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AED
Automatic External
Defibrillator Articles |
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Resuscitation
2000 Apr;44(2):97-104 Cardiac arrest outcomes at the Melbourne Cricket
Ground and shrine of remembrance using a tiered response strategy-a
forerunner to public access defibrillation.
Wassertheil J, Keane G, Fisher N, Leditschke JF
St John
Ambulance Australia, Melbourne, Victoria. JWassertheil@phcn.vic.gov.au
The provision of medical, paramedical and first aid services at major public events is an important concern for pre-hospital emergency medical care providers. Patient outcomes of a cardiac arrest response strategy employed at the Melbourne Cricket Ground (MCG) and the Shrine of Remembrance by St John Ambulance Australia volunteers are reported. Twenty-eight consecutive events occurring between December 1989 and December 1997 have been analysed. Included are three cardiac arrests managed at ANZAC day parades utilising the same response strategy by the same unit. The incidence of cardiac arrest at the MCG was 1:500000 attendances. Of the 28 patients, 24 (86%) left the venue alive and 20 (71%) were discharged home from hospital. In all cases the initial rhythm was ventricular fibrillation (VF). All 26 patients (93%) who were defibrillated by St John teams had this intervention within 5 min from the documented time of collapse. One patient in VF spontaneously reverted during CPR. Of the eight fatalities, four died at the scene. At major public venues and events, a co-ordinated emergency life support provision strategy, tailor made for the venue, is necessary for the delivery of prompt CPR, timely defibrillation and advanced life support. |
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Prehosp Emerg Care
2000 Oct-Dec;4(4):314-7 Automated external defibrillators in long-term care
facilities are cost-effective.
Foutz RA, Sayre MR
Department
of Emergency Medicine, University of Cincinnati College of Medicine, Ohio
42567-0769, USA.
OBJECTIVE: To assess the cost per life saved of equipping long-term care facilities (LTCFs) with automated external defibrillators (AEDs). METHODS: Outcomes for cardiac arrests within LTCFs were retrieved for 1994 to 1997 from a comprehensive out-of-hospital cardiac arrest registry in a mid-sized U.S. city. The total expense for all LTCFs to obtain and maintain AEDs and to educate and maintain staff skill was estimated for a theoretical four-year period. The cost per life saved to the time of hospital discharge was calculated based on an estimated survival rate of 25% of patients found in ventricular fibrillation (VF) with placement of AEDs in LTCFs. A sensitivity analysis that varied survival rates and costs was conducted. RESULTS: Over four years, there were 160 actual arrests in 43 LTCFs, with a hospital discharge survival rate of 2/160. Twenty of 160 presented to emergency medical services in VF. Training costs for four years were $1,225 per AED. Purchase and maintenance expenses for one AED over four years were $3,941. Placing AEDs in LTCFs would cost $87,837 per life saved if 25% of patients found in VF survived to hospital discharge. Sensitivity analysis using survival rates of 5%, 15%, and 35% established the cost per life saved at $439,184, $146,395, and $62,741, respectively. When costs were calculated at one-half and twice the estimated expense, the cost per life saved was $43,918 and $175,674, respectively. CONCLUSION: Placing AEDs in LTCFs is cost-effective at $87,837 per life saved, if a hospital discharge survival rate of 25% of patients in VF can be achieved. |
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Br J Gen Pract
1999 Apr;49(441):297-8 The role of automated external defibrillators in
rural general practice.
Hanley K, Dowling J, Bury G, Murphy A
University
College Galway, Republic of Ireland.
In a
questionnaire survey (100% response rate) investigating the availability
and use of automated external defibrillators (AEDs), it was found that the
success rate (number discharged alive) compared favourably with
pre-hospital defibrillation by other providers, and that AEDs aided the
management of dysrhythmias not commonly seen in general practice. With
appropriate training they are useful in rural general practice. |
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Prehosp Emerg Care
1999 Oct-Dec;3(4):303-5 Public-access defibrillation: where do we place the
AEDs?
Gratton M, Lindholm DJ, Campbell JP
University
of Missouri-Kansas City School of Medicine and Department of Emergency
Medicine, Truman Medical Center 64108, USA. mgratton@cctr.umkc.edu
BACKGROUND: Many prehospital cardiac arrests occur in public places. Even the best EMS systems have a finite response time. Therefore, it has been recommended that automated external defibrillators (AEDs) be placed in public areas for immediate access by trained members of the general public. OBJECTIVE: To determine the locations of multiple cardiac arrests in order to plan for placement of public-access AEDs. METHODS: Retrospective review of all primary cardiac arrests in calendar year 1997. Cardiac arrests in which resuscitation was not attempted (DOA), traumatic cases, pediatric cases, and those due to "other" causes were excluded. Location of the cardiac arrest was obtained from the ambulance run ticket. The EMS system is an urban, Midwestern, all-ALS, public-utility model system with fire department first responders that transports approximately 58,000 patients annually. RESULTS: There was scene response to 922 cardiac arrests. 377 DOAs and 219 nonprimary cardiac arrests were excluded. There were 326 primary cardiac arrests. Sixteen locations had more than one cardiac arrest: 11 locations had two cardiac arrests, four locations had three cardiac arrests, and one location had four cardiac arrests. The airport, an airline overhaul facility, a casino, and two hotels each had two cardiac arrests; the other locations of multiple cardiac arrests were in nursing homes. The professional sports stadiums had no cardiac arrests. CONCLUSIONS: Since very few locations had more than one cardiac arrest, it may be difficult to identify high-yield public places in which to place an AED. Nursing homes may want to consider AED availability. |
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J Am Dent Assoc
1999 Jun;130(6):837-45 The automated external cardiac defibrillator:
lifesaving device for medical emergencies.
