Mobile Coronary Care Unit Research Articles

Mobile coronary care units: the Dundee experience

A Mobile Coronary Care Unit was established in 1977 and opened to the public in June 1978. The Mobile Coronary Care Unit uses a specially adapted van manned by medical and nursing coronary care staff. The first months (June-October, 1978 following the opening of the service to the public in 1978 have been compared to an equivalent period in 1984. This shows an increase in the total number of calls and a change in the source of the calls. Despite the increase in calls the number of proven infarctions has not substantially changed. The referral times from receipt of the call to the Mobile Coronary Care Unit attending the patient has fallen since 1978. An increase is shown in the referral time from onset of pain until the Mobile Coronary Care Unit is requested. A Mobile Coronary Care Unit is most effective in initiating early medical treatment therefore a reduction in the referral times is vital.

Defibrillators in general practice.

After a successful pilot scheme introduced in 1975, when six portable defibrillators were provided for health centres, an additional 50 defibrillators were provided in February 1982 for general practitioners to use. Between December 1975 and February 1984 defibrillation was attempted in 54 patients who collapsed with clinical cardiac arrest in the presence of general practitioners or less than five minutes before their arrival. A cardiac output was achieved in 32 patients, 28 survived to reach hospital via a mobile coronary care unit, and 22 were discharged alive. Of the 28 admitted to hospital, 24 were found to have myocardial infarction. If all general practitioners carried defibrillators they might make an important dent in the early mortality from myocardial infarction in addition to that achieved by a mobile coronary care unit.

Automatic external defibrillation: Evaluations of its role in the home and in emergency medical services

Many recent efforts to improve emergency medical services (EMS) and increase survival rates are simply efforts to get defibrillation to patients as rapidly as possible. In the 1960s physicians traveled in mobile coronary care units to bring the defibrillator to cardiac arrest patients. Later, paramedics, rather than physicians, were used. During the late 1970s the concept of early out-of-hospital defibrillation expanded as emergency medical technicians (EMTs) learned to defibrillate. Researchers in several settings confirmed the effectiveness of early defibrillation by EMTs. The automatic detection of ventricular fibrillation (VF) creates new opportunities for the early defibrillation concept. This includes both automatic implantable defibrillators and automatic external defibrillators (AED). The King County, Washington, EMS is conducting two projects to evaluate AEDs. One is a randomized, controlled crossover study in which EMTs use either an AED or a standard manual defibrillator. Outcome measurements include time to countershock, conversion rates, and survival rates. In the second project family members of patients who have survived out-of-hospital VF randomly receive an AED and cardiopulmonary resuscitation (CPR) instruction, or CPR instruction alone. This study was designed to determine whether family members can be trained adequately to use the device effectively. Psychological tests measure the effect of learning about, living with, and using such technology. These studies may help define the role of AEDs in the future management of out-of-hospital VF.

The Belfast experience with resuscitation ambulances

The majority of sudden deaths are due to ventricular fibrillation. In the initiation of ventricular fibrillation, an R on T extrasystole was the most important factor. A late cycle ectopic, ventricular tachycardia and idioventricular rhythm initiated ventricular fibrillation less frequently. An increase or marked slowing of the heart rate were predisposing factors in the initiation of ventricular fibrillation. The first successful correction of ventricular fibrillation outside the hospital was achieved by the Belfast Mobile Coronary Care Unit in 1966. A single shock of 100 or 200 watt seconds (stored) was highly successful in the correction of ventricular fibrillation. The most likely factor in unsuccessful defibrillation is incorrect paddle application. For the correction of ventricular fibrillation during the first hour of the onset of symptoms, ≤ 2DC shocks were required in 41% of patients. Only 8% of patients required more than ten shocks. Smaller portable defibrillators are now available for use by family practitioners. Lidocaine 100 mg intravenously and 300 mg intramuscularly failed to prevent the development of ventricular tachycardia and ventricular fibrillation during the first hour of the drug's administration. Patients who survived ventricular fibrillation that occurred within four hours of the onset of symptoms of myocardial infarction were younger, tended to have had a mild coronary attack, and had the most favorable long-term prognosis. The early control of chest pain, autonomic disturbances, arrhythmias, and hemodynamic disturbance leads to a reduced incidence of cardiogenic shock and hospital mortality.

