Delphi-study for the construction and pilot validation of the withdrawal ICU ScalE (WISE)

OBJECTIVES: There is currently no validated tool for the screening and assessment of iatrogenic withdrawal syndrome in the adult ICU population. The main objective of this study is the development of the Withdrawal ICU ScalE (WISE) METHODS: The design was a two-round Delphi study and a prospective observational pilot validation study. The Delphi study was conducted using an international group of experts, consisting of (neuro)intensivists, ICU-nurses, and pharmacists. The validation study was conducted in the ICU of a general and academic hospital in the Netherlands among adult ICU patients, receiving mechanical ventilation ≥ 48 h and opioids or sedation ≥ 3 days. RESULTS: During the Delphi study the experts deemed 19 out of 45 items relevant for inclusion in the WISE. We tested feasibility with ICU-nurses resulting in merging some items. Finally, the WISE consisted of 17 items. For the validation study, each shift nurses filled out the Numeric Rating Scale (NRS)-withdrawal and WISE for included patients. A total of 131 patients met the inclusion criteria, for 41 patients' consent was obtained. Of those, data were obtained of 36 patients with a median age 56 years old. A total of 362 paired measurements of NRS-withdrawal and WISE were conducted. The NRS-withdrawal and WISE had a correlation of 0.37 and showed an Area Under the Curve (AUC) of 0.73. The NRS-withdrawal had a median of 0 (IQR 0 - 2), where the WISE had a median of 2 (IQR 2 - 4). The Intra Class Correlation (ICC) of the WISE was 0.92 single measures. CONCLUSIONS: This study shows that the WISE is a promising assessment tool for screening IWS in adult ICU-patients. Further validation in a large multicentre validation study is needed. IMPLICATIONS FOR CLINICAL PRACTICE: While promising, the WISE needs further validation before clinical use is possible.