Background: Intraoperative hypotension (IOH) is common in infant anesthesia, but its long-term impact on neurodevelopment remains poorly defined in non-cardiac surgery. This study aimed to investigate the association between the severity and duration of IOH and neurodevelopmental outcomes at 24 months of age. Methods: A prospective observational cohort study was conducted in a tertiary pediatric hospital. We enrolled 150 full-term infants aged <12 months undergoing elective major abdominal or thoracic surgery lasting >2 hours. Invasive mean arterial pressure (MAP) was recorded. IOH was defined as a MAP less than the age-specific threshold (MAP < 40 mmHg for 0-2 months, <45 mmHg for 3-5 months, <50 mmHg for 6-12 months). The primary outcome was the Bayley Scales of Infant and Toddler Development, Fourth Edition (Bayley-4) composite cognitive score at 24 months. Secondary outcomes included Bayley-4 motor and language scores. Results: The median (IQR) cumulative duration of IOH was 18.5 (6.0-35.2) minutes. Multivariable linear regression, adjusting for gestational age at birth, preoperative illness severity, surgery type, and baseline maternal education, revealed that each 10-minute increase in IOH duration was associated with a 1.2-point decrease in the 24-month cognitive composite score (β = -1.2, 95% CI: -2.1 to -0.3; p=0.009). Infants with IOH duration >20 minutes (n=62) had significantly lower mean cognitive scores compared to those with ≤20 minutes (94.3 vs. 101.7, p=0.002). Conclusion: A longer duration of intraoperative hypotension, defined by age-specific thresholds, was independently associated with lower neurodevelopmental scores at 24 months in infants undergoing major non-cardiac surgery. These findings highlight the potential neurodevelopmental vulnerability of the infant brain to hemodynamic instability.

Intraoperative Hypotension; Infant; Anesthesia; Neurodevelopment; Outcomes; Pediatrics.