The development of monitoring techniques in mobile coronary care

Mobile coronary care was first introduced by Pantridge and Geddes at the Royal Victoria Hospital in 1966. Traditional emergency equipment i.e. defibrillation and monitors were unsuitable for application in this environment. In the succeeding years the defibrillator was made highly portable, and significantly reduced in size. Specialized monitoring apparatus was also developed to provide display and recording facilities to meet the special needs of the mobile coronary care unit. However current display systems utilize the cathode ray oscilloscope, which does not lend itself to miniaturization, is fragile, and cannot be placed at close proximity to the patient. A flat screen electroluminescent matrix of 256 × 128 dots has been developed as a physiological data display. The panel achieves a line density of approximately 83 per inch and with a time compressed memory and interpolated drive technique provides an acceptable display.

The effect of a mobile coronary care unit on mortality in patients with acute myocardial infarction or cardiac arrest outside hospital.

Patients requesting an ambulance for symptoms suggestive of acute myocardial infarction (AMI) were randomized by the ambulance controllers to the hospital-based mobile coronary care unit (MCCU) or to a standard ambulance (STA) in the proportions 60% and 40%, respectively. The MCCU was operated by two ambulance drivers and two CCU nurses. Eight hundred and twenty-one patients under 75 years of age were included in the study, of whom 56 patients were found to have cardiac arrest. Two of the 36 in the MCCU group were successfully resuscitated and discharged from hospital. No patient in the STA group of 20 survived. Among 765 patients who were alive when the ambulance arrived, 163 had a definite hospital diagnosis of AMI, 99 in the MCCU and 64 in the STA group. Median delay time from the start of the symptoms to the call for an ambulance was 2 h. During transport, two patients in the MCCU developed ventricular fibrillation and were successfully resuscitated. Two patients in the STA died suddenly and could not be resuscitated. No significant difference in mortality in the prehospital and hospital phase was found for any of the randomized patients. For AMI patients, alive when the ambulance arrived, mortality was 17% for MCCU patients and 33% for STA patients ( P =0.036). The difference in mortality remained for up to five years. It is concluded that a MCCU caused a moderate reduction in mortality in patients with cardiac arrest outside hospital and a significant reduction of mortality in AMI patients alive at the arrival of the ambulance.

Pre-hospital identification of patients with acute myocardial infarction. A pilot study for a mobile coronary care unit.

The aim of this study was to determine what proportion of patients with acute myocardial infarction (AMI) could be identified over the telephone by the staff of a Swedish ambulance center (AC). Over a 12-week period in 1973, the ambulance controllers in the Gothenburg region registered all patients requesting an ambulance whom they suspected to have AMI. Two hundred and fourteen such patients were suspected by the AC staff to have AMI. Forty-seven (22%) had a subsequent hospital diagnosis of AMI and 16 (7%) were dead from ischaemic heart disease on the arrival of the ambulance to the patient. Thus, 63 patients (29%) would probably have benefited from the existence of a mobile coronary care unit. During this period 180 AMI patients arrived alive at the hospital. Fifty-seven per cent arrived by ambulance. The ambulance controller had correctly diagnosed 47% of the AMI patients who requested ambulances, i.e. 27% of all AMI patients. AMI patients who requested ambulances had a significantly higher hospital mortality than AMI patients who arrived at hospital by other means (28 v. 10.8%). During the study period, 81 patients died from ischaemic heart disease outside hospital. Only 16 (20%) of these were identified by the AC staff. Our conclusion must be that the AC staff had a low detection rate for patients dying outside hospital of ischaemic heart disease. However, 47% of AMI patients who requested ambulances were identified and these patients had a high hospital mortality. This group of AMI patients should be an important target group for intensive treatment in the pre-hospital phase, in attempts to reduce AMI mortality.

Reduction of mortality from prehospital myocardial infarction by prudent patient activation of mobile coronary care system

Numerous recent studies have documented the fact that lives are saved by prehospital mobile coronary care units (MCCU).lm6 As a result, such units, of various designs and types, have proliferated in the United States and in Europe.7v8 In spite of this development in emergency medical services (EMS), there is still some uncertainty regarding its impact on death from acute myocardial infarction (AMI) and sudden death in patients with coronary artery disease (CAD). Furthermore, arguments have been raised that MCCU often serve patients at low risk of death, who could well be treated by other means? This presentation is concerned with our S-year experience with a mobile coronary care system in Columbus, Ohio. A single advanced life support (ALS) vehicle manned by a physician and paramedics (Heartmobile) was added to a long-standing and well-utilized EMS system in April, 1969. Over the next 8 years the ALS system as well as the entire EMS system grew dramatically.‘O With respect to cardiac emergencies, it had been our impression that persons served by the ALS units were predominantly those with high risk of death. This was clearly true of an original cohort of 214 consecutive cases analyzed in 1970 when the Heartmobile was in use. However, we had no data concerning those patients with AM1 not seen by the EMS system. As a result, factors influencing patient decisions to use the

