Thrombolysis in acute myocardial infarction: the safety and efficiency of treatment in the accident and emergency department

Door to Needle Times Bulls' Eye or Just Bull? The Effect of Reducing Door to Needle Times on the Appropriate Administration of Thrombolysis: Implications and Recommendations

The provision of thrombolysis in a timely fashion is the mainstay of treatment for acute myocardial infarction. With the publication of the National Service Framework (NSF) for Coronary Heart Disease increasing efforts have been put into the reduction of the ‘pain to needle time’. Of the various parts of the patient journey the time delays in hospital are the easiest to resolve. Published research shows that the time taken for the patient to call for help is intractable at present. Therefore, the obvious target for the reduction in the overall time from pain to treatment is the in hospital portion of the delay (the door to needle time). There are several methods that have been recommended for the reduction of the door to needle time. However, the increasing focus on the door to needle time is leading health care providers away from other issues such as the safety and accuracy of assessment by a non-cardiologist. Furthermore, the standards for audit of the door to needle time have not been set by the NSF and this has led to the presentation of selected data and the avoidance of discussing issues of accuracy and appropriateness.

Reflections on the Process of Auditing Myocardial Infarction

The publication of the National Service Framework for Coronary Heart Disease has meant that audit is becoming an increasingly important part of cardiac healthcare provision in England. Comparisons between hospitals will be made so it is essential that the audit data is as robust as possible. Nurses often play a key role in the collection of such data. This article reflects on this process, with particular reference to thrombolysis in acute myocardial infarction. Topics discussed include eligibility, the role of a clinician, electrocardiogram interpretation, justified delays, inappropriate and ‘missed’ administration. As some of the information is, arguably, open to interpretation, the authors believe that clinical auditors will inevitably have to grapple with such clinical definitions and their implications.

Effective Factors in Door-to-Needle Time for Streptokinase Administration in Patients With Acute Myocardial Infarction Admitted to the Emergency Department

Background:

Cardiovascular incidents are a common cause of death around the world. Acute myocardial infarction (AMI) poses high risks for the patient due to plaque rupture or erosion along with a superimposed non-occlusive thrombus; therefore, timely treatment with antithrombotic agents plays a key role in reducing an AMI mortality rate.

Objectives:

The present study aimed to assess the time interval between the admission of AMI-suspected patients and treatment initiation.

Patients and Methods:

This cross-sectional study was conducted on 110 patients admitted to the emergency department of Imam Hussein hospital in Tehran, Iran. Data were collected using checklists, completed by the patients’ next of kin or the emergency staff. To analyze the data, student t- test and analysis of variance were used.

Results:

In this study, 31 female and 79 male subjects were included, respectively. The mean time to receive the first dose of streptokinase was 66.39 minutes (73.74 minutes for females and 63.5 minutes for male patients), varying from 49.92 minutes in the morning to 69.78 minutes in the afternoon and 72.68 minutes during night shifts.

Conclusions:

The door-to-needle (DTN) time, in a standard setting, is recommended to be less than 30 minutes. According to the results of this study, the DTN time is comparatively two times longer in females and afternoon and night shifts. Different variables including emergency staff, physicians, patients’ characteristics, and environmental/physical factors induced this difference.

A review of interventions and system changes to improve time to reperfusion for ST-segment elevation myocardial infarction

OBJECTIVE

Identify and describe interventions to reduce time to reperfusion for patients with ST-segment elevation myocardial infarction (STEMI).

DATA SOURCE

Key word searches of five research databases: MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Web of Science, and Cochrane Clinical Trials Registry.

INTERVENTIONS

We included controlled and uncontrolled studies of interventions to reduce time to reperfusion. One researcher reviewed abstracts and 2 reviewed full text articles. Articles were subsequently abstracted into structured data tables, which included study design, setting, intervention, and outcome variables. We inductively developed intervention categories from the articles. A second researcher reviewed data abstraction for accuracy.

