What follows are highlights from these studies:

HSS Study Uses Machine Learning to Predict Risk of Long-Term Pain After Knee Replacement Surgery

A new study led by researchers at HSS used a type of AI known as machine learning (ML) to identify key clinical and biological factors that raise a person’s risk of having persistent pain after total knee arthroplasty (TKA). Risk factors included elevated levels of certain inflammatory cytokines (proteins) in the blood, severe preoperative pain, and a longer period of tourniquet use in the operating room.

“These findings highlight the importance of incorporating biological markers like cytokine levels with patient-specific pain profiles and what the surgeon does during the operation to more accurately predict the risk of long-term pain after surgery,” says Meghan Kirksey, MD, PhD, an anesthesiologist at HSS and senior author of the study.

ML is a specialized approach that uses algorithms and statistical models to analyze patterns in large amounts of data to learn, predict, and make recommendations.

“Machine learning is allowing us to look at patient and clinician information in new ways,” says Alexandra Sideris, PhD, Director of the HSS Pain Prevention Research Center and a coauthor of the study. “It gives us a multidimensional approach to understanding patients’ pain experience that we didn’t have in our arsenal even five or 10 years ago.”

One in five people has significant knee pain months after having TKA, also known as total knee replacement surgery. “The lingering pain greatly affects their daily activities and quality of life, so that’s why it’s an important focus for us,” explains Dr. Sideris.

Persistent postoperative pain (PPP) is typically flagged when a patient has lasting pain at the site of the operation that is above a four on a scale of zero to 10 and severely impacts their activities of daily living three to six months after surgery.

The researchers used four different ML models to analyze data from a previously published study that collected comprehensive clinical information and blood samples from 160 patients before and after TKA at HSS. The new study identified key predictors associated with PPP beyond risk factors that were already known such as sex (women tend to have a higher risk), preexisting pain, and mental health issues like anxiety and depression.

The findings showed that having high blood levels of an inflammatory marker called TARC immediately after surgery raises the risk of PPP. “This molecule hasn’t been extensively studied in pain, but the evidence shows that it was consistently associated with persistent pain six months after surgery across all four ML models we tested,” notes Dr. Kirksey.

Other top predictors of PPP that emerged from the analysis included a higher preoperative pain score at rest, longer tourniquet time (a tourniquet is a device that squeezes the leg to help clear the area of blood flow during surgery), and higher blood levels of other inflammatory cytokines right after surgery.

In this study, researchers entered 318 clinical and biological characteristics collected from patients in the older study and asked each of the ML models to figure out the most important features associated with pain after TKA. The researchers also evaluated the accuracy of the ML models they used and found that XGBoost was the most informative.

“To my knowledge, this is the first study that looked at all of this information and tried to make sense of the best ML approach to use,” says Dr. Sideris. “What is exciting to us is that there was one feature – TARC – that consistently popped up across all four models and it wasn’t on anybody’s radar beforehand…this gives us hope that ML can help us identify with high integrity targets that haven’t been studied before.”

The researchers note that more research is needed to know if their findings can be used to impact clinical care. “Our goal is to be able to use these tools and data to tailor pain management strategies, prevent long-term complications, and personalize treatment decisions,” says Dr. Kirksey.

HSS AI Analysis Reveals What Patients Are Googling About Local Anesthesia

A new study by researchers at HSS used AI to systematically evaluate the types of questions that patients are Googling related to regional (local) anesthesia, identify websites that are frequently presented in search results, and assess the quality of the information provided.

“We knew that patients frequently search for information about anesthesia online, but we wanted to know exactly what they were looking for so that we could proactively address these topics and concerns in our conversations in the clinic and our patient education materials,” says Jashvant Poeran, MD, PhD, Director of Research in the Department of Anesthesiology, Critical Care and Pain Management at HSS and lead author of the study.

The analysis found that most patients’ questions focused on risks, complications, and details surrounding medications, awareness during sedation, nerve block duration, and the recovery process. The study also found that while the overall quality of information accessed during Google searches was accurate, the source of that information was not always clear.

Anesthesiologists see patients in the clinic for a short period to prepare them for surgery and manage expectations.

“There’s so much information being conveyed during that limited time that sometimes patients forget what to ask, or they don’t even know what they should be asking during the visit,” explains Dr. Poeran. “Our study results will help us anticipate some of their questions and give us a starting point when we sit down with them so it’s not so much of a guessing game.”

The researchers entered seven search terms into Google Web Search: “regional nerve block,” “regional anesthesia,” “peripheral nerve block,” “pain block,” “neuraxial anesthesia,” “epidural anesthesia,” and “spinal anesthesia.” The top 200 questions in the “People Also Ask” section and its associated websites were collected, totaling 1,400 question and website combinations.

The authors then used AI to categorize themes and assess website quality. They found that most questions pertained to facts around risks and complications, comparisons between different techniques and approaches, technical details, and indications.

“We were expecting questions around risks and complications, but it was surprising that so many patients were looking at technical details, specifically around sedation,” notes Dr. Poeran. “They were not always aware that you can be awake for a peripheral nerve block, for example.”

