254
JOURNAL OF PUBLIC HEALTH MEDICINE
References 1 Collins SE, Haining RP, Bowns IR, et al. Errors in postcode to enumeration district mapping and their effect on small area analyses of health data. J Publ Hlth Med 1998; 20(3): 325–330. 2 Aszkenasy M, Hutchison S. Births, gestation and birthweights in South Tees, 1990–1996. J Publ Hlth Med 2000; 22: 457–461. 3 Crofts DJ, Bowns IR, Williams TS, et al. Hitting the target – the equitable distribution of health visitors across caseloads. J Publ Hlth Med 2000; 22: 295–301. 4 Spencer NJ, Logan S, Gill L. Trends and social patterning of birthweight in Sheffield, 1985–94. Arch Dis Child 1999; 81: F138–F140.
Yours faithfully, David M. B. Hall Professor of Community Paediatrics Alan S. Rigby Senior Lecturer in Statistics and Epidemiology Ian R. Bowns Senior Research Fellow T. Sim Williams Research Associate Debbie Crofts Research Health Visitor University of Sheffield SCHARR Community Sciences Centre, Northern General Hospital, Sheffield S5 7AU
Treatment of acute myocardial infarction Sirs, In their paper describing a method of improving door-to-needle time for the thrombolysis of patients with myocardial infarction, Lloyd et al.1 have shown that the intervention of skilled health care workers can greatly improve decision-making for time-critical interventions. Even allowing for the Hawthorne effect in this non-randomized unblinded evaluation, the addition of the extra staff to the emergency department (ED) to expedite formal diagnosis and administer drugs is not really comparable with the control period where no extra staff were available to hasten the treatment of these patients. Conclusions drawn from this intervention should be based upon this fact. It should also be noted that the previous method of acute myocardial infarction (AMI) diagnosis and treatment (‘usual practice’) is inherently slow, requiring the on-call medical team to see the patient after the ED doctor has done so. Often the patient then had to wait until transfer to the coronary care unit (CCU), before thrombolysis was administered. Even during the study period the CCU nurse practitioners delayed thrombolysis to transfer the patients to CCU (five patients who could have
started treatment within 30 min, but did not do so). It is clear from the literature that ED staff, medical or nursing, administering thrombolysis in the ED provide a far more rapid door-toneedle time than systems requiring CCU admission first.2 It is also of concern that despite having an additional staff member employed and a 24 h rota of CCU nurses, four (5 per cent) patients still had delayed thrombolysis as a result of ‘failure to attend the patient’. The authors’ conclusion that cardiac nurse practitioner prescribing of thrombolysis is safe has not been proven in the study. Despite the additional training and operation under strict protocol of such staff, eight patients thrombolysed after the intervention were judged to have inappropriate thrombolysis, whereas 11 patients did beforehand; it is hard to see this as much of an improvement. The comparison presented in the paper seems spurious, as the authors’ percentages (73 per cent versus 36 per cent) are percentages of patients with no significant cardiac enzyme rise. A more valid analysis would have been inappropriate thrombolysis within the whole cohort (thus 15 per cent versus 10 per cent, p 0.37). No information is provided in the paper about other adverse events or differences in 30-day mortality between the two groups. In their discussion, the authors are somewhat disparaging about the ‘casualty’ nursing and medical staff. They suggest such staff have less experience with AMI, yet all of the patients with community onset of AMI (i.e. the study population) would have arrived via the triage nurse in the ED. Although much can be made of the reported ‘deeper understanding’ of the CCU staff regarding coronary presentations, it should be remembered that CCU staff generally treat only patients with proven acute coronary syndromes. Over 90 per cent of patients attending the ED with chest pain, collapse or sudden onset of breathlessness do not have any acute coronary syndrome at all, and it is the ability to rapidly screen and select high-risk patients that is one of the key skills of the triage nurse in the ED. After all, according to the authors, the CCU nurse practitioners attended the ED only after the triage nurse had performed a primary assessment. Thus, the triage nurses were an integral and vital part of the reported success of the study in time improvements. The simple answer is that having appropriate triage criteria for determining high-risk patients, performing a 12-lead ECG within 10 min of arrival, and having strict protocols for staff to follow in the ED that allow for immediate decision-making will lead to rapid improvements in door-to-needle times for thrombolysis in AMI.3–5 Whether the staff involved are the ED nurses, the CCU nurses or the ED doctors is irrelevant. What has been proven to delay the times are unnecessary time spent in decisionmaking, in the past mostly by inadequately supported junior doctors, and unnecessary transfer to CCU for the thrombolytic to be commenced. Clear clinical decision pathways and protocols can be followed by medical as well as nursing staff, and further work in this area needs to explore multidisciplinary treatment pathways that can be followed by any of the team members.
CORRESPONDENCE
References 1 Lloyd G, Roberts A, Bashir I, et al. An audit of clinical nurse practitioner led thrombolysis to improve the treatment of acute myocardial infarction. J Publ Hlth Med 2000; 22(4): 462–465. 2 Hourigan CT, Mountain D, Langton PE, et al. Changing the site of delivery of thrombolytic treatment for acute myocardial infarction from the coronary care unit to the emergency department greatly reduces door to needle time. Heart 2000; 84(2): 157–163. 3 Somauroo JD, McCarten P, Appleton B, Amadi A, Rodrigues E. Effectiveness of a ‘thrombolysis nurse’ in shortening delay to thrombolysis in acute myocardial infarction [see comments]. J R Coll Phys Lond 1999; 33(1): 46–50. 4 Saturno PJ, Felices F, Segura J, Vera A, Rodriguez JJ. Reducing time delay in the thrombolysis of myocardial infarction: an internal quality improvement project. ARIAM Project Group. Analisis del Retraso en Infarto Agudo de Miocardio. Am J Med Qual 2000; 15(3): 85–93.
255
5 Wilmshurst P, Purchase A, Webb C, Jowett C, Quinn T. Improving door to needle times with nurse initiated thrombolysis. Heart 2000; 84(3): 262–266.
Yours faithfully, Peter Leman Consultant in Emergency Medicine Niall O’Connor Consultant in Emergency Medicine Emergency Department, St Thomas’ Hospital, Lambeth Palace Road, London SE1 7EH E-mail:
[email protected]
