- Email: [email protected]
The effect of experience of on-site physicians on survival from prehospital cardiac arrest
-
resuscitation
Resuscitation 31 (1996) 101-105
The effect of experience of on-site physicians on survival from prehospital cardiac arrest Tom Silfvast *a, Ari Ekstr andb ‘Department
of Annesrhesia,
Helsinki University Central Hospital, ‘Helsinki City Rescue Department.
Haartmannink. 4. FIN Helsinki, Finland
Of.UW, Helsinki,
Firdarfd
Received 13 July 1995;revision received 10 October 1995;accepted 24 October 1995
_-
.__..---.-.
Abstract
Outcome from prehospital cardiac arrest was studied 1 year before (Period I) and after (Period II) a reorganisation of the work and the simultaneous change of all physiciansparticipatingin the careof prehospitalpatientsin the emergency medical service system in Helsinki. There were 444 patients during Period I and 395 patients during Period II. Resuscitation was initiated in 279 patients during Period I and in 323 patients (P < 0.001) during Period 11.The number of patients with ventricular fibrillation who suffered a witnessed cardiac arrestdue to presumedheartdiseasewas 120and 130,respectively. During Period I, 70 of thesepatients were successfully resuscitatedand admitted to hospital, 41(34%)survivedto dischargehomefrom hospital.Correspondingfiguresduring Period II were 79 and 33 (25%, NS). Compared with Period I, a larger proportion of the successfully resuscitated patients either died in hospital or were discharged to an institution during Period II (P < 0.05). Keywork
Cardiopulmonaryresuscitation;Prehospital;Outcome;Cardiac arrest ------.
1. Introduction
A well functioning emergency medical service (EMS) system is required to ensure maximal possibility of survival from from prehospital cardiac arrest. Whereas the beneficial effects of bystander initiated CPR and early defibrillation have been documented [l-3], the role of the care delivered by the advanced cardiac life support (ACLS) providers in this ‘chain of survival’ [4] is less clear. In the United States, ACLS is usually
l
Corresponding author.
provided by paramedicswho treat patients according to protocols or after consulting with an emergency physician. In many European cities [5-71, physicians provide ACLS. Emergency medicine is not a recognisedspeciality in several countries, including Finland. The physicians in the prehospital emergency care unit in Helsinki have acquired their knowledge by working exclusively in the prehospital environment after initial education by an experiencedphysician. This paper tries to evaluate the role of the experience of the on-site physician in the EMS in Helsinki, using the Utstein template [8] for reporting on prehospital cardiac arrest as an indicator.
0300-9572/96/$15.00 0 1996 Elsevier Science Ireland Ltd. All rights reserved SSDI
0300-9572(95)00915-G
-..--
102
T. Sirfast.
A. Ekstrand/ Resuscitation 31 (19%) 101-105
2. Pdients and methods The EMS system in Helsinki, a city of 510 000 inhabitants, is a multitiered systemoperated by the rescuedepartment and administered by the health department [9]. The first tier consists of firemenemergency medical technicians (EMT-D) trained to use semiautomateddefibrillators. They respond either in ambulancesor tire engines.An intermediate paramedic tier consists of two units manned with specially trained EMTs capable of orotracheal intubation and intravenous medication. Becausetheseunits are not selectively used as ACLS units but respond to all calls within their operating area, they are often occupied and not systematically available. The ACLS tier consists of one prehospital emergency care unit (PECU), staffed with a physician and two EMT-Ds at all times. The EMS is activated via the national emergencyphone number ‘ 112’,which connects all calls for emergencycare in the city to the regional alarm center. Specially trained alarm personnel evaluate the calls and dispatch the closest first responding unit and the PECU in suspected life threatening emergencies. Annually, the EMS responds to roughly 30 000 urgent calls, lO?/ of which also involve the PECU. During the 198Os,the EMS system in Helsinki went through a series of major developments. Theseincluded the education of the dispatchers to use criteria based computer&d dispatch and unit tracing, the training of the EMTs to use semiautomated defibrillators, and the use of a tiered response including tire engines as first responding units. As a result, survival figures from prehospital cardiac arrest in Helsinki are comparable to those from other major EMS [lO,l 11. In cardiac arrest, the EMT-Ds of the first responding unit determine the patients initial cardiac rhythm and initiate defibrillation and basic life support (BLS) until the PECU arrives. BLS is not started if the patient has developed postmortem lividity or rigor mortis, or if the body is severely mutilated by trauma. Based on the clinical situation, the PECU physician decideswhether to continue resuscitation and start ACLS, or discontinue BLS and proclaim the patient dead. If the patient
