By Pat Anson, PNN Editor

With an increasing number of surgery patients being sent home from U.S. hospitals with little more than Tylenol for pain relief, it’s more important than ever to make sure that surgeries and post-operative recovery periods are as pain-free as possible.

A medical device that monitors anesthetized patients during surgery may do just that, letting doctors know when they should reduce or increase the use of pain medication. The PMD-200 monitor has been available in Canada, Europe and the UK for several years, but was just recently cleared by the FDA for marketing in the U.S.

Made by Medasense Biometrics, a medical technology company based in Israel, the monitor measures a patient’s nociception level (NOL) – their physiological response to pain -- through the use of a wearable finger probe that tracks their heart rate, blood pressure, sweat and movement. The monitor then uses machine learning to analyze the data and gauge a patient’s pain. Since fully anesthetized patients can’t speak or communicate during surgery, their NOL level essentially does the talking for them.

“We call it the signature of pain,” says Galit Zuckerman-Stark, CEO of Medasense. “During the surgery, if a physician sees the (NOL) number rising for more than one minute, he or she needs to consider giving more pain medication.”

The reverse is true as well. Surgeons may find that a patient doesn’t need as much medication as someone else who is more sensitive to pain. The goal is to provide individualized care -- the right dose at the right time for each patient.  

“We are very, very different from each other, both in terms of how the body responds to pain and also to medication. There can be a major difference between one patient and another,” Zuckerman-Stark told PNN.

In clinical studies in Europe, Medasense found that patients who had their opioid use guided by NOL were 70% less likely to have severe pain in the first 90 minutes after surgery. This was attributed to more objective and personalized opioid dosing during the surgery itself. 

Less pain during and immediately after surgery means patients will need fewer pain relievers when they are sent home – a key objective for many U.S. hospitals that are under pressure to reduce their opioid use.

"The anesthesia community has needed a technology like NOL for a long time," says Frank Overdyk, MD, a South Carolina anesthesiologist and consultant for Medasense.

"We have devices that monitor depth of anesthesia, we have TOF cuffs to check for patient movement, but the missing piece of the puzzle is a way to monitor the effect of the opioid or opioid sparing analgesia. Relying on patient's heart rate and blood pressure is neither specific nor sensitive enough to pain. This technology as an adjunctive to clinical judgment will provide a window into the patient's nociceptive state during surgery so we can personalize the way we administer analgesia, improving the patient's recovery."

This promotional video was produced by Medasense to help explain how the PMD-200 works:

In recent years, the amount of opioids prescribed in the U.S. for post-operative pain has plummeted, falling by 50% since 2017.

While many hospitals now send patients home from minimally invasive surgeries with acetaminophen or even gabapentin, most Americans still believe that opioids are necessary for pain after surgery. A 2021 Harris Poll found that 65% are more concerned about pain relief after surgery than opioid addiction and 60% prefer strong prescription painkillers over OTC pain relievers.