BRIEF REPORT agonal respirations cardiac arrest
Incidence of Agonal Respirations in Sudden Cardiac Arrest From the Centerfor Evaluation of Emergency Medical Services, Emergency Medical Services Division, Seattle-King County Department of Public Health;* and the Department of Medicine, University of Washington, Seattle. t Received for publication .March 30, 1992. Revision received July 11, 1992. Accepted for publication July 20, 1992.
Jill J Clark* Mary Pat Larsen, MS* Linda L Culley* Judith Reid Graves, RN, MA* Mickey S Eisenberg, MD, PhD*t
Study objective: To discover the frequency of agonal respirations in cardiac arrest calls, the ways callers describe them, and discharge rates associated with agonal respirations. Design: We reviewed taped recordings of calls reporting cardiac arrests and emergency medical technician and paramedic incident reports for 1991. Arrests after arrival of emergency medical services were excluded.
Setting: King County, Washington, excluding the city of Seattle. Participants: Four hundred forty-five persons with out-of-hospital cardiac arrests receiving emergency medical services. Interventions: Telephone CPR, emergency medical techniciansdefibrillation, and advanced life support by paramedics. Measurements and main results: Any attempts at breathing described by callers were identified, as well as whether agonal respirations could be heard by dispatcher, emergency medical technicians, or paramedics. Agonal respirations occurred in 40% of 445 out-of-hospital cardiac arrests. Callers described agonal breathing in a variety of ways. Agonal respirations were present in 46% of arrests caused by cardiac etiology compared with 32% in other etiologies (P< .01). Fifty-five percent of witnessed arrests had agonal activity compared with 16% of unwitnessed arrests (P< .001). Agonal respirations occurred in 56% of arrests with a rhythm of ventricular fibrillation compared with 34% of cases with a nonventricular fibrillation rhythm (P< .001). Twenty-seven percent of patients with agonal respirations were discharged alive compared with 9% without them (P< .001). Conclusion: There is a high incidence of agonal activity associated with out-of-hospital cardiac arrest. Presence of agonal respirations is associated with increased survival. These findings have implications for public CPR training programs and emergency dispatcher telephone CPR programs. [Clark JJ, Larsen MP, Culley LL, Graves JR, Eisenberg MS: Incidence of agonal respirations in sudden cardiac arrest. Ann EmergMed December 1991;21:1464-1467.]
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ANNALS OF EMERGENCY MEDICINE 21:12
DECEMBER1992
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i
INTRODUCTION Identification of cardiac arrest by emergency dispatchers must occur before initiation of life-saving telephone CPR instructions. 1-3 During regular review of dispatcher-assisted telephone CPR calls in King County, Washington, we encountered cardiac arrest incidents in which the caller described breathing present in the patient. The presence of some respiratory activity often caused confusion for dispatchers in their attempts to identify cardiac arrest and delayed or prevented initiation of telephone-directed CPR. The purposes of this study were to determine the frequency of and the ways in which agonal respirations are described to dispatchers by callers; the etiology, witnessed status, cardiac rhythm, and discharged alive rates associated with agonal respirations; and the duration of agonal respirations. MATERIALS AND METHODS We selected all nontraumatic out-of-hospital cardiac arrests that occurred before emergency medical services arrival in King County, Washington (population 1 million), excluding Seattle, from J a n u a r y 1, 1991, through December 31, 1991. An ongoing cardiac arrest surveillance system provided us with the date, location, and time of call. 4 We excluded arrests in physicians'offices or clinics and nursing homes. We reviewed taped recordings from nine dispatch centers. Times from collapse to accessing 911, initiation of CPR, first defibrillation shock, and arrival of paramedics were estimated based on information from incident reports and a review of dispatch tapes. Medical incident reports were completed by both emergency medical technicians and paramedics. Estimates for these time intervals were made only for witnessed cardiac arrest episodes. "Witnessed arrest" was defined as the collapse of the patient that was directly seen or heard. Estimates for the interval of collapse to calling 911 were based on information obtained from witnesses at the scene. The reasons to believe respiratory activity was present were identified. A patient was considered to have agonal respirations if any attempt at breathing was described by the caller. Also recorded was whether agonal respirations could be heard over the telephone or whether they were noted by emergency medical technicians or paramedics on the incident report form. The cardiac rhythm on arrival of emergency medical technicians and paramedics also was obtained. Etiology was determined using all available sources of information, including incident report forms, hospital records, and autopsy and death certificate information. Cardiac etiology was defined as arrest caused by underlying ischemic heart disease. It was not possible to separate cases of primary ventricular fibrillation from ventricular fibrillation secondary to acute ischemia. We used Z2 for statistical analysis.
