Survival from prehospital cardiac arrest is critically dependent upon response time

STUDY OBJECTIVE

This study correlated the delay in initiation of bystander cardiopulmonary resuscitation (ByCPR), basic (BLS) or advanced cardiac (ACLS) life support, and transport time (TT) to survival from prehospital cardiac arrest. This was a secondary endpoint in a study primarily evaluating the effect of bicarbonate on survival.

DESIGN

Prospective multicenter trial.

SETTING

Patients treated by urban, suburban, and rural emergency medical services (EMS) services.

PATIENTS

Eight hundred and seventy-four prehospital cardiac arrest patients.

INTERVENTIONS

This group underwent conventional ACLS intervention followed by empiric early administration of sodium bicarbonate noting resuscitation times. Survival was measured as the presence of vital signs on emergency department (ED) arrival. Data analysis utilized Student's t-test and logistic regression (p<0.05).

RESULTS

Survival was improved with decreased time to BLS (5.52 min versus 6.81 min, p=0.047) and ACLS (7.29 min versus 9.49 min, p=0.002) intervention, as well as difference in time to return of spontaneous circulation (ROSC). The upper limit time interval after which no patient survived was 30 min for ACLS time, and 90 min for transport time. There was no overall difference in survival except at longer arrest times when considering the primary study intervention bicarbonate administration.

CONCLUSION

Delay to the initiation of BLS and ACLS intervention influenced outcome from prehospital cardiac arrest negatively. There were no survivors after prolonged delay in initiation of ACLS of 30 min or greater or total resuscitation and transport time of 90 min. This result was not influenced by giving bicarbonate, the primary study intervention, except at longer arrest times.

End tidal CO2 monitoring in condition of constant ventilation: a useful guide during advanced cardiac life support

Success of advanced cardiac life support (ACLS) depends on several factors: character and severity of the primary insult, time interval between cardiac arrest and effective basic life support (BLS) and the ensuing ACLS, patient's general condition before the insult, environmental circumstances and efficacy of BLS and ACLS. From these factors, only the efficacy of ACLS is under control of emergency personnel. The end tidal partial pressure of CO2 (P(ET)CO2) has been shown to be an indicator of the efficiency of ACLS and a general prognostic marker. In this study P(ET)CO2 was monitored during out-of hospital ACLS in three cases of cardiac arrest of different aetiology. The aetiology included lung oedema, tension pneumothorax and high voltage electric injury. P(ET)CO2 served for adjustments of ACLS. In these three cases the predictive value of P(ET)CO2 monitoring corresponded to previously reported recommendations.

Advanced cardiac life support before and after tracheal intubation—direct measurements of quality

STUDY HYPOTHESIS

Tracheal intubation should improve the quality of cardiopulmonary resuscitation (CPR) by enabling adequate ventilation without pauses in external chest compressions.

METHODS

Out-of-hospital cardiac arrests of all causes were sampled in this non-randomized, observational study of advanced cardiac life support in three ambulance services (Akershus, London and Stockholm). Prototype defibrillators (Heartstart 4000SP, Philips Medical Systems, Andover, MA, USA and Laerdal Medical AS, Stavanger, Norway) registered all chest compressions via an extra chest pad with an accelerometer mounted over the lower part of sternum and ventilations from changes in transthoracic impedance between the standard defibrillator pads. The quality of CPR was analyzed off-line for 119 episodes. Numbers and differences are given as mean +/- S.D. and differences as mean and 95% confidence intervals.

RESULTS

Chest compressions were not given in cardiac arrest for 61 +/- 20% of the time before intubation compared to 41 +/- 18% after intubation (difference: 20% (16-24%)). Compressions and ventilations per minute increased from 47 +/- 25 to 71 +/- 23 (difference: 24 (19, 29)) and 5.6 +/- 3.7 to 14 +/- 5.0 (difference: 8.7 (7.6, 9.8)) respectively. Four cases of unrecognized oesophageal intubation (3%) were suspected from the disappearance of ventilation induced changes in thoracic impedance after intubation.

CONCLUSION

The quality of CPR improved after tracheal intubation, but the fraction of time without blood flow was still high and not according to international guidelines. On-line analysis of thoracic impedance might be a practicable aid to avoid unrecognized oesophageal intubation, but this area needs further research.

