endotracheal intubation (ETI) is commonly used by paramedics for definitive airway management. The predictors of success and therapeutic value with regard to oxygenation are not well studied. OBJECTIVES: 1) To explore the relationship between intubation success and perfusion status, Glasgow Coma Scale (GCS) score, and end-tidal carbon dioxide (EtCO2); 2) to describe the incidence of unrecognized esophageal intubations with use of continuous capnometry; and 3) to document the incremental benefit of invasive versus noninvasive airway management techniques in correcting hypoxemia. METHODS: This was a prospective, observational study conducted in a large urban emergency medical services system. Paramedics completed a telephone debriefing interview with quality assurance personnel following delivery of all patients in whom invasive airway management had been attempted. Continuous capnometry was used for confirmation of tube position in all patients. Descriptive statistics were used to document airway management performance, including first-attempt ETI success, overall ETI success, and Combitube insertion (CTI) success. In addition, the incidence of unrecognized esophageal intubation was recorded. The relationship between intubation success and perfusion status, GCS score, and initial EtCO2 value was explored using logistic regression. Finally, recorded SpO2 values and the incidence of hypoxemia (SpO2 < 90%) at baseline, following noninvasive airway maneuvers, and after invasive airway management were compared for perfusing patients. RESULTS: A total of 703 patients were enrolled over 12 months. First-attempt ETI success was 61%, and overall ETI success was 81%; invasive airway management (ETI or CTI) was unsuccessful in 11% of patients. A single unrecognized esophageal intubation was observed (0.1%). A clear relationship between airway management success and perfusion status, GCS score, and initial EtCO2 value was observed. Only EtCO2 demonstrated an independent association with ETI success after adjusting for the other variables. Significant improvements in mean SpO2 and the incidence of hypoxemia over baseline were observed with both noninvasive and invasive airway management techniques in 168 perfusing patients. CONCLUSIONS: A relationship between intubation success and perfusion status, GCS score, and initial EtCO2 value was observed. Capnometry was effective in eliminating unrecognized esophageal intubations. Both noninvasive and invasive airway management strategies were effective in increasing SpO2 values and decreasing the incidence of hypoxemia, with additional benefit observed with invasive airway maneuvers in some patients.

The three-phase model of cardiac arrest as applied to ventricular fibrillation in a large, urban emergency medical services system.

BACKGROUND: Cardiac arrest is responsible for significant morbidity and mortality, with consistently poor outcomes despite the rapid availability of prehospital personnel for defibrillation attempts in patients with ventricular fibrillation (VF). Recent evidence suggests a period of cardiopulmonary resuscitation (CPR) prior to defibrillation attempts may improve outcomes in patients with moderate time since collapse (4-10 min). OBJECTIVES: To determine cardiac arrest outcomes in our community and explore the relationship between time since collapse, performance of bystander CPR, and survival. METHODS: Non-traumatic cardiac arrest data were collected prospectively over an 18-month period. Patients were excluded for: age <18 years, a "Do Not Attempt Resuscitation" (DNAR) directive, determination of a non-cardiac etiology for arrest, and an initially recorded rhythm other than VF. Patients were stratified by time since collapse (<4, 4-10, > 10 min, and unknown) and compared with regard to survival and neurological outcome. In addition, patients with and without bystander CPR were compared with regard to survival. RESULTS: : A total of 1141 adult non-traumatic cardiac arrest victims were identified over the 18-month study period. This included 272 patients with VF as the initially recorded rhythm. Of these, 185 had a suspected cardiac etiology for the arrest; survival to hospital discharge was 15% in this group, with 82% of these having a good outcome or only moderate disability. Survival was highest among patients with time since collapse of less than 4 min and decreased with increasing time since collapse. There were no survivors among patients with time since collapse greater than 10 min. Among patients with time since collapse of 4 min or longer, survival was significantly higher with the performance of bystander CPR; there was no survival advantage to bystander CPR among patients with time since collapse less than 4 min. CONCLUSIONS: The performance of bystander CPR prior to defibrillation by EMS personnel is associated with improved survival among patients with time since collapse longer than 4 min but not less than 4 min. These data are consistent with the three-phase model of cardiac arrest.