fails to regain spontaneous circulation on the scene during ACLS efforts, resuscitation is considered unsuccessful.These patients are proclaimed dead and transported to the forensic department by a different system.Successfulresuscitation is defined as restoration of a stable circulation in the field, and the patient is then transported to hospital. Survival is defined as discharge home from hospital. During the first part of this study, there were five full time physicians (medical director and four other doctors) in the EMS sharing all calls in the PECU. Their mean duration of experience of prehospital work was 6 years. The turnover of physicians was less than one annually. As these posts were unique in our country, no formal competence requirements existed, but the medical director required a new physician to have experiencefrom internal medicine and anaesthesia. The work in the EMS was reorganised at the end of July in 1992.The prehospital posts in the PECU were integrated into the city hospital and a simultaneous change of all physicians took place. From having been exclusively engaged with prehospital care, the physicians became hospital based and were on call in the PECU together with their hospital work. Thus, the proportion of time spent by an individual in the EMS was reduced to less than 50% of their total working time. The number of physicians sharing the calls in the PECU was increasedby one. Of the new physicians, one was an anaesthesist,two were residents in anaesthesiaand the remaining three were residents in general surgery. None had previously worked in prehospital or emergency medicine. There was no on-site introduction to field work before starting in the PECU. All other factors and personnel in the EMS, i.e. the dispatch procedures, the number and location of different responding units, the EMTDs and early defibrillation protocols remained unchanged, therefore the new setting provided a unique opportunity to study whether a sudden change within the ACLS link in the chain of survival in our EMS affected survival from prehospital cardiac arrest. Data were retro- and prospectively collected from the trip sheetsof all patients in cardiac arrest seen by the PECU. The study period was 12
103
T. Siljvast. A. Ekstrand/ Resuscitation 31 (19%) JOJ-JOS
months before (Period I, 1 August 1991to 31 July 1992,retrorpective) and after (Period II, 1 August 1992to 31 July 1993, prospective) the reorganisation. Collected data inchtded age and sex of patients, condition of arrest (witnessed or not, obvious cause of arrest), time interval from the beginning of the emergency phone call to the arrival at the sceneof the first responding unit and the PECU, initial cardiac rhythm, and outcome from rcswcitation. Due to differences in completing the trip sheets during the two periods, it was not possible to collect data on presence of bystander initiated CPR, time of the first defibrillatory shock, intubation and return of spontaneouscirculation during Period II and these were omitted from analysis. Data are reported according to the Utstein template [8]. Those patients who were discharged to their homes (not to another facility) from hospital were defined as survivors. Further follow-up of the patients condition after discharge was not possible. Statistical analyses inchrde the Student’s r-test for nonparametric data and F&hers exact test for parametric data.
1
CONFIRMED CONSIDERED
pr
!?A
444
395
RESUSCITATION
ATTEMPTED
279
323
COLLAPSE
I
FIBRILLATION
120
1
I I
257
VENTRICULAR
ADMITTED
f
WITNESSED
202
3. Remits The PECU was dispatched to 839 cardiac arrest patients in Helsinki during the two study periods, 444 patients during Period I and 395 patients during Period II (Fig. 1). ACLS was initiated in 279 patients (63%) during Period I and in 323 patients (82%) during Period II (P < 0.001). Resuscitation was successfitlin 120patients (43%) during Period I and in 131patients (46%) during Period II. Of all cardiac arrest patients in whom ACLS was initiated, 50 patients ( 18%)survived to be discharged home from hospital during Period I, compared to 37 patients (11%) during Period II (P < 0.05). The arrest was witnessed,the presumed causeof arrest cardiac and the initial cardiac rhythm ventricular fibrillation (VF) in 120 patients during Period I and in 130 patients during Period II. The mean age of these patients was 64 and 68 years, respectively(NS). The mean time interval from the beginning of the phone call to the arrival of the first responding unit was 5.4 min during Period I and 6.5 min during Period II (NS). The corresponding time intervals for ACLS were 11.O and 11.7
CARDIAC ARRESTS FOR RESUSCITATION
130
TO HOSPITAL
70
79
DISCti;RGED
;I3;ME
1
Fig. 1. Outcome from prehospital cardiac amst according to the Utstein template during the two study periods (P I period I; P II, period II).
