Intraoperative Use of Vasoactive Agents in Non-Cardiac Surgery: Protocol for a Post Hoc Cohort Study

Intraoperative hypotension is a well-known clinical condition and often treated with vasoactive agents. Previous cohort studies have indicated that large numbers of patients receive this treatment, but they have been limited to specific surgical populations or single agents. Furthermore, it is unknown which agents are the most frequently used and whether certain patient factors make intraoperative vasoactive treatment more likely. With this study, we aim to describe the proportion of patients receiving intraoperative vasoactive agents and the choice of agent; to highlight patient characteristics associated with the need for treatment and, finally, to describe prevalences of postoperative complications.

We will conduct a secondary study of the international cohort study 'Vasopressor use after non-cardiac surgery: an international observational study (SQUEEZE)', specifically focusing on intraoperative data from approximately 19,000 adult patients undergoing non-cardiac, non-obstetric, non-transplant surgery as in-patients. Data were collected at each participating site during one consecutive week between October 2020 and October 2023. The primary outcome is the proportion of patients who received intraoperative vasoactive treatment. The secondary outcomes are the proportion of patients receiving each one of the pre-specified agents and the proportion of patients experiencing pre-specified postoperative complications including death and hospital length of stay. We will descriptively present data on the prevalence of intraoperative use of vasoactive agents, the choice of agents, and postoperative complications. We will conduct logistic regression analyses to assess possible associations between baseline variables and use of intraoperative vasoactive therapy.

The outlined study will provide valuable epidemiological data on the intraoperative use of vasoactive agents in adult patients undergoing non-cardiac, non-obstetric, non-transplant surgery.