February 28, 2019
2 min read

PRODIGY score identifies opioid-induced respiratory depression risk

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Ashish Khanna 2019
Ashish K. Khanna

A novel risk prediction tool, known as the PRODIGY score, accurately identified patients at high risk for opioid-induced respiratory compromise, according to data presented at the Society of Critical Care Medicine’s 48th Critical Care Congress.

“The general care floor is regarded as a safe haven for patients transitioning to leave the hospital,” Ashish K. Khanna, MD, associate professor of anesthesiology and intensivist at the Wake Forest School of Medicine, told Healio Primary Care Today. “However, sudden acute cardiorespiratory events are common in these settings. Opioid-induced respiratory depression is a common cause of these acute events. When these events occur, mortality is to the tune of up to 40%.”

“Our current monitoring standards on the floor are static, snap shots in time and usually fail to capture impending events, since a pattern change in vital signs is not detected in a timely fashion,” he added. “In addition, it remains difficult if not impossible to predict which patients are likely to deteriorate on the general care floor.”

Khanna and colleagues conducted a prospective, multi-center study known as PRODIGY (PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY) to develop a risk prediction tool to identify patients receiving opioid medication on hospital general care floors for postsurgical or nonsurgical pain who have a higher risk for opioid-induced respiratory depression.

The researchers studied 1,496 patients across 16 sites in the United States, Europe and Asia. They used the Capnostream respiratory monitor (Medtronic) to collect continuous capnography and pulse oximetry data. During the monitoring phase, screens were blinded and alarms were silenced, while standard monitoring, including spot-checking, were unblinded.

Respiratory depression was defined by having at least one of the following: etCO2 ≤ 15 mm Hg or ≥ 60 mm Hg for ≥ 3 minutes; respiratory rate ≤ 5 breaths for ≥ 3 minutes; SpO2 ≤ 85% for ≥ 3 minutes; apnea > 30 seconds; or a respiratory opioid-related adverse event.

Of the total study population, 41.4% demonstrated signs of respiratory depression.

In a modified analysis involving 1,384 monitored patients taking opioids, the researchers identified several positive predictors of opioid-induced respiratory depression, including age 70 and older, male sex, major organ failure, chronic heart failure or cardiac disease, coronary artery disease, COPD or pulmonary disease, pneumonia, type 2 diabetes, hypertension, kidney failure and opioid naivety. Negative predictors of opioid-induced respiratory depression included BMI 35 kg/m² or higher and asthma.

The researchers used five predictors, including age, sex, chronic heart failure, sleep disorders and opioid naivety, to develop a validated, novel risk prediction tool for opioid-induced respiratory depression, known as the PRODIGY score. The score ranged from 0 to 39, with low risk between 0 and 7, intermediate risk between 8 and 15 and high risk more than 15.


The score identified 76% of the patients with confirmed respiratory depression.

“The PRODIGY score was able to correctly estimate an increasing risk of respiratory depression episodes, with significant intergroup separation at all levels,” Khanna said. “For example, a patient at the highest risk of respiratory depression based on the score was at a 6 times higher risk compared with a patient at the lowest risk.”

The tool should be used as a bedside measure of assessment of risk and allows clinicians and nurses to triage patients to continuous monitoring and other proactive interventions, according to Khanna. – by Alaina Tedesco



Khanna AK, et al. Derivation and validation of a novel opioid induced respiratory depression risk prediction tool. Presented at: Society of Critical Care Medicine’s 48th Critical Care Congress; Feb. 17-20, 2019; San Diego.

Disclosures: Khanna reports receiving consulting fees for the PRODIGY Trial Steering Committee.