Randomised trial of a mobile coronary care unit for emergency calls.

A randomised trial was conducted to assess the value of sending a mobile coronary care unit (MCCU) to all emergency calls other than those for children or for patients injured in road-traffic accidents or brawls. Over 15 months 6223 calls for emergency ambulances were considered for the study, but a routine ambulance had to be dispatched on 2583 occasions because the MCCU was not available. A group of 1664 patients was randomly allocated to transport by the MCCU and 1676 patients to routine transport. In these groups the prehospital mortality among patients with heart attacks was 45% and 47%, and no patient survived resuscitation attempts long enough to leave hospital. During the same period general practitioners sent 190 patients with heart attacks to hospital in routine ambulances and none of them died during the interval between the call for the ambulance and arrival at hospital. Although it may be worth equipping all emergency ambulances with a defibrillator, MCCUs as at present envisaged will not appreciably affect mortality from heart attacks.     

Pre-hospital Coronary Care Service

The Dublin cardiac ambulance service operates two specially-equipped ambulances from a private ambulance station; five metropolitan hospitals provide coronary care beds on a rota system. The service covers an area of 450 square miles (1,165 sq km) and a population of 800,000. The ambulances are staffed solely by trained ambulance personnel. During the first three years 1,973 patients were transported to hospital. Primary ventricular fibrillation was encountered in 20 patients and successfully treated in 17. No deaths occurred in the ambulance.Over 98% of the patients were transferred uneventfully to hospital, so a medical team from the hospital on duty was called on 30 occasions only. A feature of the Dublin service is the low cost of a standard ambulance call, at about £7·50.     

Follow-up of emergency ambulance calls in Nottingham: implications for coronary ambulance servie.

Information about patients in ambulance service records has been linked to that in the patients'' hospital records in an attempt to make the most efficient use of a special ambulance service for patients suspected of having heart attacks. During one week 248 emergency (999) calls for an ambulance were made by the public in the city of Nottingham. The quality of information given to the ambulance centre was poor, and all four patients eventually found to have had a myocardial infarction were described as having collapsed. A further study of patients who were also described as having collapsed has led to a system which allows an ambulance controller to send a "coronary ambulance" only in answer to those emergency calls where there is a reasonable possibility that the patient has had a heart attack.     

Medical Aspects of Ambulance Design

Various observations have shown that the interior layout of many ambulances leaves much to be desired. The lighting levels are inadequate, heat loss could be prevented, vehicle identification and passage through traffic could be improved, and measurable differences exist between the ride characteristics of commercially available ambulances, a prototype purpose-built ambulance, and a private car. Moreover the condition of some patients may be affected by the motion of the vehicle either directly or indirectly. Even though they form a small percentage of the total number carried, they represent a very considerable financial risk. A personally conducted survey of ambulance chief officers showed a deep interest and involvement in the upgrading of the service with a general dissatisfaction with many of the vehicles currently available. Hence there is a market for the purpose-built ambulance, which would benefit the patient and the ambulanceman alike.The inadequacies of many vehicles currently in use as ambulances have been shown to work against the interests of the patient requiring life support treatment, and it is suggested that this warrants urgent attention and action. A more extensive research project involving medical observations on the supine sick and injured, attendant task performance, and instrumentation analysis of linear and angular vehicle motions should enable the harmful effects of ride motion to be identified.None of these investigations, however, will be of any value unless they are used in developing future ambulances. Such development must also parallel an increase in the awareness of the importance of ambulance design and its relation to the increased comfort and chance of survival of the patients carried.     

The Brighton resuscitation ambulances: a continuing experiment in prehospital care by ambulance staff.

