Troponin Use in A&E/EAUDr Gemina Doolub, Dr Gina Hadley, Dr Jeremy Dwight.

Abstract

Objectives-The purpose of this audit was to ascertain whether troponin tests were requested appropriately for admissions via A&E and EAU (Emergency admissions Unit) at the John Radcliffe Hospital. Methods-Data was collected on two 24-hour periods. Admissions were monitored on the electronic whiteboard through Case-Notes. Primary outcome was whether troponin was appropriately requested based on criteria set by cardiologists. Results- 55 patients had one or more troponin tests requested.40% of these requests were found to be inappropriate. One patient admitted with urine retention was started inappropriately on dual antiplatelets. The cost of inappropriate tests totaled £280.00. Conclusion- Although there were no adverse events in patients sampled during this audit, one patient was started inappropriately on ACS treatment based on an inappropriate test.

There were a total of 55 acute admissions that had troponin tests sent to the laboratory on the days audited (27 during the first 24 hour and 28 during the second).

The average patient age was 72.3 years. Of the 55 patients, 9 were admitted through EAU and the majority through A&E. There were 33 appropriate troponin tests. This means that 40% of the troponin tests requested for consecutive admissions over a 24 hour audit period were requested inappropriately. It is important to note that one patient was started inappropriately on ACS treatment based on an inappropriate test.

The cost of the inappropriate troponin tests totaled £280.00 (including repeat troponins). By extrapolation this would represent an unnecessary annual cost of £51,100 per annum. The mean time for the first troponin was 365 minutes. Of the inappropriately requested troponin tests, only one was requested by EAU, and the remainder by A&E. 86% of inappropriate troponin requests were requested by nursing staff (19/22), the rest being requested by doctors in A&E (ST5 an above as well as staff grades). This should be interpreted with caution as the majority of blood tests are requested by nursing staff anyway.

Results

1. Troponin I sensitivity and specificity for the diagnosis of acute myocardial infarction. J. Am Osteopath Assoc. 2000 Jan; 100(1): 29-32

2. NICE (March 2010). Chest pain of recent onset Assessment and diagnosis of recent onset chest pain or discomfort of suspected cardiac origin www.nice.org.uk/nicemedia/live/

http://www.alfascientific.com/alfa-products/cardiac-markers/troponin-i

References

Data were collected on two 24-hour periods for all admissions to A&E and EAU. The first sampling period was 08:00 on 15th May 2011 until 08:00 on 16h May 2011. The second was 07:00 on 26th June 2011 until 07:00 27th June 2011. The investigator was resident on level 1 of the John Radcliffe Hospital in 12 hour shifts.

Admission were monitored on the electronic whiteboard and follow up was through a combination of reading notes and using ‘Case-Notes’. Data was collected using Proforma 1. The primary outcome was whether the troponin test was requested appropriately. The criteria for deciding whether a troponin test was appropriate or not were decided by experienced cardiologists at the John Radcliffe Hospital.

Methods and Materials

This audit was presented at several local meetings, and guidelines for requesting troponin tests have emerged after discussion with cardiologists and ED staff. This audit will be re-audited in the near future to assess implementation of these guidelines in the Emergency department and on EAU.

The key message from this audit should be extended to the wards for junior staff to review existing patients where they might inappropriately request a troponin test. This may prevent the ACS protocol being started inappropriately in a population at risk of falling and the inherent risks of anticoagulating this population.

Conclusions

Introduction

Troponins are selective biomarkers for damage to the myocardium. Some caution should however be attached to interpreting these results, as they are not 100% specific. Troponin levels can be raised for e.g. in sepsis, pulmonary embolus and acute renal failure. Starting patients on ACS protocol i.e. dual antiplatelets, is not without risk. Further to the risk of intracerebral bleed, administering anticoagulants in the context of an aortic dissection could prove fatal. In addition to spontaneous intracerebral bleed, the population most at risk of falls are the very people who present to the acute service. There are also financial implications of inappropriate troponin tests. Each test costs £10.00. In this age of austerity, this is certainly something we should be mindful of. The appropriateness of troponin tests is likely to become more pertinent given more rapid bedside tests that are being developed (i-STAT).

The following information was collected for each patient:

oDate of admission (time that they were first entered on Case-Notes was taken to be admission time)oPatient hospital numberoAgeoReferral source (whether A&E or EAU)oPresenting complaintoAppropriateness of request based on above criteriaoRequester (doctor or nurse and their grade)oTiming of test (minutes/hours after admission)oTest result (positive or negative)oAction taken (e.g. patient started on ACS protocol in situations where troponin levels should not have been measured in the first instance)

Table 1-Criteria for appropriateness of request

Chest pain of ANY nature

Breathlessness and pulmonary oedema on CXR

Breathlessness and new ECG changes or abnormal admission ECG if no previous

Syncope with new ECG changes or abnormal admission ECG if no previous

Unexplained hypotension and new ECG changes or abnormal admission ECG if no previous

Stroke/TIA only if new ECG changes or abnormal admission ECG if no previous

New onset AF or atrial flutter

Sepsis only if new ECG changes or abnormal admission ECG if no previous

Congestive cardiac failure if new ECG changes or abnormal admission ECG