- A wrist-worn wearable could provide early warning of the severe acute pain episodes that affect patients with sickle cell disease.
- Researchers at Children's Hospital Los Angeles (CHLA) tested the idea that the narrowing of blood vessels predicts the events in a clinical trial that reported data in 2019. They partnered with Biostrap to develop the blood flow biomarker that year.
- Biostrap, which sells a wearable that measures changes in blood volume, issued a statement about the collaboration ahead of World Sickle Cell Day on June 19.
In recent years, a team at CHLA has worked to validate the idea that the pain crises experienced by people with sickle cell disease are driven by vasoconstriction, the medical term for the narrowing of blood vessels. The idea is that the narrowing of the vessels reduces blood flow and thereby increases the likelihood that red blood cells will become lodged.
The studies showed that photoplethysmography (PPG), a way to measure changes in blood volume that is used in pulse oximeters, can predict the painful vaso-occlusive crises that affect patients with sickle cell. PPG monitors blood volume by measuring changes in light absorption and the researchers used the technology to record the median magnitude of vasoconstriction (Mvasoc).
In their work to validate the use of PPG to detect pain crises, the CHLA researchers used devices that attach to the finger. Such devices are commonly used in medical settings to track variables including blood oxygen levels but are unsuited for continuous use.
Wrist-worn wearables could make Mvasoc more useful for people with sickle cell disease. Rather than having to manually attach a sensor, patients could wear a device on their wrist and automatically collect Mvasoc data. That thinking led the researchers at CHLA to partner with Biostrap in 2021.
The only cure for sickle cell anemia is regular blood transfusion or bone marrow transplant, which is not available for everyone, meaning a pain crisis may occur suddenly and without a noticeable warning. The Biostrap wearable could change that, the company said in an emailed statement.
Researchers hope the wearable will be able to detect the onset of a pain crisis days before the patient feels it. That early detection would be key for administering medications or other interventions early, lowering the risk of severe pain or complication, or hospitalization.
“We are really excited about this collaboration with CHLA,” Biostrap CEO Sameer Sontakey said in the statement. “We’ve always believed in the power of raw PPG. There’s so much knowledge embedded deep into it, and the biomarker CHLA researchers are developing shows the beauty of what PPG has to offer to the world in managing various health conditions.”
Other companies sell wearable devices that use PPG to track variables other than Mvasoc. Apple, for example, uses the technology in the optical heart sensor in its Watch wearable device, as does Masimo.