Two ambulances from the existing fleet in Brighton and one in Hove are equipped with portable defibrillator-oscilloscope units. Selected attendants have been trained not only to defibrillate patients but also to perform endotracheal intubation and administer intravenous atropine and lignocaine for carefully defined indications. In the two years up to December 1975 the ambulances responded to 2253 calls which were considered possible emergencies. Retrospective analysis showed that half of these had been for patients with myocardial infarction, coronary insufficiency, or angina. The ambulances took a median time of five minutes to reach a patient. Attempts at resuscitation were made in 207 patients with circulatory arrest, of whom 160 had ventricular fibrillation. Coordinated rhythm was restored at least transiently in 66 patients, and 27 of them survived to leave hospital. Sixteen of the survivors had been in ventricular fibrillation before the arrival of the ambulance. The delay before admission to hospital was reduced: over 50% of patients carried in the ambulances were admitted within two hours of the onset of major symptoms. No extra ambulance staff have been employed for the scheme. The increased load on hospital services has been limited by encouraging a rational admission policy and also by early discharge.     

Use of the automatic external defibrillator-pacemaker by ambulance personnel: the Stockport experience.

In an attempt to reduce the number of people who die from a cardiac arrest in the Stockport area ambulances were equipped with automatic external defibrillator-pacemakers, and ambulance personnel were trained in their use. Over an 18 month period ambulance personnel attended 113 patients in cardiac arrest with these devices. One patient subsequently survived, and three patients survived for up to three days. The reasons for these poor initial results include the failure of bystanders to provide cardiopulmonary resuscitation, a delay in calling for the ambulance, and too few defibrillators being available.     

Duration of Last Attack in 998 Fatal Cases of Coronary Artery Disease and its Relation to Possible Cardiac Resuscitation

All the deaths attributed to coronary artery disease and occurring in Belfast during one year were studied.The frequency distributions of the cases by interval of time between onset of the last attack and death are given for those not admitted to hospital, for those admitted to hospital, and for those already in hospital for some other cause of illness.Sixty per cent. of all the deaths occurred outside hospital. This indicates that the problem of cardiac resuscitation in coronary artery disease is to a considerable extent an extra-hospital one.Twenty-seven per cent. of the men and 22% of the women died within 15 minutes, but the median period of survival was 3 hours 30 minutes for men and 6 hours 18 minutes for women.The median time interval from the onset of the attack to sending for medical aid was 1 hour 17 minutes for men and 1 hour 6 minutes for women, and from summoning medical aid to sending for the ambulance 59 minutes for men and 1 hour 26 minutes for women. Ninety-six per cent. of the ambulance journeys to the patient were accomplished in less than 20 minutes.It was found among men, but not among women, that the duration of survival tended to be longer in older patients and in second or subsequent attacks.Of the 596 who did not gain admission to hospital 229 (23% of all the 998 patients) were known to have survived for more than half an hour after the onset of the fatal attack; 182 (18%) survived for more than one hour; and 143 (14%) survived for more than two hours. It is among these that there would appear to be special scope for the cardiac ambulance, providing that medical aid is sought and the ambulance is summoned without delay.     

Advanced training for ambulance crews: implications from 403 consecutive patients with cardiac arrest managed by crews with simple training.

Sixty seven ambulance staff in Nottinghamshire completed a simple extended training programme in managing cardiac arrest and using a defibrillator. This enabled around one third of the ambulance emergency shifts to be manned by such a crew, with a defibrillator as part of their standard equipment. Forty four of 403 consecutive patients who suffered cardiac arrest in the community were managed by these crews and survived to leave hospital. The training programme does not include endotracheal intubation, intravenous infusion, or drug administration. The new official advanced training course for ambulance crews, which includes these skills, is inappropriate in its methods and may delay widespread introduction of emergency ambulances equipped with defibrillators.     

Cardiac arrest: comparison of paramedic and conventional ambulance services.

A prospective study conducted in the Greater Vancouver area compared survival rates in prehospital cardiac arrest managed by an advanced life support (paramedic) service with those in cardiac arrest managed by conventional ambulance service. Management by the paramedic service was associated with higher survival rates for patients found in cardiac arrest but not for patients who suffered the arrest while the ambulance was present. Cardiopulmonary resuscitation by bystanders was associated with a significant increase in survival rates when combined with paramedic services but not when only basic life support services were available.     

