[Evaluation of heart impact in the 100 m extreme intensity sport using near-infrared non-invasive muscle oxygen detecting device and sports heart rate detection technology].

Using continuous two wavelength near-infrared technology to detect the variation in the consistency of oxygen hemoglobin in the muscle and the sports heart rate wireless real time collection technology, we devised the real time muscle tissue oxygenation and instantaneous heart rate experiment scheme and implemented it for the process of the 100 m run with two parameters given simultaneously. The experiment shows that the concentration of the oxygen hemoglobin in the muscle tissue continues decreasing after the end of the 100 m run, and the time interval between the moment when the concentration of the oxygen hemoglobin attains the minimum value and the moment when the athletes finish the 100 m run is (6.65 +/- 1.10) sec; while the heart rate continues increasing after the end of the 100 m run, and the time interval between the moment when the heart rate attains the maximum value and the moment when the athletes finish the 100 m run is (8.00 +/- 1.57) sec. The results show that the two wavelength near-infrared tissue oxygenation detection technology and the sports heart rate real time collection equipment can accurately measure the sports tissue oxygenation and the heart rate in the extreme intensity sport, and reveal the process of muscle oxygen transportation and consumption and its dynamic character with the heart rate in the extreme intensity sport.

[Evaluation of kinematic capability of different groups by detecting oxygen saturation of muscle using near infrared spectroscopy].

Based on the principles of organizational optics, the noninvasive tissue oxygenation saturation monitor was developed. The monitor was used to continuously monitor the changes in regional oxygen index of the thigh vastus lateralis in 101 volunteers, who performed an incremental intensity exercise on bicycle ergometer. Among the volunteers, 42 are athletes, 25 are patients whose spleens are asthenic, and the other 34 are controls. Hemoglobin concentration (CtHb) measured was heavily influenced by the thickness of fattiness; however, regional oxygen saturation (rSO2) was influenced much lightly. In the experiment, following increasing exercise intensity of the volunteers, their CtHb increased, while their rSO2 decreased. When the volunteers stopped the exercise, both of their C1Hb and rSO2 increased quickly. The results showed that the regional saturation of oxygen of muscle was closely correlated with physical performance. The changes of regional saturation of oxygen of muscle can be used to evaluate the balance between supply and consumption of oxygen, and quantitatively assess the capability of oxidative metabolism in muscles.

[Noninvasive detection of the concentrations of pigments in pork tissue using near infrared spectroscopy].

Based on the absorption spectra of hemoglobin and myoglobin in the near infrared band, the concentrations of these pigments in the biological tissues can be obtained using near infrared spectroscopy (NIRS) by detecting the intensity attenuation of the emitted light compared with the incident light. Based on the steady-state spatially resolved NIRS, the prototype for detecting the concentrations of tissue hemoglobin and myoglobin was independently developed by our group. The probe consisted of an LED light source which could emit three different wavelengths in the near infrared band, and two detectors which were placed on the same line with and at the distances of 30/40 mm to the LED. The pigment concentrations of two pieces of pork, one from the erector spinae and the other from the rectus femoris, were detected using this prototype. The total concentrations of hemoglobin and myoglobin (c(total)) were (6.42 + 1.51) micromol x L(-1) in the erector spinae, and (15.48 +/- 4.54) micromol x L(-1) in the rectus femoris, respectively. The myoglobin was dominant in both of the results. These were consistent with the recent empirical reports. In summary, the NIRS method and prototype are authentic in detecting the pigment concentrations of pork tissue non-invasively, real-time, directly and conveniently.

[Evaluating fatigue resistance effect of health food by near-infrared tissue oximeter].

Currently, chronic fatigue syndrome (CFS) seriously affects people's normal living and work. In the present paper, the physiological parameters, such as tissue oxygenation saturation and heart rate, were used to evaluate the subjects' fatigue degree, and the fatigue resistance capsule and coffee were taken as a measure to adjust the fatigue. Human tissue oxygen saturation (rSO2) can be monitored noninvasively and in real time by near infrared spectroscopy (NIRS) based on spatially-resolved spectroscopy. Aiming at those brainworkers who need to work in an office for a long time; two static experiments were designed to evaluate the fatigue degree of the subjects who either take the fatigue resistance capsules/coffee or not. The rSO2 and heart rate (HR) of the subjects in the experiment group and contrast group were measured respectively for fatigue evaluation. This work particularly analyzed the changes in rSO2 in these two groups. The results show that the rSO2 of subjects in the experiment group evidently increased compared to that in the contrast group when the subjects took the fatigue resistance capsule or coffee, thereby show that the health food can reduce the fatigue to a certain extent.

