Game-changing point-of-care testing: Improving ACS diagnosis in the emergency department

Emergency department (ED) overcrowding is a global issue that has been linked to negative consequences for patient care and outcomes. Dr. Martin Than, Director of Emergency Medicine Research at the Christchurch Hospital in New Zealand, tells us more about the need for rapid decision making in the emergency department. He also shares the ways in which implementing point-of-care (POC) cardiac troponin testing could potentially help in addressing the issue of overcrowding while outlining key considerations for successful integration of POC assays.

Many studies conducted in hospital EDs worldwide – some involving analysis from over 15 million patients – have shown that overcrowding is correlated with fundamental patient harm¹. Additionally, overcrowding is inconvenient to patients and increases the clinical and administrative burden on hospital staff. Research shows that for an ED that houses 10% of its patients for more than six hours, the mortality and morbidity for every patient in that department goes up by 10%². “Longer-than-necessary patient length of stay is a primary contributor to ED overcrowding, which can lead to mistakes in patient diagnosis and treatment. Looking for ways to reduce length of stay may sound like an operational task or even management speak, but it is fundamental to good patient care and patient outcomes,” explains Than.

Enabling rapid decision making in emergency medicine

In developed countries, one of the most commonly presenting patient groups to the ED are patients with possible heart attack (acute myocardial infarction or AMI). AMI is an urgent condition triggered by a blood clot in a coronary artery and is defined by the death of cardiac muscles.

Typically, electrocardiograms and other tests are used to identify patients who are suspected of acute myocardial infarction some of whom may then be moved up to the catheterization lab for further treatment.Negative patients, on the other hand, may have appropriate follow-up arranged, and are then released. Statistics show that it is actually a small proportion (5-15%, depending on the healthcare setting^3,4) of all presenting patients that suffer from acute myocardial infarction. For ED specialists, it is crucial to swiftly identify the patients with suspected acute myocardial infarction, from the 80% or so who don’t, says Than. “Currently, central lab tests only provide results after a turnaround time of 60-90 minutes. However, our research shows that time from ED attendance to patient examination, to aligning on next steps, needs to be around 30-40 minutes to enable optimal decision making,” he explains. “If the result is not back within this timeframe, then the clinician will not be able to plan further management before moving on to tasks with another patient, and it may take some time before they can return”.

This is where POC assays such as the high-sensitivity cardiac troponin (hs-cTn) test can help in rapid decision making and potentially reduce the length of stay for patients in ED settings. The hs-cTn results aid in the diagnoses of acute myocardial infarction which facilitates the institution of timely treatments and enables appropriate disposition decisions. “The turnaround time of the troponin test is eight minutes, shorter than with central lab assays, meaning that test results are promptly available to the clinician and that they can also be actioned upon immediately. This short turnaround is crucial in emergency medicine,” adds Than.

Key considerations for implementing POC testing

High diagnostic accuracy is essential to getting buy-in from clinicians to use a POC test. But, developing a reliable and reproducible POC assay like the hs-cTn is only part of the battle won, cautions Than. Other challenges remain, such as introducing the tests into existing healthcare settings in a structured manner. Essential to addressing such challenges, notes Than, is providing clear guidance on how different test levels need to be integrated in a patient context and outlining the decision making that flows from this integration.

Successful integration of POC testing involves cross-speciality, such as the nursing staff, the lab members, and physicians from other specialties including general medicine and cardiology. “Additional investments may also be required, in terms of staff training and time to perform the tests,” continues Than. “The teams need to be aligned on the big picture, that the tradeoffs in terms of patient length of stay and outcome make the initiative well worth the work.”

It is also important to be cognizant of the needs of the specific setting into which the POC test is being introduced. If a hospital has already integrated similar capabilities and is familiar with the workings of POC testing, integration can be straightforward. However, significant setup issues can arise when tests are deployed in a point-of-care naïve environment. “Planning ahead ensures that POC testing can be deployed in a safe and effective manner,” asserts Than. “POC manufacturers, hospital management and staff need to systematically consider and address requirements on connectivity, power and data outlets, staff training, operational changes, safe disposal of waste, and much more.”

The future of point-of-care testing

Combining high-sensitivity troponin tests along with other diagnostic tools, such as computed tomography (CT), holds the promise of providing meaningful data to optimize long-term patient care, says Than: “In the near future, with information from patient history and clinical examination, supported by predictive weightings from tests like hs-cTn and CT, we will be able to determine the likely probability of a patient developing problems from coronary artery disease.” Powered by modern-day advances in machine learning and data analytics, making accurate estimations on medium- and long-term risk from such diseases will soon become a reality, he continues.

Even in the short term, with improved turnaround times and ready results enabling rapid decision making, Than predicts POC hs-cTn tests are set to have an immense impact on healthcare systems overall. “In primary care, particularly in rural areas where patients might have to be transferred long distances to get a lab test or hospital assessment, POC testing will prove to be crucial. Other potential value-adds it can provide include enabling testing for certain groups such as low-risk patients or in specific settings such as in ambulances. These endless possibilities make POC tests a fundamental game changer for healthcare,” concludes Than.

Learn more about the impact of high-sensitivity cardiac troponin testing at the point of care by watching our video series with leading clinicians on The Scientists’ Channel.

References:

Guttmann A, Schull MJ, Vermeulen MJ, Stukel TA. Association between waiting times and short term mortality and hospital admission after departure from emergency department: population based cohort study from Ontario, Canada. BMJ. 2011

Jones PG, van der Werf B. Emergency department crowding and mortality for patients presenting to emergency departments in New Zealand. Emerg Med Australas. 2021

Goodacre S, Cross E, Arnold J, Angelini K, Capewell S, Nicholl J. The health care burden of acute chest pain. Heart. 2005

Pitts SR, Niska RW, Xu J, Burt CW. National Hospital Ambulatory Medical Care Survey: 2006 emergency department summary. Natl Health Stat Report. 2008