One thousand heart attacks in Grampian: the place of cardiopulmonary resuscitation in general practice.

The outcome of 1011 heart attacks in patients under the care of general practitioners who practised cardiopulmonary resuscitation and were equipped with defibrillators is reported. The 28 day mortality was 36% (367 patients), and 59% of deaths occurred outside hospital. The general practitioner was the first medical contact in 92% of heart attacks and was equipped with a defibrillator in 80% of such calls. Fifty six patients had a cardiac arrest in the presence of a general practitioner, and resuscitation was attempted in 47 cases, representing 5% of all calls for heart attacks. Twenty one (45%) resuscitated patients reached hospital alive, and 13 (28%) survived to leave hospital. The opportunities for cardiopulmonary resuscitation in general practice occur sufficiently often to warrant training and equipping general practitioners for advanced life support. The results of resuscitation by general practitioners working alone compare favourably with those of mobile coronary care units based in hospitals.     

Mobile Coronary Care Provided by Ambulance Personnel

Mobile coronary care has been provided in Brighton by ambulance personnel without immediate help from physicians or nurses. No additional vehicles or staff were required. The capital cost of the experiment was therefore small and additional running costs were negligible. The results have been monitored by retrospective analysis of electrocardiograms recorded in the ambulance and stored on magnetic tape. In the first 12 months of operation to July 1972, 1,082 patients with suspected cardiac emergencies were carried in two vehicles. Subsequent analysis showed that 76% of these patients had acute symptoms from ischaemic heart disease or had circulatory arrest. Eighty-six per cent. of arrhythmias were diagnosed correctly by the ambulance attendants. Though only eight cases of primary ventricular fibrillation occurred during or shortly before transit all were successfully reversed, and five of these patients subsequently left hospital alive. Other benefits of the scheme have included an appreciable reduction in the median delay between onset of presenting symptoms in patients with acute myocardial ischaemia and their admission to hospital.     

Comparison of mortality of patients with heart attacks admitted to a coronary care unit and an ordinary medical ward.

During a 32-month period 2047 patients suspected of having heart attacks were admitted to hospital and were followed up prospectively. Out of 1480 eventually found to have definite or probable myocardial infarction, 483 had initially been admitted to an ordinary medical ward because of the shortage of coronary care unit (CCU) beds. More patients aged over 65 had been admitted to a ward than to a CCU, and more patients aged 65 or less had been admitted initially to a CCU. Within each age group, however, patients admitted initially to a CCU were clinically similar to those admitted initially to a ward. There was a higher proportion of successful resuscitations among patients admitted to a CCU, but there was no significant difference in mortality in either age group between patients admitted to a CCU and a ward.     

An Observational Study of Patient Characteristics Associated with the Mode of Admission to Acute Stroke Services in North East,England

Objective

Effective provision of urgent stroke care relies upon admission to hospital by emergency ambulance and may involve pre-hospital redirection. The proportion and characteristics of patients who do not arrive by emergency ambulance and their impact on service efficiency is unclear. To assist in the planning of regional stroke services we examined the volume, characteristics and prognosis of patients according to the mode of presentation to local services.

Study design and setting

A prospective regional database of consecutive acute stroke admissions was conducted in North East, England between 01/09/10-30/09/11. Case ascertainment and transport mode were checked against hospital coding and ambulance dispatch databases.

Results

Twelve acute stroke units contributed data for a mean of 10.7 months. 2792/3131 (89%) patients received a diagnosis of stroke within 24 hours of admission: 2002 arrivals by emergency ambulance; 538 by private transport or non-emergency ambulance; 252 unknown mode. Emergency ambulance patients were older (76 vs 69 years), more likely to be from institutional care (10% vs 1%) and experiencing total anterior circulation symptoms (27% vs 6%). Thrombolysis treatment was commoner following emergency admission (11% vs 4%). However patients attending without emergency ambulance had lower inpatient mortality (2% vs 18%), a lower rate of institutionalisation (1% vs 6%) and less need for daily carers (7% vs 16%). 149/155 (96%) of highly dependent patients were admitted by emergency ambulance, but none received thrombolysis.