Alexander RE
Department
of Oral and Maxillofacial Surgery and Pharmacology, Baylor College of
Dentistry, Dallas, Texas, USA.
BACKGROUND:
More than 350,000 adult Americans die each year of sudden cardiac arrest,
or SCA. The event is unpredictable and can occur in patients with no
history of cardiac disease or cardiac symptoms. Drugs and cardiopulmonary
resuscitation, or CPR, save only a small percentage of victims. The
necessary response is rapid application of electrical shock, and the
chances of success are reduced 10 percent for every minute of delay. TYPES
OF STUDIES REVIEWED: The author reviewed the literature on resuscitation
of people who have undergone SCA, and examined the emerging technology of
automated external defibrillators, or AEDs, for correcting cardiac
ventricular fibrillation. Included is a review of the controversies
surrounding AED waveforms and energy levels. RESULTS: Automated cardiac
defibrillators are becoming readily available because of improved
technology and decreasing prices. AEDs are now commonly found in
commercial aircraft, gambling casinos, sports arenas and public buildings,
and will soon become as readily available as fire extinguishers. The use
of AEDs is being taught in standard CPR courses. CLINICAL IMPLICATIONS:
AEDs are being installed in more public locations, including some dental
offices. As costs decrease and availability increases, there is
significant potential use for AEDs in managing SCAs in dental offices.
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JAMA 1999 Apr
7;281(13):1182-8 Influence of cardiopulmonary resuscitation prior to
defibrillation in patients with out-of-hospital ventricular fibrillation.
Cobb LA, Fahrenbruch CE, Walsh TR, Copass MK,
Olsufka M, Breskin M, Hallstrom AP
Department
of Medicine, University of Washington, Harborview Medical Center, Seattle
98104, USA.
lcobb@u.washington.edu
CONTEXT: Use of automated external defibrillators (AEDs) by first arriving emergency medical technicians (EMTs) is advocated to improve the outcome for out-of-hospital ventricular fibrillation (VF). However, adding AEDs to the emergency medical system in Seattle, Wash, did not improve survival. Studies in animals have shown improved outcomes when cardiopulmonary resuscitation (CPR) was administered prior to an initial shock for VF of several minutes' duration. OBJECTIVE: To evaluate the effects of providing 90 seconds of CPR to persons with out-of-hospital VF prior to delivery of a shock by first-arriving EMTs. DESIGN: Observational, prospectively defined, population-based study with 42 months of preintervention analysis (July 1, 1990-December 31, 1993) and 36 months of post-intervention analysis (January 1, 1994-December 31, 1996). SETTING: Seattle fire department-based, 2-tiered emergency medical system. PARTICIPANTS: A total of 639 patients treated for out-of-hospital VF before the intervention and 478 after the intervention. INTERVENTION: Modification of the protocol for use of AEDs, emphasizing approximately 90 seconds of CPR prior to delivery of a shock. MAIN OUTCOME MEASURES: Survival and neurologic status at hospital discharge determined by retrospective chart review as a function of early (<4 minutes) and later (> or =4 minutes) response intervals. RESULTS: Survival improved from 24% (155/639) to 30% (142/478) (P=.04). That benefit was predominantly in patients for whom the initial response interval was 4 minutes or longer (survival, 17% [56/321] before vs 27% [60/220] after; P = .01). In a multivariate logistic model, adjusting for differences in patient and resuscitation factors between the periods, the protocol intervention was estimated to improve survival significantly (odds ratio, 1.42; 95% confidence interval, 1.07-1.90; P = .02). Overall, the proportion of victims who survived with favorable neurologic recovery increased from 17% (106/634) to 23% (109/474) (P = .01). Among survivors, the proportion having favorable neurologic function at hospital discharge increased from 71% (106/150) to 79% (109/138) (P<.11). CONCLUSION: The routine provision of approximately 90 seconds of CPR prior to use of AED was associated with increased survival when response intervals were 4 minutes or longer. |
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Resuscitation
1998 Dec;39(3):145-51 Seven years' experience with early defibrillation
by police and paramedics in an emergency medical services system.
