Troponin Use in A&E/EAU
Dr Gemina Doolub, Dr Gina Hadley, Dr Jeremy Dwight.
Abstract
Results
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.
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).
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.
Doctors
14%
60%
40%
Methods and Materials
Appropriate requests
Inappropriate requests
Fig 1-Percentage of appropriate tests
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.
Fig 2- Inappropriate tests by requester
400
350
300
Time post admission (min)
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.
Nurses
86%
250
200
150
100
50
0
Table 1-Criteria for appropriateness of request
Fig 3- Timing of 1st troponin test (mins)
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
Conclusions
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
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.
Congestive cardiac failure if new ECG changes or abnormal admission ECG
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 number
oAge
oReferral source (whether A&E or EAU)
oPresenting complaint
oAppropriateness of request based on above criteria
oRequester (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)
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.
References
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