NIRS Device Research Articles

A novel multimodal computational system using near-infrared spectroscopy predicts the need for ECMO initiation in neonates with congenital diaphragmatic hernia

Background/purposeThe purpose of this study was to develop a computational algorithm that would predict the need for ECMO in neonates with congenital diaphragmatic hernia (CDH). MethodsCDH patients from August 2010 to 2016 were enrolled in a study to continuously measure cerebral tissue oxygen saturation (cStO2) of left and right cerebral hemispheres. NIRS devices utilized were FORE-SIGHT, CASMED and INVOS 5100, Somanetics. Using MATLAB©, a data randomization function was used to deidentify and blindly group patient's data files as follows: 12 for the computational model development phase (6 ECMO and 6 non-ECMO) and the remaining patients for the validation phase. ResultsOf the 56 CDH patients enrolled, 22 (39%) required ECMO. During development of the algorithm, a difference between right and left hemispheric cerebral oxygenation via NIRS (ΔHCO) was noted in CDH patients that required ECMO. Using ROC analysis, a ΔHCO cutoff >10% was predictive of needing ECMO (AUC: 0.92; sensitivity: 85%; and specificity: 100%). The algorithm predicted need for ECMO within the first 12h of life and at least 6h prior to the clinical decision for ECMO with 88% sensitivity and 100% specificity. ConclusionThis computational algorithm of cerebral NIRS predicts the need for ECMO in neonates with CDH. Level of evidenceII

Using Functional Near-Infrared Spectroscopy to Measure Effects of Delta 9-Tetrahydrocannabinol on Prefrontal Activity and Working Memory in Cannabis Users.

Intoxication from cannabis impairs cognitive performance, in part due to the effects of Δ9-tetrahydrocannabinol (THC, the primary psychoactive compound in cannabis) on prefrontal cortex (PFC) function. However, a relationship between impairment in cognitive functioning with THC administration and THC-induced change in hemodynamic response has not been demonstrated. We explored the feasibility of using functional near-infrared spectroscopy (fNIRS) to examine the functional changes of the human PFC associated with cannabis intoxication and cognitive impairment. Eighteen adult regular cannabis users (final sample, n = 13) performed a working memory task (n-back) during fNIRS recordings, before and after receiving a single dose of oral synthetic THC (dronabinol; 20–50 mg). Functional data were collected using a continuous-wave NIRS device, in which 8 Sources and 7 detectors were placed on the forehead, resulting in 20 channels covering PFC regions. Physiological changes and subjective intoxication measures were collected. We found a significant increase in the oxygenated hemoglobin (HbO) concentration after THC administration in several channels on the PFC during both the high working memory load (2-back) and the low working memory load (0-back) condition. The increased HbO response was accompanied by a trend toward an increased number of omission errors after THC administration. The current study suggests that cannabis intoxication is associated with increases in hemodynamic blood flow to the PFC, and that this increase can be detected with fNIRS.

Handheld NIR device: A non-targeted approach to assess authenticity of fish fillets and patties

This study evaluates the reliability of a handheld NIR device in distinguishing fillets and patties of Atlantic cod (n = 80) from those of haddock (n = 90), in comparison with a FT-NIR benchtop spectrometer. The authentication issue was faced by Linear Discriminant Analysis (LDA) and Soft Independent Modelling of Class Analogy (SIMCA), pre-treating spectral data with different algorithms, and validating models both internally and externally. The best LDA models gave 100% correct classification in prediction. Sensitivity >65% and specificity >74% in prediction were calculated for the best SIMCA models. No significant differences (P > .05) were found between the two instruments by McNemar test. Thus, the work demonstrated that a handheld NIR device can be a simple, cost-effective, and reliable alternative to benchtop spectrometers in fish fillet and patty authentication. These important findings can help in improving commercial fraud fight, extending the possibility to authenticate fish species also in processed products.