[The network for the management of acute coronary syndromes in Milan: results of a four-year experience and perspectives of the prehospital and interhospital cardiological network]

In patients with acute ST-elevation myocardial infarction (STEMI), in order to shorten the time to definitive treatment, it is essential to coordinate the intervention between the local healthcare system and the hospitals. In 1999, a Working Group for Prehospital Emergency in Cardiology was established in Milan, and a network for 12-lead ECG transmission between advances life support (ALS) ambulances, the headquarter of 118 Rescue Service and the Coronary Care Units (CCU) or Divisions of Cardiology was developed: between February 1, 2001 and May 1, 2005, 6821 patients with suspected heart attack were rescued and their ECG recorded and transmitted (177 patients/month, 20% of them with an ST-segment shift, 11% ST-segment elevation, 9% non-ST-segment elevation, 24% with normal ECG). The rate of false positive automatic diagnosis of acute myocardial infarction was 0.3%, the rate of false negative was 0.8%. Forty-six patients with ventricular fibrillation underwent DC-shock. After May 1, 2004, clinical data of patients with STEMI transferred to the hospitals by ALS ambulances were reported in a database: 82% of the 89 patients were treated with primary angioplasty. The time (median, interquartile ranges) between ECG arrival to the CCU and the ECG report was 2 min (1-5), between ECG arrival to the CCU and patient arrival to the hospital was 34 min (24-42), between ECG arrival to the CCU and primary angioplasty was 69 min (50-93); the door-to-balloon time was 33 min (22-60). The telephone ECG transmission has been demonstrated to be a useful and rapid tool, easy to use; the automatic ECG diagnosis was accurate. In patients with STEMI the telephone ECG transmission shortened the time of delivery of therapy, helped to recover arrhythmic complications, allowed both the coordination between the 118 System and the Divisions of Cardiology and the implementation of the triage for primary angioplasty. Increasing the technological level of the service will be the next step of the program: the protocol will be upgraded in order to increase the number of patients rescued, to shorten the time of operation and to administer prehospital fibrinolytic therapy in selected patients.

[Analysis of the intra-hospital attending of ventricular fibrilation/ventricular taquicardia simulated events]

OBJECTIVE

To analyze the time intervals between the beginning of the Ventricular Fibrilation/Ventricular Taquicardia (VF/VT) and the main procedures made.

METHODS

Twenty VF/VT simulations were performed and filmed in a hospital environment, using a static mannequin, on random days at random times. All teams had the same level of skills. The times (in sec.) related to basic life support (BLS) - arrival of the team (AT), confirmation of the arrest (CAT), beginning of the CPR (IT) and the times related to the advanced life support (ALS) - 1st defibrillation (DT), 1st dose of adrenalin (AT) and orotracheal intubation (OTIT). The variables were analyzed and compared in two groups: intensive care unit (ICU) and wards with telemetry (TLW).

RESULTS

The results in both groups was in that order (GW x ICU ) - AT (70.2+38.7 x 38.6+49.2); CCA (89.4+57.1 x 71+63.9); SC (166.8+81.1 x 142+66.2); FD (282.5+142.8 x 108.4+52.5); FE (401.4+161.7 x 263.3+122.8) e OI (470.3+150.6 x 278.8+98.8). Shows the comparison of the average times between the two groups.

CONCLUSION

The differences noted in relation to DT, AT and OTIT favorable to ICU are associated to the facility of performance of the ALS maneuvers in such environment. The BLS-related times were similar in both groups, which reinforce the need for the use of semi-automatic defibrillators, even in a hospital environment.

Cardiac arrest during pregnancy

This case involves cardiac arrest of a 29-week old pregnant African American woman, occurring 2 days after surgical correction of an incarcerated ventral hernia with small bowel obstruction. The patient could not be resuscitated from this arrest. Details of the case are presented, and diagnostic and unique management considerations for this uncommon occurrence are set forth.

The effect of pulse oximetry on emergency medical technician decision making

OBJECTIVE

Relatively little is known about the use of pulse oximetry in the prehospital setting. The purpose of this study was to determine how emergency medical technicians (EMTs) use pulse oximetry information to influence their decisions regarding the involvement of advanced life support (ALS) personnel in a two-tiered emergency medical services (EMS) system.

METHODS

EMTs were trained and authorized to use pulse oximetry in predefined clinical situations. The EMTs completed a questionnaire describing the influence of the oximetry information on their decision making regarding the involvement of ALS units.

RESULTS

The EMTs reported an influence on their decisions whether to involve ALS care in 35 (12%) of 302 cases. The addition of the pulse oximetry information caused the EMTs to request ALS dispatch in 11 cases, to cancel a previously dispatched ALS response in eight cases, and not to request an ALS response from the scene when they otherwise would have requested it in 16 cases.

CONCLUSION

Prehospital pulse oximetry has a measurable influence on EMT decisions concerning ALS involvement in a two-tiered EMS system. It improves system efficiency by helping to match patients to an appropriate level of care.

