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Professional bystander CPR in prehospital coarse ventricular fibrillation
ABSTRACTS
We studied the effects of carbon dioxide, lidoflazine, and deferoxamine on the 10-day survival rate and subsequent neurologic function of rats initially resuscitated from 7 rain of cardiorespiratory arrest. Cardiac arrest was induced by injection of cold 1% KC1 into the left ventricles of ketamine-anesthetized rats pretreated with succinyl choline and positive pressure ventilation discontinued at time zero. CPR was begun at 7 min, and animals with return of Spontaneous circulation entered the study. Treated rats (20) were ventilated for 1 h with 7% CO2 and 93% Oz, and were given lidoflazine (2.0 mg/kg IV) and deferoxamine (50 mg/kg IV) 5 min after cardiac resuscitation. Control rats (20) were ventilated for 1 h with 100% Oz and given lidoflazine vehicle and def e r o x a m i n e vehicle. Lidoflazine t r e a t m e n t (1.0 mg/kg), or lidoflazine vehicle for control rats, was repeated at 8 h. At 2 days, 75% of treated rats and 25% of control rats were alive (chi square = 10.0; df = 1; P < .01). At 10 days, 60% of treated rats and 25% of control rats were alive (chi square = 5.01; df = 1; P < .05). There was no detectable neurologic deficit among survivors in either group at 15 days. Although administered after return of spontaneous circulation, the c o m b i n a t i o n of carbon dioxide, lidoflazine, and deferoxamine can nonetheless improve the probability of neurologically intact survival in this a n i m a l model of cardiorespiratory arrest and CPR.
5
Protective Head Cooling During Cardiac Arrest in Dogs
E Brader, D Jehle, P Safar / Division of Emergency Medicine, Allegheny General Hospital; Resuscitation Research Center, Pittsburgh
Prolonged external CPR cannot reliably sustain brain viability during cardiac arrest (CA). A need exists for adjuncts to CPR that are applicable in the field. Preliminary dog studies have suggested that surface cooling during CA and CPR can, within 10 rain, achieve protective levels of brain h y p o t h e r m i a (30 C). Vasoconstriction induced by profound hypothermia of extracranial vasculature could redirect CPR-generated blood flow from face to brain. Cooling of the head (in comparison to systemic surface cooling) would m i n i m i z e afterdrop and increase convenience. Head cooling could thereby be initiated by laymen in the field. Twelve dogs under light ketamine-halothane-nitrous oxide endotracheal anesthesia were arrested by transthoracie fibrillation. The treated group consisted of 6 dogs whose shaven heads were moistened with saline and packed in ice. Six control clogs remained at room temperature. All 12 dogs were subjected tO 4 rain ventricular fibrillation followed by 20 min standard CPR. Spontaneous circulation was restored with drugs and countershocks. Intensive care was provided for 5 postarrest. Dogs were then returned to their cages and observed for 24 h. In both the headcooled and control groups, 5 of 6 dogs had spontaneous circulation restored. At the end of 20 rain of CPR, mean core temperature dropped to 36.3 C in the head-cooled group and 36.9 C in the control group (P < .05). After 1 rain of spontaneous circulation, mean core temperature dropped to 34.9 C in the headcooled dogs and 36.5 C in control dogs (P < .001). After 3 h, mean neurological deficit (ND = 100% = brain death; 0% = normal) averaged 37% in head-cooled dogs and 62% in control dogs (P < .02). Two of 6 dogs in the head-cooled group survived 24 h with neurological deficits of 0% and 9%, respectively. None of the control dogs survived 24 h. Head cooling for brain protection during prolonged CPR appears promising and deserves further investigation. Afterdrop was noted in head-cooled dogs, but was not of sufficient magnitude that cardiac resuscitation was affected.