Over 10% EQE Near‐Infrared Electroluminescence Based on a Thermally Activated Delayed Fluorescence Emitter

Significant effort has been made to develop novel material systems to improve the efficiency of near‐infrared organic light‐emitting diodes (NIR OLEDs). Of those, fluorescent chromophores are mostly studied because of their advantages in cost and tunability. However, it is still rare for fluorescent NIR emitters to present good color purities in the NIR range and to have high external quantum efficiency (EQE). Here, a wedge‐shaped D‐π‐A‐π‐D emitter APDC‐DTPA with thermally activated delayed fluorescence property and a small single‐triplet splitting (ΔEst) of 0.14 eV is presented. The non‐doped NIR device exhibits excellent performance with a maximum EQE of 2.19% and a peak wavelength of 777 nm. Remarkably, when 10 wt% of APDC‐DTPA is doped in 1,3,5‐tris(1‐phenyl‐1H‐benzimidazol‐2‐yl)benzene host, an extremely high EQE of 10.19% with an emission peak of 693 nm is achieved. All these values represent the best result for NIR OLEDs based on a pure organic fluorescent emitter with similar device structure and color gamut.

Rapid screening of commercial extra virgin olive oil products for authenticity: Performance of a handheld NIR device

The performance of a handheld near infrared spectroscopic device was evaluated for the rapid screening of extra virgin olive oil for authenticity. Without any sample preparation, the spectra of authentic reference extra virgin olive oils, refined olive oils, potential adulterants consisting of edible oils, extra virgin olive oil spiked with adulterants, and a total of 93 commercial olive oil products were each rapidly (10 s) measured in the transflection mode. The univariate conformity index and the multivariate supervised soft independent modeling of class analogy classification tools were used to differentiate among the various oils investigated. Out of 88 commercial products labeled extra virgin olive oil, 39 (44%) were classified as belonging to the class of authentic extra virgin olive oils. The results were compared to those recently reported for analyses carried out with a benchtop Fourier transform-near infrared spectrometer.

Evaluation of different near-infrared spectroscopy technologies for assessment of tissue oxygen saturation during a vascular occlusion test.

An increasing number of NIRS devices are used to provide measurements of peripheral tissue oxygen saturation (StO2). The aim of the present study is to test the hypothesis that despite technological differences between devices, similar trend values will be obtained during a vascular occlusion test. The devices compared are NIRO-200NX, which measures StO2 and oxyhemoglobin by spatially resolved spectroscopy and the Beer-Lambert law, respectively, and INVOS 5100C and Foresight Elite, which both measure StO2 with the Beer-Lambert law, enhanced with the spatial resolution technique. Forty consenting adults scheduled for CABG surgery were recruited. The respective sensors of the three NIRS devices were applied over the brachioradial muscle. Before induction of anesthesia, 3min of ischemia were induced by inflating a blood pressure cuff at the upper arm, whereafter cuff pressure was rapidly released. Tissue oxygenation measurements included baseline, minimum and maximum values, desaturation and resaturation slopes, and rise time. Comparisons between devices were performed with the Kruskal-Wallis test with post hoc Mann-Whitney pairwise comparisons. Agreement was evaluated using Bland-Altman plots. Oxyhemoglobin measured with NIRO responded faster than the other NIRS technologies to changes in peripheral tissue oxygenation (20 vs. 27-40s, p≤0.01). When comparing INVOS with Foresight, oxygenation changes were prompter (upslope 311 [92-523]%/min vs. 114[65-199]%/min, p≤0.01) and more pronounced (minimum value 36 [21-48] vs. 45 [40-51]%, p≤0.01) with INVOS. Significant differences in tissue oxygen saturation measurements were observed, both within the same device as between different devices using the same measurement technology.

Bootstrap Analyses of Anxiety Index Measuring the Prefrontal Cortex of Subjects at Rest with Two-Channel Portable NIRS Device

ABSTRACTThis article presents statistical analyses of a mental stress index obtained with a two-channel portable near-infrared spectroscopy device placed on the forehead of a subject at rest. Using nonparametric bootstrap analyses, the authors show that the distribution of the Pearson correlation coefficient between the target NIRS-based index and the State Trait Anxiety Inventory index is positive. Further, they show that the correlation coefficient is statistically invariant to age, gender, and location, insofar as the null hypothesis—that is, when the two distributions are equivalent—is not rejected. Finally, they show that there is a sharper distribution to the Pearson correlation coefficient and a higher mean value for subjects under mental stress than for subjects at rest. Because the device is easy to wear, and because the proposed index is relatively simple, the target index can be used in conjunction with the device to help users (regardless of age, gender, and location) to manage mental stress.

