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External transcutaneous pacemakers in interhospital transport of cardiac patients
ORIGINAL CONTRIBUTION aeromedical transport; external transcutaneous pacemakers
External Transcutaneous Pacemakers in Interhospital Transport of Cardiac Patients From October 1985 to April 1988, 297 patients with presumed unstable angina, acute myocardial infarction, or permanent pacemaker failure were transferred by helicopter from community hospitals to our medical center for tertiary care. Fifty-six patients (19%) experienced treatable bradycardia (heart rate of less than 50) and hypotension (systolic pressure of less than 80 m m Hg); nine patients (16%) improved without treatment, 24 (43%) responded to atropine, and 23 (41%) were unresponsive to atropine. An external transcutaneous pacemaker (EXTP) was applied to patients unresponsive to atropine if a transvenous pacemaker could not be placed. In the atropine-unresponsive group, 11 (48%) had a transvenous pacemaker 9laced successfully, two (9%) had poor transvenous pacemaker capture (followed by EXTP capture), and ten (43%) were treated with EXTP alone. Eleven patients experienced EXTP capture and improved. Six had profound bradycardia and apnea before EXTP application. Of the 297 patients, 23 (8%) required transvenous or external pacing, and 12 of these patients (52%) survived. The availability of external pacing during interhospital transport of high-risk cardiac patients seems necessary for the management of symptomatic bradycardia and hypotension. [Vukov LF, Johnson DQ: External transcutaneous pacemakers in interhospital transport of cardiac patients. Ann Emerg Med July 1989;18:738-740.] INTRODUCTION Patients experiencing symptoms of acute myocardial ischemia and infarction frequently present to emergency facilities in small c o m m u n i t y hospitals; subsequent transfer to large referral hospitals is often needed. These transfers are frequently undertaken in basic life support (BLS) ambulance services with or without an intensive care or emergency nurse or in advanced life support (ALS} units without external transcutaneous pacemaker (EXTP I capabilities. Bradycardic rhythm disturbances with hypotension that are unresponsive to conventional pharmacologic therapy may occur en route. It has been well established that many of these rhythms, in the presence of a viable myocardium, can be externally paced until more definitive therapy is rendered or the rhythm improves. >s Our prospective study was undertaken to establish the incidence, efficacy, safety, and impact on patient outcome of using an external pacemaker in a rotorwing transport service that transfers many patients for tertiary care from small communities with primarily BLS services.
Larry F Vukov, MD* Dean Q Johnson, RNt Rochester, Minnesota From the Division of Emergency Medical Services, Mayo Clinic and Mayo Foundation;* and the Department of Nursing Services, Saint Marys Hospital,IRochester, Minnesota. Received for publication September 7, 1988. Revision received December 5, 1988. Accepted for publication January 10, 1989. Presented at the Scientific Assembly of the American College of Emergency Physicians in New Orleans, September 1988. Address for reprints: Larry F Vukov, MD, Mayo Clinic, 200 First Street, SW, Rochester, Minnesota 55905.
METHODS From October 1, 1985, to April 1, 1988, our institution's air medical transport service used a Pace Aid 53A ® EXTP {Cardiac Resuscitator Corporation, Portland, Oregon) under the following physician protocol. After conventional pharmacologic therapy with 1 to 2 mg IV atropine, flight nurses certified in advanced cardiac life support (ACLS) skills were instructed to place pacemaker electrodes in an anterior-posterior location on all patients with bradyasystolic cardiac arrest or with symptomatic primary or postcountershock bradycardia (heart rate less than 50) and hypotension {systolic blood pressure less than 80 m m Hg). Heart rate and blood pressure values were chosen to ensure that the pacemaker would be used only for patients in obvious need of pacing. Rapid application (less than
18:7 July 1989
Annals of Emergency Medicine
738/45
TRANSCUTANEOUS PACEMAKERS Vukov & Johnson
FIGURE. Management of 56 patients
with bradycardia and hypotension transferred from small community hospitals.