DECEMBER1992
21:12 ANNALS OF EMERGENCY ME[31C/NE
RESULTS During the study period there were 445 cardiac arrest incidents that met our case selection criteria. Some description of agonal activity was noted in 179 (40%) of 445 cardiac arrests. In 65 (36%) of the 179 calls with agonal respirations, multiple descriptions of agonal activity were given. The patient was said to be barely breathing in 33 calls (18%), having heavy or labored breathing in 18 calls (10%), problems breathing in 16 calls (9%), noisy breathing in 15 calls (8%), and gasping in 12 calls (7%). Terms such as snorting, gurgling, moaning, and groaning described the remaining calls. Agonal respirations actually could be heard on the tape during the call in 23 instances (13% of the time), and emergency medical technicians and/or paramedics noted the presence of agonal breathing on incident reports in 60 cases (34%). Among the 196 witnessed arrests, 55% had agonal respirations. Among these without witnessed arrests, 20% had agonal respirations (P < .001). The witnessed status for 56 arrests could not be determined. Fifty-six percent of the arrests with ventricnlar fibrillation had agonal activity compared with 34% of cases without ventricular fibrillation (P < .001). Forty-two percent of cases with citizen CPR had agonal respirations compared with 39% of those without citizen CPR (P = NS). Agonal activity was strongly associated with being discharged alive. Twenty-seven percent of those patients with agonal respirations were discharged alive compared with 9% of those without agonal respirations. Among those discharged alive, 68% had agonal respirations. Among those who died, 35% had agonal respirations (P < .001). Seventy-one patients were discharged alive. Of the 60 patients with agonal respirations when the emergency medical technicians arrived, three were lost to follow-up, and 19 of 57 (33%) were discharged alive from the hospital. Of the total cases, 267 (63%) were caused by cardiac etiology (ischemic heart disease). Other leading causes of arrest were 28 (6%) nonischemic cardiac causes (aortic valve disease, cardiomyopathy, aortic stenosis), 28 (6%) respiratory causes, 22 (5%) sudden infant death syndrome, 19 (4%) cancer, 19 (4%) suicides, and ten (2%) overdose. Etiologies of the balance of calls included drowning and neurologic and unknown causes. The frequency of agonal respirations in cardiac etiology cases was 46% compared with 32% in all other cases (P < .01). Estimates of duration of agonal respirations could be made by determining the number of times emergency medical personnel noted agonal activity present on arrival at the scene. Of the 179 cases with agonal activity as reported by callers, continued agonal activity was noted by emergency medical personnel in 60 cases. The median response time of these 60 incidents was four minutes. In 83% of times in which agonal activity was noted by emergency medical technicians, the response time was six minutes or less.