White RD, Hankins DG, Bugliosi TF
Department
of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA.
PRIMARY OBJECTIVE: To assess the outcome of patients with out-of-hospital cardiac arrest with ventricular fibrillation as the presenting rhythm in an emergency medical services system utilizing a combined police/paramedic response to provide early defibrillation. MATERIALS AND METHODS: Police and paramedics were dispatched from law enforcement and ambulance communications centers, respectively. First-arriving personnel delivered initial shocks, all using automated external defibrillators. Patients were classified according to response to initial shocks: restoration of pulses with shocks only or in need of advanced life support, including epinephrine. Discharge survival was defined as return to home without disabling neurologic injury. RESULTS: Over the 7-year period of study 131 patients presented with ventricular fibrillation: 58 were first treated by police and 73 by paramedics. Restoration of pulses with shocks only and discharge survival were not different in police and paramedic groups, with overall survival of 40% (53 of 131 patients). Among the survivors, 19% (18/95 patients) obtained a spontaneous circulation only after administration of epinephrine and other ALS interventions. CONCLUSION: Both restoration of a functional circulation, without need for advanced life support interventions, and discharge survival without neurologic disability are very dependent upon the rapidity with which defibrillation is accomplished, regardless of who delivers the shocks. In addition, a smaller but significant number of patients who require ALS interventions, including epinephrine, for restoration of a spontaneous circulation survive to discharge. Short time differences, on the order of 1 min, are significant determinants of both immediate response to shocks and discharge survival. |
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Ann Emerg Med
1998 Aug;32(2):200-7 Use of automated external defibrillators by police
officers for treatment of out-of-hospital cardiac arrest.
Mosesso VN Jr, Davis EA, Auble TE, Paris PM, Yealy
DM
Department
of Emergency Medicine, University of Pittsburgh, PA, USA.
OBJECTIVE: To determine the feasibility of police officers providing defibrillation with automated external defibrillators (AEDs) and to assess the effectiveness of this strategy in reducing time to defibrillation of victims of out-of-hospital sudden cardiac arrest. METHODS: This was a prospective, interventional cohort study with historical controls conducted in 7 suburban communities in which police usually arrived at the scene of medical emergencies before EMS personnel. All adult patients who suffered cardiac arrest before EMS arrival and on whom EMS personnel attempted resuscitation were enrolled. Police officers who were trained to use and equipped with AEDs during the intervention phase were dispatched simultaneously with EMS to medical emergencies. Police were instructed to use the AED immediately on determination of pulselessness. Outcome measures were the difference between control and intervention phases in interval from the time the call was received at dispatch to the time of first defibrillation and in rate of survival to hospital discharge for patients initially in ventricular fibrillation. RESULTS: EMS personnel attempted 183 resuscitations in the control phase and 283 during the intervention; of these, 80 (44%) and 127 (45%), respectively, involved patients with initial ventricular fibrillation rhythms. Mean time to defibrillation decreased from 11.8+/-4.7 minutes in the control phase to 8.7+/-3.7 minutes in the intervention phase (P<.0001). Survival to hospital discharge of patients in ventricular fibrillation did not differ between phases (6% control versus 14% intervention, P=.1). When police arrived before EMS personnel, shock administered by police compared with shock administered by EMS was associated with improved survival (26% [12/46] versus 3% [1/29], P=.01). Logistic regression analysis revealed AED use was an independent predictor of survival to hospital discharge. CONCLUSION: In 7 suburban communities, police use of AEDs decreased time to defibrillation and was an independent predictor of survival to hospital discharge. |
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Resuscitation
1998 Apr;37(1):3-7 Experience with the use of automated external
defibrillators in out of hospital cardiac arrest.
Herlitz J, Bang A, Axelsson A, Graves JR, Lindqvist
J
Division of
Cardiology, Sahlgrenska University Hospital, Goteborg, Sweden.
AIM: To describe the sequences of arrhythmias, number of shocks delivered and the number of failures in a consecutive series of patients with out-of-hospital cardiac arrest attended by our emergency medical service (EMS) and in whom cardio-pulmonary resuscitation (CPR) was initiated and in whom automated external defibrillators (AEDs) were used. PATIENTS: All patients with out-of-hospital cardiac arrest attended by the EMS and in whom AEDs were used. Time for inclusion in the study: January 1st, 1987 to December 31st, 1992. RESULTS: In all there were 1781 out of hospital cardiac arrests during the study period. Among them AEDs were used in 383 cases (22%). The total number of interpreted rhythms delivered in these patients was 2719. Among all rhythm sequences coarse ventricular fibrillation (VF) was found on 375 occasions (14%); fine VF on 107 occasions (4%) and ventricular tachycardia (VT) on 12 occasions (0.4%). In ten cases with coarse VF (nine patients) the AED did not advise a shock (2.7%). In five of those nine patients a human error was interpreted as the explanation and in four there was a possible technical error. In these four patients defibrillation was delayed by 33-43 s, respectively. Among the 2225 rhythm sequences not judged as VF/VT the AED advised a shock on one occasion (0.04%). CONCLUSION: Among patients with coarse VF AED gave inaccurate instructions in 2.7%. However, the majority of the failures were judged to be caused by human errors. |
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Pediatrics 1998
Mar;101(3 Pt 1):393-7 Accurate recognition and effective treatment of
ventricular fibrillation by automated external defibrillators in
adolescents.