6
Factors in Sudden Cardiac Death Decision Making
C Aprahamian, JC Darin, BM Thompson, JR Mateer, JF Tucker, HA Stueven / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee
Decision making relative to initiating prehospital emergency 190/510
cardiac care (ECC) or its termination remains a confusing problem. We reviewed our series of 445 consecutive nontraumatic sudden cardiac deaths seen by paramedics in a tiered urban EMS system and report our experience. ECC was initiated in 319 (70%) and not in 126 (Group A). Eighty-seven patients (Group D) were admitted to the ED w i t h a palpable pulse and an organized rhythm. In the remaining 232, ECC was terminated by paramedics in 131 (Group B) and continued in the remaining 101 (Group C). Thirty-two patients were discharged alive (Group E). An initial rhythm of asystole, unwitnessed arrest, absence of bystander/first responder CPR, onset times greater than 15 minutes, and final ECG rhythms were evaluated for each group. The table summarizes the results.
Group N A 126 B 131 C 101 D 87 E 32
> 15 Final Final Final Initial Unwit. Absence Min Rhythm Rhythm Rhythm Asystole Arrest CPR Onset Asystole EMD Organized 126 118 85 119 126 0 0 59 55 28 43 98 32 0 21 36 24 17 34 57 0 17 35 31 7 0 0 32 0 15 16 3 0 0 32
No patients presenting with asystole or whose final rhythm was asystole survived. The probability of surx;ival in unwitnessed arrest and/or absence of CPR and/or onset greater than 15 minutes was evaluated in the ECC-treated patients. Survival was poorest in the combination of all three (P = .001). The increased onset time alone (P = .025) or a combination of any of the three factors also was critical (P = .01). We conclude that any patient presenting with asystole and any of the 3 factors need not have ECC initiated. Our data also suggest that once treatment has been initiated, it can be terminated after the rhythm has deteriorated into asystole, especially in patients who have an unwitnessed arrest or where there is absence of CPR and whose onset time is greater than 15 minutes.
7
Bystander/First Responder CPR: Ten-Year Experience in a Paramedic System
HA Stueven, P Troiano, B Thompson, JR Mateer, EH Kastenson, D Tonsfeldt, K Hargarten, R Kowalski, C Aprahamian, J Darin / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee; Department of Emergency Medicine, William Beaumont Hospital, Royal Oak, Michigan
The effectiveness of bystander CPR recently has been challenged. We undertook a 10-year retrospective review of Our prehospital experience with witnessed cardiorespiratory arrest to ascertain save rates in patients receiving and not receiving CPR before paramedic ALS. Traumatic and poisoning arrests and children less than 18 years old were excluded. A total of 1905 patients who presented to a paramedic system from 11/01/73 to 10/31/83 were bystander-witnessed arrests and attempted paramedic resuscitations. Four-hundred-five paramedic-witnessed arrests were excluded. One-hundred-eighty-two of 1,248 (14.6%) who had CPR initiated before paramedic ALS arrival were saves, as compared to 38 of 252 (15%) who had no CPR initiated until paramedic arrival (P = NS). A save was defined as a patient discharged from the hospital. The respective save rates for coarse ventricular fibrillation were 148 of 628 (23.6%) vs 35 of 151 (23.2%); EMD, 11 of 209 (5.3%) vs 0 of 38; asystole, 19 of 401 (4.7%) vs 3 of 61 (4.9%); and ventricular tachycardia, 4 of 10 (40%) vs 0 of 2. In this prehospital system, bystander/first responder CPR is found not to improve hospital discharge rate.
