Wearable naloxone injector detects and reverses opioid overdose

December 23, 2021
Wearable naloxone injector detects and reverses opioid overdose

A team of scientists at the University of Washington (UW) have developed prototype wearable device that monitors breathing patterns to detect and reverse an opioid overdose. Successful trials of the automated system show its capability in administering care in the event of an unwitnessed overdose.

“The opioid epidemic has become worse during the pandemic and has continued to be a major public health crisis,” said Justin Chan, a UW doctoral student in the Paul G. Allen School of Computer Science & Engineering. “We have created algorithms that run on a wearable injector to detect when the wearer stops breathing and automatically inject [the antidote] naloxone.”

Naloxone must be administered quickly to be effective, and this is where the new device comes in, working as a ‘closed-loop’ — a fully automatic system triggered by feedback needing no human intervention.

The closed-loop system has an algorithm that triggers the injector in the presence of apnoea (breathing cessation) lasting more than 10 seconds. The simple design comprises a pair of accelerometers placed on the abdomen to measure respiration, a microcontroller to track the halt of motion associated with breathing, and an automated injection system to administer the naloxone dose.

The device also transmits breathing rates to a nearby smartphone via Bluetooth, adding an extra layer of safety.

“A closed-loop naloxone injector system has the potential to complement existing evidence-based harm reduction strategies, and, in the absence of bystanders, help make opioid toxicity events functionally witnessed and in turn more likely to be successfully resuscitated.”

The UW scientists tested the device on 25 volunteers in a supervised injection facility and another parallel trial in a hospital among participants who manifested signs of apnoea by holding their breath. The scientists said these trials were crucial to developing breathing algorithms involving real-world, opioid-induced changes.

[The tests measured breathing patterns only to develop the respiratory algorithm and did not involve the injection of naloxone due to the risk involving potentially fatal overdoses.]

In the first study, the scientists noted that the device could accurately track respiration rates among people with an opioid-use disorder and was also able to detect opioid-induced apnoea. In the second study, results showed that it took 16.9 to 25.9 seconds from an apnoea event for the injector to activate. The scientists verified the level of naloxone in the participant’s bloodstream before and after the injection, and noted no adverse reactions across all subjects in the study.

Based on these results, the scientists believe the system could deliver the antidote into the blood, showing its potential to reverse opioid overdoses. The scientists also admit studies are needed to assess the safety and portability of the device over more extended periods.

Category: Features, Technology & Devices

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