Comparison of the Zurich Observation Pain Assessment with the Behavioural Pain Scale and the Critical Care Pain Observation Tool in nonverbal patients in the intensive care unit: A prospective observational study

To determine the concordance of Zurich Observation Pain Assessment (ZOPA) with the behavioural Pain Scale (BPS) and the Critical Care Pain Observation Tool (CPOT) to detect pain in nonverbal ICU patients.; Prospective observational study [BASEC-Nr. PB_2016-02324].; A total of 49 ICU patients from cardiovascular, visceral and thoracic surgery and neurology and neurosurgery were recruited. Data from 24 patients were analyzed.; Three independent observers assessed pain with the BPS, the CPOT or ZOPA prior, during and after a potential painful nursing intervention. Tools were randomized concerning the pain management after each pain assessment. Frequency of nine additional pain indicating items from a previous qualitative, explorative study was calculated.; ZOPA was positive in 32 of 33 measuring cycles (97.0%; 95%CI: 84.2-99.9%), followed by the CPOT (28/33 cycles, 84.8%; 95%CI: 68.1-94.9%) and the BPS (23/33 cycles, 67.0%; 95%CI: 51.3-84.4%). In 22/33 cycles all tools were concordant (66.7%; 95%CI: 48.2-82.0%). Analgesics were provided in 29 out of 33 cycles (87.9%; 95%CI: 71.8-96.6%). Additional pain indicating items were inconsistently reported.; ZOPA is concordant with the BPS and the CPOT to indicate pain but detects pain earlier due to the low threshold value. Inclusion of further items does not improve pain assessment.