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AGONAL RESPIRATIONS Clark et al
DISCUSSION The presence of agonal activity in 40% of all cardiac arrests and 55% of witnessed cardiac arrests has important implications both for emergency dispatchers and for CPR training of the general public. Agonal activity may likely delay the recognition of cardiac arrest by the u n p r e p a r e d dispatcher and delay the onset of CPR by the bystander. Thus, a high incidence of agonal activity will lead to lower rates of b y s t a n d e r CPR in the community. Emergency dispatchers in King County, Washington, are trained in specific interrogation protocols to identify cardiac arrest over the telephone. Two key questions used to identify whether the patient is in cardiac arrest are "Is the patient conscious?" and "Is the patient breathing normally? ''1-3 If any breathing is r e p o r t e d in the unconscious patient, dispatchers are trained to identify whether the breathing is normal or abnormal. We do not instruct dispatchers to ask the caller to check for a pulse. We have found this difficult to teach the u n t r a i n e d layperson over the telephone and unnecessary for identification of a person who needs CPR. 1 The high incidence of agonal respirations also is important in training lay citizens in CPR. The occurrence of agonal respirations is likely to result in citizens not performing CPR because they think the person is breathing. In current protocols, CPR is not supposed to be initiated if the person is breathing. A discussion of agonal respirations or any reference to recognizing agonal respirations is absent in the current American H e a r t Association B a s i c Life S u p p o r t I n s t r u c t o r M a n u a l 5 and American National Red Cross C P R I n s t r u c t o r M a n u a l 6 or citizen training curricula. The rate of citizen CPR was similar for patients with and without agonal respirations. Because witnessed arrests are more likely to have citizen CPR 7 and witnessed arrests have more agonal respirations, we would expect to observe a higher rate of b y s t a n d e r CPR for patients with agonal breathing. The absence of this observation suggests that agonal breathing may be deceiving the bystander. People who r e p o r t cardiac arrest quite often are emotionally upset and confused. 3 It is not uncommon that a caller observes agonal respirations and knows it to be a change from normal breathing, but because he or she is eager to find some signs of life, the caller will r e p o r t that the patient is breathing. Furthermore, the caller is not a trained medical observer and does not know the vocabulary of agonal respirations. This can result in delays in identification of cardiac arrest and therefore delay in delivery of CPR. Since implementing a structured protocol for interrogation for cardiac arrest, we have found that inquiries about "breathing normally" are required to identify agonal activity because it often leads the caller to describe the breathing. Agonal respirations are described in many different ways, but we found common descriptive phrases used by callers. Agonal breathing is not normal in regularity and therefore often reported as occasional or breathing every once in
68/1466
awhile. In some instances, agonal activity occurred at the rate of 2 p e r minute. It is also commonly described as barely breathing, weak breathing, heavy or l a b o r e d breathing, gasping, snorting, and/or noisy breathing. Although the adjective used to describe the breathing may differ, it is clear that the caller realizes the breathing is not normal. A multivariable logistic regression model associated agonal respirations, witnessed arrest, ventricular fibrillation r h y t h m , and citizen CPR with outcome of discharged alive (ie, when only one of these factors was present, outcome was improved). The association of cardiac etiology with outcome disappeared when the other factors entered the model. Interaction effects of agonal respirations with witnessed arrest and citizen CPR also were detected (P < .01 and P = .06). The overwhelming majority of the unwitnessed arrests among those who were discharged alive showed signs of agonal activity and thus p r o b a b l y were discovered soon after collapse. This also points out that agonal respirations as well as witnessed arrest are surrogates for the same determinator of outcome, namely, early access to the patient. Because agonal respirations are a time-limited phenomenon, they were most commonly noted by callers who witnessed the collapse. Agonal respirations were described by the caller in more than half of the witnessed cases (55% compared with 16% for unwitnessed cardiac arrest). This suggests that the actual incidence of agonal respirations is more than 50%. Almost two thirds (63%) of the calls were of cardiac etiology. In cardiac etiology cases, 46% had agonal activity. Agonal respirations are found in all etiologies for cardiac arrest, with the exception of sudden infant death syndrome cases. Forty-two percent of all arrests caused by cardiac etiology and ECG rhythms of ventricular fibrillation and more than half of the ventricular fibrillation cases (58%) had agonal activity. It is noteworthy that the group with the best prognosis (ie, r h y t h m of ventricular fibrillation) has the highest incidence of agonal activity and therefore is the group most likely to have CPR withheld or delayed. The strong association of agonal activity with discharge from the hospital presents a challenge for emergency dispatchers. Although these may be the most difficult cardiac arrest cases to identify, they also are the cases with the best prognosis. Dispatchers should therefore be aggressive in encouraging bystanders to perform CPR when descriptions of agonal activity are reported. The good survival rates and outcomes seen in these cases may improve even more; greater frequency of earlier CPR may have most of its effects in better neurologic outcome. 