Effects of a higher dose of near-infrared light on clinical signs and neuroprotection in a monkey model of Parkinson's disease

We have reported previously that intracranial application of near-infrared light (NIr) – when delivered at the lower doses of 25J and 35J – reduces clinical signs and offers neuroprotection in a subacute MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) monkey model of Parkinson’s disease. In this study, we explored whether a higher NIr dose (125J) generated beneficial effects in the same MPTP monkey model (n=15). We implanted an NIr (670nm) optical fibre device within a midline region of the midbrain in macaque monkeys, close to the substantia nigra of both sides. MPTP injections (1.8–2.1mg/kg) were made over a five day period, during which time the NIr device was turned on and left on continuously throughout the ensuing three week survival period. Monkeys were evaluated clinically and their brains processed for immunohistochemistry and stereology. Our results showed that the higher NIr dose did not have any toxic impact on cells at the midbrain implant site. Further, this NIr dose resulted in a higher number of nigral tyrosine hydroxylase immunoreactive cells when compared to the MPTP group. However, the higher NIr dose monkeys showed little evidence for an increase in mean clinical score, number of nigral Nissl-stained cells and density of striatal tyrosine hydroxylase terminations. In summary, the higher NIr dose of 125J was not as beneficial to MPTP-treated monkeys as compared to the lower doses of 25J and 35J, boding well for strategies of NIr dose delivery and device energy consumption in a future clinical trial.

THE MEASUREMENT OF BRAIN ACTIVITY BY NEAR-INFRARED SPECTROSCOPY IN SUBJECTS WITH MILD COGNITIVE IMPAIRMENT

The aim of this study was to probe the brain activity in subjects with mild cognitive impairment (MCI) while they performed various tests. Fifteen MCI subjects of 78.9±9.8 years of age, with a mean MMSE score of 27.3±1.4, and 17 control subjects of 72.3±7.3 years of age, with a mean MMSE score of 29.3±0.9, were investigated using NIRS. All of the subjects took three types of tests. 1) The Kana pick-up test (Kana are Japanese letters). The subjects were instructed to select 5 specified letters from randomly arranged Kana letters (Task 1); and old Japanese fairy tales written entirely in Kana letters (Task 2). The test consists of 10 s of rest followed by 60 s to perform Task 1, then 20 s of rest and 60 s to perform Task 2. Each of these tasks was repeated twice. 2) A modified Stroop test. The subjects were asked to name the color of ink (Task 1) and the color of Chinese letters (Task 2). The test consists of 10 s of rest followed by 30 s to perform each task; the test was repeated three times. 3) The phonological verbal fluency task. The subjects were instructed to generate words beginning with a specified letter. The test consists of 10 s of task followed by 5 s of rest; the test was repeated 10 times. We used a 16-probe, 46-channeled NIRS device (OMM 3000, Shimazu Corporation, Japan). The task achievement levels in the MCI subjects were lower than those of the control subjects in the following tasks: Kana pick-up Task 1 (P<0.01), Kana pick-up Task 2 (P<0.001), modified Stroop test Task 2 (P<0.05) by Cochran-cox analysis. With the exception of Kana pick-up Task 1, the oxyHb concentrations were significantly decreased in the MCI subjects in comparison to the controls in all of the tests. The results in this study indicate that the frontal brain function was impaired in the stage of “MCI due to Alzheimer’s disease”. The measurement of oxyHb using NIRS is useful in the diagnosis of MCI.

Fabrication of a Homogeneous, Integrated, and Compact Film of Organic-Inorganic Hybrid Ni(en)3Ag2I4 with Near-Infrared Absorbance and Semiconducting Features.

The organic-inorganic hybrid crystal Ni(en)3Ag2I4 (where en represents 1,2-ethylenediamine) crystallizes in hexagonal space group P63, in which the AgI4(3-) tetrahedra connect into a diamondlike inorganic framework via sharing of the vertex and the Ni(en)3(2+) octahedra fill in the pores of the framework. UV-vis-near-IR (NIR) spectroscopy disclosed that this hybrid shows intense NIR absorbance centered at ca. 870 nm, and the variable-temperature conductivity measurement revealed that the hybrid is a semiconductor with Ea = 0.46 eV. The electronic band structure of Ni(en)3Ag2I4 was calculated using the density functional theory method, indicating that the NIR absorbance arises from d-d transition within the Ni(2+) cation of Ni(en)3(2+). The homogeneous, compact, and transparent crystalline film of Ni(en)3Ag2I4 was fabricated via a secondary seed growth strategy, which has promising application in NIR devices.

