- Email: [email protected]
The relative contributions of early defibrillation and ACLS interventions to resuscitation and survival from prehospital cardiac arrest
larger infarcts and red cell extravasation, and both processes may be aggravated by restoring blood pressure in the affected vessels.
152 Cerebral Multifocal Hypoperfusion After Cardiac Arrest in Dogs, Mitigated by Hypertension and Hemodilution F Sterz, P Safar, Y Leonov, D Johnson, R Latchaw, S Hecht, K Oku/International Resuscitation Research Center and Department of Radiology, University of Pittsburgh, Pennsylvania Hemodilution plus hypertension plus heparinization after cardiac arrest in dogs improved outcome (Safar 1976). This couldbe the result of a more homogeneous post-cardiac arrest cerebral perfusion. We monitored muhifocal (local) cerebral blood flow (1CBF) with Xe-CT (Wolfson 1988) in a dog model of ventricular fibrillation-cardiac arrest of 10 or 12.5 minutes no flow reperfusion with open-chest CPR or cardiopulmonary bypass (CPB), early defibrillation, and IPPV to six hours, with control of mean arterial pressure, hematocrit, arterial blood gases, and temperature. With normal mean arterial pressure and hematocrit after arrest (14), there was inhomogeneous hyperemia followed by hypoperfusion with multiple foci of trickle flow (0 to 10 mL/100 g/min) and low flow (0 to 20 mL), which were not present before arrest. Immediate postarrest HT (with norepinephrine) over four hours (mean arterial pressure, 150 to 130 m m Hg) (three) resulted in initial homogeneous hyperemia, followed by no trickle flow areas; with subsequent normotension, trickle flow areas appeared. However, additional normovolemic HD to hematocrit of 15% to 20% starting with reperfusion (two) resulted in sustained normalization of 1CBF patterns and normal gCBF values postarrest. At five minutes, all brain areas had flows of more than 40 mL/100 g/min with no trickle or low flow extending to six hours. No hypoperfusion state was noted. Hypertensive hemodilution seems to be able to prevent post-cardiac arrest muhifocal hypoperfusion.
153 Cerebral Ischemia and Reperfusion: Failure of Hyperbaric Oxygen Therapy to Promote Increased Survival or Neurologic Protection RE Rosenthal, J P Smith, GH Marshall, Jr, RF Shesser/Department of Emergency Medicine, The George Washington University Medical Center, Washington, DC Neurologic injury causes significant morbidity and mortality in cardiac arrest survivors. Lipid peroxidation is believed to be a major cause of ongoing neurologic damage occurring after the restoration of spontaneous circulation (ROSC). Breathing 100% 02 after global cerebral ischemia has been shown to increase lipid peroxidation and mortality. Paradoxically, hyperbaric oxygen treatment of cats subjected to circulatory arrest shortens time to EEG recovery and decreases cerebral spinal fluid lactate production. Our study was designed to determine the effect of hyperbaric oxygen on survival and neurologic injury after resuscitation from cardiac arrest. Male Wistar rats (360 to 460 g), anesthetized IP with ketamine (36 mg) and xylazine (0.5 mg), were ventilated with room air after midline tracheotomy. Intracardiae injection of 0.4 mL cold 1% KC1 followed by thoracic compression induced 6.5-minute cardiac arrest. ROSC was accomplished with IACCPR (70 per minute) synchronous with room air ventilation. Room air ventilation (40 per minute) was continued until spontaneous respirations ensued. After extubation (62 + 18 minutes), 40 animals were placed in a small animal hyperbaric chamber and alternately assigned to treatment with hyperbaric oxygen (2 atm absolute [ATA]) or room air control (1 ATA) for 90 minutes. Animal survival was recorded daily with neurologic deficit scores measured in those animals surviving three and ten days. There was no difference in survival between treatment groups (chi-squared) with 11 of 20 (55 %) hyperbaric oxygen-treated rats and ten of 20 (50 %) room air-treated rats surviving ten days. Neurologic deficit scores of survivors similarly showed no significant differences between groups at three days (hyperbaric oxygen = 5.8 +_8.7; room air = 6.9 + 6.6; P = .18) or ten days (hyperbaric oxygen = 2.4 + 3.2; room air = 1.3 + 2.8; P = .34) as measured by the two-sample t test. Hyperbaric oxygen therapy does not appear to promote increased survival or neurologic protection after cardiac arrest and survival using this experimental model for global cerebral ischemia.