8
Professional Bystander CPR in Prehospital Coarse Ventricular Fibrillation
RF Kowalski, BM Thompson, HA Stueven, C Aprahamian,
Annals of EmergencyMedicine
14:5 May 1985
JC Darin / Department of Emergency Medicine, William Beaumont Hospital, Royal Oak, Michigan; Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee Recent studies suggest that medical professionals may perform better external CPR than do nonprofessional citizens. Professional bystander CPR performed by two distinct groups was studied retrospectively, first with fire department first-responder basic EMTs and then with physicians, nurses, and other EMTs. These groups were compared independently to groups of patients receiving either citizen bystander CPR or no bystander CPR. Four hundred twenty-one consecutive witnessed cardiopulmonary arrests presenting with the initial rhythm of coarse ventricular fibrillation treated by a regional paramedic system from January 1980 to June 1982 were analyzed. Pediatric, trauma, and poisoning patients and those receiving IV or endotracheal medications prior to initial defibrillations were excluded (58). A successful defibrillation occurred if defibrillation prior to administration of medications produced an effective cardiac rhythm with pulses. Response time is defined as the difference between the time of call to arrival of the paramedic unit. There was no significant difference in response time, successful defibrillation rate, successful resuscitation rate {transport to the hospital with a pulsatile rhythm), and save rate (discharge alive from the hospital) when comparing bystander CPR done by physician, nurse, and other EMT to citizen bystander CPR and no bystander CPR. There was also no significant difference between fire department first-responder bystander CPR and citizen bystander CPR. Patients receiving fire department first-responder bystander CPR had a significantly faster response time (5.0 min vs 6.3 min, P < .025) and a significantly better successful defibrillation rate (38% [12/32] vs 22% [47/219], P < .025) than did patients receiving no bystander CPR. Patients receiving bystander CPR performed by physicians, nurses, and other EMTs do not have better clinical results than do patients receiving citizen bystander CPR or no bystander CPR. Patients receiving bystander CPR performed by fire department first responders were more likely to have a pulse after initial defibrillations when compared to patients receiving no bystander CPR, but a faster response time may be a factor in the better clinical results.
9
Enhancing Survival After Cardiac Arrest m The Effect of Initial Rhythm and a New Strategy in Emergency Care
WD Weaver, LA Cobb, MK Copass, AP Hallstrom, M Emery / Coronary Care Unit and Division of Cardiology, Harborview Medical Center, Seattle Survival rates for out-of-hospital cardiac arrest and ventricular fibrillation (VF) have averaged 26% over the first 12 years of operation of our tiered-response EMS. However, when asystole or electromechanical dissociation have been initially recorded, outcome has been poor in spite of prehospital care. In a 7-year period, 1,522 patients with asystolic arrest were treated; of these, 75 (5%) were associated with trauma. Only 220 (14%) were resuscitated and admitted to a hospital; 18 (1%) survived. Likewise, in a 5-year survey, 15 (6%) of 247 patients discovered with electromechanical dissociation (rhythm but no pulse or pressure) survived. In this latter group, survival was similar whether the initial rhythm was thought to be supraventricular or ventricular in origin; only 1 of 26 patients found in high-degree AV block and no pulse survived. We assessed the influence of clinical history and logistics on survival in 285 patients discovered in VE Using a multivariate logistic regression analysis to assess the importance of each factor, only delay from collapse until initiation of chest compressions (P < .02) and the duration of CPR before delivery of the first shock (P < .01) significantly influenced outcome. For all cases of cardiac arrest and VF treated from 1978-1982, there was a linear relationship between survival and the response time of paramedics. Survival decreased by 3% for each minute required to respond (probability of survival = 0.4043 i 0:0258 response time 14:5 May 1985
of paramedics). We have predicted that adding 20 strategically placed automatic defibrillators for use by the first tier of responding firefighters could shorten the time from collapse to defibrillation from an average of 12 minutes to 8 minutes and, by doing so, significantly improve the survival rate for witnessed cases of cardiac arrest and VE
0
Prophylactic Lidocaine in the Prehospital Patient with Chest Pain of Suspected Cardiac Origin
KM Hargarten, C Aprahamian, HA Stueven, BM Thompson, JR Mateer, J Darin / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee The prophylactic use of lidocaine in the patient with cardiac chest pain has been found by many investigators to reduce the incidence of sudden death from ventricular dysrhythmias in the hospital setting, but few studies have been done in the early prehospital phase. A randomized prospective study comparing the effects of lidocaine vs no lidocaine in patients presenting with chest pain to a paramedic system was conducted to determine the overall mortality, incidence of sudden death (due to ventricular dysrhythmias), and morbidity. Patient foflow-up was obtained and final diagnosis was determined by autopsy, EGG, and/ or serum enzyme analysis. In a 1-year period, 446 patients qualified for the study. Of the 222 patients given lidocaine, 5 had sudden death due to ventricular dysrhythmias in the prehospital and ED setting. Of the 224 patients not receiving lidocaine, 4 developed sudden death in the same setting (P < .494). The overall hospital mortality of the 2 groups was 8.1% and 6.7%, respectively (P < .349). Of those ultimately diagnosed as having sustained an acute myocardial infarction, 4 of 68 of the lidocaine group developed sudden death (14.7% overall hospital mortality), compared to 4 of 61 in the no-lidocaine group, with an overall hospital mortality rate of 13.1% (P =NS). The development of hypotension, significant dysrhythmias (frequent PVCs; VT; bradycardia; 2,3 ° heart blocks) after initiation into the study was compared in both groups of patients. There was no significant difference. We conclude that in the prehospital setting, for patients presenting with chest pain of suspected cardiac origin, prophylactic lidocaine has not been shown to be beneficial in preventing sudden death or life-threatening dysrhythmias.