Total (56) I
three minutes) of the external pacemaker was emphasized. The pacemaker was set initially to pace in a fixed mode with a rate of 60 and a current of 60 mA. If capture did not occur, the current was incrementally increased; in patients awake with capture, it was decreased if capture could be maintained. ACLS techniques such as endotracheal intubation, resuscitation drugs, and defibrillation were used as needed. Patients with transvenous pacemakers inserted before transfer were supported appropriately, and they were externally paced if transvenous pacing did not maintain capture. After admission to the coronary care unit, patients were followed up to determine a final diagnosis, procedures required during hospitalization, and outcome. Patients with hypotension and a heart rate of more than 50 were treated with pressor agents instead of the external pacemaker and were, therefore, not a part of our study.
RESULTS During the 30-month study period, 297 patients with a transfer diagnosis of unstable angina, acute myocardial infarction, or permanent pacemaker failure were transported from small community hospitals to odr medical center. Of these patients, 56 (19%) (Figure) had a documented episode of treatable bradycardia and hypotension either at the referring hospital or in the helicopter: nine (16%) improved before t r e a t m e n t could be rendered, 24 (43%) responded to single or multiple IV doses of atropine, and 23 (41%) were unresponsive to atropine and required either transvenous or external pacing. Three patients in both the atropine-responsive and the atropine-unresponsive groups had postcountershock bradycardia. All others had primary bradycardias. Of the 23 patients who required pacing (22 were hospitalized), 11 (48%) had t e m p o r a r y transvenous pacemakers placed by physicians at the referring hospital (external pacing provided temporizing support in two during the p l a c e m e n t procedure). 46/739
I
I
No treatment
Treatment required (47)
(9)
Survive (8)
I
IV atropine (24)
Transvenous pacemaker (11)
Survive
Survive (6)
(18) Eleven patients (48%)(Table)were successfully externally paced during transport because a temporary transvenous p a c e m a k e r failed (two patients), a t r a n s v e n o u s p a c e m a k e r could not be placed at the referring hospital (three), or in-flight deterioration occurred (six). These patients achieved and maintained capture between 20 and 80 mA (nine at 60 mA), and all improved hemodynamically. No apparent complications of external pacing were noted. Six of the externally paced patients (with capture) had bradycardia and apnea and were pulseless before EXTP application. On admission to the coronary care unit (Table), eight of the 11 externally paced patients required extended pacing with a transvenous pacemaker. One bradycardic, pulseless, and apneic patient did not capture with an EXTP. Postmortem examination revealed massive pulmonary embolization. Death in all other cases was attributed to complications of myocardial ischemia or infarction. D i s m i s s a l survival data of the groups showed that eight (88%) of the nine patients who did not require treatment survived, 18 (75%) of the 24 atropine-responsive patients survived, six (55%) of the 11 patients with temporary transvenous pacemakers survived, and six (50%) of the 12 patients in the EXTP group survived to hospital dismissal. All survivors were neurologically and funcAnnals of Emergency Medicine
r
I External pacemaker (12)
i
Survive (6)
tionally intact at the time of hospital dismissal.
DISCUSSION In recent years, numerous studies have clarified the role of EXTPs in emergency and prehospital care. Although prehospital and emergency patients with bradyasystolic cardiac arrest receive little benefit from EXTPs, 6-ll a group of patients with hypotension and bradycardia or early cardiac arrest seems to receive considerable benefitJ 2-14 The role of the EXTP in interhospital transport has, however, never been examined to determine its frequency of use and benefit. Each year in our region, hundreds of patients with acute ischemia or infarction are admitted to community hospitals with fewer than 150 beds. Although h e m o d y n a m i c a l l y stable patients may be kept and managed at these hospitals, patients with persistent pain or worrisome complications frequently are transferred for tertiary care. Historically, transfer has been undertaken in either BLS or ALS ambulances w i t h o u t external pacing capabilities. The data presented suggest that nearly 20% of patients considered ill e n o u g h for t r a n s f e r experienced symptomatic bradycardia and hypotension. Twenty-three patients required either transvenous or external pacing. Approximately one half of the total group and of the paced
