Improving Lay Responses to Cardiovascular Emergencies and the Potential of Shifting the Paradigm to Early Heart Attack Care
Gordon A. Ewy, MD, FACP, FCCC, FACCDirector, University Heart Center
Professor and Chief, Cardiology
University of Arizona College of Medicine
Tucson, AZ
Quick Overview
This presentation will address two different aspects of emergency cardiac care. First, a new concept that may improve the frequency of bystander cardiopulmonary resuscitation (CPR) and, second, comment on the delay between the onset of symptoms and the initiation of therapy in patients with AMI.
Improving the Frequency of Bystander CPR
Two of the major determinants of survival in out-of-hospital cardiac arrest due to ventricular fibrillation are the time to the onset of basic CPR and the time to defibrillation. Time to the onset of basic CPR can be shortened with the initiation of bystander CPR. If bystander CPR is initiated within 4 minutes and definitive therapy is delivered within 8 minutes, 43% of the patients with ventricular fibrillation survive. If CPR is not initiated by a bystander, but is delayed until the paramedics arrive (even when the units arrive within 8 minutes), survival decreases to 27%. If bystander CPR and definitive therapy is delayed by more than 8 minutes, survival is rare. (2) Early bystander CPR also improves postresuscitation neurological function. (3)It is clear that bystander-initiated CPR is essential. However, it is initiated in only 20% of out-of-hospital cardiac arrests. How can we improve on this figure and assure routine initiation of bystander CPR? The widespread use of CPR classes, CPR television instruction for the general public, increased directed CPR training of spouses or companions of high-risk patients, and the highly focused, telephone-instructed CPR to those who call 911 to report a cardiac arrest have all been advocated. However, several studies have shown that most individuals do not or would not initiate bystander CPR. (4,5) Lack of knowledge is one barrier to bystander CPR but the major impediment to bystander-initiated CPR is the aversion to or the fear of infection from mouth-to-mouth resuscitation. (5)
One solution to this problem could be the use of an infection barrier for mouth-to-mouth resuscitation or assure the availability of bag-mouth ventilation devices. This solution, while practical for healthcare providers, is impractical for the general public. Another possible solution would be to perform chest compression without ventilation. There is increasing data that for the first several minutes following nonairway obstructive cardiac arrest, ventilation is not necessary. This thought comes as a shock to most physicians. However, several studies have shown that survival with basic cardiac life support is best related to myocardial perfusion pressure and not ventilation. (6-8)
Animal studies from our laboratory have shown that 24-hour survival from 12 minutes of basic CPR followed by advanced cardiac life support (ACLS) is as effective with chest compression alone as it is with chest compression and interposed ventilation (100% survival in each group).9 In contrast, if bystander CPR was withheld and ACLS initiated at 12 minutes, the survival was only 20%. (9) Why might assisted ventilation not be necessary during the first few minutes of cardiac arrest? There are three major contributing factors. The first is that with nonrespiratory cardiac arrest, the pulmonary veins, the left atrium, the left ventricle, the aorta, and the major arteries are all filled with oxygenated blood. Secondly, with cardiac arrest the perfused area of the body (volume of distribution) becomes much smaller, ie, essentially limited to the head and thorax. Therefore, the cardiac output needed to maintain the heart and the brain only is less. And finally, when chest compression only is promptly initiated, many subjects gasp, thereby producing self-ventilation.
If, in the early minutes of CPR, chest compression alone proves effective, it will not only markedly increase the frequency of bystander-initiated CPR, but it will also make teaching lay CPR much easier. It is my prediction that this will be one of the major advances in CPR in the next decade. Again, we are not saying that chest compression alone is better than optimal basic CPR, but chest compression alone is dramatically better than no basic CPR.
Obviously, in a situation where aspiration is probable, such as "cafe coronary," attention must first be directed to clearing the airway, and if the arrest is respiratory, then artificial ventilation is vitally important.