Cardiac Emergencies

Learning to effectively treat cardiac emergencies is not an easy task. It is my opinion that mastery of material presented herein will ensure minimal competency. Finding practical experiences to help develop the necessary medical skills will require imagination and creativity. The following are offered as possible resources: 1. Attend the American Heart Association’s basis and advanced life support classes. (CPR training must be repeated at six-month intervals.) 2. Spend several days and/or nights in the emergency room at a local hospital observing (helping with) emergency care. 3. Spend time with a mobile coronary care unit if available in your community. 4. Watch and do venipunctures at the local blood bank or donor center. 5. Observe in the intensive care unit at a local hospital. 6. Assist an oral surgeon in preparing intravenous lines and monitor a patient during sedation. 7. Observe administration of oxygen by an anesthesiologist in the operating room at a local hospital.

The mobile coronary care unit and the decision to seek medical care during acute episodes of coronary artery disease.

The mobile coronary care unit (MCCU) as a means of reducing coronary artery disease (CAD) morbidity and mortality cannot be realized unless patients, lay others, and medical personnel use it. The initial medical care decision of 1,102 patients who experienced acute cardiac symptomatology was studied to determine factors contributing to expedient care-seeking and the decision to use emergency medical services (EMS), direct emergency room services, or physician consultation. An expedient decision to utilize the EMS, the only means of obtaining the MCCU, occurred when symptoms began suddenly and were incapacitating, lay others advised the EMS, and patients relinquished and lay others usurped control of care-seeking process. To increase MCCU utilization and effectiveness, it is suggested that public education about CAD be refined and the teaching of cardiopulmonary resuscitation expanded, physicians be encouraged to educate patients realistically as to CAD prognosis, and a cardiac crisis center be instituted that incorporates a registery for patients at high risk of myocardial infarction or sudden cardiac death.

The effect of a mobile coronary care unit on mortality in acute myocardial infarction. a randomized study

The effect of a mobile coronary care unit on mortality in acute myocardial infarction. a randomized study

Fundamentals of Mobile Coronary Care: A Training Manual for Emergency Medical Technicians

Mobile coronary care units render life-saving support for cardiac patients. They require emergency medical technicians well trained in cardiac resuscitation and defibrillation. This book describes in a simple and concise manner all the basic material they need for the practical treatment of the distressed patient. It is richly illustrated. This book would be of interest to nurses and physicians also.

Bedside management of acute myocardial infarction

Each year about one million people in the United States suffer an attack of acute myocardial infarction. Between 50 to 60 per cent of deaths after acute infarctions occur outside the hospital. More than 40 per cent die within the first two hours after the onset of symptoms. Prehospital care has been shown to be feasible and of great value.‘. ” Emergency medical systems (mobile coronary care units) are now available in many cities. If such units are not available, the patient should be taken to a hospital as rapidly as possible. In view of the increased incidence of arrhythmias during the first few hours of an acute infarction, it has been suggested that prophylactic prehospital treatment with lidocaine or atropine be administered.“. ’ Until further studies become available, we recommend the prehospital use of 300 mg. lidocaine intramuscularly if the heart rate is over 55 beats per minute, or atropine 0.6 mg. intravenously if the rate is below 55 beats per minute. However, a recent hospital study did not confirm this dose of lidocaine as effective in preventing primary ventricular fibrillation, possibly because the blood levels of the drug were inadequate.” In addition, the mechanism of arrhythmias in the earliest phase of myocardial infarction may be different from that in later stages. Therefore, the variable results may be due to the different times from the onset of the infarction that lidocaine has been administered. Many factors contribute to the delay in early

Mobile coronary care units : Hampton J. R. and Nicholas C. (1978) Randomised trial of a mobile coronary care unit for emergency calls. Br. Med. J.1, 1118

Mobile coronary care units : Hampton J. R. and Nicholas C. (1978) Randomised trial of a mobile coronary care unit for emergency calls. Br. Med. J.1, 1118

Prognosis after Cardiac Arrest Occurring Outside Intensive Care and Coronary Units

Emergency calls to a total of 1686 patients with verified cardiac arrest in the University Hospital, Arhus, were made in the 8-year period 1969-1977. Among the patients, cardiac arrest occurred outside the hospital in 1347, in the general wards in 240, while it was present on arrival at the emergency room in 99. Resuscitation was attempted in 1172 patients; 181 survived for at least 24 hours, and 72 were discharged alive, including 13 with residual brain damage. The prognosis was best when cardiac arrest occurred in the general wards (13% discharged) and poorest when it occurred outside the hospital (4% discharged). However, in the latter group, the prognosis showed considerable improvement when resuscitation was initiated at once by a doctor or by laymen present at the accident site (16% discharged). As regards the mechanism of cardiac arrest, ventricular fibrillation was found to be a relatively favourable prognostic sign (10% discharged), whereas almost none of the patients with asystole or severe bradycardia survived. The possibility of improving the prognosis of cardiac arrest occurring outside hospital by the establishment of mobile coronary care units and by instructing lay people in the technique of cardiopulmonary resuscitation is discussed.