Underwater Near-Infrared Spectroscopy: Muscle Oxygen Changes in the Upper and Lower Extremities in Club Level Swimmers and Triathletes.

To date, measurements of oxygen status during swim exercise have focused upon systemic aerobic capacity. The development of a portable, waterproof NIRS device makes possible a local measurement of muscle hemodynamics and oxygenation that could provide a novel insight into the physiological changes that occur during swim exercise. The purpose of this study was to observe changes in muscle oxygenation in the vastus lateralis (VL) and latissimus dorsi (LD) of club level swimmers and triathletes. Ten subjects, five club level swimmers and five club level triathletes (three men and seven women) were used for assessment. Swim group; mean±SD=age 21.2±1.6 years; height 170.6±7.5 cm; weight 62.8±6.9 kg; vastus lateralis skin fold 13.8±5.6 mm; latissimus dorsi skin fold 12.6±3.7. Triathlete group; mean±SD=age 44.0±10.5 years; height 171.6±7.0 cm; weight 68.6±12.7 kg; vastus lateralis skin fold 11.8±3.5 mm; latissimus dorsi skin fold 11.2±3.1. All subjects completed a maximal 200 m freestyle swim, with the PortaMon, a portable NIR device, attached to the subject's dominant side musculature. ΔTSI% between the vastus lateralis and latissimus dorsi were analysed using either paired (2-tailed) t-tests or Wilcoxon signed rank test. The level of significance for analysis was set at p<0.05. No significant difference (p=0.686) was found in ΔTSI (%) between the VL and LD in club level swimmers. A significant difference (p=0.043) was found in ΔTSI (%) between the VL and LD in club level triathletes. Club level swimmers completed the 200 m freestyle swim significantly faster (p=0.04) than club level triathletes. Club level swimmers use both the upper and lower muscles to a similar extent during a maximal 200 m swim. Club level triathletes predominately use the upper body for propulsion during the same exercise. The data produced by NIRS in this study are the first of their kind and provide insight into muscle oxygenation changes during swim exercise which can indicate the contribution of one muscle compared to another. This also enables a greater understanding of the differences in swimming techniques seen between different cohorts of swimmers and potentially within individual swimmers.

Effects of Acupuncture on Anxiety Levels and Prefrontal Cortex Activity Measured by Near-Infrared Spectroscopy: A Pilot Study.

There is increasing evidence that acupuncture is useful in treating somatic and psychological disorders caused by stress; however, the physiological basis of the effect remains unclear. In the present study, we evaluated the effect of acupuncture on psychological conditions (i.e., anxiety) and prefrontal cortex (PFC) activity. We studied 10 patients with anxiety disorders and measured anxiety levels by means of the State-Trait Anxiety Inventory (STAI), including state anxiety (STAI-1) and trait anxiety (STAI-2). Employing a two-channel NIRS device, we measured oxy-Hb concentration in the bilateral PFC at rest, and evaluated asymmetry of the PFC activity by calculating the Laterality Index at Rest (LIR). The patients were treated by acupuncture at Yui Clinic in Osaka. The treatment significantly decreased the STAI-1 score (p<0.001), but not the STAI-2 score (p>0.05). The NIRS measurements indicated the presence of spontaneous oscillations of oxy-Hb in the bilateral PFC at rest before and after the treatment. Notably LIR decreased significantly in 7 out of the 10 subjects (p<0.01), while 3 subjects showed an increasing tendency. The present pilot study indicates that acupuncture is effective in decreasing anxiety levels in patients with anxiety disorders. Our NIRS data suggest that acupuncture may alter the balance of PFC activity at rest, resulting in relaxation effects. Our NIRS data suggest that acupuncture changes the balance of PFC activity toward left-dominant, resulting in relaxation effects on the patients.

Effect of indocyanine green dye administration on cerebral oxygen saturation.

