AT THE AAST ANNUAL MEETING
WAIKOLOA, HAWAII – Use of an automated bedside blood monitoring platform was safe and effective in measuring glucose in critically ill patients, results from a pivotal, prospective multicenter trial demonstrated.
“The hypermetabolic stress response to injury is a well-known entity following injury,” Grant V. Bochicchio, MD, FACS, said at the annual meeting of the American Association for the Surgery of Trauma. “Hyperglycemia has been shown to be intimately associated with this response. Numerous studies have reported that hyperglycemia has been associated with increased infection and worse outcome in critically injured trauma patients.” In addition, several studies have demonstrated that the glucose meters used for trauma patients are inaccurate, whether in relation to anemia or other factors, said Dr. Bochicchio , chief of acute and critical care surgery at Washington University, St. Louis.
He presented results from a trial that evaluated the safety and accuracy of a continuous inline glucose monitor in 200 critically ill and trauma patients. The OptiScanner , an investigational device manufactured by OptiScan Biomedical, automatically measures plasma-based glucose levels to enable early detection of hypoglycemia, hyperglycemia, or glucose variability. The OptiScanner has yet to be cleared by the Food and Drug Administration, but Dr. Bochicchio said that he expects a decision from the agency in the next several months.
The system includes the device itself as well as a single-use, disposable cartridge, which is the only point of contact with the patient’s blood. A proprietary zero-depth space connector seamlessly attaches a disposable cartridge to the patient’s IV line, to ensure that blood flows smoothly without the need for heparin. “The OptiScanner automatically draws blood and the spectrometer measures blood glucose directly from the plasma sample without the need of calibration,” Dr. Bochicchio said. “Plasma glucose results are then displayed on the screen along with a trending graph of the glucose values. If the glucose values move outside of the desired range, the OptiScanner alerts the clinician by displaying the glucose value against a red background. We’re actually measuring [blood glucose] at the time of the patient in the ICU without having to send it to a lab, without having to wait 4 hours for a turnaround. This is where we have to go with ICU medicine.”
The purpose of the current trial was to evaluate the safety and accuracy of the OptiScanner in patients admitted to one of four ICUs who had an expected length of stay of 18 hours and required glucose monitoring. To be eligible they had to have a central line in place and could not have hematocrit level of less than 15% or greater than 60% on enrollment, and they had to be able to connect to the proximal port of the central venous catheter. Enrollment was defined as time of connection to the OptiScanner. Patients could remain connected for up to 72 hours. Blood draws were performed every 15 minutes, and a comparative sample was drawn within a 2-minute window at a minimum of 1-hour interval. The paired blood samples were then spun down for plasma within 15 minutes by the study team and analyzed twice by the Yellow Springs Instrument STAT Plus Glucose and Lactate Analyzer , which is the gold standard for measuring blood glucose levels remotely.
The primary endpoint was a mean absolute relative deviation (MARD) of 10% or less, while the secondary endpoint was a population coefficient of variance (PCV) of 13% or less. The mean age of the 200 patients was 62 years, 69% were male, 83% were white, and their mean Apache II score was 15.1. An analysis of 3,735 paired readings revealed that the mean MARD was 7.6%, “which is better than what we set our objective for,” Dr. Bochicchio said. The mean PCV was 9.8%, “which was the ideal,” he said. “So we achieved our primary and secondary objectives.” More than half of patients (52%) exhibited at least one form of dysglycemia, while 25% of patients exhibited at least one episode of hypoglycemia, severe hyperglycemia, or glycemic variability.
The invited discussant, Dennis Y. Kim, MD, FACS , noted that glucose control remains a key tenet of modern-day critical care. “It’s difficult to ignore the numerous technical and logistical challenges involved in obtaining a rapid and accurate glucose measurement upon which protocolized management decisions can be instituted,” said Dr. Kim, a surgeon at Harbor-UCLA Medical Center, Los Angeles. “Reliability of point of care devices, the ever-increasing work demands on our ICU nurses, and lack of sufficient data points to permit analysis of trends are but a few of the issues surrounding glycemic control. Dr. Bochicchio and his colleagues are to be congratulated on the present study, which proposes a potential solution to the aforementioned problems in managing hyperglycemia in the ICU.”
The study was funded by OptiScan Biomedical. Dr. Bochicchio reported having no financial disclosures.