Dec 30 2014
A tool that surgeons use for monitoring a patient’s blood level in physicians’ offices may also save valuable minutes in medical decision-making for critically injured trauma patients, according to study results published in the January 2015 issue of the Journal of the American College of Surgeons (JACS).
The study, conducted by trauma surgeons at the University of Arizona, Tucson, evaluated the use of the Spot check Pronto-7® Pulse CO-oximeter in 525 critically injured patients. It is believed to be the largest study of such a device, according to the study authors.
Typically trauma surgeons draw a patient’s blood and send the sample to a clinical laboratory for analysis to get a reading on the patient’s blood level, or hemoglobin count, a process that can take 10 minutes or longer, according to lead study author Bellal Joseph, MD, FACS. The spot check device uses a fingertip sensor, much like that used in hospitals and doctors’ offices to take a patient’s temperature and pulse to provide a reading within 40 seconds. Hemoglobin level is a key indicator of internal bleeding, a life-threatening condition in the critically injured.
“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,” Dr. Joseph said. “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.”
Previous studies have found that up to 70 percent of deaths among trauma patients occurred within the first 24 hours of admission and attributed 30-40 percent of trauma deaths to severe blood loss, making quick and early detection and treatment of hemorrhage in critically injured patients important in saving their lives.
Of the 525 patients in the JACS study, 450, or 86 percent, underwent the Spot check measurements successfully. Each patient had three Spot check measurements with each invasive blood draw. The study authors found the Spot check readings had a strong correlation with the lab readings of blood samples. “It was actually very accurate between each measurement,” Dr. Joseph said.
Reasons the device did not work ranged from nail polish on the patient’s fingernails or particulate matter like dust or soot on the patient’s fingers, which disrupted the sensor reading, or because the sensor did not fit the patient’s finger, according to Dr. Joseph. While the device comes in three sizes, the research team only had access to one size.
The fingertip sensor has other advantages over traditional intravenous blood draw, Dr. Joseph said. “Sometimes patients are so severely injured when they come in, we have to place a special line in their neck or more central part of body to get blood,” he said. “It does not always have to be the extreme patient, but even the patient who seems fine may have internal bleeding.” The fingertip sensor can spare the patient the discomfort of a central line and save the trauma team the time and effort of placing it.
The test also has utility in pediatric and elderly trauma patients, according to Dr. Joseph. “When you’re trying to draw blood on a four-year-old, you can have five people holding him down,” he said. “And many elderly people do not have good veins, making it hard to insert an intravenous line. This device helps get a quick, accurate reading.”
In a previous study, the University of Arizona researchers found a third method of checking blood levels, known as continuous noninvasive monitoring. While it could provide results more quickly than the traditional blood draw, it did not consistently give accurate readings in injured trauma patients. Dr. Joseph also noted the continuous sensor can be impractical in trauma patients because of the severity of their injuries, the frequency with which they are moved around to different stations, and because many are under the influence of drugs and alcohol and can be “highly agitated.”
The study did not compare costs of the three methods, Dr. Joseph said, but that is a factor for future studies to investigate. Other next steps in studying the fingertip monitor in the trauma setting are implementation of a protocol for nurses to use it, extracting readings into the patient’s electronic medical records and using it to continually monitor blood levels in patients with severe organ injuries at set time intervals, according to Dr. Joseph.
Masimo of Irvine Park, Calif., manufactures the device, which also measures blood oxygen levels, pulse and blood flow. Masimo did not provide any funding or devices for the study, and Dr. Joseph and his team did not receive any compensation from the company. However, Dr. Joseph noted that the company will supply devices for a second study to learn more about how the monitor can be used in the trauma bay.