Methemoglobin in critically ill septic patients

<b>Aim:</b> Higher nitric oxide (NO) levels correlate with adverse sepsis outcomes but are challenging to measure. Methemoglobin (MetHb), a measurable product of NO, has not been utilized for risk stratification.<b>Methodology:</b> All patients with sepsis admitted to the intensive care unit (ICU) that had at least one MetHb measurement within 24 h of ICU admission were retrospectively analyzed. We assessed the epidemiology and associations of MetHb with hospital mortality.<b>Results:</b> Among 7724 patients, 1046 qualified. Those with MetHb ≥1.6% showed significantly higher mortality and fewer days alive outside the hospital by day 28. MetHb levels ≥1.6% independently predicted increased 28-day mortality.<b>Conclusion:</b> Our findings suggest MetHb, easily obtainable from arterial blood gases, can significantly enhance sepsis risk stratification.