Validation of 3-minute diagnostic interview for CAM-defined Delirium to detect postoperative delirium in the recovery room: A prospective diagnostic study

Abstract

Background: Recent guidelines on postoperative delirium (POD) recommend POD screening in all patients, using a validated tool, starting in the recovery room. An operationalisation of the Confusion Assessment Method (CAM) criteria, the 3-Minute Diagnostic Interview for CAM-defined Delirium (3D-CAM), has been developed for use in general medical units.

Objectives: The aim of this study was to evaluate 3D-CAM performance in an adult patient population to detect POD in the recovery room.

Design: A prospective diagnostic study.

Setting: Recovery room of a tertiary care university hospital in Berlin, Germany, in 2017.

Patients: Patients at least 18 years of age undergoing elective surgery.

Main outcome measures: Patients were subjected to evaluation by blinded investigators using the 3D-CAM and the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5, reference standard). Sensitivity, specificity and positive predictive value (PPV) and negative predictive value (NPV) were analysed for 3D-CAM, in addition to test-retest and inter-rater reliability analyses.

Results: Sixteen out of 176 patients (9.1%) developed POD. The 3D-CAM demonstrated strong test performance (specificity 0.88, sensitivity 1.0, area under the curve 0.94, PPV 0.44 and NPV 1.0), with a test-retest reliability of 90% (n = 10) and inter-rater reliability of 80% (n = 10).

Conclusion: In this diagnostic study, 3D-CAM showed strong performance for detection of POD in the recovery room. Due to the low training requirements, fast application and high sensitivity, it might be particularly appropriate for clinical staff with limited experience in the assessment of POD.

Trial registration: ClinicalTrials.gov Identifier: NCT02992717.