8 , There were limitations to our study. Our data relied on lay descriptions of a critical medical phenomenon, and questions asked by dispatchers were not consistent. F o r example, "barely breathing" was described in 10% of the cases; however, there was no way to quantitate "barely." The phrases used by callers to describe agonal respirations are not consistent. Although people may have h e a r d it referred to as the death rattle or death sounds in movies and books, they do not
ANNALS OF EMERGENCY MEDICINE 21:12 DECEMBER1992
AGONAL R E S P I R A T I O N S Clark et al
know- how to describe it because they have no personal frame of reference. The witnessing of a cardiac arrest is an unusual occurrence for most people. Surprisingly, experts have no precise medical definition for agonal. The medical dictionary defines agonal as "occurring at the moment of or just before death. ''9 However, it does not define agonal in conjunction with respirations, nor does it describe respiratory activity. We chose in this study to count any descriptions of a b n o r m a l respiratory efforts described by the callers as agonal respirations. We believe these are accurate descriptions because of the spontaneous manner in which they are described by the callers and because of the episodes in which agonal activity actually was recorded on the dispatch tape. We do not believe that callers would describe sounds or motion not present. It is possible, however, that callers may not appreciate subtle signs of respiratory activity. Therefore, our findings p r o b a b l y underestimate the true incidence of agonal respirations. CONCLUSION
Our study demonstrated a high incidence of agonal respiratory activity associated with out-of-hospital cardiac arrest. The presence of agonal r e s p i r a t o r y activity may prevent bystanders from initiating CPR, may prevent dispatchers from p r o p e r l y identifying the problem, and may prevent dispatchers from providing CPR instructions. Dispatchers must be aware of the frequency of this occurrence. Recognizing agonal breathing is important, and emergency dispatchers must pursue this possibility during interrogation whenever there is evidence of a b n o r m a l breathing. If signs of agonal activity are present in the unconscious patient, dispatchers must proceed without delay with delivery of CPR instructions. These findings also have implications for all CPR instructors. The public must be trained to anticipate and recognize abnormal breathing in out-of-hospital cardiac arrests. Agonal activity is a frequent occurrence in cardiac arrest. The medical community must focus on this phenomenon and ensure that educators p r o p e r l y train the public and emergency dispatchers in its recognition.
DECEMBER1992
21:12 ANNALS OF EMERGENCY MEDICINE
REFERENCES 1. Carterw, Eisenberg M, HallstrornA, et al: Developmentand implementationof emergency CPR instruction via telephone. Ann EmergMed 1984;13:695-700. 2. Culley L, Clark J, Eisenberg M, at al: Dispatcher-assistedtelephone CPR:Common delays in time standards for delivery. Ann EmergMed I991;20:362-366. 3. Eisenberg M, CarLerW, Hallstrom A, et al: Identification of cardiac arrest by emergencydispatchers. Am J Emerg Med 1986;4:299-301. 4. Eisenberg M, Copass M, Hallstrom A, et al: Managementof out-of-hospital cardiac arrest. JAMA 1980;243:1049-1051. 5. American Heart Association: Basic Life Support Instructor ManueL Dallas,AHA, 1987. 6. American National Red Cross: BLS Instructor Manual for the Professional Rescuer. Washington, DC, ANRC, 1988. 7. Cummins R, Eisenberg M, Hallstrom A, et al: Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation.Am J Emerg Med 1985;3:114-118. 8. Longstreth W, Inui T, Cobb L, et al: Neurologic recovery after out-of-hospital cardiac arrest. Ann Intern Med 1983;98:588-592. 9. Dorland's Illustrated Medical Oictionary, ed 25. Philadelphia,WB Saunders,1974, p 48. The authors thank Richard 0 Cummins, MD, for reviewing the manuscript and providing valuable suggestions. They appreciate the cooperation of King County paramedic programs, fire departments, and dispatcher centers. Dispatch administrators and supervisors provided support in the recovery of tapes and call review. Steven Call, Manager, EmergencyMedical Services Division, provided administrative support. Katy Hein and Linda Decker provided data entry and verification. Address for reprints: Jill J Clark Center for Evaluation of EmergencyMedical Services EmergencyMedical Services Division Seattle-King County Department of Public Health 110 Prefontaine Place South, Suite 500 Seattle, Washington 98104
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Incidence of Agonal Respirations in Sudden Cardiac Arrest From the Centerfor Evaluation of Emergency Medical Services, Emergency Medical Services Division, Seattle-King County Department of Public Health;* and the Department of Medicine, University of Washington, Seattle. t Received for publication .March 30, 1992. Revision received July 11, 1992. Accepted for publication July 20, 1992.