18:7 July 1989
TABLE. C l i n i c a l d a t a f r o m 11 p a t i e n t s e x p e r i e n c i n g e x t e r n a l p a c e m a k e r c a p t u r e
Age (yr)
Sex
Diagnosis
PreEXTPt Treatment
Hospital Treatment
Outcome
69* M PPM failure Atropine New PPM Survived 53* F Inferior MI Atropine PTCA, coronary bypass Survived 63* M Inferior MI Atropine PTCA Survived 61 * M Inferior MI Atropine Swan-Ganz/pacer Died 76 M Ventricular aneurysm Swan-Ganz/pacer Aneurysm repair Survived 84 F Inferior MI Atropine TVPM Survived 81 F Complete heart block Atropine TVPM, PPM Survived 75* F Inferior MI Atropine TVPM Died 73 M Inferior MI Atropine, TVPM TVPM Died 58* M Inferior MI Atropine TVPM Died 83 F Inferior MI Atropine, dopamine Swan-Ganz/pacer Died *Patient who had bradycardia and apnea and was pulseless. ¢EXTP, external transcutaneous pacemaker; MI, myocardial infarction; PPM, permanent pacemaker; PTCA, percutaneous transluminal coronary angioptasty; TVPM, temporary transvenous pacemaker. group e x p e r i e n c e d an i n f e r i o r m y o h cardial i n f a r c t i o n . A l t h o u g h 16% of these p a t i e n t s e x p e r i e n c e d o n l y trans i e n t u n t r e a t e d s y m p t o m s , m o s t required a d m i n i s t r a t i o n of IV a t r o p i n e or t r a n s v e n o u s or e x t e r n a l p a c i n g . Although many patients developed t r e a t a b l e s y m p t o m s b e f o r e transfer, 17 r e q u i r e d drug or p a c i n g i n t e r v e n t i o n d u r i n g transport. It is difficult to k n o w e x a c t l y h o w m a n y p a t i e n t s requiring an EXTP during transport w o u l d h a v e died w i t h o u t its use, b u t t h r e e of t h e six a t r o p i n e - u n r e s p o n sive, e x t e r n a l l y p a c e d p a t i e n t s w h o d e v e l o p e d bradycardia and apnea and b e c a m e p u l s e l e s s d u r i n g transfer survived. Most patients with transient s y m p t o m a t i c b r a d y c a r d i a and h y p o t e n s i o n s u r v i v e d to h o s p i t a l d i s missal, as did 75% of t h o s e w h o w e r e a t r o p i n e - r e s p o n s i v e and 52% of t h o s e w h o r e q u i r e d t r a n s v e n o u s or e x t e r n a l pacing. T h e s e data r e i n f o r c e t h e concepts t h a t rapid i n i t i a t i o n of p a c i n g in t h e p r e s e n c e of a v i a b l e m y o c a r d i u m c a n p r o d u c e s i g n i f i c a n t surv i v a l a n d t h a t t h e a v a i l a b i l i t y of p a c i n g for t r a n s f e r r e d p a t i e n t s pred i s p o s e d to b r a d y c a r d i a a n d h y p o t e n s i o n is beneficial.
18:7 July 1989
CONCLUSION D u r i n g a 3 0 - m o n t h period, n e a r l y 8% of 297 c o n s e c u t i v e c a r d i a c patients transferred from small hospitals to o u r m e d i c a l c e n t e r r e q u i r e d t r a n s v e n o u s or e x t e r n a l p a c i n g for symptomatic bradycardia and hypot e n s i o n , and t h e i r s u r v i v a l rate was 52%. W h e t h e r t h e transfer is in a BLS or ALS g r o u n d a m b u l a n c e or in a rot o r w i n g aircraft, E X T P s s h o u l d be reg a r d e d as s t a n d a r d t r a n s p o r t e q u i p m e n t and applied early in t h e m a n a g e m e n t of s y m p t o m a t i c bradycardia and hypotension associated with m y o c a r d i a l i s c h e m i a and i n f a r c t i o n .
REFERENCES 1. Worley SJ, Bride WM: External transthoracic pacing in patients with acute myocardial infarction, in Califf RM, Wagner GS (eds): Acute Coronary Care, 1987. Boston, Kluwer Academic, 1986, p 191-201. 2. O'Toole KS, Paris PM, Heller MB, et al: Emergency transcutaneous pacing in the management of patients with bradyasystolic rhythms. J Emerg Med 1987;5:267-273. 3. Zoll PM, Zoll RH, Falk RH, et ah External noninvasive temporary cardiac pacing: Clinical trials. Circulation 1985;71:937-944. 4. Clinton JE, Zoll PM, Zoll R, et al: Emergency noninvasive external cardiac pacing. J Emerg Med 1985;2:155-162.
