Measurement of venous oxyhaemoglobin saturation in the adult human forearm by near infrared spectroscopy with venous occlusion

Measurement of the oxygenation of the peripheral tissues provides useful information about tissue perfusion. A method is described for the measurement of peripheral venous oxyhaemaglobin saturation (SvO₂) in the adult forearm by a non-invasive technique, near infrared spectroscopy (NIRS) with venous occlusion. A series of studies is performed on healthy adults to compare measurements of forearm SvO₂ made by NIRS with measurements of superficial venous SvO₂ made by co-oximetry, and to study the effect of different optode spacings. There is a significant correlation between forearm SvO₂ measured by NIRS and SvO₂ of superficial venous blood measured by cooximetry (n=19, r=0.7, p<0.0001). Higher values for SvO₂ were obtained using a 2.5 cm spacing than with a 4 cm spacing (mean difference=4.1% (95% Cl 1.4%–6.8%) n=16). This difference is likely to have been due to a more superficial volume of tissue being studied with the closer optode spacing. Peripheral SvO₂ can be measured non-invasively using NIRS with venous occlusion. It may prove to be a useful method to study circulatory disturbances.     

Estimated contribution of hemoglobin and myoglobin to near infrared spectroscopy

We calculated the light absorbing potential (LAP) of hemoglobin (Hb) and myoglobin (Mb) in mammalian skeletal muscle at rest based on analysis of published chemical and morphometric data (Part 1), interpreted changes in total[Hb + Mb] from NIRS during exercise (Part 2), and estimated the potential contribution of Hb and Mb to changes in NIRS from rest to exercise (Part 3). Part 1: [Hb] in skeletal muscle was estimated from microvascular volume, systemic blood [Hb], and microvascular hematocrit and saturation at rest and during exercise. Part 2: Changes in total[Hb + Mb] (as t[Hb + Mb]) during cycling or knee extension exercise were interpreted using the results of Part 1. Part 3: Using estimates of mean microvascular PO₂, Hb and Mb contribution at peak exercise was estimated. Across several species, [Mb] contributed ∼50–70% of the total LAP to NIRS at rest in skeletal muscle. With exercise, increases in t[Hb + Mb] of up to 30% could be entirely explained by the predicted increase in microvascular hematocrit with exercise. Finally, Mb was estimated to contribute ∼70% of the changes in NIRS from rest to peak exercise.     

A near infrared spectroscopy study investigating oxygen utilisation in hydrocephalic rats

Determination of hydrocephalus and its severity is important for optimal management of the condition. We have used near infrared spectroscopy (NIRS) to assess changes in concentrations of oxygenated (O₂Hb), deoxygenated (HHb), total haemoglobin (tHb) and cytochrome c oxidase (Caa₃) in normal and hydrocephalic Texas (HTx) rats in response to a 5 min head down tilt and a sodium pentobarbitone (NaPB) challenge. The former was used to test vascular responses and the latter to test metabolic responses. The haemoglobin oxygenation index (HbD) was derived which provides information regarding oxygen utilisation ([HbD]=[O₂Hb]−[HHb]). With the tilt challenge, a significant (P=0.001) difference was observed in [HbD] between normal (n=24) and hydrocephalic (n=14) rats (–3.50 (−6.00 to 0.00) μM cm⁻¹ and 7.50 (0.75 to 14.25) μM cm⁻¹, respectively). In another experiment we tested the response of ten rats to NaPB administration and observed a significant difference (P=0.008) in [Caa₃] between normal (n=5) and hydrocephalic (n=5) rats (−6.60 (−7.55 to −5.50) μM cm⁻¹ and −2.20 (−5.60 to −1.05) μM cm⁻¹, respectively). Coronal sections of these ten rat brains were analysed and significant (P<0.05) relationships were found between some of the NIRS parameters and cortical thickness or lateral ventricle area measurements. Our studies demonstrate that a significant difference in cerebral oxygenation and haemodynamics can be observed between normal and hydrocephalic HTx rats using NIRS.     