Sir, Near-infrared spectroscopy (NIRS) is a non-invasive continuous method of measuring regional cerebral oxygen tissue saturation (SctO2).[1] It uses a technique similar to pulse oximetry where light absorption in wavelength 600–900 nm is used. Indocyanine green (ICG) is a water soluble and iodide containing dye that fluoresces when exposed to infrared light. This property of ICG is used for the intra-operative assessment of blood flow during aneurysm surgery. Safety of ICG usage in clinical settings has been demonstrated for determining cardiac output, hepatic function and liver blood flow and for ophthalmic angiography.[2] There have been hypotension, urticarial reaction or anaphylaxis and falsely low pulse oximetry recording during or following use of ICG.[3,4] Contrary to falsely low pulse oximetry recordings, ICG administration has been shown to increase SctO2.[4] Here, we are describing the effect of ICG administration on SctO2. A 65-year-old male patient was scheduled to undergo clipping of right supraclinoid internal carotid artery aneurysm under general anaesthesia. Apart from the routine monitoring, we placed bilateral NIRS sensors over the forehead of the patient. After administration of 10 mg of ICG, the SctO2 on both the sides suddenly increased to 100 from a baseline of about 65–75% and gradually decreased to the baseline value after about 15 min [Figure 1]. There were no associated haemodynamic changes. Figure 1 Snap shot of near infrared spectroscopy monitor showing the graphical trend of the cerebral oxygen saturation. Furthermore, clearly seen is the sudden acute increase in saturation after injection of indocyanine green at two different time points and gradual ... This sudden increase in SctO2 following administration of ICG can be explained by the principle applied in NIRS sensors. NIRS uses wavelengths between 700 and 850 nm to determine regional cerebral oxygen SctO2 by differentiating oxyhaemoglobin from reduced haemoglobin in the frontal lobe. Thus, any substances that absorb infrared light of the same wavelength produced by the light-emitting diodes may affect the absorption of light as they traverse the blood and tissues.[5] ICG has a characteristic absorption peak at around 805 nm and this is likely to reduce the amount of detected light in the 810 nm wavelength of the NIRS device, which would be interpreted as an increased oxyhaemoglobin concentration leading to falsely elevated SctO2 reading.[6] The effect of this falsely elevated SctO2 on the clinical outcome of the patients is not known. Despite these changes, the remaining of the surgical procedure was uneventful or did the patient develop any new neurological deficits and patient's trachea was successfully extubated at the end of the procedure. The anaesthesiologists and neurosurgeons must be aware of this interaction of ICG and cerebral oxygen SctO2 in the intra-operative period. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Near-infrared light is neuroprotective in a monkey model of Parkinson disease.

To examine whether near-infrared light (NIr) treatment reduces clinical signs and/or offers neuroprotection in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkey model of Parkinson disease. We implanted an optical fiber device that delivered NIr (670 nm) to the midbrain of macaque monkeys, close to the substantia nigra of both sides. MPTP injections (1.5-2.1mg/kg) were made over a 5- to 7-day period, during which time the NIr device was turned on. This was then followed by a 3-week survival period. Monkeys were evaluated clinically (eg, posture, bradykinesia) and behaviorally (open field test), and their brains were processed for immunohistochemistry and stereology. All monkeys in the MPTP group developed severe clinical and behavioral impairment (mean clinical scores = 21-34; n = 11). By contrast, the MPTP-NIr group developed much less clinical and behavioral impairment (n = 9); some monkeys developed moderate clinical signs (mean scores = 11-15; n = 3), whereas the majority--quite remarkably--developed few clinical signs (mean scores = 1-6; n = 6). The monkeys that developed moderate clinical signs had hematic fluid in their optical fibers at postmortem, presumably limiting NIr exposure and overall clinical improvement. NIr was not toxic to brain tissue and offered neuroprotection to dopaminergic cells and their terminations against MPTP insult, particularly in animals that developed few clinical signs. Our findings indicate NIr to be an effective therapeutic agent in a primate model of the disease and create the template for translation into clinical trials.