Because patients’ questions are linked to specific websites, researchers also wanted to know where patients were being referred to and how reliable the information presented was. The AI analysis found that 55% of websites were academic, 19% were government, and 11% were public/social media sources. Information on government and academic/hospital websites scored the highest in terms of accuracy, and medical practice websites scored the lowest.

Dr. Poeran cautioned that some patients’ questions are nuanced, and online information can bias a person in the wrong direction.

“For example, if you ask whether regional anesthesia is better than general anesthesia you will be able to get generic information about those approaches online, but you need to talk to your doctor to get a more personalized recommendation based on your specific circumstances,” says Dr. Poeran.

While the study revealed important questions, it’s not all-encompassing. “There will be questions that aren’t captured by this study, but anesthesiologists can use this data to guide their consultations with patients scheduled for surgery, provide more-informative patient education materials, and refer them to the most reliable websites for more information,” notes Dr. Poeran.

He plans to continue leveraging AI in his future research endeavors.

“Based on the information we gathered, we will update our educational materials with the questions we now know patients ask most often and may even provide it in different languages and reading levels,” says Dr. Poeran. “We can then use AI to see how that information is perceived and understood by patients, study differences in search terms entered in different languages, etc.”

“Obstructive sleep apnea affects 40 million adults in the United States and is associated with an increased complication risk among patients undergoing surgery,” said Stavros Memtsoudis, MD, PhD, Anesthesiologist-in-Chief and Chair of the HSS Department of Anesthesiology, Critical Care & Pain Management. “Guidelines on the perioperative management of OSA patients undergoing surgery are backed by limited evidence. Current recommendations include preoperative screening for OSA and preoperative initiation of CPAP therapy. However, it remains unclear how often this recommendation is followed and how much it reduces complication risks.”

This information is especially important as healthcare systems shift from inpatient to outpatient hip and knee replacement surgery, where patients cannot be monitored as closely for perioperative complications.

To evaluate whether CPAP use among OSA patients prior to surgery led to improved outcomes compared with those patients who did not use CPAP, the researchers extracted more than 100,000 cases of outpatient hip and knee replacement surgeries performed between 2018 and 2022 from the Merative MarketScan national claims data (representing patients and their dependents with employer-sponsored healthcare coverage). The primary outcome of interest was a visit to the emergency department within one day post-discharge, which acted as a stand-in to represent post-discharge complications. The researchers conducted three comparisons: 1) patients with OSA who used a CPAP machine before surgery, compared with patients who did not; 2) patients with OSA who did not use a CPAP machine before surgery, compared with patients without OSA; and 3) patients with OSA who used CPAP before surgery, compared with patients without OSA.

The researchers found that OSA patients who underwent CPAP therapy before hip and knee replacement surgery (19% of 123,349 total hip/knee procedures studied) experienced fewer emergency department visits within one day after discharge compared with OSA patients who did not receive CPAP therapy before surgery. In addition, pre-surgical CPAP use in patients with OSA lowered their risk for complications to a similar level as patients without OSA.

“These findings are significant as they support the notion that adhering to these guidelines can benefit OSA patients undergoing surgery,” said Jashvant Poeran, MD, PhD, Director of Research in the HSS Department of Anesthesiology, Critical Care & Pain Management.  “While we had anticipated these results based on the guidelines, this is the first study to demonstrate this on such a large scale.”

This study offers key insights for both patients and clinicians on ways to reduce the risk of complications after surgery.

“It informs patients with OSA to engage in conversations with their perioperative physicians about strategies to lower their complication risk, including the preoperative initiation of CPAP therapy,” said Dr. Poeran. “Additionally, this research highlights the advantages of preoperative initiation of CPAP therapy. We believe that this study strengthens the evidence supporting the benefits of preoperative CPAP therapy and will encourage both patients and clinicians to consider its increased use.”

While further validation of these findings is necessary, particularly in other surgical cohorts such as elective general surgery, these findings represent a significant advancement in recognizing the benefits of preoperative initiation of CPAP therapy.

“These findings could influence care by emphasizing the importance of preoperative identification of OSA patients who are scheduled for surgery and subsequent initiation of CPAP therapy,” Dr. Poeran said.

In addition to replicating these findings in other surgical cohorts, future research should also examine subgroups of patients in which preoperative CPAP therapy may be even more beneficial. “These subgroups might include patients with multiple risk factors, such as OSA and obesity or other chronic conditions, as well as those with varying needs for opioid management.”

“Follow-up studies could investigate looking at other recommendations outlined in the guidelines such as preoperative screening for OSA and enhanced monitoring. This increased monitoring is crucial as hospital stays shorten and more and more surgeries are performed in an outpatient setting without an overnight stay and the subsequent opportunity to monitor these patients,” Dr. Poeran concluded.

Reference

1. Jashvant Poeran MD PhD, Haoyan Zhong MPA, Alex Illescas MPH, Lisa Reisinger MD, Crispiana Cozowicz MD, Periklis Giannakis MD, Jiabin Liu MD PhD, Stavros G. Memtsoudis MD PhD MBA. “Preoperative CPAP Use is Associated with Improved Outcomes in Patients with Obstructive Sleep Apnea Undergoing Orthopedic Surgery.” Presented at: Society of Anesthesia and Sleep Medicine (SASM) 14th Annual Meeting, October 18, 2024; Philadelphia, PA.