min (NS). Resuscitation was successful in 70 of thesepatients with VF during Period I and 79 patients during Period II @IS). Twenty nine of these successfully resuscitated patients either died in hospital or were institutionalised, while 41 patients (34% of the patients with witnessed VF) were discharged home during Period I. The correspon-
104
T. Si&ut. A. Ekstrand/Restucitation 31 (1996) 101-105
ding figures during Period II were 46 (P < 0.05) and 33 patients (25%, NS). Outcome from witnessed cardiac arrest due to VF was also compared in three 4-month intervals during Period I and Period II, i.e. AugustNovember, December-March and April-July. The proportions of patients in whom ACLS was initiated and who were admitted to hospital or discharged home were similar during these pXiOdS.
4. Discussion Earlier studies have shown that survival from prehospital cardiac arrest is influenced by the time intervals from the beginning of the event to the commencementof various interventions. The effects of bystander initiated CPR [1,2], early defibrillation [3,12] and ACLS [10,11,13] have been documented. In this study, the ‘quality’ of ACLS was the only link in the chain of survival that may have been affectedby the changeof physicians, as all other parameters remained unchanged during the two periods. Our findings suggest that the experience of the on-site physician has only a small impact on survival from prehospital cardiac arrest in our EMS. There are three possible explanations for this. The number of patients may have been too small to show more significant differences, or then there are no major differences to be detected. The isolated effect of variations within one link may be concealedby the multitude of factors affecting survival. The third possibility is that ACLS may play a relatively unimportant role in eventual survival when compared to BLS and defibrillation. Therefore, who provides the ACLS is immaterial. Our study showed no difference in the rate of successfulresuscitation from witnessed VF during the two periods. This was not surprising, as previous papers have reported that a considerable number of patients regain spontaneous circulation, and ultimately survive, after initial defibrillations and BLS only [ 14,151.Theseparameterswere not affected in our system. However, the noted slight difference in survival from prehospital cardiac arrest due to all etiologies, and the difference in the proportion of patients dying in hospital or
requiting institutionalisation after successful resuscitation from witnessed VF suggests that the ACLS link and the phase immediately after circulation is restored before admission to hospital after all are of importance. Objective data on the management of the patients during this phase during the two study periods cannot be obtained from the trip sheets, but different treatment modalities probably have existed. This assumption is supported by a recent paper studying the performance of emergencyphysicians and the timing of their interventions on the scene,documenting remarkable variations in the time spent for these procedures
WI. Previous experience,such as that of the London Ambulance Service computerisation [ 171, demonstratesthat it may not be wise to make sudden changes in EMS systems without thorough education and overlapping periods. In this respect, it was interesting to find that the outcome of the patients remained unchanged during the three consequetive4-month periods in P II. Thus the noted differences between Periods I and II cannot solely be ascribed the lack of introduction to the work during the intitial months of Period II. A possible explanation could be the lack of sufficient experiencewith prehospital patients. A reflection of this was the significantly greater proportion of patients (82% vs. 63%) in whom resuscitation was initiated during Period II, without a concomitant increase in the number of survivors. Futile resuscitational efforts occupy limited ACLS capacity and may prolong responsetimes to other calls. During P I, the physicians worked exclusively with prehospital care. After the reorganisation, the physicians were mainly engaged in hospital duties not associated with emergencymedicine, leaving the work in the EMS to less than half of the total working time. Our findings support the concept that early defibrillation plays an important role in the treatment of patients with prehospital cardiac arrest [18]. If the other links in the chain of survival are performed well, variation within the ACLS link, in this casethe experienceof the ACLS provider, are less important. The issue is closely related to the question of the basic education of the ACLS provider, as recently discussedby Dick [19], but we agreewith the data provided by Cummins et al. [4]