MEASUREMENTS AND MAIN RESULTS

We identified 666 articles, 42 of which met inclusion criteria. We identified 11 intervention categories and classified them as either process specific (e.g., emergency department administration of thrombolytic therapy, activation of the catheterization laboratory by emergency department personnel) or system level (e.g., continuous quality improvement, critical pathways). A majority of studies (59%) were single-site pre/post design, and nearly half (47%) had sample sizes less than 100 patients. Thirty-two studies (76%) reported significantly lower door to reperfusion times associated with an intervention, 12 (29%) of which met or exceeded guideline recommended times. Relative decreases in times to reperfusion ranged from 15 to 82% for door to needle and 13-64% for door to balloon.

CONCLUSIONS

We identified an array of process and system-based quality improvement interventions associated with significant improvements in door to reperfusion time. However, weak study designs and inadequate information about implementation limit the usefulness of this literature.

Assessment of Initiation Time of Thrombolytic Therapy in Patients with ST-Segment Elevation Myocardial Infarction in Hamad General Hospital

The elevation of reperfusion therapy for acute STsegment elevation myocardial infarction are time-related and there are decreasing benefits with increasing delays to therapy. To determine whether the time interval between a patient's arrival at the emergency department of Hamad General Hospital, Qatar and initiation of thrombolytic therapy in the coronary care unit (door-to-needle time) is within the 30 minutes recommended by American College of Cardiology!American Heart Association guidelines, the medical records were reviewed of 213 patients with STsegment elevation myocardial infarction who were admitted through the Emergency Department to receive thrombolysis in the Coronary Care Unit in the twelve months May 2006-April 2007. Medians were calculated for door-to-needle and painto-needle times and intermediate points. The median painto-needle and pain-to-door times were 211 and 143 minutes respectively, both increasing significantly with the age of the patient and were shorter in men than in women. The median door-to-needle time was 60 minutes with 11.7% of the sample having a door-to-needle time within the recommended 30 minutes. It is concluded that the need for transferring such patients from the emergency department to the coronary care unit of the hospital before the administration of thrombolysis incurs inevitable delays that can be minimized by administering thrombolysis in the emergency department.

Potential impact of interventions to reduce times to thrombolysis

OBJECTIVES

To estimate the lifesaving potential of interventions to accelerate the administration of intravenous thrombolysis for myocardial infarction.

METHODS

Data were analysed from a prospective, observational study of all patients transported to hospital by ambulance, who subsequently received intravenous thrombolysis at 20 hospitals and two ambulance services in Victoria, Australia (n = 1147). Regression models estimated the association between predictor variables age, sex, route of referral, symptom onset to call time, ambulance pre-notification of the receiving hospital, emergency department thrombolysis, and the outcome, time to thrombolysis. Further modelling estimated the number needed to treat to save one life by several recommended interventions to reduce time delays.

RESULTS

Presentation via a rural hospital or general practitioner was associated with an approximate doubling of the onset to call time (2.08 and 2.30 respectively). Ambulance-hospital pre-notification and emergency department thrombolysis reduced door to needle times by 21% and 27% respectively. Modelling showed that each of the following interventions would be expected to save one life: 1069 hospital pre-notifications, 714 cases of emergency department thrombolysis, 184 cases of prehospital thrombolysis, 340 cases to bypass their rural hospital, or 50 cases to bypass their general practitioner.

CONCLUSIONS

Hospital pre-notification and emergency department thrombolysis reduce time delays, although the mortality impact seems to be modest. Prehospital thrombolysis has the potential to save lives, although validation in real practice is required. Advising patients to call directly for an ambulance, rather than the general practitioner, has the greatest potential to save lives.

Emergency department thrombolysis improves door to needle times

OBJECTIVE

To identify the effect on door to needle (DTN) time of moving the site of thrombolysis delivery from the coronary care unit (CCU) to the emergency department (ED). To ascertain if moving the site of thrombolysis enables appropriate use of thrombolysis.

