Fingertip Blood Sensor Could Speed Trauma Triage

By Chuck Seegert, Ph.D.

Using an instrument typically found in physician’s offices, trauma surgeons have found a way to save time when making medical decisions. After an evaluation, the researchers determined that a device called the Pronto-7 Pulse CO-oximeter produces results with similar accuracy to traditional laboratory tests in as little as 40 seconds.

When a critically injured patient arrives at the hospital for treatment, every minute counts. In some cases, patients may have experienced severe blood loss, which accounts for 30 to 40 percent of trauma deaths, according to a recent press release from the American College of Surgeons. While external bleeding can easily be diagnosed, internal bleeding is harder to detect. In order to determine a patient’s blood level, surgeons typically use a laboratory test called a hemoglobin count, which is a key indicator of internal bleeding.

Unfortunately, traditional hemoglobin tests can take up to 10 minutes, which can be far too long for a critically injured patient. The new method, called “spot checking,” uses a fingertip sensor similar to those used to measure a patient’s pulse, and can provide a reading within 40 seconds.

“This device was initially intended for outpatient medical offices to obtain readings of people who were anemic, but the ability to get hemoglobin readings with a device that one places on the finger intrigued us,” said lead author Bellal Joseph, M.D., in the press release. “It can help make a medical decision very quickly about where this patient needs to go—to the operating room or intensive-care-unit—without waiting for laboratory results. It gives us immediate information that we otherwise could not get.”

Dr. Joseph and colleagues tested the device on a group of 525 patients by comparing spot checking to traditional, invasive hemoglobin laboratory tests, according to a recent study published by the team in the Journal of the American College of Surgeons. The spot checking was done side-by-side with the traditional lab testing for each patient, with two non-invasive readings taken per invasive test. Patients included in the study had a mean injury severity score of 21 +/- 13, and about 38 percent of patients had a hemoglobin level of <8 mg/dL. Results showed that the average value of invasive hemoglobin was 11.5 +/- 4.36 g/dL, while the spot check was 11.1 +/- 3.60 g/dL. The spot check values were strongly correlated with the invasive tests and were seen to be about 76 percent accurate with a sensitivity of 95.4 percent.

In addition to hemoglobin, another critical factor in trauma care is how well a patient’s blood will clot. Recently, a light-based test was developed that can quickly and easily measure this property.