Outcome of out-of-hospital cardiac arrest—why do physicians withhold resuscitation attempts?

OBJECTIVE

To describe the outcome of out-of-hospital cardiac arrest (OHCA) with a focus on why physicians withhold resuscitation attempts.

METHODS

Prospective collection of data during 12 months by the anaesthesiologists from the Advanced Life Support unit (ALS) of the Emergency Medical Service (EMS) according to the Utstein template.

RESULTS

In total, 499 OHCA were analysed and 266 patients received cardiopulmonary resuscitation (CPR) by the ALS unit. Initial rhythm was ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT) in 35%, asystole in 38%, and other rhythm in 27%. Of the 266 treated patients, 83 (31%) patients had a spontaneous circulation on admission to hospital. Survival to discharge from hospital was 6.2% for all cases of OHCA, 11.7% for all 266 treated patients, and 20.5% for patients with witnessed cardiac arrest and presumed cardiac aetiology in VF. On arrival, the physician decided in 233 cases to withhold or discontinue CPR. The explanation for this was prolonged anoxia (74%), terminal cancer (8%), and severe trauma (7%). The most common incident locations were the patient's home and nursing homes. These locations were more common in the group where resuscitation was not attempted and these patients were older and the proportions of females and asystole were significantly higher. Bystander CPR was provided in 82 (16%) overall, but only in 8 (3%) in the group where resuscitation was not attempted.

CONCLUSION

Survival to discharge from hospital in all cases of OHCA was 6.2% but 20.5% in witnessed, presumed cardiac aetiology in VF. The decision to withhold resuscitation was based upon presumed prolonged anoxia in the majority of cases.

Can we define patients with no chance of survival after out-of-hospital cardiac arrest?

OBJECTIVE

To evaluate whether subgroups of patients with no chance of survival can be defined among patients with out-of-hospital cardiac arrest.

PATIENTS

Patients in the Swedish cardiac arrest registry who fulfilled the following criteria were surveyed: cardiopulmonary resuscitation (CPR) was attempted; the arrest was not crew witnessed; and patients were found in a non-shockable rhythm.

SETTING

Various ambulance organisations in Sweden.

DESIGN

Prospective observational study.

RESULTS

Among the 16,712 patients who fulfilled the inclusion criteria, the following factors were independently associated with a lower chance of survival one month after cardiac arrest: no bystander CPR; non-witnessed cardiac arrest; cardiac arrest occurring at home; increasing interval between call for and arrival of the ambulance; and increasing age. When these factors were considered simultaneously two groups with no survivors were defined. In both groups patients were found in a non-shockable rhythm, no bystander CPR was attempted, the arrest was non-witnessed, the arrest took place at home. In one group the interval between call for and arrival of ambulance exceeded 12 minutes. In the other group patients were older than 80 years and the interval between call for and arrival of the ambulance exceeded eight minutes.

CONCLUSION

Among patients who had an out-of-hospital cardiac arrest and were found in a non-shockable rhythm the following factors were associated with a low chance of survival: no bystander CPR, non-witnessed cardiac arrest, the arrest took place at home, increasing interval between call for and arrival of ambulance, and increasing age. When these factors were considered simultaneously, groups with no survivors could be defined. In such groups the ambulance crew may refrain from starting CPR.

Secondary confirmation of endotracheal tube position by ultrasound image

OBJECTIVE

Secondary confirmation of endotracheal (ET) tube position by ultrasound image.

DESIGN

Prospective, randomized study.

SETTING

A medical center-based tertiary pediatric intensive care unit.

PATIENTS

A total of 59 patients aged from newborn to 17 yrs old underwent ET tube insertion because of cardiopulmonary arrest or impending respiratory failure.

INTERVENTION

Ultrasound imaging was performed immediately before and after the ET tube placement procedure. The most frequently used ultrasonic scanning window was the subxiphoid window at the mid-upper abdominal, just beneath the xiphoid process and the lower margin of liver. The sector angle was set as wide as possible (90 degrees) so that the bilateral diaphragm could be well scanned.

MEASUREMENTS AND MAIN RESULTS

Using the ultrasound imaging method, we successfully identified all of two esophageal intubations and eight incidents of initial ET tube misplacement, which had been positioned down to the right main bronchus. Finally, we successfully identified all 59 of the correct placements of ET tubes in the trachea.

CONCLUSIONS

Ultrasound imaging of diaphragm motion is a useful, quick, noninvasive, portable, and direct anatomic method for assessment of ET tube position. We think it should be considered the method of choice for the secondary confirmation of the ET tube position.

