Definition of clinically relevant intraoperative hypotension: A data-driven approach

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Perioperative Medicine

Background:

• Intraoperative hypotension (IOH) definitions vary across studies, hindering comparability and clinical application.
• Previous research lacks clarity on which IOH definitions best predict key postoperative outcomes.
• This study addresses the need for standardized IOH definitions to improve patient outcome prediction.

Purpose of the Study:

• To identify the most effective definitions of intraoperative hypotension (IOH).
• To determine IOH definitions that best predict 30-day mortality, hospital length of stay (hLOS), and postanesthesia care unit length of stay (PACU-LOS).
• To provide data-driven recommendations for IOH definition selection in clinical practice and research.

Main Methods:

• A retrospective cohort study involving 65,454 patients undergoing noncardiothoracic surgery.
• The dataset was divided into two subsets: one for selecting optimal IOH definitions and another for independent validation.
• Statistical analysis focused on associations between various IOH definitions and postoperative outcomes.

Main Results:

• Nearly all tested IOH definitions showed associations with adverse outcomes, with risk increasing as mean arterial pressure (MAP) decreased.
• The optimal definitions identified were: relative time with MAP <80 mmHg for 30-day mortality, lowest MAP for one minute for hLOS, and lowest MAP for one cumulative minute for PACU-LOS.
• Independent validation confirmed the significant associations between these selected IOH definitions and the studied outcomes.

Conclusions:

• This study identified data-driven, best-fitting definitions for intraoperative hypotension (IOH) concerning 30-day mortality, hLOS, and PACU-LOS.
• The findings underscore the critical importance of carefully selecting IOH definitions for accurate outcome prediction.
• Standardizing IOH definitions can enhance the reliability and clinical utility of research in perioperative medicine.