This prospective observational study investigated the validity and reliability of a new postoperative track assessment tool. We hypothesized, first, that this tool estimates the indication and benefit of a management in an intermediate care unit (IMC). Second, we hypothesized that a) health care providers of IMC or postoperative anaesthesia care unit (PACU) have similar estimations using this tool and b) that this estimation is accurately established in the first 2 hours.

The tool includes 2 visual analog scale (VAS) scores estimating indication of an IMC admission and benefit of an IMC stay. The tool was tested in a PACU and in an IMC unit of a Swiss tertiary centre in 2019/2020 (before COVID pandemic). Three raters: one nurse, one physician in charge and the consultant physician, were asked to fill the VAS at the same time for each included patient. The score was done in the 2 first hours following admission in the unit and during the multi professional morning round at day 1.

Reliability was estimated by testing internal consistency (homogeneity), interrater reliability and agreement and test-retest validity (stability). Validity included content validity, construct validity and criterion validity.

Inclusion Criteria:

• PACU patients admitted on Mondays
• IMC patients admitted 7:30am-7:30pm on weekdays

Exclusion Criteria:

• night admission
• PACU patient ASA < 3 or minor intervention

This study was a random sample from the PACU and IMC patients' population. Included patients' variables for demographic description of the population of interest and for the validity testing were: Age in years, gender (male / female), ASA physical score classification (ASA PS), do not resuscitate order (DNR), duration of intervention (min), severity of intervention (minor/intermediate/major), type of surgery (abdominal, orthopedic, trauma and other surgical and non-surgical interventions), elective or non-elective, palliative intervention, SAPS II (admission (2 h after arrival in IMC)), NEMS (admission (2 h after arrival) and during stay in IMC), SAS.

Participating raters were voluntary health care providers working in the peri-interventional unit (PACU and IMC).