Two Tissue Blood Volume Parameters Show Different Dynamics During Prolonged Exercise

In previous studies, total hemoglobin changes (cHb), which were calculated by adding the oxygenated and deoxygenated hemoglobin, measured by near-infrared continuous-wave spectroscopy (NIR-CWS), are used as tissue blood volume changes (BV). During moderate to high intensity cycling exercise, cHb decreases temporarily at the onset of exercise, and then increases gradually. However, since NIR-CWS parameters, especially oxygenated hemoglobin, are affected by skin blood flow changes, it was hypothesized that BV assessed by cHb was overestimated, especially during prolonged exercise. On the other hand, it was reported that tissue oxygen saturation and a normalized tissue hemoglobin index (nTHI), monitored by NIR spatially-resolved spectroscopy (NIR-SRS), were less influenced. PURPOSE:The aim of this study was to compare the two BV parameters, cHb and nTHI, in the working muscle during prolonged cycling exercise. METHODS :Seven active male subjects (age, 22 ± 3 yr.) performed a 60-min cycling exercise test at 65 to 70% of the peak of pulmonary oxygen uptake (162 ± 25 W). Two BV parameters, cHb and nTHI, from the vastus lateralis muscle were continuously monitored by the commercially available NIR device. The values of the two parameters were relatively evaluated; 100% of BV was taken as the resting value and 0% of BV was taken as the minimum value for 30 s after the onset of exercise. All data are represented as mean ± SE. RESULTS::Both cHb and nTHI decreased acutely at the onset of exercise, and then increased. The relative values of cHb at the 10th, 30th, and 60th minutes were 230 ± 70%, 277 ± 74%, and 291 ± 56%, respectively. On the other hand, those of nTHI were 173 ± 37%, 177 ± 39%, and 170 ± 45%, respectively. There was significant interaction between the two parameters (p < 0.01). The maximal values in cHb and nTHI were 321 ± 76% and 235 ± 36% (N.S.), and the timing at the maximal value in cHb was significantly increased compared to nTHI (53.4 ± 5.1 min vs. 22.5 ± 19.6 min, p < 0.01). CONCLUSION: These results suggest that BV assessed by cHb during exercise is overestimated. Hence, it is likely that BV within the working muscle might be little changed or slightly decreased during prolonged exercise.

Regional oxygen saturation index (rSO2) in brachioradialis and deltoid muscle. Correlation and prognosis in patients with respiratory sepsis

ObjectiveTo compare oxygen saturation index (rSO2) obtained simultaneously in two different brachial muscles. DesignProspective and observational study. SettingIntensive care unit. PatientsCritically ill patients with community-acquired pneumonia. InterventionsTwo probes of NIRS device (INVOS 5100) were simultaneously placed on the brachioradialis (BR) and deltoid (D) muscles. VariablesrSO2 measurements were recorded at baseline (ICU admission) and at 24h. Demographic and clinical variables were registered. Pearson's correlation coefficient was used to assess the association between continuous variables. The consistency of the correlation was assessed using the intraclass correlation coefficient (ICC) and Bland•Altman plot. The predictive value of the rSO2 for mortality was calculated by ROC curve. ResultsNineteen patients were included with an ICU mortality of 21.1%. The rSO2 values at baseline and at 24h were significantly higher in D than in BR muscle. Values obtained simultaneously in both limbs showed a strong correlation and adequate consistency: BR (r=0.95; p<0.001; ICC=0.94; 95% CI: 0.90•0.96; p<0.001), D (r=0.88; p=0.01; ICC=0.88; 95% CI: 0.80•0.90; p>0.001) but a wide limit of agreement. Non-survivors had rSO2 values significantly lower than survivors at all times of the study. No patient with rSO2 >60% in BR died, and only 17.6% died with an rSO2 value >60% in D. Both muscles showed consistent discriminatory power for mortality. ConclusionBoth BR and D muscles were appropriate for measuring rSO2.

An Attempt on Methemoglobinemia: It’s Treatment and Relationship between Treatment and Cerebral Oximeter Value: Case Presentation