Atkins DL, Hartley LL, York DK
Department
of Pediatrics, University of Iowa, Iowa City, Iowa 52242, USA.
OBJECTIVES:
To evaluate the accuracy and efficacy of automated external defibrillators
(AEDs) in patients <16 years old. BACKGROUND: AEDs are standard therapy
in out-of-hospital resuscitation of adults and have led to higher success
rates. Their use in children and adolescents has never been evaluated,
despite recommendations from the American Heart Association that they be
used in children >8 years of age. METHODS: This was a retrospective
cohort study of children <16 years old who underwent out-of-hospital
cardiac resuscitation and on whom an AED was used during the
resuscitation. The setting was rural and urban prehospital emergency
medical systems. Patients were identified by review of a database of
cardiac arrests maintained by a large surveillance program of these
services. RESULTS: AEDs were used to assess cardiac rhythm in 18 patients
with a mean age of 12.1 +/- 3.7 years. The cardiac rhythms were analyzed
67 times and included ventricular fibrillation (25), asystole/pulseless
electrical activity (32), sinus bradycardia (6), and sinus tachycardia
(4). The AEDs recognized all nonshockable rhythms accurately and advised
no shock. Ventricular fibrillation was recognized accurately in 22 (88%)
of 25 episodes and advised or administered a shock 22 times. Sensitivity
and specificity for accurate rhythm analysis were 88% and 100%,
respectively. One patient with a nonshockable rhythm survived, whereas 3
of 9 patients with ventricular fibrillation survived. CONCLUSIONS: These
data furnish evidence that AEDs provide accurate rhythm detection and
shock delivery to children and young adolescents. AED use is potentially
as effective for children as it is for adults. |
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Prehospital Disaster Med
1997 Oct-Dec;12(4):284-7 Automatic external defibrillation and its effects
on neurologic outcome in cardiac arrest patients in an urban, two-tiered
EMS system.
Ho J, Held T, Heegaard W, Crimmins T
Department
of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN
55415, USA. ho911doc@aol.com
OBJECTIVE:
To describe the use of the Automatic External Defibrillation (AED) device
in an urban, two-tiered Emergency Medical Service (EMS) response setting
with regard to its potential effects on cardiac arrest patient survival
and neurologic outcome. METHODS: A retrospective and descriptive design
was utilized to study all cardiac arrest patients that had resuscitations
attempted in the prehospital environment over a 30-month period. The study
took place in a two-tiered EMS system serving an urban population of
368,383 persons. The first tier of EMS response is provided by the City
Fire Department, which is equipped with a standard AED device. All
first-tier personnel are trained to the level of Emergency Medical
Technician-Basic. The second tier of EMS response is provided by personnel
from one of two ambulance services. All second-tier personnel are trained
to the level of Emergency Medical Technician-Paramedic. RESULTS: 271
cardiac arrest patients were identified for inclusion. One-hundred nine of
these patients (40.2%) had an initial rhythm of either ventricular
fibrillation or pulseless ventricular tachycardia and were shocked using
the AED upon the arrival of first-tier personnel. Forty-two patients
(38.5%) in this group had a return of spontaneous circulation in the field
and 22 (20.2%) survived to hospital discharge. Of the survivors, 17
(77.3%) had moderate to good neurologic function at discharge based on the
Glasgow-Pittsburgh Cerebral Performance Categories. Faster response times
by the first-tier personnel appeared to correlate with better neurologic
outcomes. CONCLUSION: First responder-based AED usage on patients in
ventricular fibrillation or pulseless ventricular tachycardia can be
applied successfully in an urban setting utilizing a two-tiered EMS
response. In this study, a 20.2% survival to hospital discharge rate was
obtained. Seventy-seven percent of these survivors had a moderate to good
neurologic outcome based on the Glasgow-Pittsburgh Cerebral Performance
Categories. |
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G Ital Cardiol
1997 Nov;27(11):1121-4 Italian experience with automated external
defibrillators (AED).
Bandini F, Destro A, Rellini G, Deganuto L, Fantini
A, Vergassola R
Department
of Cardiology, S.M. Annunziata Hospital, Florence.