Impact of a Mobile Coronary Care Unit on the Sudden Coronary Mortality in a Community

A 6-month feasibility study on a mobile coronary care unit (MCCU) was implemented in an urban community provided with a WHO Acute Ischemic Heart Disease Register. MCCU was able to reach in time less than 5% of all cases of unexpected cardiac arrest in the community. For cases of myocardial infarction and cardiac arrest transported by MCCU, a pair-matched control series was obtained from a period of 2-8 months before the beginning of the MCCU activity. No difference was found in the first 28 days' mortality rate between MCCU and control groups. The operation of MCCU did not induce any reduction of the patient delay time in the community.

Prehospital and hospital coronary care.

This article reviews the current state of services for coronary care. Since the majority of deaths from coronary heart disease occur early and outside the hospital, the importance of the prehospital phase is emphasized. The delay in this period, which is very dangerous for the patient, should be reduced and mobile coronary care units (MCCU's) are one possibility to reduce the rate of sudden coronary death. Different systems of MCCU's are discussed: (1) those based on a hospital coronary care unit, usually accompanied by a nurse and/or a doctor and (2) those integrated into an already existing decentralized emergency system (e.g. fire department) run by paramedics. Although long-term survival of patients resuscitated from ventricular fibrillation is not so good, the results of many of these units are remarkable.

MASQUERADES OF MYOCARDIAL INFARCTION

I summarize these observations in Figure 1. It represents every person in a hypothetical population who has myocardial infarction. A large but unknown number, some believe almost half, never get help. Mobile coronary care units are reducing this group, but so far only a little. When the diagnosis is not understood the disease is not recognized. Then come discovery and popularization. Hereafter masquerades hide some cases and the diagnosis is missed. Somewhere fairly early the diagnostic fad leads to false positive diagnosis. As new techniques are discovered, perfected and mastered, false positive errors and masquerades leading to oversights diminish but still exist. All the skill and technical virtuosity in the world will not be applied if we do not think of the disease. When we think of it, even obscure cases may be resolved easily.

Anxiety on admission to a coronary care unit

Abstract The degree of anxiety was measured, by means of a short questionnaire, in 338 patients with acute ischaemic heart disease immediately after admission to a coronary care unit. Admission to the coronary care unit did not increase anxiety more than that seen in patients admitted as medical emergencies to the general wards. Women were more anxious than men and patients with myocardial ischaemia were more disturbed than those with infarction. Speed of admission to the unit was associated with the clinical state of the patient, not with the degree of anxiety; those with cardiogenic shock or failure being admitted fastest. The way in which patients arrived at the coronary care unit did not affect their degree of anxiety—in particular the use of a mobile coronary care unit for transport of patients to hospital did not alarm the patients. Plasma catecholamines were estimated in 19 of the patients with myocardial infarction. Raised concentrations were associated with the severity of the infarction, not with the individual's anxiety measurement. High anxiety was found to be associated with mortality in the hospital but not with patients who arrested but were successfully resuscitated, suggesting that anxiety is not a precursor of cardiac arrest of the primary arrhythmic type.

The effectiveness of mobile coronary care in a nonurban area

During an eight-month period 225 patients in a nonurban area (65,000 population) received care from a mobile coronary care unit (MCCU) staffed by coronary care nurses from the hospital coronary care unit. There were 29 (13%) deaths. One hundred and twenty-six of the patients were eventually diagnosed as coronary disease cases (including the 29 deaths) while 99 were released with the noncardiac diagnoses. The provision of definitive emergency medical care prior to hospitalization resulted in eight lives definitely saved (three "long-term saves" and five "short-term saves") and seven lives possibly saved (six long-term saves and one short-term save). On an annual basis, per 100,000 population, these results would account for 18.5 definite saves (6.9 long-term saves and 11.5 short-term saves) and 16.2 possible saves (13.9 long-term saves and 2.3 short-term saves).