[Comparison of the models of acute hypoxia and hypoxic-ischemia in newborn piglets].

OBJECTIVE: To compare the newborn piglet models of hypoxic ischemic brain damage in hypoxia and hypoxia combined with occlusion of both carotid arteries. METHODS: Twenty four 7-day-old piglets were divided into two groups. Group H: mechanical ventilation with low concentration of oxygen, Group HI: mechanical ventilation with low concentration of oxygen combined with occlusion of both carotid arteries. The piglets were inhaled with 10%, 8%, and 6% low-concentration oxygen for 30 min, and grouped into mild, moderate, and severe hypoxia ones. The changes of physiological parameter, cerebral blood flow and cerebral oxygen perfusion were detected. RESULTS: There were no significant differences in blood gas analysis of oxygen saturation, blood lactic acid and pH between the two groups(P>0.05).The mean arterial pressure of severe hypoxia in HI was significantly lower than in H (P<0.05). The cerebral blood flow in H and HI was relatively stable after different degrees of hypoxia. As compared with the cerebral blood flow perfusion in group H and HI, there were no significant differences between them(P>0.05). The cerebral oxygen perfusion in H and HI was significantly descent after different degrees of hypoxia(P<0.05). As compared with the cerebral oxygen perfusion in groups H and HI, there were no significant differences between them. CONCLUSION: H and HI have the same effect on physiological parameter, cerebral volume and cerebral oxygen perfusion of newborn piglets. The mechanical ventilation with low concentration of oxygen to newborn piglets can develop the HIBD model, it is not necessary to occlude carotid arteries.

[Pseudo color method for the infrared thermogram display of local breast focus tissue].

An infrared thermogram which reflects the human body surface temperature distribution can be obtained through detecting the infrared thermal radiation from each point on the human body surface. When a malignant tumor occurs in a breast, it will cause an increase in the prominent temperature in the breast surface focus region due to the abnormal blood transmission state of local focus tissue. Breast cancer can be detected through the visual analysis of the focus regions by physicians. In order to help physicians better find these focus regions, the present paper improved the traditional pseudo color display method by introducing visual effect factor and made the focus regions have a better display effect. The efficacy of this method was verified in the breast infrared thermograms of 47 breast cancer patients. The result from visual analysis of the focus region in infrared thermogram by this method can also be compared with the tissue blood transmission state from near infrared spectroscopy (NIRS) and other methods. It will be helpful to obtain more accurate diagnostic information.

[Application of near infrared spectroscopy in monitoring blood oxygen saturation of fibula flaps].

OBJECTIVE: To study the change of tissue oxygen index (TOI) by non-invasive near infrared spectroscopy (NIRS) and to investigate the blood flow variety of fibula flaps after operation. METHODS: Thirty-six patients who accepted fibula flap reconstruction were chosen as subjects. Authors measured the TOI of the fibula flaps and the control side every four hours in the first twenty-four hours, and measured these positions with the intermittence of twelve hours from second to eighth day after operation. RESULTS: Thirty-five flaps were successful and one failed. The TOI of fibula flaps shortly after operation was significantly lower than that before the operation( P<0.05). In the successful cases the TOI of fibula flaps and the control sides was fluctuated from 50.0% to 72.0%. The TOI of fibula flaps was significantly lower than that of the control sides within 144 hours after operation(P<0.05). After 144 hours the TOI was equal to that of the control side. TOI of the failed case decreased dramatically. CONCLUSIONS: NIRS can reliably indicate the change of TOI in buried flaps and detect ischemia at the early stage. The TOI of the fibula flaps depress at the early stage and returns to normal at 144 hours after operation.

[Optimally designing the probe of the near infrared oximeter to detect human tissue oxygen saturation non-invasively].