1
Prehospital Use of Isoproterenol for Complete Heart Block
EH Kastenson, HA Stueven, D Tonsfeldt, B Thompson, J Darin / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee lsoproterenol has been recommended by the American Heart Association for "immediate control of hemodynamically significant and atropine refractory bradycardia due to heart block." Concern has been raised that isoproterenol may lower the blood pressure in bradycardia associated with hypotension. A retrospective analysis of the prehospital use of isoproterenol for atropine refractory complete heart block and hypotension (systolic BP less than 90) for a 4-year period revealed 25 cases. Twelve of the 25 improved and 6 worsened (P = NS). Nine of 25 (36%) showed a mean increase in blood pressure after isoprotereno] from 71 to 101 m m Hg systolic. Three patients had a pulse and no pressure preisoproterenol, and a postisoproterenol average mean increase from 0 to 126 m m Hg. Seven of 25 (28%) showed no significant change in pressure. Three of 25 (12%) developed a drop in blood pressure. Three of 25 (12%) sustained cardiorespiratory arrest and were not resuscitated. Isoproterenol m a y be of benefit in improving blood pressure in a selective group of hypotensive complete heart block patients; however, a subset may worsen with its use.
Annals of Emergency Medicine
511/191
We studied the effects of carbon dioxide, lidoflazine, and deferoxamine on the 10-day survival rate and subsequent neurologic function of rats initially resuscitated from 7 rain of cardiorespiratory arrest. Cardiac arrest was induced by injection of cold 1% KC1 into the left ventricles of ketamine-anesthetized rats pretreated with succinyl choline and positive pressure ventilation discontinued at time zero. CPR was begun at 7 min, and animals with return of Spontaneous circulation entered the study. Treated rats (20) were ventilated for 1 h with 7% CO2 and 93% Oz, and were given lidoflazine (2.0 mg/kg IV) and deferoxamine (50 mg/kg IV) 5 min after cardiac resuscitation. Control rats (20) were ventilated for 1 h with 100% Oz and given lidoflazine vehicle and def e r o x a m i n e vehicle. Lidoflazine t r e a t m e n t (1.0 mg/kg), or lidoflazine vehicle for control rats, was repeated at 8 h. At 2 days, 75% of treated rats and 25% of control rats were alive (chi square = 10.0; df = 1; P < .01). At 10 days, 60% of treated rats and 25% of control rats were alive (chi square = 5.01; df = 1; P < .05). There was no detectable neurologic deficit among survivors in either group at 15 days. Although administered after return of spontaneous circulation, the c o m b i n a t i o n of carbon dioxide, lidoflazine, and deferoxamine can nonetheless improve the probability of neurologically intact survival in this a n i m a l model of cardiorespiratory arrest and CPR.