T. Siljvast, A. Ekstrand/ Resuscitation31 (1996) 101-105
which indicates that trimming all links to optimal performance in the chain of survival ensures the best possibility of survival. 5. References Ill Ritter Cl, Wolfe RA, Goldstein S et al. The effect of bystander CPR on survival of out-of-hospital cardiac arrest victims. Am Heart J 1985; 110: 932-937. PI Wik L, Steen PA, Bircher NG. Quality of bystander cardiopulmonary resuscitation influences outcome after prehospital cardiac arrest. Resuscitation 1994;28: 195-203. [31 Eisenberg MS, Copass MK, Hallstrom AP et al. Treatment of out-of-hospital cardiac arrest with rapid dedbrillation by emergency medical technicians. N Engl J bled 1980;302: 1379-1383. 141 Cummins RO, Omato JP, Thies WH et al. Improving survival from sudden cardiac arrest: the ‘chain of survival’ concept. Circulation 1991;83: 1832-1847. Pl Mob P, Beaucame E, Bruininx J et al. Early deftbrillation by EMTs: the Brussels experience. Resuscitation 1994;27: 129-136. I61 Kimman GP, lvens EMA, Hartman JAM et al. Longterm survival after successfulout-of-hospital resuscitation. Resuscitation 1994,28: 227-232. [71 Einanson 0, Jakobsson F, SigurdssonG. Advanced cardiac life support in the prehospital setting: the Reykjavik experience. J Intern Med 1989;225: 129-135. PI Cummins RO, Chamberlain DA et al. Recommended guidelines for uniform reporting of data from out-ofhospital cardiac arrest: the Utstein style. Circulation 1991;84: 960-975. 191 Silfvast T. Prehospital resuscitation in Helsinki, Finland, Am J Emerg Med 1990;8: 359-364. [lOI Eisenberg MS, Hallstrom AP, Copass MK et al. Treatment of ventricular fibrillation: Emergency medical
\!.I’
technician defibrillation and paramedic services. J Am Med Assoc 1984;251: 1723-1726. 1111Weaver WD, Cobb LA, Fahrenbruch CE et al. Use of the automatic external defibrillator in the management of out-of-hospital cardiac arrest. N Engl J Med 1988:319: 661-666. WI Stults KR, Brown DD, Schug VI et al. Prehospital defibrillation performed by emergency medical technicians in rural communities. N Engl J Med 1984: 3 IO: 219-223. 1131 Eisenberg MS, Bergner L, Hallstrom A. Paramedic programs and out-of-hospital cardiac arrest: 1. Factors associatedwith successfulresuscitation. AJPH 1979:69. 30-38. 1141 Cummins RO, Graves JR, Horan S et al. The relative contributions of early defibrillation and ACLS interventions to resuscitation and survival from prehospital cardiac arrest [abstract]. Ann Emerg Med 1989; 18. 468-469. II51 Callaham M, Madsen CD, Barton CW et al. A randomixed clinical trial of high-dose epinephrine and norepinephrine vs. standard dose epinephrine in prehospital cardiac arrest. J Am Med Assoc 1992: 26X. 2667-2672. 1161SchneiderT, Mauer M, Diehl P et al. Quality of on-site performancein prehospital advancedcardiac life suppor: (ACLS). Resucitation 1994,27: 207-213. I171 Kingman S. London ambulance chaos due to risky computer system. Br Med J 1993;306: 603. 1181Auble TE, Menegaxzi JJ, Paris PM. Effect of out-ofhospital defibrillation by basic life support providers on cardiac arrest mortality: a metaanalysis. Ann Emerg Med 1995;25: 642-648. 1191 Dick WF. Does prehospital care by physicians result in a better outcome than resuscitation by other EMS personnel? [editorial]. Resuscitation 1993: 26: IO+-! IO.
resuscitation
Resuscitation 31 (1996) 101-105
The effect of experience of on-site physicians on survival from prehospital cardiac arrest Tom Silfvast *a, Ari Ekstr andb ‘Department
of Annesrhesia,
Helsinki University Central Hospital, ‘Helsinki City Rescue Department.