Noninvasive measurement of cerebral hemoglobin oxygen saturation using two near infrared spectroscopy approaches

Spatially resolved spectroscopy (SRS) is a new near infrared spectroscopy (NIRS) method that, using the multi-distance approach, measures local cerebral cortex hemoglobin oxygen saturation [J. Matcher, P. Kirkpatrick, K. Nahid, M. Cope, and D. T. Delpy, Proc. SPIE 2389, 486-495 (1995)]. Using a conventional continuous wave NIRS photometer, cerebral venous oxygen saturation (SvO2) can be calculated from oxyhemoglobin and total hemoglobin rise induced by partial occlusion of jugular vein [C. E. Elwell, S. J. Matcher, L. Tyszczuk, J. H. Meek, and D. T. Delpy, Adv. Exp. Med. Biol. 411, 453-460 (1997)]. The aim of this study was to compare direct measurements of forehead tissue oxygenation index (TOI) with the calculated SvO2 during venous occlusion in 16 adult volunteers using a clinical two-channel SRS oximeter (NIRO-300). Measured TOI and calculated SvO2 values of either right or left forehead did not significantly differ. A good agreement between the two NIRS methods was also demonstrated. On 16 other subjects, no significant differences were found between the right and left forehead TOI values measured simultaneously, and between the TOI values measured by channel 1 or 2 on the same side. The results confirm that cerebral cortex hemoglobin oxygen saturation, measured directly by the SRS method, reflects predominantly the saturation of the intracranial venous compartment of circulation.     

Characterization of healthy skin using near infrared spectroscopy and skin impedance

Near infrared spectroscopy (NIR) and skin impedance (IMP) spectroscopy are two methods suggested for diagnoses of diseases inducing adverse effects in skin. The reproducibility of these methods and their potential value in non-invasive diagnostics were investigated. Measurements were performed in vivo on healthy skin at five anatomic body sites on eight young women. partial least squares discriminant analysis showed that both methods were useful for classification of the skin characteristics at the sites. Inter-individually the NIR model gave 100% correct classification while the IMP model provided 92%. Intra-individually the NIR model gave 88% correct classification whereas the IMP model did not provide any useful classification. The correct classification was increased to 93% when both datasets were combined, which demonstrates the value of adding information. Partial least squares discriminant analysis gave 72% correct predictions of skin sites while the combined model slightly improved to 73%.     

Skeletal muscle StO<Subscript>2</Subscript> kinetics are slowed during low work rate calf exercise in peripheral arterial disease

The time course of muscle oxygen desaturation (StO₂ kinetics) following exercise onset reflects the dynamic interaction between muscle blood flow and muscle oxygen consumption. In patients with peripheral arterial disease (PAD), muscle StO₂ kinetics are slowed during walking exercise; potentially reflecting altered muscle oxygen consumption relative to blood flow. This study evaluated whether StO₂ kinetics measured using near infrared spectroscopy (NIRS) would be slowed in PAD during low work rate calf exercise compared with healthy subjects under conditions in which blood flow did not differ. Eight subjects with PAD and eight controls performed 3 min of calf exercise at 5, 10, 30, and 50% of maximal voluntary contraction (MVC). Calf blood flow responses were measured by plethysmography. Power outputs were similar between groups for all work rates. In PAD, the time constants of StO₂ kinetics were significantly slower than controls during 5% MVC (13.5 ± 1.7 vs. 6.9 ± 1.2 s, P < 0.05) and 10% MVC work rates (14.5 ± 2.7 vs. 6.8 ± 1.1 s, P < 0.05). Blood flow assessed when exercise was interrupted after 30 s did not differ between PAD and control subjects at these work rates. In contrast, the StO₂ time constants were not different between groups during 30 and 50% MVC work rates, where blood flow responses in PAD subjects were lower as compared with controls. Thus in PAD, the slowed StO₂ kinetic responses under conditions of unimpaired calf blood flow reflect slowed muscle oxygen consumption in PAD skeletal muscle during low work rate plantar flexion exercise as compared with healthy skeletal muscle.     

Forearm oxygen consumption and forearm blood flow in healthy children and adolescents measured by near infrared spectroscopy

The assessment of forearm oxygen consumption (VO(2)) and forearm blood flow (FBF) by means of near infrared spectroscopy has become widespread in adults, whereas in children and adolescents no data are available. The aim of the present study was to analyze VO(2) and FBF in healthy children and adolescents. METHODS: In a prospective cohort study, 20 male and 20 female healthy children and adolescents were investigated. The measurements of VO(2) and FBF were performed by means of near infrared spectroscopy in combination with the venous occlusion method. RESULTS: Mean VO(2) was 0.08 +/- 0.04 ml 100 g(-1) min(-1) in male and 0.09 +/- 0.05 ml 100 g(-1) min(-1) in female subjects. Mean FBF was 1.95 +/- 1.25 ml 100 g(-1) min(-1) in male and 1.82 +/- 0.98 ml 100 g(-1) min(-1) in female subjects. No significant difference was found between male and female subjects. A significant negative correlation of VO(2) and FBF to age was observed in both groups. CONCLUSION: In the present study we were able to show that VO(2) and FBF decreased with increasing age in children and adolescents without significant differences between male and female subjects.     