In order to achieve widespread use
of automated external defibrillators (AEDs) in Italy, we evaluated several
models of AEDs in different clinical and artificial settings. We enrolled
268 consecutive patients with various rhythms and arrhythmias. Among
these, 129 patients were referred to two different hospitals and 139 were
enrolled by the pre-hospital care providers. AED was applied in 209
patients without symptoms of cardiac arrest and in 59 patients with
cardiac arrest. The AEDs exhibited a 100% specificity (no false positives
in 220 patients with non-shockable rhythm). Sensitivity was 92.3% (4 false
negatives and 48 true positives in patients with VT/FV). This study
confirms the absolute clinical safety and the high level of diagnostic
reliability offered by the AEDs that were tested. |
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Acad Emerg Med
1997 Jun;4(6):552-8 Population density, automated external
defibrillator use, and survival in rural cardiac arrest.
Stapczynski JS, Svenson JE, Stone CK
Department
of Emergency Medicine, University of Kentucky Medical Center, Lexington
40536-0084, USA. jsstap01@pop.uky.edu OBJECTIVE: To determine whether
population density is an independent predictor of survival from
out-of-hospital cardiac arrest managed by basic life support (BLS)
services using automated external defibrillators (AEDs). METHODS: A
retrospective, observational study in Kentucky of 34 BLS services covering
22 counties during the years 1992 to 1994 who used AEDs to treat patients
who had out-of-hospital cardiac arrests. RESULTS: Of 311 patients who had
out-of-hospital cardiac arrests, 110 (35%) were defibrillated, 46 (15%)
were resuscitated to hospital admission, and 19 (6%) survived to hospital
discharge. Univariate predictors for survival to hospital discharge were
emergency medical services response interval (from call receipt to
ambulance arrival) < 8 minutes, defibrillation by the AED, initial
rhythm of ventricular fibrillation or ventricular tachycardia (VF/VT), and
population density > 100/square mile (sq mi) for the BLS service area
(p < 0.001). A forced logistic regression model of survival to hospital
discharge, using these 4 factors plus the presence of a witnessed arrest
or bystander CPR, demonstrated that population density > 100/sq mi was
highly significant (OR 9.4, 95% CI: 1.7 to 51.4, p < 0.01). Stepwise
logistic regression models with combinations of these 6 factors found that
survival to hospital discharge was best predicted by an initial rhythm of
VF/VT (p = 0.004) and population density > 100/sq mi (p = 0.011).
CONCLUSIONS: Population density is strongly associated with survival from
out-of-hospital cardiac arrest. BLS services within areas with population
densities < or = 100/sq mi sustained little benefit from the addition
of AEDs to their treatment of patients who had out-of-hospital cardiac
arrests. |
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J Ky Med Assoc
1995 Apr;93(4):137-41 Automated external defibrillators used by emergency
medical technicians: report of the 1992 experience in Kentucky.
Stapczynski JS, Burklow M, Calhoun RP, Svenson JE
Department
of Emergency Medicine, University of Kentucky College of Medicine,
Lexington, USA.
Automated
external defibrillators (AED) have been authorized for use by Emergency
Medical Technicians (EMT) in Kentucky since March 1991. Emergency Medical
Services (EMS) which use these devices are required to submit annual
reports to the EMS Branch. During 1992, 17 services were approved to use
AEDs. The device was used by 12 services on 93 victims of out-of-hospital
cardiac arrest. Of the 93 victims, 27 were defibrillated, eight were
resuscitated to hospital admission, and three survived to hospital
discharge. The overall survival rate was 3/93 (3.2%). For patients
receiving defibrillatory shocks, the survival rate was 3/27 (11%). This
percentage is comparable with the survival rates reported from other
predominately rural states where AEDs have been used by EMTs. Possible
protocol violations and inadequate documentation were also identified from
these reports. In summary, EMTs in predominately rural Kentucky can use
AEDs to achieve survival rates for out-of-hospital cardiac arrest
comparable with other rural states. |
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Ann Emerg Med
1996 May;27(5):638-48 Relationship of timeliness of paramedic advanced
life support interventions to outcome in out-of-hospital cardiac arrest
treated by first responders with defibrillators.
Callaham M, Madsen CD
Division of
Emergency Medicine, University of California, San Francisco, USA.
STUDY
OBJECTIVE: We sought to determine whether the interval between the arrival
of first responder/defibrillators and paramedic advanced life support
(ALS) interventions is associated with outcome. METHODS: We carried out a
prospective observational study of adults in out-of-hospital cardiac
arrest treated by both first responders and paramedics in an urban
emergency medical services system between July 15, 1992, and May 27, 1993
(N = 544). RESULTS: The gap between first-responder and medic arrival was
short (3.2 minutes); medics arrived before first-responder shock in 22% of
ventricular fibrillation (VF) cases. Just 10% of patients has a pulse when
medics arrived, but the presence of pulse on medic arrival was a powerful
predictor of hospital discharge (odds ratio [OR], 20.5; sensitivity, 39%;
specificity, 98%; positive predictive value, 55%; negative predictive
value, 97%) or a Cerebral Performance Category score on discharge of 1 or
2 (OR, 2.9). No response or individual ALS treatment interval was related
to outcome, including the interval from first-responder to medic arrival.