154 A Dose-Response Study of an Experimental Iron Chelator for Inhibition of DNA Damage by Oxygen Radicals 188/468
BC White, DM Feldman, LI Grcssman/Section of Emergency Medicine, Department of Surgery, and Department of Molecular Biology and Genetics and Center for Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan Iron-catalyzed free radical-induced D N A damage may contribute to disorganization of brain cell nuclei during reperfusion after cardiac arrest. Partial support for this scheme is provided by the previous demonstration that the iron chelator deferoxamine inhibits reperfusion membrane injury; however, it does not appear to enter cells in adequate quantities to prevent nuclear damage. Therefore, our study was undertaken to examine iron-mediated oxygen radical D N A damage as well-as to characterize the doseresponse for D N A protection by an experimental iron chelator (1ethyl-2-methyl-3-hydroxypyrid-4-one; EMHP), whose chemical properties suggest improved penetration both of cell membranes and of the blood-brain barrier. Supercoiled closed circular DNA provides a sensitive detection system for strand breaks. One break in either strand uncoils the DNA, giving a nicked circle form that migrates more slowly on gel electrophoresis. We used a small plasmid D N A (pBS; 2,700 bp) to study hydroxyl radical damage, pB8 D N A (200 ng) was exposed to the normal intracellular concentration of H~O 2 (30 micromolar) and various ferrous iron concentrations at pH 7.5. After 15 minutes in 1 m M Fe 2+, there is extensive degradation; little damage occurs at 50 nM Fe ~÷.At the low molecular weight iron concentration (0.4 mM) seen in the brain by two hours of reperfusion after a i 5-minute cardiac arrest, all the pBS is converted to nicked circles by 15 minutes at 37 C and is completely fragmented by four hours. EMHP has a molecular weight of 162 and a partition coefficient of 0.5 between n-octanol and water. The chelator coordinates at three sites on iron, and all three sites must be filled to render the transition metal inactive in redox reactions. The EMHP to Fe ratio was varied from 0:1 to 32:1 in reactions conducted with 200 ng pBS at 37 C, pH 7.5 in 0.4 m M Fe 2÷and 30 micromolar H20~. After 30 minutes and four hours of incubation, the pBS was subjected to electrophoresis. Lower (4:1 and 8:1) concentrations of EMHP showed some protective effect after 30 minutes. However, marked damage was evident by four hours. Higher (16:1 and 32:1) concentrations of EMHP protected completely at 30 minutes. At four hours, a trace of damage was still visible at 16:1, but complete protection was achieved by the 32:i dose. However, in no case did the damage seen at the lower ratios of EMHP exceed the damage in its complete absence. EMHP has potentially superior properties for crossing the blood-brain barrier. We have shown that EMHP is effective in preventing in vitro D N A damage in an assay that detects the break of one sugar-phosphate bond in 5,400.
155 The Relative Contributions of Early Defibrillation ~ind ACLS Interventions to Resuscitation and Survival From Prehospital Cardiac Arrest RO Cummins, JR Graves, SHoran, MP Larsen, K Crump/ Department of Medicine, University of Washington; Center for Evaluation of Emergency Medical Services, King County, Washington, Division of Emergency Medical Services; School of Medicine, University of Washington, Seattle We analyzed the arrest records of 828 consecutive people resuscitated from prehospital cardiac arrest from 1981 through 1987 to determine the relative contributions of defibrillation and the additional advanced cardiac life support (ACLS) interventions of endotracheal intubation and IV pharmacology to resuscitation and long-term survival. In our two-tiered EMS system (EMT-D plus paramedics), we defined two groups: patients who regained a sustained perfusing rhythm for more than six hours under the care of EMTs trained to defibrillate (EMT-D Resus) and those who regained a sustained perfusing rhythm under the care of paramedics (Medic Resus). Four hundred fifty-one of the resuscitations (54%) were long~term survivors. Most resuscitations (583, 7 0 % ) w e r e initially in ventricular fibrillation, and most long-term survivors were in ventricular fibrillation (361, 80%). EMT-Ds, on the arrest scene an average of 5.5 minutes Before arrival of the paramedics, were able to achieve 27% (99) of all ventricular fibrillation survivors, 22% (99) of all long-term survivors, and 15% (124) of all resuscitations. Long-term survival was significantly better (P < .01) in the EMT-D Resus group (79%, with 4% to nursing homes), compared with the Medic Resus group (50%, with 8% to nursing homes). Our data reconfirm that early arrival of defibrillation alone can improve survival rates for prehospital cardiac arrest. The data suggest, however, limitations to early defibrillation programs that operate without close ACLS backup. The additional interventions
Annals of Emergency Medicine
18:4 April 1989
of early intubation and IV pharmacology are required to achieve maximum prehospital survival.
