Association of Intraoperative Occult Hypoxemia With 30-Day and 1-Year Mortality.

Summary

In 25,234 anesthetized patients with intraoperative ABGs, 1.4% experienced occult hypoxemia (SaO2 <88% despite SpO2 >92%). These events were independently associated with increased 30-day mortality (OR 2.89) and 1-year mortality (HR 1.90) with no significant race/ethnicity interaction.

Key Findings

• Occult hypoxemia (SaO2 <88% with SpO2 >92%) occurred in 1.4% of 25,234 patients.
• Associated with higher 30-day mortality (OR 2.89; 95% CI 1.46–5.72; P=.002).
• Associated with higher 1-year mortality (HR 1.90; 95% CI 1.48–2.43; P<.001).
• No significant interaction by self-reported race/ethnicity.

Clinical Implications

Consider strategies to detect occult hypoxemia (e.g., ABG confirmation during discordance, waveform/pleth variability analysis, alternative sensors), cautious interpretation of SpO2 in high-risk contexts, and targeted quality improvement around oxygen monitoring.

Limitations

• Single-center retrospective design with potential residual confounding.
• Only patients with intraoperative ABGs were included, limiting generalizability.

Future Directions

Prospective multicenter studies to validate prognostic thresholds and evaluate device/calibration strategies; interventional trials testing monitoring algorithms to reduce occult hypoxemia and improve outcomes.