DESIGN

Prospective cohort study.

SETTING

CCU and ED of a 450 bed Scottish district general hospital without on-site primary angioplasty.

PARTICIPANTS

Primary site for thrombolysis of patients presenting to the hospital with ST elevation MI (STEMI) moved from CCU to ED on 1 April 2000. Study patients who had a confirmed STEMI and/or received thrombolytic therapy before this date were defined as the pre-change group; those who were diagnosed as STEMI and/or received thrombolytic therapy after this date were defined as the post-change group.

STATISTICAL ANALYSIS

Mann-Whitney test was used to compare medians and chi(2) test for categorical data.

RESULTS

1349 patients were discharged from CCU with a diagnosis of STEMI or received thrombolysis in the ED or CCU between April 1998 and April 2002. There were 632 patients in the pre-change group and 654 patients in the post-change group. Sixty three patients were excluded. Median DTN time for the pre-change group (321 thrombolysed patients) was 64 minutes and median DTN time for the post-change group (324 thrombolysed patients) was 35 minutes, a median difference of 25 minutes (95% CI for difference 20 to 29 minutes, p<0.0001, Mann-Whitney U test). A total of 37 patients were thrombolysed but did not have a final diagnosis of STEMI.

CONCLUSION

A significant reduction in DTN times accompanied this change in practice in this hospital.

Improving Door-to-Drug time and ST segment resolution in AMI by moving thrombolysis administration to the Emergency Department

BACKGROUND

We describe a combination of measures to reduce Door-to-Drug (DTD) time and improve the Emergency Department (ED) management of ST elevation MI (STEMI): appointment of a Cardiology Nurse Specialist, application of the American College of Cardiology and the American Heart Association (ACC/AHA) guidelines, changing the site of thrombolysis from the CCU to the ED, the introduction of a single bolus thrombolytic agent.

METHODS

The 12-month period before and after the introduction of the measures were retrospectively reviewed. One hundred and sixty patients were discharged from the CCU with the diagnosis of myocardial infarction confirmed by ECG and enzyme criteria. Eighty patients had STEMI and fulfilled criteria for thrombolytic therapy at the time of presentation to hospital. A full data set was available on 35/38 of patients in the 12 months prior to the measures (Year 1), and 39/42 in the 12 months subsequent (Year 2).

RESULTS

Median DTD time fell from 80 to 22 min after institution of the measures. Median Pain-to-Drug time also fell from 270 to 140 min. Thrombolytic agent given in the ED rose from 3% in Year 1, to 72% in Year 2. IV beta-blocker administered in the ED rose from 12% to 79%, resulting in median time to receiving IV beta-blocker falling from 63 to 19 min. Elevated ST segments resolved by >/=70% in <2 h in 53% of Year 2 patients, compared with 23% of Year 1 patients. Combined major in-hospital adverse clinical events were reduced from 49% to 15%.

CONCLUSION

This combination of measures reduces DTD time, improves speed to delivery of important concomitant medications, and significantly improves the time to ST segment resolution and outcome in STEMI.

Impact of a region-wide approach to improving systems for heart attack care: the West Midlands thrombolysis project

OBJECTIVE

To describe changes in delay to administration of thrombolytic therapy associated with a region-wide audit.

DESIGN

Observational study of patients admitted with suspected myocardial infarction (MI) based on continuous audit.

SUBJECTS

18877 patients admitted to 23 hospitals with suspected MI between April 1995 and March 1998.

RESULTS

Of 11232 patients with a discharge diagnosis of definite MI, 8802 (46.6%) received thrombolytic therapy during hospitalisation, with 5155 patients eligible for treatment on admission to hospital on the basis of established indications. Call-to-needle time for those eligible for treatment on admission fell from median 105 min in the first year of the project to 85 min in year 3 (P<0.001), and door-to-needle time fell from 45 to 35 min (P<0.001). Forty percent of eligible patients were treated within the then current national standard of 90 min from time of call for help, with nearly 49% in the final year and 20% being treated within the new national standard of 60 min, by the third year.

