Intraoperative Heart Rate Thresholds and Postoperative Mortality

This is a retrospective cohort study conducted to evaluate the clinical impact of intraoperative heart rate on postoperative 30-day mortality in patients undergoing non-cardiac surgery. Patient data were extracted from a large institutional electronic medical record database, including demographic variables, comorbidities, anesthesia records, and perioperative outcomes.

Heart rate was continuously recorded at 1-minute or 5-minute intervals during the surgery. Various heart rate parameters-such as minimum, maximum, average, and time-weighted average-were analyzed, and threshold-based metrics (e.g., minutes spent below or above defined thresholds) were computed using a piecewise cubic Hermite interpolating polynomial (PCHIP) method to smooth minute-by-minute fluctuations.

The primary outcome was all-cause mortality within 30 days after surgery. Multivariable logistic regression and sensitivity analyses were performed to adjust for potential confounders. The study aimed to provide clinical insight into the prognostic value of intraoperative heart rate dynamics and to identify modifiable intraoperative risk factors for mortality.

Inclusion criteria

• Patients who underwent non-cardiac surgery at our medical center between March 2019 and February 2023
• Age ≥ 18 years
• Availability of complete laboratory data and perioperative vital signs
• Only the first surgery performed after hospital admission was included for patients with multiple

Exclusion criteria

• Cardiac-related surgical procedures
• Pregnancy at the time of surgery
• Age < 18 years
• Surgeries lasting less than 30 minutes
• Cadaveric procedures
• Missing or incomplete laboratory values or vital sign data