Quantitative assessment of cytochrome C oxidase patterns in muscle tissue by the use of near-infrared spectroscopy (NIRS) in healthy volunteers.

Cytochrome C oxidase (CCO) acts as final electron acceptor in the respiratory chain, possibly providing information concerning cellular oxygenation. CCO is a chromophore with a broad absorption peak in the near-infrared spectrum in its reduced state (835 nm). However, this peak overlaps with deoxygenated haemoglobin (HHb; 755 nm) which is present in much higher concentrations. NIRO-300 measures CCO signals, but did not receive FDA approval for this use due to presumed lack of independency of the measured CCO changes. However, there is no proven evidence for this assumption. We hypothesized that the NIRO-300 provides a HHb independent measurement of CCO concentration changes. In this single-center crossover randomized controlled trial in healthy volunteers, subjects were randomized to receive arterial occlusion to the left arm and venous stasis on the right arm (n = 5) or vice versa (n = 5) during 5 min. After a resting period, the second part of the cross over study was performed. We placed the NIRO-300 optodes bilateral at the level of the brachioradial muscle in order to collect NIRS data continuously. Data was analysed using a generalized additive mixed model. HHb and CCO follow a significant different trend over time during the intervention period for both arterial occlusion (F = 20.645, edf = 3.419, p < 0.001) and venous stasis (F = 9.309, edf = 4.931, p < 0.001). Our data indicate that CCO concentration changes were not affected by HHb changes, thereby proving independency.Clinical trial registration: B670201732023 on June 28, 2017.

Prediction of return of spontaneous circulation during cardiopulmonary resuscitation by pulse-wave cerebral tissue oxygen saturation: a retrospective observational study.

BACKGROUND: It is difficult to predict the return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). Cerebral tissue oxygen saturation during CPR, as measured by near-infrared spectroscopy (NIRS), is anticipated to predict ROSC. General markers of cerebral tissue oxygen saturation, such as the tissue oxygenation index (TOI), mainly reflect venous oxygenation, whereas pulse-wave cerebral tissue oxygen saturation (SnO2), which represents hemoglobin oxygenation in the pulse wave within the cerebral tissue, is an index of arterial and venous oxygenation. Thus, SnO2 may reflect arterial oxygenation to a greater degree than does TOI. Therefore, we conducted this study to verify our hypothesis that SnO2 measured during CPR can predict ROSC. METHODS: Cardiac arrest patients who presented at the Emergency Department of Yamagata University Hospital in Japan were included in this retrospective, observational study. SnO2 and TOI were simultaneously measured at the patient's forehead using an NIRS tissue oxygenation monitor (NIRO 200-NX; Hamamatsu Photonics, Japan). We recorded the initial, mean, and maximum values during CPR. We plotted receiver operating characteristic curves and calculated the area under the curve (AUC) to predict ROSC. RESULTS: Forty-two patients were included. SnO2 was significantly greater in the ROSC group than in the non-ROSC group in terms of the initial (37.5% vs 24.2%, p = 0.015), mean (44.6% vs 10.8%, p < 0.001), and maximum (79.7% vs 58.4%, p < 0.001) values. Although the initial TOI was not significantly different between the two groups, the mean (45.1% vs 36.8%, p = 0.018) and maximum (71.0% vs 46.3%, p = 0.001) TOIs were greater in the ROSC group than in the non-ROSC group. The AUC was 0.822 for the mean SnO2 (95% confidence interval [CI]: 0.672-0.973; cut-off: 41.8%), 0.821 for the maximum SnO2 (95% CI: 0.682-0.960; cut-off: 70.8%), and 0.809 for the maximum TOI (95% CI: 0.667-0.951; cut-off: 49.3%). CONCLUSION: SnO2 values measured during CPR, including immediately after arrival at the emergency department, were higher in the ROSC group than in the non-ROSC group.

Anatomical and physiological variables influencing measurement of regional cerebral oxygen saturation by near infrared spectroscopy using the Sensmart Model X-100TM.

The Sensmart Model X-100 (Nonin Medical Inc, Plymouth, MN, USA) is a relatively new device that possesses two sets of emitters and detectors and uses near infrared spectroscopy (NIRS) to measure regional cerebral oxygen saturation (rSO2). The value of rSO2 obtained by other NIRS devices is affected by physiological and anatomical variables such as hemoglobin concentration, area of cerebrospinal fluid (CSF) layer and skull thickness. The effects of these variables have not yet been determined in measurement of rSO2 by Sensmart Model X-100. We examined the effects of area of CSF, hemoglobin concentration, and skull thickness on the values of rSO2 measured by Sensmart Model X-100 and tissue oxygen index (TOI) measured by NIRO-200NX (Hamamatsu Photonix, Hamamatsu, Japan). Forty neurosurgical, cardiac and vascular surgical patients who underwent preoperative computed tomographic (CT) scan of the brain were enrolled in this study. Regional cerebral oxygen saturation (rSO2) at the forehead was measured sequentially by NIRO-200NX and by Sensmart Model X-100. Simultaneously, mean arterial pressure, hemoglobin concentration, and partial pressure of carbon dioxide in arterial blood (PaCO2) were measured. To evaluate the effects of anatomical factors on rSO2, we measured skull thickness and area of CSF layer using CT images of the brain. Multiple regression analysis was used to examine the relationships between the rSO2 values and anatomical and physiological factors. The area of the CSF layer and hemoglobin concentration had significant associations with rSO2 measured by the Sensmart Model X-100, whereas none of the studied variables was significantly associated with TOI. The measurement of rSO2 by Sensmart Model X-100 is not affected by the skull thickness of patients. Area of the CSF layer and hemoglobin concentration may be the main biases in measurement of rSO2 by Sensmart Model X-100.

Cerebral Tissue Oxygenation Index Using Near-infrared Spectroscopy during Extracorporeal Cardio-pulmonary Resuscitation Predicted Good Neurological Recovery in a Patient with Acute Severe Anemia.

We herein report the clinical course of a patient who had a good neurological outcome despite severe anemia, high serum lactate levels, and a long period of time from cardiac arrest (CA) to extracorporeal cardio-pulmonary resuscitation (ECPR) establishment. During the period of resuscitation, the tissue oxygenation index (TOI) values were measured continuously by a near-infrared spectroscopy monitoring device and were kept within the normal range. The TOI seems to reflect cerebral perfusion and the balance between the oxygen supply and demand in the brain during ECPR, thereby predicting the neurological outcome. Continuous TOI monitoring is useful for predicting the neurological outcome during ECPR.