Phosphorus-31 magnetic resonance spectroscopy of forearm flexor muscles in student rowers using an exercise protocol adjusted for differences in cross-sectional muscle area

Summary To assess exercise energy metabolism of forearm flexor muscles in rowers, six male student rowers and six control subjects matched for age and sex were studied using phosphorus-31 magnetic resonance spectroscopy (³¹P-MRS). Firstly, to adjust for the effect of differences in cross-sectional muscle area, the maximal cross-sectional area (CSA_max) of the forearm flexor muscles was estimated in each individual using magnetic resonance imaging. Multistage exercise was then carried out with an initial energy production of 1 J · cm^–2 CSA_max for 1 min and an increment of 1 J · cm^–2 CSA_max every minute to the point of muscle exhaustion. A series of measurements of³¹P-MRS were performed every minute. The CSA_max was significantly greater in the student rowers than in the control subjects [19.8 (SD 2.2) vs 17.1 (SD 1.2) cm²,P<0.05]. The absolute maximal exercise intensity (J · min^–1) was greater in the rowers than in the control subjects. However, the maximal exercise intensity per unit of muscle cross sectional area (J · min^–1 · cm^–2) was not significantly different between the two groups. During mild to moderate exercise intensities, a decrease in phosphocreatine and an increase in inorganic phosphate before the onset of acidosis were significantly less in the rowers, indicating a requirement of less adenosine 5-diphosphate to drive adenosine 5-triphosphate production. The onset of acidosis was also significantly delayed in the rowers. No difference was observed in forearm blood flow between the two groups at the same exercise intensity (J · min^–1 · cm^–2). These results demonstrated that the findings of the maintenance of a higher level of phosphocreatine and a lower level of inorganic phosphate with less acidosis observed in the rowers were the results of the intrinsic characteristics of energy metabolism of their muscles and that these characteristics were independent of their greater cross-sectional muscle area.     

Oxygenation, EMG and position sense during computer mouse work. Impact of active versus passive pauses

We investigated the effects of active versus passive pauses implemented during computer mouse work on muscle oxygenation and EMG of the forearm extensor carpi radialis muscle, and on wrist position sense. Fifteen healthy female subjects (age: 19–24 years) performed a 60-min mouse-operated computer task, divided into three 20 min periods, on two occasions separated by 3–6 days. On one occasion a passive pause (subjects resting) was implemented at the end of each 20-min period, and on another occasion an active pause (subjects performed a number of high intensity extensions of the forearm) was implemented. Also at the end of each 20-min period, test contractions were conducted and subjective ratings of fatigue and stress were obtained. Another parameter of interest was total haemoglobin calculated as the summation of oxy-and deoxy-haemoglobin, since it reflects blood volume changes. The most interesting findings were an overall increasing trend in total haemoglobin throughout the mouse work (P<0.001), and that this trend was greater for the active pause as compared to the passive pause (P<0.01). These data were accompanied by an overall increase in oxygen saturation (P<0.001), with a tendency, albeit not significant, toward a higher increase for the active pause (P=0.13). EMG amplitude and median frequency tended to decrease (P=0.08 and 0.05, respectively) during the mouse work but was not different between pause types. Borg ratings of forearm fatigue showed an overall increase during the activity (P<0.001), but the perceptions of stress did not change. Position sense did not change due to the mouse work for either pause type. While increasing trends were found for both pause types, the present study lends support to the hypothesis of an enhancement in oxygenation and blood volume for computer mouse work implemented with active pauses. However, a presumption of an association between this enhancement and attenuated fatigue during the mouse work was not supported.     

帕金森大鼠纹状体区近红外光谱活体微创在位检测研究

目的:探讨近红外光谱技术(NIRS)测量帕金森(PD)大鼠纹状体区局部优化散射系数(μs')与局部脑血容量(rCBV)的特点.方法:利用光学探头微创测量40只模型组大鼠毁损侧与健侧纹状体区的μs'与rCBV,并与20只假手术组和20只正常组大鼠双侧纹状体测量结果进行比较.结果:模型组毁损侧μs'与rCBV值分别与模型组...     