Advanced cardiac life support in out-of-hospital cardiac arrest

BACKGROUND

The Ontario Prehospital Advanced Life Support (OPALS) Study tested the incremental effect on the rate of survival after out-of-hospital cardiac arrest of adding a program of advanced life support to a program of rapid defibrillation.

METHODS

This multicenter, controlled clinical trial was conducted in 17 cities before and after advanced-life-support programs were instituted and enrolled 5638 patients who had had cardiac arrest outside the hospital. Of those patients, 1391 were enrolled during the rapid-defibrillation phase and 4247 during the subsequent advanced-life-support phase. Paramedics were trained in standard advanced life support, which includes endotracheal intubation and the administration of intravenous drugs.

RESULTS

From the rapid-defibrillation phase to the advanced-life-support phase, the rate of admission to a hospital increased significantly (10.9 percent vs. 14.6 percent, P<0.001), but the rate of survival to hospital discharge did not (5.0 percent vs. 5.1 percent, P=0.83). The multivariate odds ratio for survival after advanced life support was 1.1 (95 percent confidence interval, 0.8 to 1.5); after an arrest witnessed by a bystander, 4.4 (95 percent confidence interval, 3.1 to 6.4); after cardiopulmonary resuscitation administered by a bystander, 3.7 (95 percent confidence interval, 2.5 to 5.4); and after rapid defibrillation, 3.4 (95 percent confidence interval, 1.4 to 8.4). There was no improvement in the rate of survival with the use of advanced life support in any subgroup.

CONCLUSIONS

The addition of advanced-life-support interventions did not improve the rate of survival after out-of-hospital cardiac arrest in a previously optimized emergency-medical-services system of rapid defibrillation. In order to save lives, health care planners should make cardiopulmonary resuscitation by citizens and rapid-defibrillation responses a priority for the resources of emergency-medical-services systems.

Best evidence topic report. Cardiopulmonary bypass and the survival of patients in cardiac arrest

A short cut review was carried out to establish whether cardiopulmonary bypass improves survival and function after cardiac arrest resistant to ACLS. Altogether 387 papers were found using the reported search, of which nine presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.

Guidelines for appropriate in-hospital emergency team time management: the Brooke Army Medical Center approach

Successful outcome following cardiac arrest have been reported in the range of 13-59%. It is well established that the time from the onset of a ventricular arrhythmia to successful defibrillation predicts outcome. Recent out of hospital arrest protocols minimizing time to defibrillation have reported significant improvement in outcomes. The Bethesda conference and American Heart Association (AHA) both set standards for defibrillation time for in hospital codes but do not set standards for other interventions. In February 2000, the Brooke Army Medical Center (BAMC) cardiopulmonary resuscitation committee published time guidelines for the initiation of CPR, emergency team arrival, first defibrillation and first medication. We sought to evaluate resuscitation outcomes before and after this intervention.

METHODS

Data on each response time was prospectively collected as was etiology for the event, emergency location, patient age, gender, and emergency outcome for the 7 months prior to the guideline introduction and 15 months afterwards.

RESULTS

The mean response times (in minutes) for initiation of CPR (1.3 vs. 0.4), emergency team arrival (1.6 vs. 1.2), first defibrillation (7.8 vs. 6.6) and first medication (4.1 vs. 3.8) demonstrated trends toward improvement. Compliance with the time standards also increased (67-91, 85-95, 67-71 and 93-86%, respectively). Emergency survival trended toward improvement (47 vs. 57%) while discharge survival significantly increased from 3 to 24% (P=0.017).

CONCLUSIONS

Setting time guidelines for Advanced Cardiac Life Support (ACLS) improved initiation of CPR, emergency team arrival, first defibrillation, and first medication administration. These time reductions were accompanied by improved event survival and a statistically improved survival to discharge.

The influence of urban, suburban, or rural locale on survival from refractory prehospital cardiac arrest