ALS interventions by medics were associated with poorer outcomes; even the
need for nothing more than additional defibrillation by medics decreased
the survival rate of VF patients threefold. By contrast, bystander CPR
improved survival more than fourfold and early defibrillation of VF by
first responders more than ninefold. Ninety-one percent of all patients
discharged from the hospital who received only minimal ALS other than
intubation had good neurologic outcome and longer survival after
discharge. Half the total survivors of VF arrest (and 59% of all arrest
survivors) were resuscitated by medics with aggressive ALS measures, but
80% had very poor neurologic outcomes and 50% died within a year of
hospital discharge. Even the need for only additional defibrillation by
medics worsened neurologic outcome by a factor of 2.8. CONCLUSION: Faster
response by medics, or any individual ALS intervention other than
first-responder defibrillation, demonstrated no benefit in this urban
population with short intervals between responder arrivals. Aggressive ALS
increased the number of survivors but also decreased their neurologic
quality. The benefit of rapid ALS backup to first responder/defibrillators
needs further study in other systems. System performance cannot be judged
without knowledge of neurologic outcome. |
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Ann Emerg Med
1996 Nov;28(5):480-5 High discharge survival rate after out-of-hospital
ventricular fibrillation with rapid defibrillation by police and
paramedics.
White RD, Asplin BR, Bugliosi TF, Hankins DG
Mayo Clinic
and Medical School, Rochester, Minnesota.
white.roger@Mayo.edu
STUDY OBJECTIVE: To assess outcome
in patients with ventricular fibrillation (VF) treated by
defibrillator-equipped police and emergency medical technician-paramedics
in an advanced life support (ALS) emergency medical services (EMS) system.
METHODS: We carried out a retrospective observational outcome study of all
consecutive adult patients with atraumatic cardiac arrest treated from
November 1990 through July 1995. The study was carried out in a city with
a population of 76,865 in an area of 32.6 square miles. Central 911
dispatched police and an ALS ambulance simultaneously. Accurate intervals
were obtained with the synchronization of all defibrillator clocks with
the 911 dispatch clock. The personnel who arrived first delivered the
initial shock. After shocks delivered by police, paramedics provided
additional treatment if needed. Main outcome measures were time elapsed
before delivery of the first shock, restoration of spontaneous circulation
(ROSC), and survival to discharge home. RESULTS: Of 84 patients, 31 (37%)
were first shocked by police. Thirteen of the 31 demonstrated ROSC,
without need for ALS treatment. All 13 survived to discharge. The other 18
patients required ALS; 5 (27.7%) survived. Among the 53 patients first
shocked by paramedics, 15 had ROSC after shocks only, and 14 survived. The
other 38 needed ALS treatment; 9 survived. Call-to-shock time for all
patients was less in the police group than in the paramedic group (5.6
versus 6.3 minutes, P = .038). For all patients, call-to-shock time was
less in those with ROSC after shocks only than in those who needed ALS
(5.4 versus 6.3 minutes, P = .011). Survival to discharge was 49% (41 of
84), with 18 of 31 (58%) in the police group and 23 of 53 (43%) in the
paramedic group. Call-to-shock time for survivors was 5.8 minutes; it was
6.4 minutes for the nonsurvivors (P = .020). Neither ROSC nor discharge
survival was significantly different between police and paramedic-shocked
patients. ROSC after initial shock and call-to-shock time were major
determinants of survival, whether the first shocks were administered by
police or by paramedics. With ROSC after shocks only, 27 of 28 (96%)
survived, whereas 14 of 56 (25%) needing ALS survived (P < .001).
CONCLUSION: A high discharge-to-home survival rate was obtained with early
defibrillation by both police and paramedics. When shocks resulted in ROSC,
the overwhelming majority of patients survived (96%). Even brief time
decreases (eg. 1 minute) in call-to-shock time increase the likelihood of
ROSC from shocks only, with a consequent decrease in the need for ALS
intervention. Short call-to-shock time and ROSC response to shocks only
are major determinants of a high rate of survival after VF. |
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Ann Emerg Med
1995 Feb;25(2):163-8 Strengthening the in-hospital chain of survival
with rapid defibrillation by first responders using automated external
defibrillators: training and retention issues.
Kaye W, Mancini ME, Giuliano KK, Richards N, Nagid
DM, Marler CA, Sawyer-Silva S
Department
of Surgery, Brown University, Miriam Hospital, Providence, RI.
