Can point-of-care testing save your patient's life?
Decisions happen more quickly
"Our ED does several point-of-care tests," she says. "All are quick, accurate, life-saving, and cost-effective. They are well-validated tools that allow decision-making to happen more quickly."
According to a recent study, as lab turnaround time decreased from 120 minutes to 10 minutes, the average ED length of stay also decreased (from 2.77 hours down to 2.17 hours) and average daily throughput increased (from 104 patients to 120 patients).1
Technology improves flow
EDs should consider processes to improve turnaround time, such as point-of-care testing, to obtain these goals, says Alan B. Storrow, MD, the study's lead author and vice chairman for research and academic affairs in the Department of Emergency Medicine at Vanderbilt University Medical Center in Nashville, TN.
"I believe ED nurses and lab personnel will be increasingly relied upon to improve patient flow through implementation of technologies such as point-of-care testing," Storrow says.
Vanderbilt administrators are discussing the possibility of doing more point-of-care testing in the ED, reports Gary Howard, RN, MHA, director of emergency services. ED nurses do some point-of-care testing now for human immunodeficiency virus screening, urinalysis, and blood glucose. Soon, ED nurses might perform tests for cardiac markers, venous thrombosis markers, electrolytes, renal function, sepsis, and complete blood count.
"Point-of-care testing is expensive, as a general rule, and does not produce the hoped-for revenue downstream, as is often stated when arguments are being made for this," he says. "That said, it does enable clinical decisions to made more rapidly than the conventional method of the utilizing a central laboratory."
Speed your treatment
Rapid identification of positive cardiac markers for myocardial infarction can speed appropriate treatment and save heart muscle, adds Storrow. "Negative markers can decrease the time to exercise or similar testing," he says. "Faster identification of electrolyte disorders, such as abnormalities in sodium or potassium, can speed potentially life-saving therapies."
In Vanderbilt's ED, nurses doing a fingerstick blood glucose can decide in a minute or less whether a patient needs insulin or glucose. "The alternative is the blood has to be drawn, labeled, and the specimen sent to the lab. From there, the specimen has to be processed and ran with results reported out," says Howard. "That process could take an hour or longer."
Point-of-care testing is likely to result in better outcomes for patients with clinical problems that are improved with faster time to treatment, such as cardiac ischemia and infarction, hyperkalemia, hyponatremia, life-threatening anemia, hypoglycemia, and some infections, says Storrow.
"In addition, other diagnostic tests that require a lab result prior to starting will be able to be performed more expeditiously," says Storrow. "For example, our patients with chest pain and nondiagnostic initial EKGs frequently wait on cardiac markers to determine whether aggressive anti-ischemic treatment needs to be started. Point-of-care testing allows that decision to be made in minutes."
- Storrow AB, Zhou C, Gaddis G, et al. Decreasing lab turnaround time improves emergency department throughput and decreases emergency medical services diversion: A simulation model. Acad Emerg Med 2008; 15:1-6.
These POC tests can be 'literally lifesaving'
Results are less painful and cheaper
Below are some point-of-care (POC) tests done by ED nurses at Harborview Medical Center in Seattle:
• Blood glucose testing at the bedside.
"Over the years, the monitoring and management of hyperglycemia has changed," says Darlene Matsuoka, RN, MN, CEN, CCRN, ED clinical nurse educator at Harborview. The strict normoglycemic protocols instituted by intensive care units (ICUs) have relaxed, she says. Current target goals for insulin drips range between 100 mg/dL-140 mg/dL for ICUs or 80 mg/dL-180 mg/dL for inpatient floors.
"In the ED, we realize that even a patient with a normal glucose may change during the hours of his stay," she says. For this reason, ED nurses check glucose levels for a Type I diabetic every two hours, and they check levels every six hours for a Type II diabetic.
"Having an Accu-Chek machine allows serial finger sticks to be done quickly instead of venous lab draws. This is less painful, and cheaper," says Matsuoka.
• Urine toxicology screens.
ED nurses use Syva RapidTest d.a.u. 10 (manufactured by Deerfield, IL-based Siemens Healthcare Diagnostics) with 10 indicators. They are methamphetamines, opiates, cocaine, cannabinoids, phencyclidine, benzodiazepines, barbiturates, methadone, tricyclic antidepressants, and amphetamines. (See the ED's competency validation checklist for urine drug abuse screens.)
The screening device requires six drops of urine, costs about $15, and detects even low levels of drugs used by the patient several days ago. "The volume of chemically impaired patients or patients who need drug screening at our ED is high," says Matsuoka. "The staff use it on trauma patients, medicine patients, and psych patients when there is altered mentation or possible drug use. We do about 30 tests a day."
However, when ED nurses first started using the urine tox screens, the hospital's psychiatric emergency services staff were skeptical of the accuracy. To address this concern, side-by-side testing was done comparing results of laboratory and point-of-care tests. "A patient who showed up negative on the lab urine tox, showed up positive for THC [tetrahydrocannabinol] with the point-of-care test. The patient admitted to having done THC days ago," says Matsuoka.
Getting these results quickly "is of utmost importance," says Matsuoka. "Having the HemoCue machine available is literally life-saving," she says. "With trauma patients, a dropping or low hemoglobin value means immediate blood transfusions, and decisions to go to angio or the OR."
The ED switched last year from using a hematocrit centrifuge spinner to the HemoCue Hb 201 machine (manufactured by Lake Forest, CA-based HemoCue). Even though the values obtained by centrifuge spinning were very accurate, there were problems with blood splatter, potential exposure, and frequent breakdowns, says Matsuoka.
"The HemoCue machine is ED breakdown-resistant and provides values quickly," says Matsuoka. "We look for Hgb values that drop more than one point — an approximate hematocrit change of 3%. Our ED averages 60 tests a day."