Survey of Opioid-Induced Respiratory Depression in Critically Ill Patients Without Mechanical Ventilation and Construction of a Risk Nomogram

Abstract Objectives To investigate the current status of opioid-induced respiratory depression (OIRD) and potential risk factors in critically ill patients without mechanical ventilation in the intensive care unit (ICU) and to construct a risk nomogram to predict OIRD. Methods A total of 103 patients without (or who were weaned from) mechanical ventilation who had stayed for more than 24 h in the ICU between June 1, 2021 and September 31, 2021, were included. Patient data, including respiratory depression events, were recorded. The least absolute shrinkage and selection operator regression model were used to select features that were then used to construct a prediction model by multivariate logistic regression analysis. A nomogram was established for the risk of respiratory depression events in patients without mechanical ventilation. The discriminatory performance and calibration of the nomogram were assessed with Harrell’s concordance index and a calibration plot, respectively, and a bootstrap procedure was used for internal validation. Results Respiratory depression was diagnosed in 49/103 (47.6%) patients. Factors included in the nomogram were cardiopulmonary disease (odds ratio [OR]=5.569, 95% confidence interval [CI]=0.751–118.083), respiratory disease (OR=32.833, 95% CI=4.189–725.164), sepsis (OR=6.898, 95% CI=1.756–33.000), duration of mechanical ventilation (OR=3.019, 95% CI=0.862–11.322), lack of mechanical ventilation (OR=20.757, 95% CI=2.409–502.222), and oxygenation index (OR=7.350, 95% CI=2.483–24.286). The nomogram showed good performance for predicting respiratory depression events in critically ill patients without mechanical ventilation. Conclusion The nomogram can be used to identify ICU patients without mechanical ventilation who are at risk of opioid-induced respiratory depression and may therefore benefit from early intervention.