156 EMT-D Survivors: The Contribution of Defibrillation D Fark, J LaRochelle, DW Olson, G Hendley, TP Aufderheide, HA Stueven/Department of Emergency Medicine, Milwaukee County Medical Complex, Medical College of Wisconsin, Milwaukee Emergency medical technician-defibrillator (EMT-D) programs have improved survival from prehospital cardiac arrest in many settings. However, the countershocks delivered by EMT-Ds do not appear to contribute to the resuscitation of all survivors. In Wisconsin, 64 rural and subUrban manual EMT-D services forward reports for medical review. The contribution of defibrillation in the first 44 survivors is reported. The arrest rhythm was ventricular fibrillation in 42 survivors (95%) and electromechanical dissociation in two 15%). Forty-one ventricular fibrillation patients received countershocks and were divided into two groups. Group 1, 29 patients (66%), achieved a perfusing rhythm that persisted to provision of advanced life support (ALS). Their final countershock was delivered 8.9 + 5.5 minutes before ALS. Group 2, 12 patients (27%)) remained in full arrest at the time of ALS, though eight had earlier regained at least transient perfusing or electromechanical dissociation rhythms. Overall, 31 patients returned to a prearrest neurologic state/70%) including 21 from group ! (72%) and seven from group 2 (58%, P = N8). Within group 1, the patients who returned to a prearrest neurologic state had a significantly shorter time from arrest to perfusing rhythm than those who deteriorated (8.9 + 3.6 versus 17.8 + 8.6 minutes, P < .002). In our review, defibrillation by EMT-Ds clearly contributed to resuscitation from prehospital cardiac arrest in 29 of 44 survivors {66%, group 1) by restoring a perfusing rhythm before ALS provision.
157 Prehospital Transcutaneous Cardiac Pacing Phase II JR Hedges, S Feero, R Easter, B Shultz, SA Syverud, WC Dalsey/ Oregon Health Sciences University, Portland; Thurston County Medic One, Olympia, Washington; UniversitYof Cincinnati; Witford Hall Medical Center, Lackiand AFB, San Antonio, Texas Controlled outcome studies of prehospital transcutaneous cardiac pacing (PACE) have suggested that early administration of pacing is needed to improve survival. We performed a prospective study of PACE available on a daily basis with comparison to a historical control population of patients from the same EMS system with PACE available only on an alternate-day basis. We hypothesized that daily availability would shorten the time from cardiac decompensation until PACE and subsequently improve survival. Estimated survival probabilities were calculated from logistic regression models of survivai to hospital admission and survival to hospital discharge based on historical control population characteristics {144 witnessed arrests}. Comparison of actual to expected survival was made with a Z test. Other dichotomous variables were compared with chi-square analysis. Continuous variables were compared with an unpaired t test. A significance level of P < .05 was used throughout. During the four-month study period, 25 patients with witnessed cardiac decompensation received PACE during management of their prehospital care (group A). These patients were compared with 144 witnessed arrest patients from the control period (group B). There were no differences in mean times from decompensation to advanced life support (ALS), decompensation to PACE, or ALS to PACE for group A versus paced group B patients. However, when considering all group B patients, the proportion of controls paced within ten minutes was less than for group A (4% versus 30%; P < .001). The group A survival rate to hospital admission was not significantly different from the group B rate (28% versus 29%), even after adjustment for patient characteristics. The group A survival rate to hospital discharge was significantly greater than group B's (24% versus 9%; P < .05). This difference was enhanced after adjustment for patient arrest characteristics (Z = 3.57; P = .0002}. Early prehospital PACE can improve patient long-term survival.
158 Survival Prognosis for the Elderly After Out-ofHospital Cardiac Arrest MJ Bonnin, PE Pepe, P S Clark/Departmentsof Medicine and Surgery, Baylor College of Medicine; City of Houston Emergency Medical Services, Houston, Texas The appropriateness of aggressive CPR of the elderly patient (> 70 years) has often been questioned in the medical literature.