5
Protective Head Cooling During Cardiac Arrest in Dogs
E Brader, D Jehle, P Safar / Division of Emergency Medicine, Allegheny General Hospital; Resuscitation Research Center, Pittsburgh
Prolonged external CPR cannot reliably sustain brain viability during cardiac arrest (CA). A need exists for adjuncts to CPR that are applicable in the field. Preliminary dog studies have suggested that surface cooling during CA and CPR can, within 10 rain, achieve protective levels of brain h y p o t h e r m i a (30 C). Vasoconstriction induced by profound hypothermia of extracranial vasculature could redirect CPR-generated blood flow from face to brain. Cooling of the head (in comparison to systemic surface cooling) would m i n i m i z e afterdrop and increase convenience. Head cooling could thereby be initiated by laymen in the field. Twelve dogs under light ketamine-halothane-nitrous oxide endotracheal anesthesia were arrested by transthoracie fibrillation. The treated group consisted of 6 dogs whose shaven heads were moistened with saline and packed in ice. Six control clogs remained at room temperature. All 12 dogs were subjected tO 4 rain ventricular fibrillation followed by 20 min standard CPR. Spontaneous circulation was restored with drugs and countershocks. Intensive care was provided for 5 postarrest. Dogs were then returned to their cages and observed for 24 h. In both the headcooled and control groups, 5 of 6 dogs had spontaneous circulation restored. At the end of 20 rain of CPR, mean core temperature dropped to 36.3 C in the head-cooled group and 36.9 C in the control group (P < .05). After 1 rain of spontaneous circulation, mean core temperature dropped to 34.9 C in the headcooled dogs and 36.5 C in control dogs (P < .001). After 3 h, mean neurological deficit (ND = 100% = brain death; 0% = normal) averaged 37% in head-cooled dogs and 62% in control dogs (P < .02). Two of 6 dogs in the head-cooled group survived 24 h with neurological deficits of 0% and 9%, respectively. None of the control dogs survived 24 h. Head cooling for brain protection during prolonged CPR appears promising and deserves further investigation. Afterdrop was noted in head-cooled dogs, but was not of sufficient magnitude that cardiac resuscitation was affected.
6
Factors in Sudden Cardiac Death Decision Making
C Aprahamian, JC Darin, BM Thompson, JR Mateer, JF Tucker, HA Stueven / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee
Decision making relative to initiating prehospital emergency 190/510
cardiac care (ECC) or its termination remains a confusing problem. We reviewed our series of 445 consecutive nontraumatic sudden cardiac deaths seen by paramedics in a tiered urban EMS system and report our experience. ECC was initiated in 319 (70%) and not in 126 (Group A). Eighty-seven patients (Group D) were admitted to the ED w i t h a palpable pulse and an organized rhythm. In the remaining 232, ECC was terminated by paramedics in 131 (Group B) and continued in the remaining 101 (Group C). Thirty-two patients were discharged alive (Group E). An initial rhythm of asystole, unwitnessed arrest, absence of bystander/first responder CPR, onset times greater than 15 minutes, and final ECG rhythms were evaluated for each group. The table summarizes the results.
Group N A 126 B 131 C 101 D 87 E 32
> 15 Final Final Final Initial Unwit. Absence Min Rhythm Rhythm Rhythm Asystole Arrest CPR Onset Asystole EMD Organized 126 118 85 119 126 0 0 59 55 28 43 98 32 0 21 36 24 17 34 57 0 17 35 31 7 0 0 32 0 15 16 3 0 0 32
No patients presenting with asystole or whose final rhythm was asystole survived. The probability of surx;ival in unwitnessed arrest and/or absence of CPR and/or onset greater than 15 minutes was evaluated in the ECC-treated patients. Survival was poorest in the combination of all three (P = .001). The increased onset time alone (P = .025) or a combination of any of the three factors also was critical (P = .01). We conclude that any patient presenting with asystole and any of the 3 factors need not have ECC initiated. Our data also suggest that once treatment has been initiated, it can be terminated after the rhythm has deteriorated into asystole, especially in patients who have an unwitnessed arrest or where there is absence of CPR and whose onset time is greater than 15 minutes.