Increase in oxygen consumption induced by selective spinal cord cooling in the exercising pigeon

Six domestic pigeons with chronically implanted spinal thermodes were exercised on a treadmill at neutral ambient temperature. During the exercise the spinal cord was cooled to 34.7±0.4°C (mean±S.E.M.). Oxygen consumption of the pigeons increased from 28.3 ±2.1 to 61.2±3.7 ml·min^–1·kg^–1 due to exercise per se, and superimposed cooling of the spinal cord during exercise induced an additional increase in oxygen consumption to 84.9±4.5 ml·min^–1·kg^–1. The result demonstrates that cooling of the spinal cord elicits shivering in exercising pigeons at thermoneutral conditions.     

Effect of short-term energy intake level and exercise on oxygen consumption in men

Summary The influence of short-term energy intake and cycle exercise on oxygen consumption in response to a 1.5 MJ test meal was investigated in ten young, adult men. On the morning after a previous day's low-energy intake (LE regimen) of 4.5 MJ, the mean resting oxygen consumption increased by 0.7 ml · kg^–1 · min^–1 after the test meal (P<0.025). After a high-energy intake (HE regimen) of 18.1 MJ, the resting measurement was unchanged (+0.4 ml · kg^–1 · min^–1) after the meal (n.s.). These trends are the reverse of what would be expected if oxygen consumption in response to feeding is a factor in the acute control of body weight. The mean fasting oxygen consumption during cycle exercise at 56% of (constant work) for both LE and HE prior intakes was not different at 31.1 ml · kg^–1 · min^–1. Oxygen consumption during exercise increased after feeding by 0.5 ml · kg^–1 · min^–1 on the LE regimen (n.s.) and decreased by 1.2 ml · kg^–1 · min^–1 on the HE regimen (n.s.). These results are also the reverse of what would be expected if oxygen consumption in response to exercise is related to short-term energy intake.     

近红外光谱技术在临床检测中的应用

近红外光谱（near infrared spectroscopy,NIRS）分析技术是近年来发展最快、最引人注目的 分析技术,广泛应用于石油、化工、食品等分析化学各领域.本文在介绍NIRS技术基本原理、技术特点的基础上,阐述了NIRS技术在临床检测领域的研究情况,主要包括在无创血糖监测、无创血氧测量、乳腺肿块检测、尿液成分分析等方面的应用与进展,最后初步探讨了该技术在应用中存在的局限性,并对NIRS分析技术在临床检测领域中的应用前景进行了展望.     

Tissue proteoglycans studied by infrared spectroscopy

Intersectorial Research Technology Complex Ocular Microsurgery, State Research and Production Enterprise, Moscow. (Presented by Academician of the Russian Academy of Medical Sciences D. S. Sarkisov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 114, No. 9, pp. 246–249, September, 1992.     

Detection of cerebral oxyhaemoglobin changes during vestibular Coriolis cross-coupling stimulation using near infrared spectroscopy

Near infrared spectroscopy (NIRS) has been successful in monitoring cerebral haemodynamics when the subject is immobilized during surgery, and when there is a drastic depletion of blood from the cerebral cortex during positive acceleration. In this study, we monitored subtle changes of cerebral oxygen level using NIRS during vestibular stimulation. For the control conditions, cerebral oxygen status was monitored in six stationary subjects sitting upright, and while they executed head movements in the pitch axis with eyes opened and eyes closed. The experimental conditions involved the subjects making a head movement which required a 45 degrees pitch-down followed by a return to upright head movements 12 s later during yaw rotation (Coriolis cross coupling) at 10 and 20 rotations per minute (rpm) in a random order. Oxyhaemoglobin (O(2)Hb), deoxyhaemoglobin (HHb) and total haemoglobin levels were recorded every 0.5 s from both the parietal and the occipital lobe simultaneously. A significant rotation effect was observed in total Hb level changes from baseline in both regions. Occipital O(2)Hb increased significantly after the head movement with eyes opened at 20 rpm. Our findings appear to be consistent with previous vestibular studies that significant changes in brain blood flow occur during caloric stimulation. NIRS can be used to monitor discrete cortical blood flow changes resulting from vestibular and other forms of stimulation.     