18:4 April 1989
However, the out-of-hospital cardiac arrest victim represents a different patient population with different pathophysiologies of arrest. We, therefore, prospectively studied the outcome of all elderly victims of out-of-hospital cardiac arrest treated within a single large, urban paramedic EMS system over a six-month period to determine their overall prognosis and to identify any specific survival factors. Patient outcomes were analyzed with respect to multiple variables including age, sex, whether monitored, whether witnessed, bystander CPR, and blood pressure or cardiac rhythm on hospital arrival. Outcomes evaluated included in-hospital admission (resuscitated) and successful discharge from the hospital (survival). For the purposes of our study, patients whose arrest was associated with injury, hemorrhage, or a clear respiratory etiology (eg, foreign body aspiration) were excluded. The results demonstrated that of 177 consecutive elderly cardiac arrest victims evaluated, 39 (22%) were successfully resuscitated and 11 (6%) survived overall. Of these 177 patients, 59 (33%} had ventricular fibrillation/tachycardia as their initial arrest rhythm. The majority of survivors were found in this subgroup, as 25 (42%) of these elderly ventricular fibrillation/tachycardia patients were resuscitated and nine (15%1 survived. Apart from having ventricular fibrillation/tachycardia as the initial rhythm, bystander CPR also appeared to contribute to better survival rates. During the same study period, there were 300 total cardiac arrest victims less than 70 years old, of whom 78 (26%) were resuscitated and 41 (14%) survived. These data confirm that the prognosis for elderly victims of out-of-hospital cardiac arrest is not entirely bleak and, in fact, is very reasonable if Ventricular fibrillation/tachycardia is the presenting rhythm.
159 Prehospital Prophylactic Lidocaine Does Not Favorably Affect the Outcome of Patients With Chest Pain KM Hargarten, PD Chapman, HA Stueven, EM Waite, JR Mateer, P Haecker, TP Aufderheide, DW Olson/Department of Emergency Medicine, Milwaukee County Medical Complex, Medical College of Wisconsin, Milwaukee Some prehospital paramedic systems administer prophylactic lidocaine to all patients who present with chest pain of suspected cardiac origin in hopes of preventing malignant ventricular arrhythmias. Although many reports have been written on efficacy in coronary care units, prehospital data are scarce. A randomized prospective study of prophylactic lidocaine was conducted on all stable patients with suspected cardiac chest pain presenting to a paramedic system from January 1984 through January 1988. During this period, 1,427 patients were entered; 704 received lidocaine, and 723 did not. Discharge diagnosis included 31% acute myocardial infarction, 33% unstable angina, 7% other cardiac, and 29% noncardiac, with an overall mortality of 7.4%. There was an equal distribution of deaths between the lidocaine (57) and no lidocaine (48} groups. Only six cardiopulmonary arrests prehospital occurred, and 15 occurred in the emergency department. Malignant ventricular arrhythmias as the precipitating arrest rhythm in patients with acute myocardial infarction were similar for both the lidocaine and no-lidocaine groups. The incidence of adverse effects including bradycardias, second- or third-degree heart blocks, tinnitus, and altered mental status were similar in both groups. Patients in the lidocaine group had more subjective complaints of dizziness (2.6% [18] versus 0.6% [4]; P = .002) and development of hypotension (4.8% [34] versus 2.4% [17]; P = .008) when compared with the no: lidocaine group. There were no benefits manifested from the use of prophylactic lidocaine in patients with stable prehospital chest pain; therefore, routine use in this setting appears unwarranted.