Jill J Clark* Mary Pat Larsen, MS* Linda L Culley* Judith Reid Graves, RN, MA* Mickey S Eisenberg, MD, PhD*t
Study objective: To discover the frequency of agonal respirations in cardiac arrest calls, the ways callers describe them, and discharge rates associated with agonal respirations. Design: We reviewed taped recordings of calls reporting cardiac arrests and emergency medical technician and paramedic incident reports for 1991. Arrests after arrival of emergency medical services were excluded.
Setting: King County, Washington, excluding the city of Seattle. Participants: Four hundred forty-five persons with out-of-hospital cardiac arrests receiving emergency medical services. Interventions: Telephone CPR, emergency medical techniciansdefibrillation, and advanced life support by paramedics. Measurements and main results: Any attempts at breathing described by callers were identified, as well as whether agonal respirations could be heard by dispatcher, emergency medical technicians, or paramedics. Agonal respirations occurred in 40% of 445 out-of-hospital cardiac arrests. Callers described agonal breathing in a variety of ways. Agonal respirations were present in 46% of arrests caused by cardiac etiology compared with 32% in other etiologies (P< .01). Fifty-five percent of witnessed arrests had agonal activity compared with 16% of unwitnessed arrests (P< .001). Agonal respirations occurred in 56% of arrests with a rhythm of ventricular fibrillation compared with 34% of cases with a nonventricular fibrillation rhythm (P< .001). Twenty-seven percent of patients with agonal respirations were discharged alive compared with 9% without them (P< .001). Conclusion: There is a high incidence of agonal activity associated with out-of-hospital cardiac arrest. Presence of agonal respirations is associated with increased survival. These findings have implications for public CPR training programs and emergency dispatcher telephone CPR programs. [Clark JJ, Larsen MP, Culley LL, Graves JR, Eisenberg MS: Incidence of agonal respirations in sudden cardiac arrest. Ann EmergMed December 1991;21:1464-1467.]
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ANNALS OF EMERGENCY MEDICINE 21:12
DECEMBER1992
AGONAL RESPIRATIONS Clark et al
i
INTRODUCTION Identification of cardiac arrest by emergency dispatchers must occur before initiation of life-saving telephone CPR instructions. 1-3 During regular review of dispatcher-assisted telephone CPR calls in King County, Washington, we encountered cardiac arrest incidents in which the caller described breathing present in the patient. The presence of some respiratory activity often caused confusion for dispatchers in their attempts to identify cardiac arrest and delayed or prevented initiation of telephone-directed CPR. The purposes of this study were to determine the frequency of and the ways in which agonal respirations are described to dispatchers by callers; the etiology, witnessed status, cardiac rhythm, and discharged alive rates associated with agonal respirations; and the duration of agonal respirations. MATERIALS AND METHODS We selected all nontraumatic out-of-hospital cardiac arrests that occurred before emergency medical services arrival in King County, Washington (population 1 million), excluding Seattle, from J a n u a r y 1, 1991, through December 31, 1991. An ongoing cardiac arrest surveillance system provided us with the date, location, and time of call. 4 We excluded arrests in physicians'offices or clinics and nursing homes. We reviewed taped recordings from nine dispatch centers. Times from collapse to accessing 911, initiation of CPR, first defibrillation shock, and arrival of paramedics were estimated based on information from incident reports and a review of dispatch tapes. Medical incident reports were completed by both emergency medical technicians and paramedics. Estimates for these time intervals were made only for witnessed cardiac arrest episodes. "Witnessed arrest" was defined as the collapse of the patient that was directly seen or heard. Estimates for the interval of collapse to calling 911 were based on information obtained from witnesses at the scene. The reasons to believe respiratory activity was present were identified. A patient was considered to have agonal respirations if any attempt at breathing was described by the caller. Also recorded was whether agonal respirations could be heard over the telephone or whether they were noted by emergency medical technicians or paramedics on the incident report form. The cardiac rhythm on arrival of emergency medical technicians and paramedics also was obtained. Etiology was determined using all available sources of information, including incident report forms, hospital records, and autopsy and death certificate information. Cardiac etiology was defined as arrest caused by underlying ischemic heart disease. It was not possible to separate cases of primary ventricular fibrillation from ventricular fibrillation secondary to acute ischemia. We used Z2 for statistical analysis.