Cerebral blood flow and behavioural effects of caffeine in habitual and non-habitual consumers of caffeine: a near infrared spectroscopy study

Caffeine has been shown to modulate cerebral blood flow, with little evidence of tolerance to these effects following habitual use. However, previous studies have focused on caffeine levels much higher than those found in dietary servings and have compared high caffeine consumers with low consumers rather than ‘non-consumers’. The current placebo-controlled double-blind, balanced-crossover study employed near infrared spectroscopy to monitor pre-frontal cerebral-haemodynamics at rest and during completion of tasks that activate the pre-frontal cortex. Twenty healthy young habitual and non-habitual consumers of caffeine received 75 mg caffeine or placebo. Caffeine significantly decreased cerebral blood flow but this was subject to a significant interaction with consumption status, with no significant effect being shown in habitual consumers and an exaggerated effect in non-habitual consumers. These findings suggest that caffeine, at levels typically found in a single dietary serving, is able to modulate cerebral blood flow but these effects are subject to tolerance.     

人体脂肪近红外无损检测方法

人体脂肪含量是人体测量的一个重要指标，合理地控制人体脂肪含量对人体健康有重要意义，根据人体脂肪、肌肉近红外光吸收系数的不同及光子在双层介质中随机迁移理论，我们设计了一种用近红外光人体脂肪含量的方法。并利用光子在组织中随机迁移模型进行简要分析。用此方法测定人体肱二头肌中点脂肪厚度，再加上对身高、体重的测量，经过统计回归可得到人体脂肪总体含量的百分值。经试验验证，此方法有较高的准确度且安全、迅速、可靠     

Is muscle structure influenced by genetical or functional factors? A study of three forearm muscles

Relative fibre type composition and weights of 3 forearm muscles; the m. extensor carpi radialis longus (ECRL). m. extensor carpi radialis hrevis (ECRB) and the m. bruchioradialis (BR) from both the left and right arm were determined. Fibre type 1 muscle weight of the ECRB. which cocontracts posturally during gripping, was significantly greater in the right than the left forearm. Weights of type 2 fibres in this muscle were. however, similar in the left and right arm. Fibre type weights of both ECRL and BR were also similar in both arms. For all these muscles, intra-individual co-variation in relative fibre type occurrence was found. It is proposed that genetic factors may play a role in determining the relative fibre type composition at least as far as the upper extremities are concerned. However, functional demands are also important determining factors for development of muscle structure.     

NIRS-EEG联合检测技术在脑功能分析中的研究进展

近红外光谱技术（Near Infrared Spectroscopy, NIRS）和脑电（Electroencephalographic, EEG）在脑科学研究中占有重要地位。联合NIRS和EEG的检测技术（简称NIRS-EEG联合检测技术）在脑功能分析领域可以达到比单一检测技术更好的效果,从而更好地理解大脑生理机制。本文首先介绍NIRS和EEG技术的原理,并比较了这两种技术与其他脑检测技术的优缺点。然后指出目前联合检测技术在系统设计时需要注意的技术要点。接着列举在联合检测技术在脑功能分析中的应用,并总结目前该技术的优势和面临的问题,并根据出现这些问题的原因做出相应的分析,提出对策和建议。最后对这项技术的未来应用做出展望。     

Effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense

The present study investigated the effects of time pressure and precision demands during computer mouse work on muscle oxygenation and position sense in the upper extremity. Twenty-four healthy subjects (12 males and 12 females) performed a 45-min standardized mouse-operated computer task on two occasions. The task consisted of painting rectangles that were presented on the screen. On one occasion, time pressure and precision demands were imposed (more demanding task, MDT), whereas, on the other occasion, no such restraints were added (less demanding task, LDT). The order of the two task versions was randomized. Tissue oxygen saturation in the trapezius and extensor carpi radialis muscles was recorded throughout, and the position-matching ability of the wrist was measured before and after the tasks. In addition, measurements of autonomic nervous system reactivity and subjective ratings of tenseness and physical fatigue were obtained. Performance was measured in terms of the number of rectangles that were painted during the task. During MDT, oxygen saturation in extensor carpi radialis decreased (P<0.05) compared to LDT. These data were paralleled by increased electrodermal activity (P<0.05), skin blood flow (P<0.05), ratings of tenseness and fatigue (P<0.01), and increased performance (P<0.01) during MDT. Females exhibited lower oxygen saturation than males, during rest as well as during the computer tasks (P<0.01). Wrist repositioning error increased following LDT as compared to MDT (P<0.05). In conclusion, computer mouse work under time pressure and precision demands caused a decrease in forearm muscle oxygenation, but did not affect wrist position sense accuracy. We attribute our changes in oxygenation more to increased oxygen consumption as a result of enhanced performance, than to vasoconstriction.Presented in part at the 49th Nordiska Arbetsmiljömötet in Savonlinna Finland, August 25–27, 2003