Haartmannink. 4. FIN Helsinki, Finland
Of.UW, Helsinki,
Firdarfd
Received 13 July 1995;revision received 10 October 1995;accepted 24 October 1995
_-
.__..---.-.
Abstract
Outcome from prehospital cardiac arrest was studied 1 year before (Period I) and after (Period II) a reorganisation of the work and the simultaneous change of all physiciansparticipatingin the careof prehospitalpatientsin the emergency medical service system in Helsinki. There were 444 patients during Period I and 395 patients during Period II. Resuscitation was initiated in 279 patients during Period I and in 323 patients (P < 0.001) during Period 11.The number of patients with ventricular fibrillation who suffered a witnessed cardiac arrestdue to presumedheartdiseasewas 120and 130,respectively. During Period I, 70 of thesepatients were successfully resuscitatedand admitted to hospital, 41(34%)survivedto dischargehomefrom hospital.Correspondingfiguresduring Period II were 79 and 33 (25%, NS). Compared with Period I, a larger proportion of the successfully resuscitated patients either died in hospital or were discharged to an institution during Period II (P < 0.05). Keywork
Cardiopulmonaryresuscitation;Prehospital;Outcome;Cardiac arrest ------.
1. Introduction
A well functioning emergency medical service (EMS) system is required to ensure maximal possibility of survival from from prehospital cardiac arrest. Whereas the beneficial effects of bystander initiated CPR and early defibrillation have been documented [l-3], the role of the care delivered by the advanced cardiac life support (ACLS) providers in this ‘chain of survival’ [4] is less clear. In the United States, ACLS is usually
l
Corresponding author.
provided by paramedicswho treat patients according to protocols or after consulting with an emergency physician. In many European cities [5-71, physicians provide ACLS. Emergency medicine is not a recognisedspeciality in several countries, including Finland. The physicians in the prehospital emergency care unit in Helsinki have acquired their knowledge by working exclusively in the prehospital environment after initial education by an experiencedphysician. This paper tries to evaluate the role of the experience of the on-site physician in the EMS in Helsinki, using the Utstein template [8] for reporting on prehospital cardiac arrest as an indicator.
0300-9572/96/$15.00 0 1996 Elsevier Science Ireland Ltd. All rights reserved SSDI
0300-9572(95)00915-G
-..--
102
T. Sirfast.
A. Ekstrand/ Resuscitation 31 (19%) 101-105
2. Pdients and methods The EMS system in Helsinki, a city of 510 000 inhabitants, is a multitiered systemoperated by the rescuedepartment and administered by the health department [9]. The first tier consists of firemenemergency medical technicians (EMT-D) trained to use semiautomateddefibrillators. They respond either in ambulancesor tire engines.An intermediate paramedic tier consists of two units manned with specially trained EMTs capable of orotracheal intubation and intravenous medication. Becausetheseunits are not selectively used as ACLS units but respond to all calls within their operating area, they are often occupied and not systematically available. The ACLS tier consists of one prehospital emergency care unit (PECU), staffed with a physician and two EMT-Ds at all times. The EMS is activated via the national emergencyphone number ‘ 112’,which connects all calls for emergencycare in the city to the regional alarm center. Specially trained alarm personnel evaluate the calls and dispatch the closest first responding unit and the PECU in suspected life threatening emergencies. Annually, the EMS responds to roughly 30 000 urgent calls, lO?/ of which also involve the PECU. During the 198Os,the EMS system in Helsinki went through a series of major developments. Theseincluded the education of the dispatchers to use criteria based computer&d dispatch and unit tracing, the training of the EMTs to use semiautomated defibrillators, and the use of a tiered response including tire engines as first responding units. As a result, survival figures from prehospital cardiac arrest in Helsinki are comparable to those from other major EMS [lO,l 11. In cardiac arrest, the EMT-Ds of the first responding unit determine the patients initial cardiac rhythm and initiate defibrillation and basic life support (BLS) until the PECU arrives. BLS is not started if the patient has developed postmortem lividity or rigor mortis, or if the body is severely mutilated by trauma. Based on the clinical situation, the PECU physician decideswhether to continue resuscitation and start ACLS, or discontinue BLS and proclaim the patient dead. If the patient