DECEMBER1992
21:12 ANNALS OF EMERGENCY ME[31C/NE
RESULTS During the study period there were 445 cardiac arrest incidents that met our case selection criteria. Some description of agonal activity was noted in 179 (40%) of 445 cardiac arrests. In 65 (36%) of the 179 calls with agonal respirations, multiple descriptions of agonal activity were given. The patient was said to be barely breathing in 33 calls (18%), having heavy or labored breathing in 18 calls (10%), problems breathing in 16 calls (9%), noisy breathing in 15 calls (8%), and gasping in 12 calls (7%). Terms such as snorting, gurgling, moaning, and groaning described the remaining calls. Agonal respirations actually could be heard on the tape during the call in 23 instances (13% of the time), and emergency medical technicians and/or paramedics noted the presence of agonal breathing on incident reports in 60 cases (34%). Among the 196 witnessed arrests, 55% had agonal respirations. Among these without witnessed arrests, 20% had agonal respirations (P < .001). The witnessed status for 56 arrests could not be determined. Fifty-six percent of the arrests with ventricnlar fibrillation had agonal activity compared with 34% of cases without ventricular fibrillation (P < .001). Forty-two percent of cases with citizen CPR had agonal respirations compared with 39% of those without citizen CPR (P = NS). Agonal activity was strongly associated with being discharged alive. Twenty-seven percent of those patients with agonal respirations were discharged alive compared with 9% of those without agonal respirations. Among those discharged alive, 68% had agonal respirations. Among those who died, 35% had agonal respirations (P < .001). Seventy-one patients were discharged alive. Of the 60 patients with agonal respirations when the emergency medical technicians arrived, three were lost to follow-up, and 19 of 57 (33%) were discharged alive from the hospital. Of the total cases, 267 (63%) were caused by cardiac etiology (ischemic heart disease). Other leading causes of arrest were 28 (6%) nonischemic cardiac causes (aortic valve disease, cardiomyopathy, aortic stenosis), 28 (6%) respiratory causes, 22 (5%) sudden infant death syndrome, 19 (4%) cancer, 19 (4%) suicides, and ten (2%) overdose. Etiologies of the balance of calls included drowning and neurologic and unknown causes. The frequency of agonal respirations in cardiac etiology cases was 46% compared with 32% in all other cases (P < .01). Estimates of duration of agonal respirations could be made by determining the number of times emergency medical personnel noted agonal activity present on arrival at the scene. Of the 179 cases with agonal activity as reported by callers, continued agonal activity was noted by emergency medical personnel in 60 cases. The median response time of these 60 incidents was four minutes. In 83% of times in which agonal activity was noted by emergency medical technicians, the response time was six minutes or less.
