Editor's Note: Since this story was originally published, Ashish Khanna, MD, who was interviewed for the story, has taken a new position. He is now an associate professor of anesthesiology and intensivist at the Wake Forest School of Medicine.
Anyone who has ever been a hospital patient on a general care floor should be familiar with the standard vital check routine in which a nurse enters the room every four- to six-hours to chart your blood pressure and other vital signs to monitor your condition.
But what if your condition suddenly deteriorates in between those routine checks? Is there a better way to monitor these patients? Ashish Khanna, MD, an anesthesiologist and researcher at the Cleveland Clinic believes there is.
"The problem with that approach is that we are essentially seeing our patients at a snapshot of time and ignoring large chunks of time where they are possibly showing signs of deterioration," Khanna told MD+DI.
In a manuscript recently published by the Journal of Critical Care, Khanna described how challenging it is to predict episodes or severity of cardiorespiratory decompression in patients who appear to be in stable condition and staying on the general care floor. The paper also describes the protocol for an ongoing global trial that could go a long way toward better monitoring protocols to detect signs of deterioration earlier.
The PRODIGY trial builds on an earlier study at Cleveland Clinic that Khanna was involved with. The investigators put all of the institution's post-surgical patients who were recovering on the general care floor on continuous monitoring but blinded the clinicians to the monitoring by covering up the device and silencing the monitor's alarms.
"We uncovered that 90% of our patients had some degree of hypoxemia, meaning oxygen saturation less than 90%, that was going undetected because of our current monitoring patterns," Khanna said. "This is not to say that an institution like Cleveland Clinic is not doing a good job of monitoring, but what I’m saying is that we didn’t even know this problem existed."
The researchers published that paper about four years ago and Khanna said he published a series of subsequent papers in an effort to look at potential predictors of hypoxemia. The problem, he concluded, is that hypoxemia is very unpredictable and there isn't a good prediction model to understand which patients are at risk for cardiorespiratory depression. Worse yet is the fact that about 40% of patients who develop the condition end up dying, according to some studies, he said.
The primary goal of the PRODIGY trial (PRediction of Opioid-induced Respiratory Depression In Patients Monitored by capnoGraphY) is to derive a risk prediction score for respiratory depression (RD) on the general care ward. Khanna said the validation-derivation cohort design of the trial will derive this score from RD detected by continuous, blinded, multiparameter cardiorespiratory monitoring of patients. The trial will use Medtronic's Capnostream 35 portable respiratory monitor.
The trial is being conducted across 16 centers in seven different countries (four in Europe, three in Asia, and nine in the United States) and will include a total of 1650 patients. All of the PRODIGY patients will be put on continuous cardiorespiratory monitoring for at least 48 hours using the Capnostream device, which Medtronic inherited through its Covidien acquisition, but like the earlier study, the clinicians will be blinded to the monitor because the researchers want to understand how these respiratory depression patterns happen, Khanna said. The patients will continue to receive the standard vital sign monitoring every four to six hours as normal.
Khanna said the data will help uncover patterns to determine real-time predictors of which patients are likely to experience respiratory depression, when they might experience it, and which patients should receive more intensive monitoring than the current standard of care.
“My hope is that someday you’re going to walk into a hospital and you’re going to get a smart device, almost like an iWatch, on you that will continuously monitor you through your surgery, through your stay in the hospital, and possibly even after you go home because these events happen at home as well,” Khanna said. "The PRODIGY trial is going to push a step closer to better monitoring and allow for quicker recovery for our patients."
In addition to post-surgical patients, the trial will include patients receiving opioid therapy, either through an IV or an epidural.
"We wanted to see, based on our current pain practice guidelines, how we could better improve monitoring to allow patients a safer recovery in our hospitals," he said. "Because it is a global trial it gets even more interesting because pain prescription practices are not the same across the world. They’re very different in Asia, and in Europe."
Khanna said the researchers want to find out if opioids are part of the problem, or if there are genetic or cultural factors that make some patients more prone to respiratory compromise than others.
Is Continuous Cardiorespiratory Monitoring Cost Effective?
While the investigators of the PRODIGY trial won't be able to analyze cost data from all of the patients included in the trial because of regulatory restrictions in certain parts of the world, Khanna said they should at least be able to analyze the cost-effectiveness for about 50% of the patients enrolled. Such data could help hospital administers decide if investing in continuous capnography monitoring devices like the Capnostream would be a worthwhile investment for at least some patients on the general care floor.
“In the end, nothing speaks like hard data. My hope is that once we’re able to prove that there is a prediction model that can be effectively used to understand who needs more intensive monitoring and then we can ultimately show that it’s cost effective, we will hopefully move in that direction."
But simply purchasing the equipment and putting patients on continuous monitoring is one step of a more complicated process toward preventing respiratory depression. Khanna said bedside nurses will need to be educated on how to use the equipment and integrate continuous monitoring into their workflow. It will be a cultural change and will take some time, he said, probably "another few years" before this type of monitoring is used effectively in the general care environment.
The trial is expected to be completed before the end of the year and Khanna said the results should be available to the public in early 2019.