Conclusion

Presentations of new stroke without emergency ambulance involvement were not unusual but were associated with a better outcome due to younger age, milder neurological impairment and lower levels of pre-stroke dependency. Most patients with a high level of pre-stroke dependency arrived by emergency ambulance but did not receive thrombolysis. It is important to be aware of easily identifiable demographic groups that differ in their potential to gain from different service configurations.     

Survival of 1476 patients initially resuscitated from out of hospital cardiac arrest.

OBJECTIVES--To determine the short and long term outcome of patients admitted to hospital after initially successful resuscitation from cardiac arrest out of hospital. DESIGN--Review of ambulance and hospital records. Follow up of mortality by "flagging" with the registrar general. Cox proportional hazards analysis of predictors of mortality in patients discharged alive from hospital. SETTING--Scottish Ambulance Service and acute hospitals throughout Scotland. SUBJECTS--1476 patients admitted to a hospital ward, of whom 680 (46%) were discharged alive. MAIN OUTCOME MEASURES--Survival to hospital discharge, neurological status at discharge, time to death, and cause of death after discharge. RESULTS--The median duration of hospital stay was 10 days (interquartile range 8-15) in patients discharged alive and 1 (1-4) day in those dying in hospital. Neurological status at discharge in survivors was normal or mildly impaired in 605 (89%), moderately impaired in 58 (8.5%), and severely impaired in 13 (2%); one patient was comatose. Direct discharge to home occurred in 622 (91%) cases. The 680 discharged survivors were followed up for a median of 25 (range 0-68) months. There were 176 deaths, of which 81 were sudden cardiac deaths, 55 were non-sudden cardiac deaths, and 40 were due to other causes. The product limit estimate of 4 year survival after discharge was 68%. The independent predictors of mortality on follow up were increased age, treatment for heart failure, and cardiac arrest not due to definite myocardial infarction. CONCLUSION--About 40% of initial survivors of resuscitation out of hospital are discharged home without major neurological disability. Patients at high risk of subsequent cardiac death can be identified and may benefit from further cardiological evaluation.     

Statement of the ad hoc committee on the laboratory diagnosis of infectious and serum hepatitis.

A prospective study was carried out to determine the prognostic factors in patients with second-degree and complete heart block following acute myocardial infarction and to re-examine the indications for artificial transvenous pacing. Of the 117 consecutive patients with proved acute myocardial infarction, 15 developed advanced heart block (second degree and complete). The presence of the following factors, either alone or in combinations, were attended with poor prognosis: preceding Stokes-Adams syndrome, cardiogenic shock, congestive heart failure, complications secondary to cardiac arrest, anterior infarction and wide QRS complex. In the nine cases requiring artificial transvenous pacemaker because of Stokes-Adams attacks, congestive heart failure or frequent multifocal ventricular ectopic beats, there were five deaths. The remaining six patients, who were without complications and were not paced, all survived; these patients had normal QRS duration with heart rates above 60 per minute. This study indicates that prophylactic transvenous catheter insertion in acute heart block does not appear justified unless specific indication(s) arise. Postmortem studies revealed significant narrowing of all the major coronary vessels in all five fatalities. The overall mortality in this series of cases of acute heart block was 33%.     

Resuscitation of patients with cardiac arrest by ambulance staff with extended training in West Yorkshire.