CONCLUSION

The proportion of eligible patients receiving thrombolysis within 1 h of the call for help doubled during the 3-year project but the majority of patients still wait longer than 60-min 'call-to-needle'. New systems to reduce delays to administration of thrombolysis to within 60 min of call for help are required, including consideration of pre-hospital treatment.

Nurse initiated thrombolysis in the accident and emergency department: safe, accurate, and faster than fast track

OBJECTIVE

To reduce the time between arrival at hospital of a patient with acute myocardial infarction and administration of thrombolytic therapy (door to needle time) by the introduction of nurse initiated thrombolysis in the accident and emergency department.

METHODS

Two acute chest pain nurse specialists (ACPNS) based in A&E for 62.5 hours of the week were responsible for initiating thrombolysis in the A&E department. The service reverts to a "fast track" system outside of these hours, with the on call medical team prescribing thrombolysis on the coronary care unit. Prospectively gathered data were analysed for a nine month period and a head to head comparison made between the mean and median door to needle times for both systems of thrombolysis delivery.

RESULTS

Data from 91 patients were analysed; 43 (47%) were thrombolysed in A&E by the ACPNS and 48 (53%) were thrombolysed in the coronary care unit by the on call medical team. The ACPNS achieved a median door to needle time of 23 minutes (IQR=17 to 32) compared with 56 minutes (IQR=34 to 79.5) for the fast track. The proportion of patients thrombolysed in 30 minutes by the ACPNS and fast track system was 72% (31 of 43) and 21% (10 of 48) respectively (difference=51%, 95% confidence intervals 34% to 69%, p<0.05).

CONCLUSION

Diagnosis of acute myocardial infarction and administration of thrombolysis by experienced cardiology nurses in A&E is a safe and effective strategy for reducing door to needle times, even when compared with a conventional fast track system.

Emergency nurse practitioners: a three part study in clinical and cost effectiveness

AIMS

To compare the clinical effectiveness and costs of minor injury services provided by nurse practitioners with minor injury care provided by an accident and emergency (A&E) department.

METHODS

A three part prospective study in a city where an A&E department was closing and being replaced by a nurse led minor injury unit (MIU). The first part of the study took a sample of patients attending the A&E department. The second part of the study was a sample of patients from a nurse led MIU that had replaced the A&E department. In each of these samples the clinical effectiveness was judged by comparing the "gold standard" of a research assessment with the clinical assessment. Primary outcome measures were the number of errors in clinical assessment, treatment, and disposal. The third part of the study used routine data whose collection had been prospectively configured to assess the costs and cost consequences of both models of care.

RESULTS

The minor injury unit produced a safe service where the total package of care was equal to or in some cases better than the A&E care. Significant process errors were made in 191 of 1447 (13.2%) patients treated by medical staff in the A&E department and 126 of 1313 (9.6%) of patients treated by nurse practitioners in the MIU. Very significant errors were rare (one error). Waiting times were much better at the MIU (mean MIU 19 minutes, A&E department 56.4 minutes). The revenue costs were greater in the MIU (MIU pound 41.1, A&E department pound 40.01) and there was a great difference in the rates of follow up and with the nurses referring 47% of patients for follow up and the A&E department referring only 27%. Thus the costs and cost consequences were greater for MIU care compared with A&E care (MIU pound 12.7 per minor injury case, A&E department pound 9.66 per minor injury case).

CONCLUSION

A nurse practitioner minor injury service can provide a safe and effective service for the treatment of minor injury. However, the costs of such a service are greater and there seems to be an increased use of outpatient services.