160 Comparison of Topical Anesthetic Agents in the Repair of Facial and Scalp Lacerations in Children DS Ross, DSqroggins, J Taylor, G Muskett, B Singal, S Bernardon, K Gardner, J Fowler/Universityof Cincinnati College of Medicine; William Booth Memorial Hospital, Florence, Kentucky Topical anesthetics have recently been used successfully in minor wound care. Their use may be of particular benefit in the pediatric population. We compared three different solutions in a prospective, randomized, double-blind study. One solution contained a combination of 0.5 % tetracaine, 1:15,000 adrenaline, and 10% cocaine (TAC}. The second contained 1.87% tetracaine and 1:15,000 adrenaline (TA). The third solution contained 2% tetracaine only (T). One hundred eighty-six children with scalp o r facial lacerations were randomized to receive one of the three solutions in a 2-mL aliquots on cotton applicators. The solutions were
Annals of Emergency Medicine
469/189
152 Cerebral Multifocal Hypoperfusion After Cardiac Arrest in Dogs, Mitigated by Hypertension and Hemodilution F Sterz, P Safar, Y Leonov, D Johnson, R Latchaw, S Hecht, K Oku/International Resuscitation Research Center and Department of Radiology, University of Pittsburgh, Pennsylvania Hemodilution plus hypertension plus heparinization after cardiac arrest in dogs improved outcome (Safar 1976). This couldbe the result of a more homogeneous post-cardiac arrest cerebral perfusion. We monitored muhifocal (local) cerebral blood flow (1CBF) with Xe-CT (Wolfson 1988) in a dog model of ventricular fibrillation-cardiac arrest of 10 or 12.5 minutes no flow reperfusion with open-chest CPR or cardiopulmonary bypass (CPB), early defibrillation, and IPPV to six hours, with control of mean arterial pressure, hematocrit, arterial blood gases, and temperature. With normal mean arterial pressure and hematocrit after arrest (14), there was inhomogeneous hyperemia followed by hypoperfusion with multiple foci of trickle flow (0 to 10 mL/100 g/min) and low flow (0 to 20 mL), which were not present before arrest. Immediate postarrest HT (with norepinephrine) over four hours (mean arterial pressure, 150 to 130 m m Hg) (three) resulted in initial homogeneous hyperemia, followed by no trickle flow areas; with subsequent normotension, trickle flow areas appeared. However, additional normovolemic HD to hematocrit of 15% to 20% starting with reperfusion (two) resulted in sustained normalization of 1CBF patterns and normal gCBF values postarrest. At five minutes, all brain areas had flows of more than 40 mL/100 g/min with no trickle or low flow extending to six hours. No hypoperfusion state was noted. Hypertensive hemodilution seems to be able to prevent post-cardiac arrest muhifocal hypoperfusion.
153 Cerebral Ischemia and Reperfusion: Failure of Hyperbaric Oxygen Therapy to Promote Increased Survival or Neurologic Protection RE Rosenthal, J P Smith, GH Marshall, Jr, RF Shesser/Department of Emergency Medicine, The George Washington University Medical Center, Washington, DC Neurologic injury causes significant morbidity and mortality in cardiac arrest survivors. Lipid peroxidation is believed to be a major cause of ongoing neurologic damage occurring after the restoration of spontaneous circulation (ROSC). Breathing 100% 02 after global cerebral ischemia has been shown to increase lipid peroxidation and mortality. Paradoxically, hyperbaric oxygen treatment of cats subjected to circulatory arrest shortens time to EEG recovery and decreases cerebral spinal fluid lactate production. Our study was designed to determine the effect of hyperbaric oxygen on survival and neurologic injury after resuscitation from cardiac arrest. Male Wistar rats (360 to 460 g), anesthetized IP with ketamine (36 mg) and xylazine (0.5 mg), were ventilated with room air after midline tracheotomy. Intracardiae injection of 0.4 mL cold 1% KC1 followed by thoracic compression induced 6.5-minute cardiac arrest. ROSC was accomplished with IACCPR (70 per minute) synchronous with room air ventilation. Room air ventilation (40 per minute) was continued until spontaneous respirations ensued. After extubation (62 + 18 minutes), 40 animals were placed in a small animal hyperbaric chamber and alternately assigned to treatment with hyperbaric oxygen (2 atm absolute [ATA]) or room air control (1 ATA) for 90 minutes. Animal survival was recorded daily with neurologic deficit scores measured in those animals surviving three and ten days. There was no difference in survival between treatment groups (chi-squared) with 11 of 20 (55 %) hyperbaric oxygen-treated rats and ten of 20 (50 %) room air-treated rats surviving ten days. Neurologic deficit scores of survivors similarly showed no significant differences between groups at three days (hyperbaric oxygen = 5.8 +_8.7; room air = 6.9 + 6.6; P = .18) or ten days (hyperbaric oxygen = 2.4 + 3.2; room air = 1.3 + 2.8; P = .34) as measured by the two-sample t test. Hyperbaric oxygen therapy does not appear to promote increased survival or neurologic protection after cardiac arrest and survival using this experimental model for global cerebral ischemia.
