More than 70% of all dug overdose deaths involved an opioid in 2019, the most recent study published by the CDC. Naloxone is a medicine that quickly reverse opioid overdoses. Naloxone is usually injected, although the FDA has also approved a nasal spray. In 2018, we wrote about an opioid overdose detection wristband wearable developed by students at Carnegie Mellon’s Institute for Software Research that detects an opioid overdose by measuring blood oxygen level with an oximeter. If the software detects descending oxygen levels it sends an alert to pre-established emergency contacts via an associated smartphone.

A research team at the University of Washington’s Allen School of Computer Science and Engineering recently published the results of a proof-of-concept wearable device that detects and then reverses an opioid overdose by injecting naloxone. Published in Scientific Reports, the study found that the closed-loop system has the potential to successfully resuscitate people from opioid overdoses when there is no bystander available to administer an injection.

The UW wearable administers naloxone when it detects apnea. The device has sensors that measure respiration and an algorithm that identifies opioid overdose-induced apnea. When the algorithm detects an opioid overdose it activates a commercially available injection system to inject naloxone subcutaneously. The study is the result of a multiyear collaboration with West Pharmaceutical Services of Exton, Pennsylvania, the company that developed the wearable injector. The system can also send data to an associated smartphone.

The study included two groups of volunteer participants. In one test with a group of 25 people with opioid use disorder, the testing showed the device was able to detect opioid-induced apnea: a state that commonly occurs prior to potentially fatal overdose. The device did not inject naloxone to the first group. A second group of 20 healthy subjects held their breath for 15 seconds, enough to trigger the wearable system to detect the lack of movement and inject naloxone.

The two studies showed the system could detect overdose apnea and deliver the life-saving drug. Next steps include studying discreteness and comfort for long term use of the wearable in unsupervised settings.

Our previous coverage of wearable closed-loop systems focuses on artificial pancreas solutions for people with diabetes. It will be interesting to follow further development of closed loop systems such as the one at UW that can reverse life-threatening opioid overdoses.