STUDY OBJECTIVE: To determine whether staff outside critical care areas who were proficient in basic life support (BLS) could be easily trained to use automated external defibrillators (AEDs) and whether they would retain these skills. DESIGN: Prospective, longitudinal cohort series. SETTING: Two university teaching hospitals. PARTICIPANTS: One hundred forty nurses who had previously learned BLS and constituted the staff from three medical/surgical nursing units from each study hospital. INTERVENTIONS: The nurses were taught how to use the Heartstart 1000s, a lightweight portable shock-advisory AED, in a 2-hour class with an instructor and manikin-to-student ratio of 1:5. The course emphasized hands-on practice of the BLS-AED algorithm on a computerized manikin. RESULTS: Using a similar scenario, each nurse was evaluated on the computerized manikin immediately after training (posttest). At 1 to 3, 4 to 6, and 7 to 9 months after the initial training, convenience samples of the cohort in three different groups were evaluated for retention. Satisfactory performance was defined as delivery of the first AED shock within 2 minutes of recognition of the arrest. At the posttest after training, 139 of 140 nurses (99%) demonstrated satisfactory performance. Of 77 nurses evaluated, 31 of 32 at 1 to 3 months, 18 of 18 at 4 to 6 months, and 24 of 27 at 7 to 9 months after initial training (95% overall) performed satisfactorily. CONCLUSION: As has been demonstrated with prehospital emergency personnel, nurses outside critical care areas who are proficient in BLS can easily learn and retain the knowledge and skills to use AEDs. Automated external defibrillation, a BLS skill, should be incorporated into BLS programs (BLS-AED) for all hospital personnel expected to respond to a patient in cardiac arrest, with rapid defibrillation taking priority over CPR. |
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Ann Emerg Med
1994 May;23(5):1009-13 Early defibrillation by police: initial experience
with measurement of critical time intervals and patient outcome.
White RD, Vukov LF, Bugliosi TF
Department
of Anesthesiology, Mayo Clinic, Rochester, MN.
STUDY
OBJECTIVE: To assess the feasibility of consistent acquisition of precise
and clinically important time intervals in a city police department
defibrillation study. DESIGN: On a daily basis, clocks at 911 dispatch
were synchronized with those at ambulance dispatch, and all clocks on all
defibrillators were synchronized to this time. Times were obtained from
recordings at dispatch centers and from defibrillator memory modules.
SETTING: City with a population of 70,745 and an area of 30 square miles.
PARTICIPANTS: All patients in ventricular fibrillation (VF) treated by
police officers using semiautomated defibrillators. INTERVENTIONS: On
receipt of a call at 911 dispatch, the nearest squad car was dispatched.
If police arrived before the ambulance and a cardiac arrest was confirmed,
the closest squad car with a defibrillator was dispatched. Police
delivered up to three shocks before ambulance arrival. RESULTS: Of 44
patients in VF, 14 were initially treated by police. Seven of 14 regained
a spontaneous circulation with police shocks and seven required additional
advanced life support care for restoration of pulses. Ten of the 14 were
discharged home. The 911 call-to-shock time interval was 4.9 +/- 1.3
minutes for the seven who regained a spontaneous circulation with police
shocks and 6.1 +/- 0.7 minutes for the seven without restoration of pulses
by police (P = .035, one-sided, two-sample t-test). CONCLUSION:
Acquisition of precise times for determination of time intervals is
feasible with a concerted effort to synchronize all clocks from which
times are derived. Even small differences in call-to-shock time intervals
appear to be critical determinants of restoration of a spontaneous
circulation. |
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Resuscitation
1994 Jan;27(1):39-45 Training St John Ambulance volunteers to use an
automated external defibrillator.
Walters G, Glucksman E, Evans TR
Bromley
Hospitals NHS Trust, Farnborough Hospital, Orpington, Kent, UK.
The key to
improving survival from pre-hospital cardiac arrest lies in reducing the
time interval between onset of cardiac arrest and defibrillation. Placing
automated external defibrillators at strategic points in the community
could potentially reduce this time interval, but would necessitate
widespread training in defibrillation for lay people in addition to health
care workers. There are unanswered questions regarding the ability of lay
people to acquire and retain this skill when the training programme is, by
necessity, very brief, (otherwise it would not be possible to train large
enough numbers of people) and the skill is used infrequently. In this
study, nurse and lay volunteer first-aiders were taught to use an
automated external defibrillator, either by a 2-h, or a 4-h course, and
their skills were assessed at training, and at 3 and 6 months afterwards.
Using stringent assessment criteria, 54% of volunteers passed the
assessment at every session. Little difference in acquisition or retention
of skills between the nurse and lay volunteers, and the 2- and 4-h course
groups was found. It is concluded that brief training in defibrillation
for volunteer first-aiders is feasible. |
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JAMA 1993 Oct
13;270(14):1708-13 Impact of first-responder defibrillation in an
urban emergency medical services system.
Kellermann AL, Hackman BB, Somes G, Kreth TK, Nail
L, Dobyns P
Division of
Emergency Medicine, University of Tennessee, Memphis.