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AGONAL RESPIRATIONS Clark et al
DISCUSSION The presence of agonal activity in 40% of all cardiac arrests and 55% of witnessed cardiac arrests has important implications both for emergency dispatchers and for CPR training of the general public. Agonal activity may likely delay the recognition of cardiac arrest by the u n p r e p a r e d dispatcher and delay the onset of CPR by the bystander. Thus, a high incidence of agonal activity will lead to lower rates of b y s t a n d e r CPR in the community. Emergency dispatchers in King County, Washington, are trained in specific interrogation protocols to identify cardiac arrest over the telephone. Two key questions used to identify whether the patient is in cardiac arrest are "Is the patient conscious?" and "Is the patient breathing normally? ''1-3 If any breathing is r e p o r t e d in the unconscious patient, dispatchers are trained to identify whether the breathing is normal or abnormal. We do not instruct dispatchers to ask the caller to check for a pulse. We have found this difficult to teach the u n t r a i n e d layperson over the telephone and unnecessary for identification of a person who needs CPR. 1 The high incidence of agonal respirations also is important in training lay citizens in CPR. The occurrence of agonal respirations is likely to result in citizens not performing CPR because they think the person is breathing. In current protocols, CPR is not supposed to be initiated if the person is breathing. A discussion of agonal respirations or any reference to recognizing agonal respirations is absent in the current American H e a r t Association B a s i c Life S u p p o r t I n s t r u c t o r M a n u a l 5 and American National Red Cross C P R I n s t r u c t o r M a n u a l 6 or citizen training curricula. The rate of citizen CPR was similar for patients with and without agonal respirations. Because witnessed arrests are more likely to have citizen CPR 7 and witnessed arrests have more agonal respirations, we would expect to observe a higher rate of b y s t a n d e r CPR for patients with agonal breathing. The absence of this observation suggests that agonal breathing may be deceiving the bystander. People who r e p o r t cardiac arrest quite often are emotionally upset and confused. 3 It is not uncommon that a caller observes agonal respirations and knows it to be a change from normal breathing, but because he or she is eager to find some signs of life, the caller will r e p o r t that the patient is breathing. Furthermore, the caller is not a trained medical observer and does not know the vocabulary of agonal respirations. This can result in delays in identification of cardiac arrest and therefore delay in delivery of CPR. Since implementing a structured protocol for interrogation for cardiac arrest, we have found that inquiries about "breathing normally" are required to identify agonal activity because it often leads the caller to describe the breathing. Agonal respirations are described in many different ways, but we found common descriptive phrases used by callers. Agonal breathing is not normal in regularity and therefore often reported as occasional or breathing every once in
68/1466
awhile. In some instances, agonal activity occurred at the rate of 2 p e r minute. It is also commonly described as barely breathing, weak breathing, heavy or l a b o r e d breathing, gasping, snorting, and/or noisy breathing. Although the adjective used to describe the breathing may differ, it is clear that the caller realizes the breathing is not normal. A multivariable logistic regression model associated agonal respirations, witnessed arrest, ventricular fibrillation r h y t h m , and citizen CPR with outcome of discharged alive (ie, when only one of these factors was present, outcome was improved). The association of cardiac etiology with outcome disappeared when the other factors entered the model. Interaction effects of agonal respirations with witnessed arrest and citizen CPR also were detected (P < .01 and P = .06). The overwhelming majority of the unwitnessed arrests among those who were discharged alive showed signs of agonal activity and thus p r o b a b l y were discovered soon after collapse. This also points out that agonal respirations as well as witnessed arrest are surrogates for the same determinator of outcome, namely, early access to the patient. Because agonal respirations are a time-limited phenomenon, they were most commonly noted by callers who witnessed the collapse. Agonal respirations were described by the caller in more than half of the witnessed cases (55% compared with 16% for unwitnessed cardiac arrest). This suggests that the actual incidence of agonal respirations is more than 50%. Almost two thirds (63%) of the calls were of cardiac etiology. In cardiac etiology cases, 46% had agonal activity. Agonal respirations are found in all etiologies for cardiac arrest, with the exception of sudden infant death syndrome cases. Forty-two percent of all arrests caused by cardiac etiology and ECG rhythms of ventricular fibrillation and more than half of the ventricular fibrillation cases (58%) had agonal activity. It is noteworthy that the group with the best prognosis (ie, r h y t h m of ventricular fibrillation) has the highest incidence of agonal activity and therefore is the group most likely to have CPR withheld or delayed. The strong association of agonal activity with discharge from the hospital presents a challenge for emergency dispatchers. Although these may be the most difficult cardiac arrest cases to identify, they also are the cases with the best prognosis. Dispatchers should therefore be aggressive in encouraging bystanders to perform CPR when descriptions of agonal activity are reported. The good survival rates and outcomes seen in these cases may improve even more; greater frequency of earlier CPR may have most of its effects in better neurologic outcome. 