154 A Dose-Response Study of an Experimental Iron Chelator for Inhibition of DNA Damage by Oxygen Radicals 188/468
BC White, DM Feldman, LI Grcssman/Section of Emergency Medicine, Department of Surgery, and Department of Molecular Biology and Genetics and Center for Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan Iron-catalyzed free radical-induced D N A damage may contribute to disorganization of brain cell nuclei during reperfusion after cardiac arrest. Partial support for this scheme is provided by the previous demonstration that the iron chelator deferoxamine inhibits reperfusion membrane injury; however, it does not appear to enter cells in adequate quantities to prevent nuclear damage. Therefore, our study was undertaken to examine iron-mediated oxygen radical D N A damage as well-as to characterize the doseresponse for D N A protection by an experimental iron chelator (1ethyl-2-methyl-3-hydroxypyrid-4-one; EMHP), whose chemical properties suggest improved penetration both of cell membranes and of the blood-brain barrier. Supercoiled closed circular DNA provides a sensitive detection system for strand breaks. One break in either strand uncoils the DNA, giving a nicked circle form that migrates more slowly on gel electrophoresis. We used a small plasmid D N A (pBS; 2,700 bp) to study hydroxyl radical damage, pB8 D N A (200 ng) was exposed to the normal intracellular concentration of H~O 2 (30 micromolar) and various ferrous iron concentrations at pH 7.5. After 15 minutes in 1 m M Fe 2+, there is extensive degradation; little damage occurs at 50 nM Fe ~÷.At the low molecular weight iron concentration (0.4 mM) seen in the brain by two hours of reperfusion after a i 5-minute cardiac arrest, all the pBS is converted to nicked circles by 15 minutes at 37 C and is completely fragmented by four hours. EMHP has a molecular weight of 162 and a partition coefficient of 0.5 between n-octanol and water. The chelator coordinates at three sites on iron, and all three sites must be filled to render the transition metal inactive in redox reactions. The EMHP to Fe ratio was varied from 0:1 to 32:1 in reactions conducted with 200 ng pBS at 37 C, pH 7.5 in 0.4 m M Fe 2÷and 30 micromolar H20~. After 30 minutes and four hours of incubation, the pBS was subjected to electrophoresis. Lower (4:1 and 8:1) concentrations of EMHP showed some protective effect after 30 minutes. However, marked damage was evident by four hours. Higher (16:1 and 32:1) concentrations of EMHP protected completely at 30 minutes. At four hours, a trace of damage was still visible at 16:1, but complete protection was achieved by the 32:i dose. However, in no case did the damage seen at the lower ratios of EMHP exceed the damage in its complete absence. EMHP has potentially superior properties for crossing the blood-brain barrier. We have shown that EMHP is effective in preventing in vitro D N A damage in an assay that detects the break of one sugar-phosphate bond in 5,400.
155 The Relative Contributions of Early Defibrillation ~ind ACLS Interventions to Resuscitation and Survival From Prehospital Cardiac Arrest RO Cummins, JR Graves, SHoran, MP Larsen, K Crump/ Department of Medicine, University of Washington; Center for Evaluation of Emergency Medical Services, King County, Washington, Division of Emergency Medical Services; School of Medicine, University of Washington, Seattle We analyzed the arrest records of 828 consecutive people resuscitated from prehospital cardiac arrest from 1981 through 1987 to determine the relative contributions of defibrillation and the additional advanced cardiac life support (ACLS) interventions of endotracheal intubation and IV pharmacology to resuscitation and long-term survival. In our two-tiered EMS system (EMT-D plus paramedics), we defined two groups: patients who regained a sustained perfusing rhythm for more than six hours under the care of EMTs trained to defibrillate (EMT-D Resus) and those who regained a sustained perfusing rhythm under the care of paramedics (Medic Resus). Four hundred fifty-one of the resuscitations (54%) were long~term survivors. Most resuscitations (583, 7 0 % ) w e r e initially in ventricular fibrillation, and most long-term survivors were in ventricular fibrillation (361, 80%). EMT-Ds, on the arrest scene an average of 5.5 minutes Before arrival of the paramedics, were able to achieve 27% (99) of all ventricular fibrillation survivors, 22% (99) of all long-term survivors, and 15% (124) of all resuscitations. Long-term survival was significantly better (P < .01) in the EMT-D Resus group (79%, with 4% to nursing homes), compared with the Medic Resus group (50%, with 8% to nursing homes). Our data reconfirm that early arrival of defibrillation alone can improve survival rates for prehospital cardiac arrest. The data suggest, however, limitations to early defibrillation programs that operate without close ACLS backup. The additional interventions
Annals of Emergency Medicine
18:4 April 1989
of early intubation and IV pharmacology are required to achieve maximum prehospital survival.