Annals of Emergency Medicine
5. Falk RH, Zoll PM, Zoll RH: Safety and efficacy of noninvasive cardiac pacing: A preliminary report. N Engl J Med 1983;309:1166-1168. 6. Eitel DR, Guzzardi LJ, Stein SE, et al: Noninvasive transcutaneous cardiac pacing in prehospital cardiac arrest. Ann Emerg Med 1987;16: 531-534. 7. Olson CM, Jastremski MS, Smith RW, et al: External cardiac pacing for out-of-hospital bradyasystolic arrest. Am J Emerg Med 1985;3: 129-131. 8. Paris PM, Stewart RD, Kaplan RM, et al: Transcutaneous pacing for bradyasystolic cardiac arrests in prehospital care. Ann Emerg Med 1985;14:320-323. 9. Falk RH, Jacobs L, Sinclair A, et al: External noninvasive cardiac pacing in out-of-hospital cardiac arrest. Crit Care Med 1983;11:779-782. 10. Knowlton AA, Falk RH: External cardiac pacing during in-hospital cardiac arrest. Am J Cardiol 1986;57:1295-1298. 11. Vukov LF, White RD: External transcutaneous pacemakers in prehospital cardiac arrest (letter). Ann Emerg Med 1988;17:554-555. 12. Hedges JR, Syverud SA, Dalsey WC: Developments in transcutaneous and transthoracic pacing during bradyasystolic arrest. Ann Emerg Med 1984;13:822-827. 13. Hanashiro PK, Wilson JR: Cardiopulmonary resuscitation: A current perspective. Med Clin North Am 1986;70:729-747. 14: Syvemd SA, Dalsey WC, Hedges JR: Transcutaneous and transvenous cardiac pacing for early bradyasystolic cardiac arrest. Ann Emerg Med 1986;15:121-124.
740/47
External Transcutaneous Pacemakers in Interhospital Transport of Cardiac Patients From October 1985 to April 1988, 297 patients with presumed unstable angina, acute myocardial infarction, or permanent pacemaker failure were transferred by helicopter from community hospitals to our medical center for tertiary care. Fifty-six patients (19%) experienced treatable bradycardia (heart rate of less than 50) and hypotension (systolic pressure of less than 80 m m Hg); nine patients (16%) improved without treatment, 24 (43%) responded to atropine, and 23 (41%) were unresponsive to atropine. An external transcutaneous pacemaker (EXTP) was applied to patients unresponsive to atropine if a transvenous pacemaker could not be placed. In the atropine-unresponsive group, 11 (48%) had a transvenous pacemaker 9laced successfully, two (9%) had poor transvenous pacemaker capture (followed by EXTP capture), and ten (43%) were treated with EXTP alone. Eleven patients experienced EXTP capture and improved. Six had profound bradycardia and apnea before EXTP application. Of the 297 patients, 23 (8%) required transvenous or external pacing, and 12 of these patients (52%) survived. The availability of external pacing during interhospital transport of high-risk cardiac patients seems necessary for the management of symptomatic bradycardia and hypotension. [Vukov LF, Johnson DQ: External transcutaneous pacemakers in interhospital transport of cardiac patients. Ann Emerg Med July 1989;18:738-740.] INTRODUCTION Patients experiencing symptoms of acute myocardial ischemia and infarction frequently present to emergency facilities in small c o m m u n i t y hospitals; subsequent transfer to large referral hospitals is often needed. These transfers are frequently undertaken in basic life support (BLS) ambulance services with or without an intensive care or emergency nurse or in advanced life support (ALS} units without external transcutaneous pacemaker (EXTP I capabilities. Bradycardic rhythm disturbances with hypotension that are unresponsive to conventional pharmacologic therapy may occur en route. It has been well established that many of these rhythms, in the presence of a viable myocardium, can be externally paced until more definitive therapy is rendered or the rhythm improves. >s Our prospective study was undertaken to establish the incidence, efficacy, safety, and impact on patient outcome of using an external pacemaker in a rotorwing transport service that transfers many patients for tertiary care from small communities with primarily BLS services.