There are many variables that can have an effect on survival in cardiopulmonary arrest. This study examined the effect of urban, suburban, or rural location on the outcome of prehospital cardiac arrest as a secondary end point in a study evaluating the effect of bicarbonate on survival. The proportion of survivors within a type of EMS provider system as well as response times were compared. This prospective, randomized, double-blind clinical intervention trial enrolled 874 prehospital cardiopulmonary arrest patients encountered by prehospital urban, suburban, and rural regional EMS area. Population density (patients per square mile) calculation allowed classification into urban (>2000/mi2), suburban (>400/mi2), and rural (0-399/mi2) systems. This group underwent standard advanced cardiac life support (ACLS) intervention with or without early empiric administration of bicarbonate in a 1-mEq/kg dose. A group of demographic, diagnostic, and therapeutic variables were analyzed for their effect on survival. Times were measured from collapse until onset of medical intervention and survival measured as the presence of ED vital signs on arrival. Data analysis used chi-squared with Pearson correlation for survivorship and Student t test comparisons for response times. The overall survival rate was approximately 13.9% (110 of 793), ranging from 9% rural, 14% for suburban, and 23% for urban sites for 372 patients (P=.007). Survival differences were associated with classification of arrest locale in this sample-best for urban, suburban, followed by rural sites. There was no difference in time to bystander cardiopulmonary resuscitation, but medical response time (basic life support) was decreased for suburban or urban sites, and intervention (ACLS) and transport times were decreased for suburban sites alone. Although response times were differentiated by location, they were not necessarily predictive of survival. Factors other than response time such as patient population or resuscitation skill could influence survival from cardiac arrest occurring in diverse prehospital service areas.

Stability of advanced life support drugs in the field

PURPOSE

The effects of wide temperature variations on the stability of atropine, epinephrine, and lidocaine stored under field conditions in advanced life support (ALS) paramedic units were evaluated.

METHODS

Vehicles from various ALS paramedic units were selected throughout Los Angeles County, California, including desert, marine, and helicopter-based divisions. A temperature-recording device was placed in the compartment where drugs are stored and used to record and store temperature data at 15-minute intervals. Three autoinjector-style syringes of atropine, epinephrine, and lidocaine were taken from stock for each ALS unit and placed in each vehicle, while three control syringes were stored in the laboratory under controlled conditions. Six samples of each drug were withdrawn at time 0 and on days 5, 10, 15, 30, and 45. Samples were analyzed using high-performance liquid chromatography. Stock solutions, created using analytical grade atropine, epinephrine, and lidocaine, were used to construct 5-point standard curves to determine the drug concentration of each sample.

RESULTS

Seven sites exceeded 104 degrees F (40 degrees C) for as little as 30 minutes and as long as 795 minutes. Ten of the sites achieved a mean kinetic temperature (MKT) above 77 degrees F (25 degrees C), with the highest MKT calculated being 84.1 degrees F (28.9 degrees C) over a 45-day period. There was no evidence of drug degradation at any site, at any temperature, or at any time point.

CONCLUSION

Atropine, epinephrine, and lidocaine can be stored at temperatures of up to 84.1 degrees F (28.9 degrees C) for up to 45 days and tolerate temperature spikes of up to 125 degrees F (51.7 degrees C) for a cumulative time of 795 minutes (13.25 hours) without undergoing degradation.

Clinical review: Reappraising the concept of immediate defibrillatory attempts for out-of-hospital ventricular fibrillation

Despite well developed emergency medical services with rapid response advanced life support capabilities, survival rates following out-of-hospital ventricular fibrillation (VF) have remained bleak in many venues. Generally, these poor resuscitation rates are attributed to delays in the performance of basic cardiopulmonary resuscitation by bystanders or delays in defibrillation, but recent laboratory data suggest that the current standard of immediately providing a countershock as the first therapeutic intervention may be detrimental when VF is prolonged beyond several minutes. Several studies now suggest that when myocardial energy supplies begin to dwindle following more prolonged periods of VF, improvements in coronary artery perfusion must first be achieved in order to prime the heart for successful return of spontaneous circulation after defibrillation. Therefore, before countershocks, certain pharmacologic and/or mechanical interventions might take precedence during resuscitative efforts. This evolving concept has been substantiated recently by clinical studies, including a controlled clinical trial, demonstrating a significant improvement in survival when basic cardiopulmonary resuscitation is provided for several minutes before the initial countershock. Although this evolving concept differs from current standards and may pose a potential problem for automated defibrillator initiatives (e.g. public access defibrillation), successful defibrillation and return of spontaneous circulation have been rendered more predictable by evolving technologies that can score the VF waveform signal and differentiate between those who can be shocked immediately and those who should receive other interventions first.

Prehospital cardiac arrest outcome is adversely associated with antiarrythmic agent use, but not associated with presenting complaint or medical history

STUDY OBJECTIVE

This study associated survival from prehospital cardiac arrest to patient historical variables including presenting complaint, medications used, and medical history as a secondary end point in a trial evaluating the effect of bicarbonate administration. This raises issues concerning extensive prehospital historical assessment that may potentially delay care and transport.