fails to regain spontaneous circulation on the scene during ACLS efforts, resuscitation is considered unsuccessful.These patients are proclaimed dead and transported to the forensic department by a different system.Successfulresuscitation is defined as restoration of a stable circulation in the field, and the patient is then transported to hospital. Survival is defined as discharge home from hospital. During the first part of this study, there were five full time physicians (medical director and four other doctors) in the EMS sharing all calls in the PECU. Their mean duration of experience of prehospital work was 6 years. The turnover of physicians was less than one annually. As these posts were unique in our country, no formal competence requirements existed, but the medical director required a new physician to have experiencefrom internal medicine and anaesthesia. The work in the EMS was reorganised at the end of July in 1992.The prehospital posts in the PECU were integrated into the city hospital and a simultaneous change of all physicians took place. From having been exclusively engaged with prehospital care, the physicians became hospital based and were on call in the PECU together with their hospital work. Thus, the proportion of time spent by an individual in the EMS was reduced to less than 50% of their total working time. The number of physicians sharing the calls in the PECU was increasedby one. Of the new physicians, one was an anaesthesist,two were residents in anaesthesiaand the remaining three were residents in general surgery. None had previously worked in prehospital or emergency medicine. There was no on-site introduction to field work before starting in the PECU. All other factors and personnel in the EMS, i.e. the dispatch procedures, the number and location of different responding units, the EMTDs and early defibrillation protocols remained unchanged, therefore the new setting provided a unique opportunity to study whether a sudden change within the ACLS link in the chain of survival in our EMS affected survival from prehospital cardiac arrest. Data were retro- and prospectively collected from the trip sheetsof all patients in cardiac arrest seen by the PECU. The study period was 12
103
T. Siljvast. A. Ekstrand/ Resuscitation 31 (19%) JOJ-JOS
months before (Period I, 1 August 1991to 31 July 1992,retrorpective) and after (Period II, 1 August 1992to 31 July 1993, prospective) the reorganisation. Collected data inchtded age and sex of patients, condition of arrest (witnessed or not, obvious cause of arrest), time interval from the beginning of the emergency phone call to the arrival at the sceneof the first responding unit and the PECU, initial cardiac rhythm, and outcome from rcswcitation. Due to differences in completing the trip sheets during the two periods, it was not possible to collect data on presence of bystander initiated CPR, time of the first defibrillatory shock, intubation and return of spontaneouscirculation during Period II and these were omitted from analysis. Data are reported according to the Utstein template [8]. Those patients who were discharged to their homes (not to another facility) from hospital were defined as survivors. Further follow-up of the patients condition after discharge was not possible. Statistical analyses inchrde the Student’s r-test for nonparametric data and F&hers exact test for parametric data.
1
CONFIRMED CONSIDERED
pr
!?A
444
395
RESUSCITATION
ATTEMPTED
279
323
COLLAPSE
I
FIBRILLATION
120
1
I I
257
VENTRICULAR
ADMITTED
f
WITNESSED
202
3. Remits The PECU was dispatched to 839 cardiac arrest patients in Helsinki during the two study periods, 444 patients during Period I and 395 patients during Period II (Fig. 1). ACLS was initiated in 279 patients (63%) during Period I and in 323 patients (82%) during Period II (P < 0.001). Resuscitation was successfitlin 120patients (43%) during Period I and in 131patients (46%) during Period II. Of all cardiac arrest patients in whom ACLS was initiated, 50 patients ( 18%)survived to be discharged home from hospital during Period I, compared to 37 patients (11%) during Period II (P < 0.05). The arrest was witnessed,the presumed causeof arrest cardiac and the initial cardiac rhythm ventricular fibrillation (VF) in 120 patients during Period I and in 130 patients during Period II. The mean age of these patients was 64 and 68 years, respectively(NS). The mean time interval from the beginning of the phone call to the arrival of the first responding unit was 5.4 min during Period I and 6.5 min during Period II (NS). The corresponding time intervals for ACLS were 11.O and 11.7
CARDIAC ARRESTS FOR RESUSCITATION
130
TO HOSPITAL
70
79
DISCti;RGED
;I3;ME
1
Fig. 1. Outcome from prehospital cardiac amst according to the Utstein template during the two study periods (P I period I; P II, period II).
