Real-time monitoring of vitamin C levels in trauma patients by electron-spin resonance spectrometry.

BACKGROUND: In critically ill patients, healthy vitamin C levels are important to avoid an imbalance in reactive oxygen species. To achieve this, oxidative stress levels in emergency patients need to be accurately measured in real-time. However, normally, reactive oxygen/nitrogen species are short-lived, rendering measurement difficult; moreover, measurement of relatively stable antioxidants and other oxidative stress markers in real-time is challenging. Therefore, we used electron-spin resonance spectrometry (ESR) to assess vitamin C levels, clarify their relationship with patients' severity, and establish more effective vitamin C therapy in critically ill patients. METHODS: We studied 103 severely ill emergency patients and 15 healthy volunteers. Vitamin C radical (VCR/dimethyl sulfoxide [DMSO]) values were analyzed in arterial blood samples by ESR at admission and once daily thereafter during the acute recovery phase. Severity scores were calculated. The relationship between these scores and VCR/DMSO values and chronological changes in VCR/DMSO values were analyzed. RESULTS: Serum VCR/DMSO values were significantly lower in critically ill patients than in healthy volunteers (0.264 ± 0.014 vs. 0.935 ± 0.052, p < 0.05), particularly in the severe trauma group and the cardiopulmonary arrest/post-cardiac arrest syndrome group. VCR/DMSO values and various severity scores did not correlate at admission; however, they correlated with SOFA scores from days 2-6. VCR/DMSO values remained low from the first measurement day through Day 6 of illness. CONCLUSIONS: Vitamin C levels were low at admission, remained low with conventional nutritional support, and did not correlate with the initial patient's severity; however, they correlated with patients' severity after admission. Some patients had normal vitamin C levels. Therefore, vitamin C levels should be measured in real-time and supplemented if they are below normal levels. TRIAL REGISTRATION: Retrospectively registered.