Larry F Vukov, MD* Dean Q Johnson, RNt Rochester, Minnesota From the Division of Emergency Medical Services, Mayo Clinic and Mayo Foundation;* and the Department of Nursing Services, Saint Marys Hospital,IRochester, Minnesota. Received for publication September 7, 1988. Revision received December 5, 1988. Accepted for publication January 10, 1989. Presented at the Scientific Assembly of the American College of Emergency Physicians in New Orleans, September 1988. Address for reprints: Larry F Vukov, MD, Mayo Clinic, 200 First Street, SW, Rochester, Minnesota 55905.
METHODS From October 1, 1985, to April 1, 1988, our institution's air medical transport service used a Pace Aid 53A ® EXTP {Cardiac Resuscitator Corporation, Portland, Oregon) under the following physician protocol. After conventional pharmacologic therapy with 1 to 2 mg IV atropine, flight nurses certified in advanced cardiac life support (ACLS) skills were instructed to place pacemaker electrodes in an anterior-posterior location on all patients with bradyasystolic cardiac arrest or with symptomatic primary or postcountershock bradycardia (heart rate less than 50) and hypotension {systolic blood pressure less than 80 m m Hg). Heart rate and blood pressure values were chosen to ensure that the pacemaker would be used only for patients in obvious need of pacing. Rapid application (less than
18:7 July 1989
Annals of Emergency Medicine
738/45
TRANSCUTANEOUS PACEMAKERS Vukov & Johnson
FIGURE. Management of 56 patients
with bradycardia and hypotension transferred from small community hospitals.
Total (56) I
three minutes) of the external pacemaker was emphasized. The pacemaker was set initially to pace in a fixed mode with a rate of 60 and a current of 60 mA. If capture did not occur, the current was incrementally increased; in patients awake with capture, it was decreased if capture could be maintained. ACLS techniques such as endotracheal intubation, resuscitation drugs, and defibrillation were used as needed. Patients with transvenous pacemakers inserted before transfer were supported appropriately, and they were externally paced if transvenous pacing did not maintain capture. After admission to the coronary care unit, patients were followed up to determine a final diagnosis, procedures required during hospitalization, and outcome. Patients with hypotension and a heart rate of more than 50 were treated with pressor agents instead of the external pacemaker and were, therefore, not a part of our study.
RESULTS During the 30-month study period, 297 patients with a transfer diagnosis of unstable angina, acute myocardial infarction, or permanent pacemaker failure were transported from small community hospitals to odr medical center. Of these patients, 56 (19%) (Figure) had a documented episode of treatable bradycardia and hypotension either at the referring hospital or in the helicopter: nine (16%) improved before t r e a t m e n t could be rendered, 24 (43%) responded to single or multiple IV doses of atropine, and 23 (41%) were unresponsive to atropine and required either transvenous or external pacing. Three patients in both the atropine-responsive and the atropine-unresponsive groups had postcountershock bradycardia. All others had primary bradycardias. Of the 23 patients who required pacing (22 were hospitalized), 11 (48%) had t e m p o r a r y transvenous pacemakers placed by physicians at the referring hospital (external pacing provided temporizing support in two during the p l a c e m e n t procedure). 46/739
I
I
No treatment
Treatment required (47)
(9)
Survive (8)
I
IV atropine (24)
Transvenous pacemaker (11)
Survive
Survive (6)
(18) Eleven patients (48%)(Table)were successfully externally paced during transport because a temporary transvenous p a c e m a k e r failed (two patients), a t r a n s v e n o u s p a c e m a k e r could not be placed at the referring hospital (three), or in-flight deterioration occurred (six). These patients achieved and maintained capture between 20 and 80 mA (nine at 60 mA), and all improved hemodynamically. No apparent complications of external pacing were noted. Six of the externally paced patients (with capture) had bradycardia and apnea and were pulseless before EXTP application. On admission to the coronary care unit (Table), eight of the 11 externally paced patients required extended pacing with a transvenous pacemaker. One bradycardic, pulseless, and apneic patient did not capture with an EXTP. Postmortem examination revealed massive pulmonary embolization. Death in all other cases was attributed to complications of myocardial ischemia or infarction. D i s m i s s a l survival data of the groups showed that eight (88%) of the nine patients who did not require treatment survived, 18 (75%) of the 24 atropine-responsive patients survived, six (55%) of the 11 patients with temporary transvenous pacemakers survived, and six (50%) of the 12 patients in the EXTP group survived to hospital dismissal. All survivors were neurologically and funcAnnals of Emergency Medicine
r
I External pacemaker (12)
i
Survive (6)
tionally intact at the time of hospital dismissal.