min (NS). Resuscitation was successful in 70 of thesepatients with VF during Period I and 79 patients during Period II @IS). Twenty nine of these successfully resuscitated patients either died in hospital or were institutionalised, while 41 patients (34% of the patients with witnessed VF) were discharged home during Period I. The correspon-
104
T. Si&ut. A. Ekstrand/Restucitation 31 (1996) 101-105
ding figures during Period II were 46 (P < 0.05) and 33 patients (25%, NS). Outcome from witnessed cardiac arrest due to VF was also compared in three 4-month intervals during Period I and Period II, i.e. AugustNovember, December-March and April-July. The proportions of patients in whom ACLS was initiated and who were admitted to hospital or discharged home were similar during these pXiOdS.
4. Discussion Earlier studies have shown that survival from prehospital cardiac arrest is influenced by the time intervals from the beginning of the event to the commencementof various interventions. The effects of bystander initiated CPR [1,2], early defibrillation [3,12] and ACLS [10,11,13] have been documented. In this study, the ‘quality’ of ACLS was the only link in the chain of survival that may have been affectedby the changeof physicians, as all other parameters remained unchanged during the two periods. Our findings suggest that the experience of the on-site physician has only a small impact on survival from prehospital cardiac arrest in our EMS. There are three possible explanations for this. The number of patients may have been too small to show more significant differences, or then there are no major differences to be detected. The isolated effect of variations within one link may be concealedby the multitude of factors affecting survival. The third possibility is that ACLS may play a relatively unimportant role in eventual survival when compared to BLS and defibrillation. Therefore, who provides the ACLS is immaterial. Our study showed no difference in the rate of successfulresuscitation from witnessed VF during the two periods. This was not surprising, as previous papers have reported that a considerable number of patients regain spontaneous circulation, and ultimately survive, after initial defibrillations and BLS only [ 14,151.Theseparameterswere not affected in our system. However, the noted slight difference in survival from prehospital cardiac arrest due to all etiologies, and the difference in the proportion of patients dying in hospital or
requiting institutionalisation after successful resuscitation from witnessed VF suggests that the ACLS link and the phase immediately after circulation is restored before admission to hospital after all are of importance. Objective data on the management of the patients during this phase during the two study periods cannot be obtained from the trip sheets, but different treatment modalities probably have existed. This assumption is supported by a recent paper studying the performance of emergencyphysicians and the timing of their interventions on the scene,documenting remarkable variations in the time spent for these procedures
WI. Previous experience,such as that of the London Ambulance Service computerisation [ 171, demonstratesthat it may not be wise to make sudden changes in EMS systems without thorough education and overlapping periods. In this respect, it was interesting to find that the outcome of the patients remained unchanged during the three consequetive4-month periods in P II. Thus the noted differences between Periods I and II cannot solely be ascribed the lack of introduction to the work during the intitial months of Period II. A possible explanation could be the lack of sufficient experiencewith prehospital patients. A reflection of this was the significantly greater proportion of patients (82% vs. 63%) in whom resuscitation was initiated during Period II, without a concomitant increase in the number of survivors. Futile resuscitational efforts occupy limited ACLS capacity and may prolong responsetimes to other calls. During P I, the