METHODS

This prospective multicentre trial enrolled 874 prehospital cardiac arrest patients encountered by urban, suburban, and rural emergency medical services. This group underwent conventional ACLS intervention followed by empiric early administration of sodium bicarbonate (1mEq/l). Survival was measured as the presence of vital signs on emergency department arrival. Data analysis used Student's t test, Fisher's exact test, chi2 with Pearson correlation, and logistic regression (p<0.05). Secondary end points were analysed including an association with common historical variables such as medical history, presenting complaint, or drugs used.

RESULTS

The overall survival rate was 13.9% (110 of 793) of prehospital arrest patients. There was no correlation between historical factors, such as chief complaint or history of present illness (p = 0.277), medical history (p = 0.425), presence of specific disease conditions (p = 0.1125-0.956), or overall drug use (p = 0.002-0.9848). However, there was an adverse association between specific antiarrhythmic use (p = 0.003) and outcome.

CONCLUSION

There is little relation of patient historical factors on the outcome from prehospital cardiac arrest raising issues of efficiency with history taking in prehospital care and transport.

Assessment of quality of life and cognitive function after out-of-hospital cardiac arrest with successful resuscitation

This prospective cohort study evaluated the impact of the time-related elements of the "chain of survival" on the quality of life of patients, taking their characteristics into account. Between 1995 and 2002, consecutive, out-of-hospital cardiac arrest patients from Amsterdam and the surrounding areas were included in this study. A total of 227 patients (12%) survived to hospital discharge and 174 were definitive survivors who were available for assessment at 6 months. Quality of life was measured with the 136-item Sickness Impact Profile (SIP); cognitive functioning was assessed through the Mini Mental State Examination. SIP profiles were compared with profiles of an open Dutch population of the elderly and patients who experienced a stroke. Time intervals of the chain of survival were calculated from the estimated moment of collapse and related to outcome using regression analysis. The SIP profile of survivors was a little above the reference profile, indicating a slightly poorer quality of life, and below the profile of patients after stroke, indicating a better quality of life. Impaired cognitive function was associated with delay in the start of cardiopulmonary resuscitation (odds ratio 4.3, 95% confidence interval 1.0 to 19). Absence of the need for advanced cardiopulmonary life support was associated with better cognitive functioning (odds ratio 0.3, 95% confidence interval 0.1 to 0.9). Female gender and older age were associated with impaired physical functioning. Trends were found for better outcomes after early access, immediate resuscitation, early defibrillation, and early advanced care.

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 randomized controlled trial of intravenous aminophylline for atropine-resistant out-of-hospital asystolic cardiac arrest

OBJECTIVES

Myocardial ischemia, during cardiopulmonary arrest, can lead to atropine-resistant bradyasystole from interstitial accumulation of endogenous adenosine. Aminophylline is a nonspecific adenosine receptor antagonist capable of reversing ischemia-induced bradyasystole in a variety of settings. The hypothesis of this study was that aminophylline improves the rate of return of spontaneous circulation (ROSC) in atropine-resistant asystolic out-of-hospital cardiac arrest when used early in the resuscitation effort.

METHODS

This was a prospective, randomized, double-blinded, placebo-controlled trial set in an urban emergency medical services system serving a population of 250,000. All non-pregnant, normothermic adults suffering nontraumatic out-of-hospital cardiac arrest (February 1999 to August 2000) with asystole were eligible. Patients remaining in asystole after initial doses of epinephrine and atropine received either aminophylline 250 mg or matching placebo as a bolus injection through a peripheral intravenous line. All other aspects of the attempted resuscitation proceeded in accordance with standard Advanced Cardiac Life Support (ACLS) guidelines. A sample size of 102 patients was calculated to yield a power of 80% to show an absolute improvement of 25% in ROSC. The aminophylline and control groups were compared by calculating 95% confidence intervals (95% CIs) and the data were modeled using logistic regression.

RESULTS

The investigators enrolled 112 consecutive patients. One subject was dropped prior to analysis because of missing data. Data for 111 patients were analyzed on an intention-to-treat basis. Baseline characteristics were similar for the two groups. Comparing the control and aminophylline groups, ROSC was achieved in 15.6% (95% CI = 6% to 29%) and 22.7% (95% CI = 13% to 35%), while reversal of asystole occurred in 26.7% (95% CI = 15% to 42%) and 40.9% (95% CI = 29% to 54%), respectively. Group allocation had an odds ratio of 1.8 (95% CI = 0.6 to 5.3) for ROSC. Witnessed arrest was an independent predictor of outcome with an odds ratio of 3.8 (95% CI = 1.3 to 11.2).

CONCLUSIONS

Addition of aminophylline appears to be a promising new intervention in the ACLS treatment of atropine-resistant asystolic out-of-hospital cardiac arrest.