8 , There were limitations to our study. Our data relied on lay descriptions of a critical medical phenomenon, and questions asked by dispatchers were not consistent. F o r example, "barely breathing" was described in 10% of the cases; however, there was no way to quantitate "barely." The phrases used by callers to describe agonal respirations are not consistent. Although people may have h e a r d it referred to as the death rattle or death sounds in movies and books, they do not
ANNALS OF EMERGENCY MEDICINE 21:12 DECEMBER1992
AGONAL R E S P I R A T I O N S Clark et al
know- how to describe it because they have no personal frame of reference. The witnessing of a cardiac arrest is an unusual occurrence for most people. Surprisingly, experts have no precise medical definition for agonal. The medical dictionary defines agonal as "occurring at the moment of or just before death. ''9 However, it does not define agonal in conjunction with respirations, nor does it describe respiratory activity. We chose in this study to count any descriptions of a b n o r m a l respiratory efforts described by the callers as agonal respirations. We believe these are accurate descriptions because of the spontaneous manner in which they are described by the callers and because of the episodes in which agonal activity actually was recorded on the dispatch tape. We do not believe that callers would describe sounds or motion not present. It is possible, however, that callers may not appreciate subtle signs of respiratory activity. Therefore, our findings p r o b a b l y underestimate the true incidence of agonal respirations. CONCLUSION
Our study demonstrated a high incidence of agonal respiratory activity associated with out-of-hospital cardiac arrest. The presence of agonal r e s p i r a t o r y activity may prevent bystanders from initiating CPR, may prevent dispatchers from p r o p e r l y identifying the problem, and may prevent dispatchers from providing CPR instructions. Dispatchers must be aware of the frequency of this occurrence. Recognizing agonal breathing is important, and emergency dispatchers must pursue this possibility during interrogation whenever there is evidence of a b n o r m a l breathing. If signs of agonal activity are present in the unconscious patient, dispatchers must proceed without delay with delivery of CPR instructions. These findings also have implications for all CPR instructors. The public must be trained to anticipate and recognize abnormal breathing in out-of-hospital cardiac arrests. Agonal activity is a frequent occurrence in cardiac arrest. The medical community must focus on this phenomenon and ensure that educators p r o p e r l y train the public and emergency dispatchers in its recognition.
DECEMBER1992
21:12 ANNALS OF EMERGENCY MEDICINE
REFERENCES 1. Carterw, Eisenberg M, HallstrornA, et al: Developmentand implementationof emergency CPR instruction via telephone. Ann EmergMed 1984;13:695-700. 2. Culley L, Clark J, Eisenberg M, at al: Dispatcher-assistedtelephone CPR:Common delays in time standards for delivery. Ann EmergMed I991;20:362-366. 3. Eisenberg M, CarLerW, Hallstrom A, et al: Identification of cardiac arrest by emergencydispatchers. Am J Emerg Med 1986;4:299-301. 4. Eisenberg M, Copass M, Hallstrom A, et al: Managementof out-of-hospital cardiac arrest. JAMA 1980;243:1049-1051. 5. American Heart Association: Basic Life Support Instructor ManueL Dallas,AHA, 1987. 6. American National Red Cross: BLS Instructor Manual for the Professional Rescuer. Washington, DC, ANRC, 1988. 7. Cummins R, Eisenberg M, Hallstrom A, et al: Survival of out-of-hospital cardiac arrest with early initiation of cardiopulmonary resuscitation.Am J Emerg Med 1985;3:114-118. 8. Longstreth W, Inui T, Cobb L, et al: Neurologic recovery after out-of-hospital cardiac arrest. Ann Intern Med 1983;98:588-592. 9. Dorland's Illustrated Medical Oictionary, ed 25. Philadelphia,WB Saunders,1974, p 48. The authors thank Richard 0 Cummins, MD, for reviewing the manuscript and providing valuable suggestions. They appreciate the cooperation of King County paramedic programs, fire departments, and dispatcher centers. Dispatch administrators and supervisors provided support in the recovery of tapes and call review. Steven Call, Manager, EmergencyMedical Services Division, provided administrative support. Katy Hein and Linda Decker provided data entry and verification. Address for reprints: Jill J Clark Center for Evaluation of EmergencyMedical Services EmergencyMedical Services Division Seattle-King County Department of Public Health 110 Prefontaine Place South, Suite 500 Seattle, Washington 98104
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