Association between postinduction hypotension and postoperative mortality: a single-centre retrospective cohort study

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Surgical Outcomes

Background:

• Hypotension during anesthesia is common.
• Distinguishing between postinduction hypotension (PIH) and intraoperative hypotension (IOH) is crucial for understanding patient outcomes.
• The association of PIH and IOH with postoperative mortality requires further investigation.

Purpose of the Study:

• To determine if postinduction hypotension (PIH) and intraoperative hypotension (IOH) are associated with 30-day and 90-day postoperative mortality.
• To analyze the impact of hypotension, defined as mean blood pressure < 65 mm Hg, on patient survival after noncardiac surgery.

Main Methods:

• Retrospective cohort study of adult patients (ASA I-IV) undergoing noncardiac surgery under general anesthesia (2015-2021).
• Calculation of four hypotensive indices, with time-weighted hypotension as the primary exposure.
• Multivariable logistic regression, propensity score matching, and RUSBoost for sensitivity analyses to assess the association between hypotension and mortality.

Main Results:

• Postinduction hypotension (PIH) was not associated with 30-day (aOR 1.03) or 90-day (aOR 1.01) postoperative mortality.
• Intraoperative hypotension (IOH) was significantly associated with increased 30-day (aOR 1.19) and 90-day (aOR 1.12) postoperative mortality.
• Sensitivity analyses confirmed the association of IOH, but not PIH, with postoperative mortality.

Conclusions:

• Intraoperative hypotension (IOH) is a significant risk factor for postoperative mortality.
• Postinduction hypotension (PIH) does not appear to be independently associated with increased postoperative mortality.
• Clinical focus should be on managing and mitigating intraoperative hypotension to improve patient outcomes.