Trauma-related hemorrhage is a leading cause of death among adults under 45 years old, as well as children of all age groups. As outlined by medical professionals at the Portland-based Oregon Health & Science University (OHSU), a core diagnostic challenge is determining the volume of blood loss, or conversely, the volume of blood remaining in circulation.
As such, OHSU startup QuantiPort, Inc. has developed a system for measuring blood volume quickly and accurately, the organization’s officials attest. This system specifically aims to help identify patients who have lost significant blood volume as well as to detect ongoing blood loss. The startup’s leaders contend that its technology provides objective blood volume information to physicians in minutes, rather than hours.
Indeed, they say, the QuantiPort Blood Volume Measurement Device (Blood Volume MD) provides advance warning and a valuable head start for physicians to initiate emergency therapeutic intervention prior to patient decompensation, overt shock and death.
Using a mini-spectrophotometer with a small display module that docks onto an adhesive patch over the skin, the device measures the dilution and elimination of an injected tracer to determine blood volume in about seven minutes. In addition to total blood volume, other diagnostically relevant information is reported, including red cell and plasma volume, hemoglobin, hematocrit and venous oxygen saturation, according to OHSU officials. Importantly, they add, the test may be repeated every 15 minutes so that physicians can see the effects of therapeutic interventions in real time.
As explained by Hobbs, “Traditional methods for measuring blood volume utilize radioiodinated human serum albumin (131I-HSA) as a tracer that is injected intravenously, and five consecutive blood draws are then taken at fixed time intervals. The concentration of the tracer in each consecutive blood sample is measured and a linear extrapolation of the concentrations to time zero is performed. As a radioactive isotope, 131I requires special handling, storage, and disposal, often requiring a nuclear medicine laboratory.”
Hobbs continues, “Additionally, the injection of a radioactive isotope prohibits this technique from being applied to pregnant women and children. Furthermore, patient preparation, injection, serial blood collection, sample preparation, and sample analysis steps delay results for several hours in many cases. During this time, patient status may change dramatically, thereby diminishing the clinical relevance of the results once obtained. The 131I-HSA tracer remains in the circulation for up to 24 hours, prohibiting repeat measures within the same day. Finally, the 131I-HSA tracer has an eight-day half-life, resulting in a short shelf life. Frequent replacement of the tracer is expensive and produces additional radioactive waste.”
However, to address these limitations, QuantiPort’s innovative method for determining blood volume “utilizes an optical fiber positioned within a peripheral vein that measures the concentration of an injected fluorophore or chromophore (non-radioactive) tracer. Rapid repeat measures—every one to two seconds—of circulating tracer concentration are used to determine blood volume in vivo patient-side within a few minutes,” Hobbs says.
In this manner, Hobbs explains, “Hundreds of data points are used for the blood volume calculation, as opposed to the traditional use of five data points for this calculation, thus theoretically improving accuracy. The proposed method involves no radioactive substance use or exposure, no serial blood samples, no laboratory processing, and will be relatively inexpensive. The rapid acquisition of patient blood volume will allow clinicians to utilize this information for immediate decision making and to monitor the effects of therapeutic interventions by simply leaving the optical fiber in place and comparing repeated measures over short time intervals. Fast, safe, and inexpensive blood volume determination is disruptive technology that will become standard practice in the management of trauma, transfusion medicine, and critical care cases,” he says.
The project is funded through a combination of DoD SBIR (Small Business Innovation Research), ONAMI (Oregon Nanoscience and Microtechnologies Institute) Launch, and Business Oregon Matching grants. The device also received funding and support from the Biomedical Innovation Program. QuantiPort is currently seeking FDA Breakthrough Device designation.
Hobbs adds that the startup is still in the development stage of the device, so it’s not yet been used in humans, but that tests in rhesus macaque subjects “are very promising.”