7
Bystander/First Responder CPR: Ten-Year Experience in a Paramedic System
HA Stueven, P Troiano, B Thompson, JR Mateer, EH Kastenson, D Tonsfeldt, K Hargarten, R Kowalski, C Aprahamian, J Darin / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee; Department of Emergency Medicine, William Beaumont Hospital, Royal Oak, Michigan
The effectiveness of bystander CPR recently has been challenged. We undertook a 10-year retrospective review of Our prehospital experience with witnessed cardiorespiratory arrest to ascertain save rates in patients receiving and not receiving CPR before paramedic ALS. Traumatic and poisoning arrests and children less than 18 years old were excluded. A total of 1905 patients who presented to a paramedic system from 11/01/73 to 10/31/83 were bystander-witnessed arrests and attempted paramedic resuscitations. Four-hundred-five paramedic-witnessed arrests were excluded. One-hundred-eighty-two of 1,248 (14.6%) who had CPR initiated before paramedic ALS arrival were saves, as compared to 38 of 252 (15%) who had no CPR initiated until paramedic arrival (P = NS). A save was defined as a patient discharged from the hospital. The respective save rates for coarse ventricular fibrillation were 148 of 628 (23.6%) vs 35 of 151 (23.2%); EMD, 11 of 209 (5.3%) vs 0 of 38; asystole, 19 of 401 (4.7%) vs 3 of 61 (4.9%); and ventricular tachycardia, 4 of 10 (40%) vs 0 of 2. In this prehospital system, bystander/first responder CPR is found not to improve hospital discharge rate.
8
Professional Bystander CPR in Prehospital Coarse Ventricular Fibrillation
RF Kowalski, BM Thompson, HA Stueven, C Aprahamian,
Annals of EmergencyMedicine
14:5 May 1985
JC Darin / Department of Emergency Medicine, William Beaumont Hospital, Royal Oak, Michigan; Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee Recent studies suggest that medical professionals may perform better external CPR than do nonprofessional citizens. Professional bystander CPR performed by two distinct groups was studied retrospectively, first with fire department first-responder basic EMTs and then with physicians, nurses, and other EMTs. These groups were compared independently to groups of patients receiving either citizen bystander CPR or no bystander CPR. Four hundred twenty-one consecutive witnessed cardiopulmonary arrests presenting with the initial rhythm of coarse ventricular fibrillation treated by a regional paramedic system from January 1980 to June 1982 were analyzed. Pediatric, trauma, and poisoning patients and those receiving IV or endotracheal medications prior to initial defibrillations were excluded (58). A successful defibrillation occurred if defibrillation prior to administration of medications produced an effective cardiac rhythm with pulses. Response time is defined as the difference between the time of call to arrival of the paramedic unit. There was no significant difference in response time, successful defibrillation rate, successful resuscitation rate {transport to the hospital with a pulsatile rhythm), and save rate (discharge alive from the hospital) when comparing bystander CPR done by physician, nurse, and other EMT to citizen bystander CPR and no bystander CPR. There was also no significant difference between fire department first-responder bystander CPR and citizen bystander CPR. Patients receiving fire department first-responder bystander CPR had a significantly faster response time (5.0 min vs 6.3 min, P < .025) and a significantly better successful defibrillation rate (38% [12/32] vs 22% [47/219], P < .025) than did patients receiving no bystander CPR. Patients receiving bystander CPR performed by physicians, nurses, and other EMTs do not have better clinical results than do patients receiving citizen bystander CPR or no bystander CPR. Patients receiving bystander CPR performed by fire department first responders were more likely to have a pulse after initial defibrillations when compared to patients receiving no bystander CPR, but a faster response time may be a factor in the better clinical results.