Avoidable Delay in Patients With Acute Myocardial Infarction
The slogan for the present goal for managing AMI is "60 minutes to therapy." It is reasonable to assume that public education would be one important step in shortening patient response times from the onset of symptoms to ED arrival. However, before one can launch massive public educational programs in an attempt to shorten patient response times, one has to evaluate the epidemiology of avoidable delay in patients with AMI and determine if patients' responses can be altered without producing mass hysteria and overburdening the healthcare system with resultant unacceptable costs.The most recent study of avoidable dely in patients with AMI was from the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto (GISSI) trial. (10) Among 5,310 patients in the GISSI trial, 590 were admitted to the CCU after 12 hours and were compared with controls. Controls included 600 patients treated within 2 hours; 603 between 2 and 6 hours; and 466 between 6 and 12 hours.The median decision time among cases who came in after 12 hours was 50-fold higher than that of the controls who presented within 2 hours. Home-to-hospital time and in-hospital time appeared to play a less important role. Among the patient-related contributors to delayed decision time were advanced age, living alone, low intensity of initial symptoms, the lack of strong pain at the onset of the infarction, history of diabetes, occurrence of symptoms at night, and the involvement of a general practitioner.(10)
Again, one might think that public education would shorten the decision time. However, patient education aimed at altering patient behavior after onset of symptoms has not been encouraging.(10) For example, a campaign conducted in King County, Wash, showed an increase in the public's knowledge of AMI, but did not lead to a significant reduction in the patient's delay in seeking care. Premessage, the delay time was 2.6 hours, and after message, the delay was 2.3 hours.(11) A possible reason for failure in this study could have been that the general awareness of the importance of early response could have been higher in this county, a county well known for its fine paramedic system. In another study, the percentage of patients who delayed less than 4 hours was the same premessage (1965 to 1966) as during the message (1976 to 1977).(12)
Two points are clear. Several studies have shown that the involvement of the patient's primary care physician delays patient therapy.(10) This is of special concern in this era of managed care. There can also be excessive delay if emergency personnel must contact a cardiologist prior to administering thrombolytic therapy. There must be a seamless interface between the ED and the CCU-the cardiologist's role must be one of advice in setting guidelines, but decisions for thrombolytic therapy must rest with the emergency personnel.
Our challenge is to determine the paradigm that must be in place to result in a significant decrease in the delay in seeking therapy for AMI. This author doubts that it will be as simple as "finding the right message." The causes of a potentially avoidable delay are complex and are related not only to patient education, but also to the patient's psychological, social, economic, and religious makeup. Concerns for the cost of emergency healthcare, the fear of the unknown, the loss of control, denial, the patient's perception of self-worth, and the patient's current outlook on life and death all will interact to make our goal of early cardiac care difficult to achieve.
New concepts in medicine are akin to alternative medicine. It has been said that "there is no such thing as alternative medicine-only medicine that has been proven effective and medicine that has not." So it is with new concepts-some will be proven to be practical and effective and others will not. Conferences such as this might help to "find the right message," but clinical studies will be necessary to determine whether we can use this message to accomplish the cost-effective goal of earlier heart attack care.
References
1. Cummins RO, Ornato JP, Thies WH, Pepe PE. Improving survival from sudden cardiac arrest: the "chain of survival" concept. Circulation. 1991;83:1832-1847.
2. Eisenberg MS, Bergner L, Hallstrom A. Cardiac resuscitation in the community: importance of rapid provision and implications for program planning. JAMA. 1979;241:1905-1907.
3. Sanders AB, Kern KB, Ewy GA. Neurologic benefits from the use of early cardiopulmonary resuscitation. Ann Emerg Med. 1987;16:142-146.
4. Ornato JP, Haliagan LF, McMahan SB, et al. Attitudes of BCLS instructors about mouth-to-mouth resuscitation during the AIDS epidemic. Ann Emerg Med. 1990;19:151-156.