OBJECTIVE--To investigate the results of resuscitation of patients with cardiac arrest by ambulance staff with extended training in West Yorkshire. DESIGN--Study of all such attempts at resuscitation over 32 months, based on the standard report form for each call made by the ambulance staff and the electrocardiogram that showed the initial rhythm in each patient. SETTING--Area covered by West Yorkshire ambulance service. SUBJECTS--1196 Patients with cardiac arrests attended by 29 ambulance staff with extended training. MAIN OUTCOME MEASURE--Result of resuscitation. RESULTS--The initial rhythm was asystole or electromechanical dissociation in 740 patients and ventricular fibrillation in 456 patients; overall 65 patients survived to be discharged from hospital. Sixty four of the 456 patients in whom ventricular fibrillation was the initial rhythm recorded, and 46 in whom ventricular fibrillation persisted after the ambulance staff arrived, survived. Only one of the 740 patients who initially had asystole or electromechanical dissociation survived. Factors associated with a greater chance of ventricular fibrillation occurring were: age less than 71, the arrest being witnessed by a bystander, resuscitation by a bystander, the arrest occurring in a public place, and a response time by the ambulance staff of less than six minutes. For patients found in ventricular fibrillation a shorter response time was associated with improved survival but resuscitation by a bystander was not. Additional skills learnt during extended training were used for 51 of the 65 patients who survived. CONCLUSIONS--Ambulance staff with extended training can save the lives of patients with cardiac arrest due to fibrillation, though asystole and electromechanical dissociation have a poor prognosis and should perhaps receive little attention during extended training.     

Simple training programme for ambulance personnel in the management of cardiac arrest in the community.

The extended training for ambulance personnel in Nottinghamshire includes a period of training in cardiac resuscitation by defibrillation, and defibrillators are now part of the standard equipment of vehicles used on the accident and emergency service. Comparison of recent results with previous attempts in the City of Nottingham to provide a service for out of hospital cardiac arrest has shown that an elementary training course and the provision of defibrillators on emergency vehicles enables the ambulance service to save the lives of a reasonable proportion of those who suffer sudden death in the community. The extended training programme as a whole has proved acceptable to ambulance personnel and we believe that this programme could be the basis for a more widespread introduction of post basic training.     

Effects of 24-Hour Shift Work with Nighttin Napping on Circadian Rhythm Characteristi in Ambulance Personnel

Forty-two ambulance personnel engaged in a 24-h shift system participated in a chronobiological field study to study the effects of 24-h shift work on circadian rhythm characteristics. Autorhythmometry of circadian rhythms of oral temperature, right and left grip strengths, and heart rate plus subjective assessment of drowsiness, fatigue, and attention was performed every ～ 4 h except during sleep for 7 days. Cosinor and power spectral analyses were applied to the longitudinal data of each individual. Changes in circadian period different from 24 h of oral temperature, grip strengths, and heart rate plus subjective drowsiness, fatigue, and attention were observed in ambulance personnel. The incidence of circadian periodicity different from 24 h in oral temperature and right and left grip strength was 28.6%, 35.7%, and 47.6%, respectively. The incidence was relatively lower than that of shift workers engaged in a discontinuous 8-h shift system we reported on previously. Working conditions allowing ambulance personnel to nap when not called for emergency (for > 4 h) might contribute to a stabilization of circadian rhythms. Furthermore, long nighttime ambulance service amounting to >100 min was significantly associated with a high incidence of at least one prominent circadian period among oral temperature and right and left grip strength rhythms different from 24 h. In conclusion, 24-h shift work altered the characteristics of circadian rhythms of ambulance personnel; nighttime naps seemed to have a favorable effect on averting changes in circadian rhythms.     

Use of Entonox in the Ambulance Service

An analgesic mixture of nitrous oxide and oxygen (Entonox) has been used in nine ambulances in Gloucestershire for self-administration by patients in severe pain. Over a period of three and a half months 66 patients have been treated. In all cases the pain was wholly or partially relieved, and in no instance was the patient''s condition worsened. No undesirable side-effects attributable to Entonox were produced. It is recommended that other ambulance authorities should consider the use of Entonox in this context.