An analysis of over 1,000 medical and surgical patients receiving IV opioids for pain found that opioid-induced respiratory depression (OIRD) occurred in 46% of patients — a percentage greater than reported in previous clinical literature, according to study-sponsor Medtronic.

The PRODIGY study (PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY), was a prospective observational, multicenter study to quantify the incidence and identify patients at high risk of OIRD. The study evaluated 1,335 patients across 16 sites in the United States, Europe and Asia.

According to the study, one or more respiratory depression episodes were detected in 46% (614 of 1335) general care floor patients continuously monitored with capnography and pulse oximetry for a median of 24 hours. In addition, mean hospital length of stay was 3 days longer in patients with ≥1 respiratory depression episode, the study reported.

“PRODIGY data confirms that respiratory depression in patients receiving parenteral opioids occur frequently and are potentially unknown to hospital healthcare providers,” said Ashish K. Khanna, MD, primary study investigator and an associate professor of Anesthesiology, section head for Research and intensivist at the Wake Forest School of Medicine.

A key objective of PRODIGY was to develop and validate an accurate and easy-to-use risk assessment scoring tool. Using data from the study, Medtronic developed the PRODIGY Risk Score, a prediction tool to identify patients at high risk of respiratory depression who would benefit from continuous monitoring with capnography and pulse oximetry.

The PRODIGY Risk Score uses risk factors including: age > 60 years, male gender, opioid naïvety, sleep disorders and chronic heart disease for respiratory depression events risk prediction.

“The PRODIGY Risk Score has acceptable accuracy for risk stratification using several robust methods of internal validation, addressing significant gaps in preventing this common and potentially deadly condition,” said Frank Chan, vice president and general manager of the Patient Monitoring business, which is part of the Minimally Invasive Therapies Group at Medtronic. “Patients with respiratory depression were more likely to experience an adverse event that prolonged hospitalization and more likely to require rescue action, including rapid response team activation.”

“Together with risk assessment using the PRODIGY Risk Score, the use of capnography and oximetry for continuous monitoring of patients identified as high risk for respiratory depression may increase safety when parenteral opioid analgesia cannot be avoided,” Dr. Khanna added.