156 EMT-D Survivors: The Contribution of Defibrillation D Fark, J LaRochelle, DW Olson, G Hendley, TP Aufderheide, HA Stueven/Department of Emergency Medicine, Milwaukee County Medical Complex, Medical College of Wisconsin, Milwaukee Emergency medical technician-defibrillator (EMT-D) programs have improved survival from prehospital cardiac arrest in many settings. However, the countershocks delivered by EMT-Ds do not appear to contribute to the resuscitation of all survivors. In Wisconsin, 64 rural and subUrban manual EMT-D services forward reports for medical review. The contribution of defibrillation in the first 44 survivors is reported. The arrest rhythm was ventricular fibrillation in 42 survivors (95%) and electromechanical dissociation in two 15%). Forty-one ventricular fibrillation patients received countershocks and were divided into two groups. Group 1, 29 patients (66%), achieved a perfusing rhythm that persisted to provision of advanced life support (ALS). Their final countershock was delivered 8.9 + 5.5 minutes before ALS. Group 2, 12 patients (27%)) remained in full arrest at the time of ALS, though eight had earlier regained at least transient perfusing or electromechanical dissociation rhythms. Overall, 31 patients returned to a prearrest neurologic state/70%) including 21 from group ! (72%) and seven from group 2 (58%, P = N8). Within group 1, the patients who returned to a prearrest neurologic state had a significantly shorter time from arrest to perfusing rhythm than those who deteriorated (8.9 + 3.6 versus 17.8 + 8.6 minutes, P < .002). In our review, defibrillation by EMT-Ds clearly contributed to resuscitation from prehospital cardiac arrest in 29 of 44 survivors {66%, group 1) by restoring a perfusing rhythm before ALS provision.
157 Prehospital Transcutaneous Cardiac Pacing Phase II JR Hedges, S Feero, R Easter, B Shultz, SA Syverud, WC Dalsey/ Oregon Health Sciences University, Portland; Thurston County Medic One, Olympia, Washington; UniversitYof Cincinnati; Witford Hall Medical Center, Lackiand AFB, San Antonio, Texas Controlled outcome studies of prehospital transcutaneous cardiac pacing (PACE) have suggested that early administration of pacing is needed to improve survival. We performed a prospective study of PACE available on a daily basis with comparison to a historical control population of patients from the same EMS system with PACE available only on an alternate-day basis. We hypothesized that daily availability would shorten the time from cardiac decompensation until PACE and subsequently improve survival. Estimated survival probabilities were calculated from logistic regression models of survivai to hospital admission and survival to hospital discharge based on historical control population characteristics {144 witnessed arrests}. Comparison of actual to expected survival was made with a Z test. Other dichotomous variables were compared with chi-square analysis. Continuous variables were compared with an unpaired t test. A significance level of P < .05 was used throughout. During the four-month study period, 25 patients with witnessed cardiac decompensation received PACE during management of their prehospital care (group A). These patients were compared with 144 witnessed arrest patients from the control period (group B). There were no differences in mean times from decompensation to advanced life support (ALS), decompensation to PACE, or ALS to PACE for group A versus paced group B patients. However, when considering all group B patients, the proportion of controls paced within ten minutes was less than for group A (4% versus 30%; P < .001). The group A survival rate to hospital admission was not significantly different from the group B rate (28% versus 29%), even after adjustment for patient characteristics. The group A survival rate to hospital discharge was significantly greater than group B's (24% versus 9%; P < .05). This difference was enhanced after adjustment for patient arrest characteristics (Z = 3.57; P = .0002}. Early prehospital PACE can improve patient long-term survival.
158 Survival Prognosis for the Elderly After Out-ofHospital Cardiac Arrest MJ Bonnin, PE Pepe, P S Clark/Departmentsof Medicine and Surgery, Baylor College of Medicine; City of Houston Emergency Medical Services, Houston, Texas The appropriateness of aggressive CPR of the elderly patient (> 70 years) has often been questioned in the medical literature.
