Brain oxymetry in the operating room: current status and future directions with particular regard to cytochrome oxidase.

Near-infrared spectroscopy (NIRS) is a cerebral monitoring method that noninvasively and continuously measures cerebral hemoglobin oxygenation and the redox state of cytochrome oxidase using highly tissue-permeable near-infrared light. This technique now has wide clinical application, and its usefulness in the measurement of cerebral hemoglobin oxygenation has been confirmed under global cerebral injury and/or hypoxemic hypoxia; however, regional cerebral infarction located far from the monitoring site may not be detected by NIRS. Furthermore, the specificity and accuracy of the measurement of the redox state of cytochrome oxidase remain controversial. We apply NIRS to both animal and clinical investigations. Based on these results, we discuss the significance of the measurement of cerebral hemoglobin oxygenation and cytochrome oxidase in vivo and in clinical medicine. Using our algorithm, cytochrome oxidase signals are unaffected by hemoglobin signals, even when hematocrit values change from 35 to 5% under cardiopulmonary bypass in a dog model. In the clinical study, cytochrome oxidase during surgery is likely to be a good (though not perfect) predictor of postoperative cerebral outcome. NIRS appears to be a promising technology, but additional investigations are required to establish its clinical efficacy and justify its routine use during operative and perioperative periods.

Clinical effects of a neutrophil elastase inhibitor, sivelestat, in patients with acute respiratory distress syndrome.

PURPOSE: We assessed the effects of a neutrophil elastase inhibitor, sivelestat, on respiratory and organ functions as well as on the mortality of patients with acute respiratory distress syndrome (ARDS) associated with systemic inflammatory response syndrome (SIRS). METHODS: We retrospectively divided 25 patients who fulfilled the diagnostic criteria for SIRS and ARDS into two groups. One group (S group, n = 12) received a continuous infusion of sivelestat (0.2 mg.kg(-1).h(-1)), and the other did not (C group, n = 13). RESULTS: Between days 1 and 10, the Pa(O2)/FI(O2) ratio in the S group significantly improved from 119.1 +/- 51.1 to 214.4 +/- 88.2 mmHg (P < 0.05). Furthermore, the S group spent significantly fewer days on a ventilator than the C group (16.7 +/- 5.8 vs 26.6 +/- 14.3 days; P < 0.05). The length of the intensive care unit stay was also significantly shorter for the S group than for the C group (18.7 +/- 4.9 vs 27.5 +/- 13.5 days; P < 0.05). However, the mortality rate at 29 days did not statistically differ between the two groups. CONCLUSION: Our results suggested that sivelestat has a beneficial effect only on the pulmonary function of ARDS patients with SIRS.