Original contribution
It is safe to manage selected patients with acute coronary syndromes in unmonitored beds1

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Abstract

This prospective, observational study evaluated the safety of the Western Hospital admission protocol for patients with suspected acute coronary syndromes. The study included all patients admitted from the Emergency Department with an admission diagnosis of unstable angina, post infarct angina, atypical chest pain, or chest pain for evaluation. Data collected included demographic data, admission diagnosis, location of admission (bed with or without cardiac monitoring), past medical history and presenting chest pain history to determine Agency for Health Care Policy (AHCPR) and Western Hospital(WH) protocol classifications, cardiac enzyme assays, electrocardiogram analysis, adverse outcomes [death, myocardial infarction (MI), dysrhythmia, acute pulmonary edema, recurrent pain], diagnosis at hospital discharge, and length of stay(LOS). There were 508 patients with a mean age of 63.7 years enrolled in the study. Three hundred nineteen (62.8%) were admitted to beds without any cardiac monitoring. There was one unexpected death in the unmonitored group, an 85 year-old patient who suffered a presumed dysrhythmia and whom the treating physician had decided was not for resuscitation. Twelve patients suffered nonfatal MI, and none suffered pulmonary edema. All MI patients made an uneventful recovery, and none required thrombolysis. If all patients had been admitted to an area of care based on AHCPR guidelines, an additional 310 admissions to monitored beds would have been required. The results of this study suggest that selected patients with suspected acute coronary syndromes can be safely managed in beds without continuous cardiac monitoring.

Introduction

In most Australian hospitals, it is the usual practice to admit patients suffering suspected acute coronary syndromes (ACS), such as unstable angina, to areas of care that have continuous cardiac monitoring such as coronary care units (CCU). The rationale for this approach is predicated on the assumption that the benefits afforded by cardiac monitoring to patients with myocardial infarction (MI) also apply to those with ACS. Although this assumption has not been confirmed by research, the requirement for cardiac monitoring for patients with suspected ACS has been reinforced by the Agency for Health Care Policy and Research (AHCPR, USA) and the National Health and Medical Research Council (Australia) guidelines on the management of unstable angina 1, 2. This practice places significant stress on a limited number of monitored beds, has proven to be costly, and may result in admission delays (or on occasion, transfer between hospitals) for patients with proven MI (3).

Recent studies from the United States have shown that a subgroup of patients with ACS can be safely managed in telemetry areas and have questioned the need for monitored beds for these patients (4).

In 1997, in response to problems accessing CCU beds and a high number of acute inter-hospital transfers caused by shortages of CCU beds, Western Hospital (WH) undertook a comprehensive, multi-disciplinary review of chest pain admission policies. This evidence-based review aimed to improve the efficiency of using monitored beds, to improve access to CCU beds for patients who had suffered MI, and to provide safe management for patients suffering unstable angina or other suspected ACS. The process and results of this protocol development have been reported previously 5, 6. The outcome was an admission protocol (WH protocol) that triaged selected patients with ACS considered at low risk of adverse events to care in ward beds without cardiac monitoring. Criteria for admission to an unmonitored bed are: pain that is relieved with glyceryl trinitrate (GTN) spray or tablet or morphine, a normal or unchanged electrocardiogram (EKG), and cardiac enzyme (CK/CKMB) level within the normal range at presentation to the Emergency Department (ED). Conversely, a patient who requires i.v. GTN for chest pain relief, who has an abnormal or changed EKG (defined as ST elevation or depression, T wave inversion or new conduction defect), or who has an elevated CK/CKMB level is admitted to the CCU. Although encouraged, the protocol is not enforced rigidly. Individual doctors may choose to assign patients to the CCU if they consider them to be at high risk.

The WH admission protocol is at odds with current international practice guidelines (1). The dichotomy between the WH protocol and AHCPR guideline lies in the management of patients with unstable angina, and more specifically, those who fall into the AHCPR intermediate classification. The AHCPR guidelines recommend these patients be admitted to monitored beds for a period of usually not less than 24 h, whereas the WH protocol triages many of these patients to unmonitored beds. It has been proposed that the classification system as proposed within the AHCPR guidelines needs to be validated, or invalidated, based on clinical data, as a means of refining and modifying the proposed model (7).

The objectives of this project were:

  • 1.

    To evaluate the safety of the WH admission protocol for patients with suspected ACS.

  • 2.

    To compare outcomes and resource use between the approach recommended by the AHCPR guidelines, “intention-to-treat” application of the WH protocol, and application of the WH protocol as occurred in reality.

Section snippets

Setting

Western Hospital is a 346-bed university teaching hospital located in Melbourne, Australia. The ED has an annual census of 36,000 adult patients with an admission rate of 40%. During the study period, the hospital had 12 monitored cardiology beds. The ED is staffed by six emergency physicians and 20 residents ranging in experience from PGY1 to PGY10. The majority of the residents are undertaking training toward specialization in Emergency Medicine. All shifts are supervised by an Emergency

Results

During the study period, 508 patients met the inclusion criteria, and all were entered in the study. For the same period, there were 22,446 presentations to the ED. There were 211 women and 297 men in the study group with an age distribution of 25 to 95 years (mean 63.7 years; median 64 years). Forty-three patients (9%) were classified as high risk by the AHCPR criteria, 449 (88%) as intermediate risk, and 16 (3%) as low risk.

Three hundred and nineteen patients (62.8%) were admitted to ward

Discussion

In most Australian hospitals, it is usual to admit patients suffering suspected ACS to monitored beds in, for example, the CCU or stepdown areas. The benefit of this practice has not been confirmed by research but has been reinforced by the AHCPR and NHMRC guidelines on the management of unstable angina. This practice places significant stress on a limited number of monitored beds, is costly, and may result in delays to admission (or, on occasion, a requirement for transfer between hospitals)

Conclusion

The results of this study suggest that selected patients with suspected ACS can be safely managed in beds without continuous cardiac monitoring.

Acknowledgements

The authors would like to thank Dr. Robert Newman, and Mrs. Liz Edmonds for their assistance in protocol development and implementation.

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    1

    Original Contributions is coordinated by John A. Marx, md, of Carolinas Medical Center, Charlotte, North Carolina

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