OBJECTIVE--To
evaluate the impact of adding first-responder defibrillation by
fire-fighters to an existing advanced life-support emergency medical
services system. DESIGN--Nonrandomized, controlled clinical trial with
periodic crossover. SETTING--Memphis, Tenn, a city of 610,337 people,
which is served by a fire department-based emergency medical services
system. All city ambulances provide advanced life support. PATIENTS--Adult
victims of out-of-hospital cardiac arrest due to heart disease.
INTERVENTION--Twenty of 40 participating engine companies were equipped
with an automated external defibrillator and ordered to apply it
immediately in all cases of cardiac arrest. The other 20 companies were
ordered to start cardiopulmonary resuscitation (CPR) immediately and wait
for paramedics to arrive. Every 75 days, group roles were reversed. Care
otherwise proceeded according to 1986 American Heart Association
guidelines. MAIN OUTCOME MEASURES--Return of spontaneous circulation in
the field, survival to hospital admission, survival to hospital discharge,
and neurological status at discharge. RESULTS--During the 39-month study
interval, 879 patients were treated by a project engine company. Four
hundred thirty-one (49%) of these were found in ventricular fibrillation.
Bystander CPR was started in only 12% of cases. Overall, firefighters
reached the scene a mean of 2.5 minutes faster than simultaneously
dispatched paramedics. Although our automated external defibrillators
proved to be reliable and efficacious for terminating ventricular
fibrillation and pulseless ventricular tachycardia, patients treated by an
automated external defibrillator-equipped engine company were no more
likely than CPR-treated controls to be resuscitated (32% vs 34%,
respectively), to survive to hospital admission (31% vs 29%), or to
survive to hospital discharge (14% vs 10%). Neurological outcomes were
also similar in the two treatment groups. CONCLUSIONS--In a fast-response,
urban emergency medical services system served by paramedics, the impact
of adding first-responder defibrillation appears to be small. Early
defibrillation alone cannot overcome low community rates of bystander CPR.
Careful attention to every link in the "chain of survival" is
needed to achieve optimal rates of survival after cardiac arrest. |
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Resuscitation
1992 Aug-Sep;24(1):73-87 Efficacy of out of hospital defibrillation by
ambulance technicians using automated external defibrillators. The
Heartstart Scotland Project.
Sedgwick ML, Watson J, Dalziel K, Carrington DJ,
Cobbe SM
Department
of Medical Cardiology, Royal Infirmary, Glasgow, Scotland, UK.
During the
Heartstart Scotland project all 407 ambulances in Scotland were equipped
with automated external defibrillators (AEDs). All cases of chest pain or
collapse aged over 10 years were monitored and multiple 3-s rhythm strips
recorded in a solid state memory module. A shockable rhythm was defined as
an organised rhythm of > or = 180 beats/min or a disorganised rhythm of
> or = 100 beats/min and amplitude > 0.1 mV. We analysed all the
stored rhythm strips in two patient populations to determine the ability
of the AED and ambulance crews to detect a shockable rhythm and to
initiate appropriate defibrillation. The first population comprised 493
patients, all of whom had received shocks. A total of 4741 rhythm strips
were analysed, of which 1461 were true positives, 33 false positives, 3161
true negatives and 86 false negatives. Overall sensitivity of the AED was
94.4% and specificity 99.0%. The second population comprised a random
sample of 200 shocked and 200 non-shocked arrests. The combined group
contained 4154 rhythm strips of which 562 were true positives, 12 false
positives, 3460 true negatives and 120 false negatives. Overall
sensitivity of the system (AED+crew) was 82.4% and specificity 99.7%.
However, only 66 of the 120 false negatives were attributable to the AED
giving a sensitivity of 90.3% for the AED. The sensitivity of the AED is
dependent on the prevalence of shockable rhythms, but will be within the
range 90.3-94.4% for most emergency medical services. We conclude that
early management of potentially lethal arrhythmias by ambulance
technicians using AEDs is practical with acceptable sensitivity and
specificity. |
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J R Soc Med 1990
Sep;83(9):563-5 Controlled trial of automated external
defibrillators in the London ambulance service.
Walters G, D'Auria D, Glucksman EE
Accident
& Emergency Department, King's College Hospital, London.
This
controlled trial was performed in London and compared outcomes of patients
treated by ambulance staff using either basic life support alone or an
automated external defibrillator (AED) as an adjunct to basic life
support. Five of the 212 (2%) patients were successfully resuscitated by
crews using basic life support alone, compared with seven of 186 (4%)
patients treated by crews equipped with the AED. Neurological outcomes in
the AED group were better. However, meaningful statistical comparisons are
not possible with so few survivors. The AED used (Lifepak 200,
PhysioControl Corp) was found to be sensitive and specific, and ambulance
staff operated the defibrillator correctly. The use of AEDs in an option
to maximize the provision of defibrillators in the community and could
readily be incorporated into basic ambulance training. |
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