DISCUSSION In recent years, numerous studies have clarified the role of EXTPs in emergency and prehospital care. Although prehospital and emergency patients with bradyasystolic cardiac arrest receive little benefit from EXTPs, 6-ll a group of patients with hypotension and bradycardia or early cardiac arrest seems to receive considerable benefitJ 2-14 The role of the EXTP in interhospital transport has, however, never been examined to determine its frequency of use and benefit. Each year in our region, hundreds of patients with acute ischemia or infarction are admitted to community hospitals with fewer than 150 beds. Although h e m o d y n a m i c a l l y stable patients may be kept and managed at these hospitals, patients with persistent pain or worrisome complications frequently are transferred for tertiary care. Historically, transfer has been undertaken in either BLS or ALS ambulances w i t h o u t external pacing capabilities. The data presented suggest that nearly 20% of patients considered ill e n o u g h for t r a n s f e r experienced symptomatic bradycardia and hypotension. Twenty-three patients required either transvenous or external pacing. Approximately one half of the total group and of the paced
18:7 July 1989
TABLE. C l i n i c a l d a t a f r o m 11 p a t i e n t s e x p e r i e n c i n g e x t e r n a l p a c e m a k e r c a p t u r e
Age (yr)
Sex
Diagnosis
PreEXTPt Treatment
Hospital Treatment
Outcome
69* M PPM failure Atropine New PPM Survived 53* F Inferior MI Atropine PTCA, coronary bypass Survived 63* M Inferior MI Atropine PTCA Survived 61 * M Inferior MI Atropine Swan-Ganz/pacer Died 76 M Ventricular aneurysm Swan-Ganz/pacer Aneurysm repair Survived 84 F Inferior MI Atropine TVPM Survived 81 F Complete heart block Atropine TVPM, PPM Survived 75* F Inferior MI Atropine TVPM Died 73 M Inferior MI Atropine, TVPM TVPM Died 58* M Inferior MI Atropine TVPM Died 83 F Inferior MI Atropine, dopamine Swan-Ganz/pacer Died *Patient who had bradycardia and apnea and was pulseless. ¢EXTP, external transcutaneous pacemaker; MI, myocardial infarction; PPM, permanent pacemaker; PTCA, percutaneous transluminal coronary angioptasty; TVPM, temporary transvenous pacemaker. group e x p e r i e n c e d an i n f e r i o r m y o h cardial i n f a r c t i o n . A l t h o u g h 16% of these p a t i e n t s e x p e r i e n c e d o n l y trans i e n t u n t r e a t e d s y m p t o m s , m o s t required a d m i n i s t r a t i o n of IV a t r o p i n e or t r a n s v e n o u s or e x t e r n a l p a c i n g . Although many patients developed t r e a t a b l e s y m p t o m s b e f o r e transfer, 17 r e q u i r e d drug or p a c i n g i n t e r v e n t i o n d u r i n g transport. It is difficult to k n o w e x a c t l y h o w m a n y p a t i e n t s requiring an EXTP during transport w o u l d h a v e died w i t h o u t its use, b u t t h r e e of t h e six a t r o p i n e - u n r e s p o n sive, e x t e r n a l l y p a c e d p a t i e n t s w h o d e v e l o p e d bradycardia and apnea and b e c a m e p u l s e l e s s d u r i n g transfer survived. Most patients with transient s y m p t o m a t i c b r a d y c a r d i a and h y p o t e n s i o n s u r v i v e d to h o s p i t a l d i s missal, as did 75% of t h o s e w h o w e r e a t r o p i n e - r e s p o n s i v e and 52% of t h o s e w h o r e q u i r e d t r a n s v e n o u s or e x t e r n a l pacing. T h e s e data r e i n f o r c e t h e concepts t h a t rapid i n i t i a t i o n of p a c i n g in t h e p r e s e n c e of a v i a b l e m y o c a r d i u m c a n p r o d u c e s i g n i f i c a n t surv i v a l a n d t h a t t h e a v a i l a b i l i t y of p a c i n g for t r a n s f e r r e d p a t i e n t s pred i s p o s e d to b r a d y c a r d i a a n d h y p o t e n s i o n is beneficial.