Background: Our paper aimed to investigate whether there was a correlation among the pulse oximetry, cerebral oximetry (CO) and MetHb (methemoglobin) values of a patient with congenital methemoglobinemia who underwent a laparoscopic cholecystectomy operation. Case: The 35-year-old male patient with a weight of 70 kg, body massindex (BMI) of 21, American Society of Anesthesia status-2(ASA-2) category who was planned for laparoscopic cholecystectomy operation was identified to have been diagnosed with congenital methemoglobinemia as per his medical history was methemoglobin levels ranged between 12% and 20% according to the periodical measurements taken for the past 3 years. The patient received standard monitoring during anesthesia and device monitoring with a cerebral oximeter (Invos 5100C somatic/cerebral oximeter, Covidien) and a CO-oximetry (Rad ?87 “Rainbow”, Masimo Inc., Irvine, CA) device to continuously follow up his MetHb values was also added. During the intra-operative follow-up, the patient’s methemoglobin level rose to 16%, his peripheral oxygen saturation levels decreased to 86% and his cerebral oximetry values were identified to have also decreased; therefore, methylene blue (MB) was intravenously administered to the patient. The patient continued to be followed up in the post-operative period and he did not develop any complications. Discussion: Appropriate treatment and monitoring enabled the prevention of potential complications. We believe that monitoring with NIRS and MASIMO CO-oximetry device will enable physicians to perform a safe follow-up and treatment in the intraoperative and postoperative follow-up of methemoglobinemia patients.

Regional oxygen saturation index (rSO2) in brachioradialis and deltoid muscle. Correlation and prognosis in patients with respiratory sepsis

ObjectiveTo compare oxygen saturation index (rSO2) obtained simultaneously in two different brachial muscles. DesignProspective and observational study. SettingIntensive care unit. PatientsCritically ill patients with community-acquired pneumonia. InterventionsTwo probes of NIRS device (INVOS 5100) were simultaneously placed on the brachioradialis (BR) and deltoid (D) muscles. VariablesrSO2 measurements were recorded at baseline (ICU admission) and at 24h. Demographic and clinical variables were registered. Pearson's correlation coefficient was used to assess the association between continuous variables. The consistency of the correlation was assessed using the intraclass correlation coefficient (ICC) and Bland–Altman plot. The predictive value of the rSO2 for mortality was calculated by ROC curve. ResultsNineteen patients were included with an ICU mortality of 21.1%. The rSO2 values at baseline and at 24h were significantly higher in D than in BR muscle. Values obtained simultaneously in both limbs showed a strong correlation and adequate consistency: BR (r=0.95; p<0.001; ICC=0.94; 95% CI: 0.90–0.96; p<0.001), D (r=0.88; p=0.01; ICC=0.88; 95% CI: 0.80–0.90; p>0.001) but a wide limit of agreement. Non-survivors had rSO2 values significantly lower than survivors at all times of the study. No patient with rSO2 >60% in BR died, and only 17.6% died with an rSO2 value >60% in D. Both muscles showed consistent discriminatory power for mortality. ConclusionBoth BR and D muscles were appropriate for measuring rSO2.

975 Peripheral Tissue Nirs Oximetry: Reproducibility and Dynamic Range of Invos 5100C, Nonin Equanox, and Fore-Sight

Background and AimsNear infrared spectroscopy (NIRS) could be a valuable tool in the NICU, but implementation into standard clinical care has yet to been seen. Different absolute values and dynamics...

A Randomized Single-Blind Controlled Trial Comparing Two Monochromatic Near-Infrared Light Devices

Use of near-infrared light (NIR) is becoming more commonplace in the treatment of different pathologies; however, its safety in terms of heat generation and penetration has not been documented. The purpose of this investigation was to determine and compare skin surface and underlying tissue temperature response during and for 15 mins after a 30-min NIR application to the posterior lower leg using two different NIR devices (Anodyne and HealthLight) and one sham treatment. With this information, recommendations regarding potential adverse skin reactions, including burns, can be made. In addition, these results can serve as a reference for further studies. This single-blind randomized controlled study used a repeated-measures design. Fifteen healthy college-age individuals randomly received 30-min treatments with two different near-infrared devices and one sham device to their lower leg. A thermistor underneath the diode and a thermocouple with temperature sensors at three depths measured the temperature at skin surface and in deep tissues, respectively, every minute during the treatment and for 15 mins posttreatment. After 30 mins of treatment, there was a significant temperature increase between the NIR devices underneath the diodes and all tissue depths and the control. The skin temperature underneath the treatment diodes increased about 9.5°C from baseline to 40°C. There was no difference between the tissue temperature changes in response to the irradiation with the two NIR heating devices. A limitation of the study is that the entire sample was drawn from a healthy college population. The surface and underlying tissue temperature heating produced by the two NIR devices is within limits considered safe for healthy subjects.