18:4 April 1989
However, the out-of-hospital cardiac arrest victim represents a different patient population with different pathophysiologies of arrest. We, therefore, prospectively studied the outcome of all elderly victims of out-of-hospital cardiac arrest treated within a single large, urban paramedic EMS system over a six-month period to determine their overall prognosis and to identify any specific survival factors. Patient outcomes were analyzed with respect to multiple variables including age, sex, whether monitored, whether witnessed, bystander CPR, and blood pressure or cardiac rhythm on hospital arrival. Outcomes evaluated included in-hospital admission (resuscitated) and successful discharge from the hospital (survival). For the purposes of our study, patients whose arrest was associated with injury, hemorrhage, or a clear respiratory etiology (eg, foreign body aspiration) were excluded. The results demonstrated that of 177 consecutive elderly cardiac arrest victims evaluated, 39 (22%) were successfully resuscitated and 11 (6%) survived overall. Of these 177 patients, 59 (33%} had ventricular fibrillation/tachycardia as their initial arrest rhythm. The majority of survivors were found in this subgroup, as 25 (42%) of these elderly ventricular fibrillation/tachycardia patients were resuscitated and nine (15%1 survived. Apart from having ventricular fibrillation/tachycardia as the initial rhythm, bystander CPR also appeared to contribute to better survival rates. During the same study period, there were 300 total cardiac arrest victims less than 70 years old, of whom 78 (26%) were resuscitated and 41 (14%) survived. These data confirm that the prognosis for elderly victims of out-of-hospital cardiac arrest is not entirely bleak and, in fact, is very reasonable if Ventricular fibrillation/tachycardia is the presenting rhythm.
159 Prehospital Prophylactic Lidocaine Does Not Favorably Affect the Outcome of Patients With Chest Pain KM Hargarten, PD Chapman, HA Stueven, EM Waite, JR Mateer, P Haecker, TP Aufderheide, DW Olson/Department of Emergency Medicine, Milwaukee County Medical Complex, Medical College of Wisconsin, Milwaukee Some prehospital paramedic systems administer prophylactic lidocaine to all patients who present with chest pain of suspected cardiac origin in hopes of preventing malignant ventricular arrhythmias. Although many reports have been written on efficacy in coronary care units, prehospital data are scarce. A randomized prospective study of prophylactic lidocaine was conducted on all stable patients with suspected cardiac chest pain presenting to a paramedic system from January 1984 through January 1988. During this period, 1,427 patients were entered; 704 received lidocaine, and 723 did not. Discharge diagnosis included 31% acute myocardial infarction, 33% unstable angina, 7% other cardiac, and 29% noncardiac, with an overall mortality of 7.4%. There was an equal distribution of deaths between the lidocaine (57) and no lidocaine (48} groups. Only six cardiopulmonary arrests prehospital occurred, and 15 occurred in the emergency department. Malignant ventricular arrhythmias as the precipitating arrest rhythm in patients with acute myocardial infarction were similar for both the lidocaine and no-lidocaine groups. The incidence of adverse effects including bradycardias, second- or third-degree heart blocks, tinnitus, and altered mental status were similar in both groups. Patients in the lidocaine group had more subjective complaints of dizziness (2.6% [18] versus 0.6% [4]; P = .002) and development of hypotension (4.8% [34] versus 2.4% [17]; P = .008) when compared with the no: lidocaine group. There were no benefits manifested from the use of prophylactic lidocaine in patients with stable prehospital chest pain; therefore, routine use in this setting appears unwarranted.
160 Comparison of Topical Anesthetic Agents in the Repair of Facial and Scalp Lacerations in Children DS Ross, DSqroggins, J Taylor, G Muskett, B Singal, S Bernardon, K Gardner, J Fowler/Universityof Cincinnati College of Medicine; William Booth Memorial Hospital, Florence, Kentucky Topical anesthetics have recently been used successfully in minor wound care. Their use may be of particular benefit in the pediatric population. We compared three different solutions in a prospective, randomized, double-blind study. One solution contained a combination of 0.5 % tetracaine, 1:15,000 adrenaline, and 10% cocaine (TAC}. The second contained 1.87% tetracaine and 1:15,000 adrenaline (TA). The third solution contained 2% tetracaine only (T). One hundred eighty-six children with scalp o r facial lacerations were randomized to receive one of the three solutions in a 2-mL aliquots on cotton applicators. The solutions were
Annals of Emergency Medicine
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