Current issues in cardiopulmonary resuscitation

Current Advanced Cardiac Life Support (ACLS) guidelines and emergency medical services (EMS) clinical protocols usually recommend immediate defibrillation for victims of out-of-hospital cardiac arrest who have ventricular fibrillation (VF). However, animal studies and results from a small number of clinical investigations now suggest that a short period of chest compressions or ACLS procedures delivered before defibrillation may improve the outcome of patients with prolonged VF. Although the basic science and clinical data supporting a chest-compression-first procedure are compelling, large, multicenter randomized trials are still necessary to determine whether such protocols do indeed improve outcome. In current EMS dispatch practice, traditional cardiopulmonary resuscitation (CPR) instructions are given when needed to bystanders who report a possible cardiac arrest. Recent literature has shown that in certain circumstances, CPR instructions involving chest compressions alone may be given more quickly and can yield an equivalent, if not better, chance of survival. Although this practice is controversial, the general consensus is that any CPR is better than none at all. Therefore, telephone CPR protocols that recommend the immediate initiation of chest compressions may be preferred, particularly for callers who have no previous training in CPR.

Effectiveness of a medical priority dispatch protocol for abdominal pain

OBJECTIVE

Medical Priority Dispatch System (MPDS) protocols are used to determine the appropriate level of emergency medical services (EMS) response that is sent to care for patients in the prehospital setting. The objective of this study was to determine the proportion of patients with abdominal pain who would benefit from advanced life support (ALS) when called for by these protocols.

METHODS

All 9-1-1 calls were processed using MPDS protocols to determine whether the patient required ALS or basic life support (BLS) services. Consecutive patients having an ALS response for a chief complaint of abdominal pain were included. Dispatch decisions that did not follow the MPDS protocols, and cases taken to facilities other than the primary study hospitals, were excluded. EMS run sheets and hospital records were reviewed to determine: 1) whether prehospital ALS interventions were required, 2) emergency department (ED) disposition, 3) hospital course, and 4) final diagnosis. Calls were classified according to the need for ALS and the seriousness of the subsequent diagnosis. Data analysis was performed by determining 95%, confidence intervals (CIs).

RESULTS

Of the 343 patients classified as 1C1 or 1C2 who were transported by ALS during the time period, 227 (67%) were transported to the study hospitals. Nine (4%) were excluded because of inappropriate dispatch, leaving 218 for analysis. Hospital records were available for 186 (86%) cases, of which 12 (6%; CI 3%, 9%) were potentially life-threatening, requiring ALS intervention. Seventeen (9%; CI 5%, 1%) were non-life-threatening, but potentially benefited from ALS intervention. The remaining 157 (84%; CI 79%, 89%) were classified as not requiring ALS.

CONCLUSIONS

Use of age- and gender-specific MPDS protocols for patients with a chief complaint of abdominal pain results in significant overtriage and overuse of ALS. Steps should be taken to develop key questions that provide more accurate classification of these patients that goes beyond age and gender classification alone.

[Interdisciplinary shock room management: responsibilities of the radiologist from the trauma surgery viewpoint]

Efficient resuscitation of major trauma requests an interdisciplinary communication between trauma surgeons, anaesthesiologists and radiologists. Trauma outcome is significantly influenced by horizontal trauma team organisation and coherence to clinical algorithms, which allow fast diagnosis and intervention. A radiologist present on patients arrival in the trauma room provides a major impact on trauma care. Nevertheless optimal integration in the trauma team implies profound knowledge of the priorities of advanced trauma life support and trauma algorithms. His or her involvement is not limited to patient care only, also active participation in trauma room design, interdisciplinary algorithm development and trauma research are essential tasks for radiologists devoted to emergency radiology. Based on the pathophysiology of polytrauma and the structure of German trauma system, current concepts and proven clinical algorithms with special regard to the radiologist and his duties and tasks will are presented.

Clinical use of sodium bicarbonate during cardiopulmonary resuscitation--is it used sensibly?