physicians worked exclusively with prehospital care. After the reorganisation, the physicians were mainly engaged in hospital duties not associated with emergencymedicine, leaving the work in the EMS to less than half of the total working time. Our findings support the concept that early defibrillation plays an important role in the treatment of patients with prehospital cardiac arrest [18]. If the other links in the chain of survival are performed well, variation within the ACLS link, in this casethe experienceof the ACLS provider, are less important. The issue is closely related to the question of the basic education of the ACLS provider, as recently discussedby Dick [19], but we agreewith the data provided by Cummins et al. [4]
T. Siljvast, A. Ekstrand/ Resuscitation31 (1996) 101-105
which indicates that trimming all links to optimal performance in the chain of survival ensures the best possibility of survival. 5. References Ill Ritter Cl, Wolfe RA, Goldstein S et al. The effect of bystander CPR on survival of out-of-hospital cardiac arrest victims. Am Heart J 1985; 110: 932-937. PI Wik L, Steen PA, Bircher NG. Quality of bystander cardiopulmonary resuscitation influences outcome after prehospital cardiac arrest. Resuscitation 1994;28: 195-203. [31 Eisenberg MS, Copass MK, Hallstrom AP et al. Treatment of out-of-hospital cardiac arrest with rapid dedbrillation by emergency medical technicians. N Engl J bled 1980;302: 1379-1383. 141 Cummins RO, Omato JP, Thies WH et al. Improving survival from sudden cardiac arrest: the ‘chain of survival’ concept. Circulation 1991;83: 1832-1847. Pl Mob P, Beaucame E, Bruininx J et al. Early deftbrillation by EMTs: the Brussels experience. Resuscitation 1994;27: 129-136. I61 Kimman GP, lvens EMA, Hartman JAM et al. Longterm survival after successfulout-of-hospital resuscitation. Resuscitation 1994,28: 227-232. [71 Einanson 0, Jakobsson F, SigurdssonG. Advanced cardiac life support in the prehospital setting: the Reykjavik experience. J Intern Med 1989;225: 129-135. PI Cummins RO, Chamberlain DA et al. Recommended guidelines for uniform reporting of data from out-ofhospital cardiac arrest: the Utstein style. Circulation 1991;84: 960-975. 191 Silfvast T. Prehospital resuscitation in Helsinki, Finland, Am J Emerg Med 1990;8: 359-364. [lOI Eisenberg MS, Hallstrom AP, Copass MK et al. Treatment of ventricular fibrillation: Emergency medical
\!.I’
technician defibrillation and paramedic services. J Am Med Assoc 1984;251: 1723-1726. 1111Weaver WD, Cobb LA, Fahrenbruch CE et al. Use of the automatic external defibrillator in the management of out-of-hospital cardiac arrest. N Engl J Med 1988:319: 661-666. WI Stults KR, Brown DD, Schug VI et al. Prehospital defibrillation performed by emergency medical technicians in rural communities. N Engl J Med 1984: 3 IO: 219-223. 1131 Eisenberg MS, Bergner L, Hallstrom A. Paramedic programs and out-of-hospital cardiac arrest: 1. Factors associatedwith successfulresuscitation. AJPH 1979:69. 30-38. 1141 Cummins RO, Graves JR, Horan S et al. The relative contributions of early defibrillation and ACLS interventions to resuscitation and survival from prehospital cardiac arrest [abstract]. Ann Emerg Med 1989; 18. 468-469. II51 Callaham M, Madsen CD, Barton CW et al. A randomixed clinical trial of high-dose epinephrine and norepinephrine vs. standard dose epinephrine in prehospital cardiac arrest. J Am Med Assoc 1992: 26X. 2667-2672. 1161SchneiderT, Mauer M, Diehl P et al. Quality of on-site performancein prehospital advancedcardiac life suppor: (ACLS). Resucitation 1994,27: 207-213. I171 Kingman S. London ambulance chaos due to risky computer system. Br Med J 1993;306: 603. 1181Auble TE, Menegaxzi JJ, Paris PM. Effect of out-ofhospital defibrillation by basic life support providers on cardiac arrest mortality: a metaanalysis. Ann Emerg Med 1995;25: 642-648. 1191 Dick WF. Does prehospital care by physicians result in a better outcome than resuscitation by other EMS personnel? [editorial]. Resuscitation 1993: 26: IO+-! IO.