18:7 July 1989
CONCLUSION D u r i n g a 3 0 - m o n t h period, n e a r l y 8% of 297 c o n s e c u t i v e c a r d i a c patients transferred from small hospitals to o u r m e d i c a l c e n t e r r e q u i r e d t r a n s v e n o u s or e x t e r n a l p a c i n g for symptomatic bradycardia and hypot e n s i o n , and t h e i r s u r v i v a l rate was 52%. W h e t h e r t h e transfer is in a BLS or ALS g r o u n d a m b u l a n c e or in a rot o r w i n g aircraft, E X T P s s h o u l d be reg a r d e d as s t a n d a r d t r a n s p o r t e q u i p m e n t and applied early in t h e m a n a g e m e n t of s y m p t o m a t i c bradycardia and hypotension associated with m y o c a r d i a l i s c h e m i a and i n f a r c t i o n .
REFERENCES 1. Worley SJ, Bride WM: External transthoracic pacing in patients with acute myocardial infarction, in Califf RM, Wagner GS (eds): Acute Coronary Care, 1987. Boston, Kluwer Academic, 1986, p 191-201. 2. O'Toole KS, Paris PM, Heller MB, et al: Emergency transcutaneous pacing in the management of patients with bradyasystolic rhythms. J Emerg Med 1987;5:267-273. 3. Zoll PM, Zoll RH, Falk RH, et ah External noninvasive temporary cardiac pacing: Clinical trials. Circulation 1985;71:937-944. 4. Clinton JE, Zoll PM, Zoll R, et al: Emergency noninvasive external cardiac pacing. J Emerg Med 1985;2:155-162.
Annals of Emergency Medicine
5. Falk RH, Zoll PM, Zoll RH: Safety and efficacy of noninvasive cardiac pacing: A preliminary report. N Engl J Med 1983;309:1166-1168. 6. Eitel DR, Guzzardi LJ, Stein SE, et al: Noninvasive transcutaneous cardiac pacing in prehospital cardiac arrest. Ann Emerg Med 1987;16: 531-534. 7. Olson CM, Jastremski MS, Smith RW, et al: External cardiac pacing for out-of-hospital bradyasystolic arrest. Am J Emerg Med 1985;3: 129-131. 8. Paris PM, Stewart RD, Kaplan RM, et al: Transcutaneous pacing for bradyasystolic cardiac arrests in prehospital care. Ann Emerg Med 1985;14:320-323. 9. Falk RH, Jacobs L, Sinclair A, et al: External noninvasive cardiac pacing in out-of-hospital cardiac arrest. Crit Care Med 1983;11:779-782. 10. Knowlton AA, Falk RH: External cardiac pacing during in-hospital cardiac arrest. Am J Cardiol 1986;57:1295-1298. 11. Vukov LF, White RD: External transcutaneous pacemakers in prehospital cardiac arrest (letter). Ann Emerg Med 1988;17:554-555. 12. Hedges JR, Syverud SA, Dalsey WC: Developments in transcutaneous and transthoracic pacing during bradyasystolic arrest. Ann Emerg Med 1984;13:822-827. 13. Hanashiro PK, Wilson JR: Cardiopulmonary resuscitation: A current perspective. Med Clin North Am 1986;70:729-747. 14: Syvemd SA, Dalsey WC, Hedges JR: Transcutaneous and transvenous cardiac pacing for early bradyasystolic cardiac arrest. Ann Emerg Med 1986;15:121-124.
740/47