9
Enhancing Survival After Cardiac Arrest m The Effect of Initial Rhythm and a New Strategy in Emergency Care
WD Weaver, LA Cobb, MK Copass, AP Hallstrom, M Emery / Coronary Care Unit and Division of Cardiology, Harborview Medical Center, Seattle Survival rates for out-of-hospital cardiac arrest and ventricular fibrillation (VF) have averaged 26% over the first 12 years of operation of our tiered-response EMS. However, when asystole or electromechanical dissociation have been initially recorded, outcome has been poor in spite of prehospital care. In a 7-year period, 1,522 patients with asystolic arrest were treated; of these, 75 (5%) were associated with trauma. Only 220 (14%) were resuscitated and admitted to a hospital; 18 (1%) survived. Likewise, in a 5-year survey, 15 (6%) of 247 patients discovered with electromechanical dissociation (rhythm but no pulse or pressure) survived. In this latter group, survival was similar whether the initial rhythm was thought to be supraventricular or ventricular in origin; only 1 of 26 patients found in high-degree AV block and no pulse survived. We assessed the influence of clinical history and logistics on survival in 285 patients discovered in VE Using a multivariate logistic regression analysis to assess the importance of each factor, only delay from collapse until initiation of chest compressions (P < .02) and the duration of CPR before delivery of the first shock (P < .01) significantly influenced outcome. For all cases of cardiac arrest and VF treated from 1978-1982, there was a linear relationship between survival and the response time of paramedics. Survival decreased by 3% for each minute required to respond (probability of survival = 0.4043 i 0:0258 response time 14:5 May 1985
of paramedics). We have predicted that adding 20 strategically placed automatic defibrillators for use by the first tier of responding firefighters could shorten the time from collapse to defibrillation from an average of 12 minutes to 8 minutes and, by doing so, significantly improve the survival rate for witnessed cases of cardiac arrest and VE
0
Prophylactic Lidocaine in the Prehospital Patient with Chest Pain of Suspected Cardiac Origin
KM Hargarten, C Aprahamian, HA Stueven, BM Thompson, JR Mateer, J Darin / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee The prophylactic use of lidocaine in the patient with cardiac chest pain has been found by many investigators to reduce the incidence of sudden death from ventricular dysrhythmias in the hospital setting, but few studies have been done in the early prehospital phase. A randomized prospective study comparing the effects of lidocaine vs no lidocaine in patients presenting with chest pain to a paramedic system was conducted to determine the overall mortality, incidence of sudden death (due to ventricular dysrhythmias), and morbidity. Patient foflow-up was obtained and final diagnosis was determined by autopsy, EGG, and/ or serum enzyme analysis. In a 1-year period, 446 patients qualified for the study. Of the 222 patients given lidocaine, 5 had sudden death due to ventricular dysrhythmias in the prehospital and ED setting. Of the 224 patients not receiving lidocaine, 4 developed sudden death in the same setting (P < .494). The overall hospital mortality of the 2 groups was 8.1% and 6.7%, respectively (P < .349). Of those ultimately diagnosed as having sustained an acute myocardial infarction, 4 of 68 of the lidocaine group developed sudden death (14.7% overall hospital mortality), compared to 4 of 61 in the no-lidocaine group, with an overall hospital mortality rate of 13.1% (P =NS). The development of hypotension, significant dysrhythmias (frequent PVCs; VT; bradycardia; 2,3 ° heart blocks) after initiation into the study was compared in both groups of patients. There was no significant difference. We conclude that in the prehospital setting, for patients presenting with chest pain of suspected cardiac origin, prophylactic lidocaine has not been shown to be beneficial in preventing sudden death or life-threatening dysrhythmias.
1
Prehospital Use of Isoproterenol for Complete Heart Block
EH Kastenson, HA Stueven, D Tonsfeldt, B Thompson, J Darin / Section of Trauma and Emergency Medicine, Medical College of Wisconsin, Milwaukee lsoproterenol has been recommended by the American Heart Association for "immediate control of hemodynamically significant and atropine refractory bradycardia due to heart block." Concern has been raised that isoproterenol may lower the blood pressure in bradycardia associated with hypotension. A retrospective analysis of the prehospital use of isoproterenol for atropine refractory complete heart block and hypotension (systolic BP less than 90) for a 4-year period revealed 25 cases. Twelve of the 25 improved and 6 worsened (P = NS). Nine of 25 (36%) showed a mean increase in blood pressure after isoprotereno] from 71 to 101 m m Hg systolic. Three patients had a pulse and no pressure preisoproterenol, and a postisoproterenol average mean increase from 0 to 126 m m Hg. Seven of 25 (28%) showed no significant change in pressure. Three of 25 (12%) developed a drop in blood pressure. Three of 25 (12%) sustained cardiorespiratory arrest and were not resuscitated. Isoproterenol m a y be of benefit in improving blood pressure in a selective group of hypotensive complete heart block patients; however, a subset may worsen with its use.
Annals of Emergency Medicine
511/191