Managing thrombolysis in the accident and emergency department

The optimal management of acute myocardial infarction (AMI) today is founded upon the 'open artery' theory and driven by the need for early reperfusion strategies. Numerous randomised controlled trials demonstrate the unequivocal benefit of thrombolytic therapy in reducing mortality and improving long-term prognosis. These benefits are most striking when the thrombolytic therapy is given early. The National Service Framework for Coronary Heart Disease introduced national standards to reduce both 'call to needle' and 'door to needle' times to further augment early treatment. Subsequently many hospitals established 'fast track', 'nurse-led' or 'nurse initiated' thrombolysis within both the Accident and Emergency and Coronary Care Departments. This paper reviews these strategies and considers the benefits and limitations associated with the role of the 'thrombolysis nurse'. Thrombolysis nurses work to agreed protocols and play a fundamental role in the assessment and appropriate management of patients with acute MI. The evidence suggests that thrombolysis nurses are safe and effective in their practice and make a significant contribution to patient outcomes and enhance interprofessional education and practice.

Prehospital thrombolysis: lessons from Sweden and their application to the United Kingdom

OBJECTIVE

To study the successful implementation of paramedic administered prehospital thrombolysis in Sweden, and to consider the implications of this for the UK.

METHODS

A series of research visits were undertaken, including visits to Uppsala Hospital and dispatch centre, ambulance stations in several counties of Sweden and Dalarna County, which has one of the longest experiences of telemedicine supported prehospital thrombolysis in Europe. Data relating to prehospital thrombolysis, stages in successful implementation, and potential barriers to change were identified.

RESULTS

Two thirds of the hospitals in Sweden now have some form of prehospital thrombolysis. A nationally agreed and standardised training programme and the fact that many ambulance paramedics are also qualified nurses has facilitated successful introduction, but Sweden's low population density is also an important factor. Data from Dalarna County indicate that the median "pain to needle" time has been reduced by 45 minutes with a concurrent reduction in complications from 50% to 25% (p=0.018). Inhospital mortality has also reduced from 12% to 6%, but with the small numbers involved this improvement does not achieve statistical significance (p=0.36).

CONCLUSION

If the outcome of acute myocardial infarction in the United Kingdom is to be improved, and National Service Framework targets met, then prehospital thrombolysis is an important development. Several technical solutions already exist, and a single bolus thrombolytic agent is now available, but the main barriers to full implementation are related to the establishment of an effective training programme and the organisational changes that will facilitate this new practice. High quality research is urgently needed to guide the implementation of prehospital thrombolysis in a clinically and cost effective way.

The Sheffield experiment: the effects of centralising accident and emergency services in a large urban setting

OBJECTIVES

To assess the effects of centralisation of accident and emergency (A&E) services in a large urban setting. The end points were the quality of patient care judged by time to see a doctor or nurse practitioner, time to admission and the cost of the A&E service as a whole.

METHODS

Sheffield is a large industrial city with a population of 471000. In 1994 Sheffield health authority took a decision to centralise a number of services including the A&E services. This study presents data collected over a three year period before, during and after the centralisation of adult A&E services from two sites to one site and the centralisation of children's A&E services to a separate site. A minor injury unit was also established along with an emergency admissions unit. The study used information from the A&E departments' computer system and routinely available financial data.

RESULTS

There has been a small decrease in the number of new patient attendances using the Sheffield A&E system. Most patients go to the correct department. The numbers of acute admissions through the adult A&E have doubled. Measures of process efficiency show some improvement in times to admission. There has been measurable deterioration in the time to be seen for minor injuries in the A&E departments. This is partly offset by the very good waiting time to be seen in the minor injuries unit. The costs of providing the service within Sheffield have increased.

CONCLUSION

Centralisation of A&E services in Sheffield has led to concentration of the most ill patients in a single adult department and separate paediatric A&E department. Despite a greatly increased number of admissions at the adult site this change has not resulted in increased waiting times for admission because of the transfer of adequate beds to support the changes. There has however been a deterioration in the time to see a clinician, especially in the A&E departments. The waiting times at the minor injury unit are very short.