5. Locke CJ, Berg RA, Sanders AB, et al. Bystander cardiopulmonary resuscitation: concerns about mouth-to-mouth contact. Arch Intern Med. 1995;155:938-943.
6. Kern KB, Ewy GA, Voorhes WD, et al. Myocardial perfusion pressure: a predictor of 24-hour survival during prolonged cardiac arrest in dogs. Resuscitation. 1988;16:241-250.
7. Sanders AB, Kern KB, Otto CW, et al. End-tidal carbon dioxide monitoring during cardiopulmonary resuscitation: a prognostic indicator for survival. JAMA. 1989;262:1347-1351.
8. Kern KB, Sanders AB, Raife JR, et al. A study of chest compression rates during cardiopulmonary resuscitation in humans: the importance of rate-directed chest compressions. Arch Intern Med. 1992;152:145-149.
9. Berg RA, Kern KB, Sanders AB, et al. Bystander cardiopulmonary resuscitation, is ventilation necessary. Circulation. 1993;88:1907-1915.
10. GISSI Avoidable Delay Study Group. Epidemiology of avoidable delay in the care of patients with acute myocardial infarction in Italy. Arch Intern Med. 1995;155:1481-1488.
11. Podell RN. Delay in hospitalization for myocardial infarction. J Med Soc NJ. 1980;77:813-816.
12. Ho MT, Eisenberg MS, Litwin PE, et al. Delay between onset of chest pain and seeking medical care: the effect of public education. Ann Emerg Med. 1989;18:727-731.
Return to Index of Articles for Clinician;
Volume 14.4
- Faculty Listing 3
- Introduction: Community Message in Acute Myocardial Ischemia 4
- Concept of Community Chest Pain Centers in Emergency Departments 5
- Reawakening Awareness of the Importance of Prodromal Symptoms in the Shifting Paradigm to Early Heart Attack Care (EHAC) 7
- The Role of Emergency Medicine in the Future of American Medical Care: A Summary of the Josiah Macy, Jr, Foundation Conference 12
- From ACC/AHA Guidelines to Best Practice: Can "Acute MI Report Cards" Save Lives?Measuring Quality of Care for Patients With Cardiovascular Disease 16
- Improving Lay Responses to Cardiovascular Emergencies and the Potential of Shifting the Paradigm to Early Heart Attack Care 18
- National Survey of Chest Pain Centers Rationale and Potential Results 21
- Outpatient Rule-Out Myocardial Infarction in Observation Units 22
- Reducing Time to Thrombolytic Treatment 24
- Intervention Programs to Reduce Patient Delays in Acute Myocardial Infarction 29
- Public Education Using the Early Heart Attack Care Program Shawnee Mission Medical Center 31
- School Component: Early Heart Attack Care Program Development and Evaluation 33
- Educational Strategies to Prevent Prehospital Delay in Patients at High Risk for Acute Myocardial Infarction 36
- Precipitating Factors in Acute Cardiovascular Disease 41
- Use of Myocardial Perfusion Imaging in the Emergency Department for Risk Stratification 44
- The Evolution of Chest Pain Centers: The Impact of Technological Advances on the Evaluation of Patients With Possible Acute Ischemic Coronary Syndrome 47
- Critical Pathways for Triage and Treatment of Chest Pain Patients in the Emergency Department 53
- Chest Pain Centers: An Emerging Model for the Emergency Evaluation of Chest Pain and Treatment of Acute Myocardial Infarction 56
- The Key to Success in the Chest Pain Emergency Department: The Observational Role of theNurse 59
- Triage in Moderate Risk Patients With Chest Pain: The Emerging Role of Real-Time Continuous ECG Monitoring 61
- Diffusion of Innovations: The Introduction and Impact of the Chest Pain Emergency
- Department and its Comparison to the Coronary Care Unit Development 64
- Economics of Chest Pain Centers: What Really Matters? 68
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