This study retrospectively analyzed the pattern of sodium bicarbonate (SB) use during cardiopulmonary resuscitation (CPR) in the Brain Resuscitation Clinical Trial III (BRCT III). BRCT III was a prospective clinical trial, which compared high-dose to standard-dose epinephrine during CPR. SB use was left optional in the study protocol. Records of 2915 patients were reviewed. Percentage, timing and dosage of SB administration were correlated with demographic and cardiac arrest variables and with times from collapse to Basic Life Support, to Advanced Cardiac Life Support (ACLS) and to the major interventions performed during CPR. SB was administered in 54.5% of the resuscitations. The rate of SB use decreased with increasing patient age-primarily reflecting shorter CPR attempts. Mean time intervals from arrest, from start of ACLS and from first epinephrine to administration of the first SB were 29+/-16, 19+/-13, and 10.8+/-11.1 min, respectively. No correlation was found between the rate of SB use and the pre-ACLS hypoxia times. On the other hand, a direct linear correlation was found between the rate of SB use and the duration of ACLS. We conclude that when SB was used, the time from initiation of ACLS to administration of its first dose was long and severe metabolic acidosis probably already existed at this point. Therefore, if SB is used, earlier administration may be considered. Contrary to physiological rationale, clinical decisions regarding SB use did not seem to take into consideration the duration of pre-ACLS hypoxia times. We suggest that guidelines for SB use during CPR should emphasize the importance of pre-ACLS hypoxia time in contributing to metabolic acidosis and should be more specific in defining the duration of "protracted CPR or long resuscitative efforts", the most frequent indication for SB administration.

Delphi type methodology to develop consensus on the future design of EMS systems in the United Kingdom

OBJECTIVE

To develop consensus opinion on future design characteristics of Emergency Medical Services (EMS) systems in the UK with particular regard to advanced life support skills (ALS).

DESIGN

A Delphi questionnaire design with two rounds to gain a consensus of opinion. Investigation of four aspects of EMS design is reported-type of response to a priority based dispatch category, transportation options, enhancement of paramedic skills, and structure of a first responder system.

SUBJECTS

Chief executives, directors of operations, and medical directors of Ambulance Trusts in the United Kingdom.

OUTCOME MEASURES

Likert scales (0-9) to score opinion on a series of statements with achievement of inter-round consistency. A median score of 0-4 was classified as disagreement and 6-9 as agreement.

RESULTS

A 65% response to the first questionnaire and with iteration, 52% response to the second questionnaire was attained. A tiered response (paramedics, technicians, and basic life support first responders) with technicians responding to selected category A and B calls and all category C calls (median score (MS) 7.5, interquartile range (IQR) 4), was recommended. Inter-unit handover of selected calls to maintain paramedic availablity ( MS 7.5, IQR 3.75) and enhancement of paramedic skills (MS 7.0, IQR 4.0) was also proposed. Finally, the development of a first responder system fully integrated into the EMS (MS 8.0, IQR 2.75) involving other agencies including the police force, fire service, and trained members of the local community was agreed.

CONCLUSIONS

Senior expert staff from Ambulance Trusts in the UK achieved consensus on certain design characteristics of EMS systems. These are significantly different from the present EMS model.

200 city survey. JEMS 2001 annual report on EMS operational & clinical trends in large, urban areas

This year's survey offered examples of evolving partnerships between the public and EMS providers with a growing number of systems implementing PAD programs. The apparent influence of a communication center's managing agency on prioritization strategies is concerning. However, further study is needed. EMS managers must pay careful attention to comm center practices and technology to ensure their ability to support response prioritization and the efficient management of EMS resources. The small reduction in the use of hot response (lights and siren) to every request for service is disappointing in light of medical literature and position statements that condemn this practice. Resource response can be safely prioritized using today's EMD protocol systems. Prioritization and changing response [figure: see text] time requirements to address impending revenue and service demand changes will require additional standardization of methodologies and reporting of response times to relate this measure to other system performance indicators (e.g., patient morbidity/mortality, cost, customer satisfaction, etc.). The future presents a difficult road for system administrators. However, the adoption of a growing number of information-management tools and changes in procedures and dispatch processes offer potential solutions. The increased use of hand-held computers or personal digital assistant (PDAs) to gather and provide information and the almost universal use of CAD will aid providers in performing the research necessary to change response time performance requirements, improving EMS system efficiency. Use of this technology will also likely improve patient care and reimbursement through more timely and accurate reporting and analysis. The medical director's role will be critical to ensuring potential changes don't compromise patient care. Obtaining a better understanding of how much time can safely elapse between the time of the 9-1-1 call and when patient-care activities commence will be an important component of future strategies. More sophisticated EMD, CAD and AVL technologies will also play an indispensable role in reforming system design and daily operations. In light of the events of Sept. 11 and events yet to occur, EMS managers and providers face significant operational challenges. Overcoming these challenges will require leadership, a willingness to question and change tradition and the ability to cope with the discomfort of changing demands and uncertainty. Maintaining the hard-fought successes of EMS will increasingly require more imagination and the willingness of current and future practitioners to study, develop and implement innovative approaches to addressing future requirements.