Human tissue oxygen saturation (rSO2) can be monitored non-invasively and in real time by near infrared spectroscopy (NIRS) based on spatially-resolved spectroscopy. To expand the clinical applications of the NIRS oximeter developed by our group based on the above principle, the accuracy of rSO2 must be ensured and enhanced as far as possible. In the present paper, the influences of the probe configuration, especially the distance between the detectors and the wavelength discreteness of the light source, on the accuracy of rSO2 were discussed. The results indicate that (1) to obtain rSOz accurately, two detectors need to be used, where the distance between them should be in the range of 5-20 mm and they should be both at least 20 mm apart from the light source; (2) there can be significant error in rSO2 (> 10%) induced by the discreteness of the two emission wavelengths especially the shorter one of the light source, so the real emission wavelengths must be accurately measured and the corresponding extinction coefficients of deoxygenated and oxygenated hemoglobin (Hb and HbO2) must be used in order to avoid this error. The above conclusions can be the guidance to optimally design the probe, which has been achieved in our NIRS oximeter.

[Detecting cerebral hypoxia-ischemia of newborn piglets using spatially-resolved near-infrared spectroscopy].

As a non-invasive technique for measuring tissue oxygenation, near-infrared spectroscopy (NIRS) has increasing applications in detecting cerebral hypoxia-ischemia. The authors, introduced the basic principle of the NIRS oximeter developed independently by our group (TSAH-100). The authors achieved the optimal coupling between the probe and the detected cerebral tissue. The present study investigated different regional oxygen saturations of brain (rSO2) measured non-invasively by NIRS, arterial blood oxygen saturation (SaO2) measured invasively by blood gas analysis and physiological parameters in newborn pigs with different hypoxia, in order to prove if the non-invasively cerebral rSO2 can indicate cerebral oxygenation status in clinical practice. Using this oximeter, cerebral rSO2 of 28 newborn piglets under different oxygenation status was detected. After mechanical ventilation and inhalation of 8%-17% oxygen for 30 min in the newborn pigs, the pigs were grouped according to the inhalation of oxygen. With the inhalation of 13%-17% oxygen was mild hypoxia group, with 10%-13% was moderate hypoxia group, and with 8%-10% was severe hypoxia group. There were 4 animals in mild hypoxia group, 8 animals in moderate hypoxia group, 12 animals in severe hypoxia group and 4 animals were in the normal control group. The physiological parameters were monitored during the experiment. The SaO2 were invasively measured by blood gas analysis after the experiment. The results indicate that both rSO2 and SaO2 decreased after different degree of hypoxia and there was a good correlation between cerebral rSO2 non-invasively measured by NIRS and SaO2 invasively measured by blood gas analysis (p<0.001). Cerebral rSO2 was also consistent with the degree of hypoxia and the changes in physiological parameters after hypoxia. The arterial pH and the mean arterial pressure (MAP) in the severe hypoxia group was lower than that in the control group (p<0.05). The blood lactic acid in the severe hypoxia group was higher than that in the control group (p<0.05). Thus, the rSO2 can accurately and directly indicate cerebral oxygenation status and can also replace the SaO2 invasively measured by blood gas analysis. Cerebral hypoxia-ischemia can be non-invasively and conveniently diagnosed using NIRS.

Evaluation of near infrared spectroscopy in monitoring postoperative regional tissue oxygen saturation for fibular flaps.

The ability of near infrared spectroscopy (NIRS) to predict vascular compromise in vascular free flaps postoperatively has been assessed, and the extent of regional tissue oxygen saturation (rSO(2)) after fibular flap transplantation was investigated quantitatively. To validate the sensibility and precision of the technique, the following methods were used. (1) Forearm vessel obstructive tests were conducted in four healthy volunteers. (2) Measurement and analysis of bilateral rSO(2) at the mandibular body and ramus were performed in 40 healthy volunteers by NIRS in the morning and afternoon. (3) Measurement and analysis of rSO(2) in transplanted fibular flaps for 41 cases with mandibular reconstruction were performed by NIRS at postoperative days 1-6. The results were: NIRS had high sensibility and precision in monitoring rSO(2) of living tissues. No significant difference in the values of rSO(2) was found across different times or areas in the normal mandible. However, rSO(2) in the transplanted fibular flaps was reduced compared to the value on the control side. rSO(2) decreased gradually 4-12 hours postoperatively. After that period, rSO(2) increased gradually and approached the value of the control side at 20 h after the operation. It can be concluded that NIRS is a reliable noninvasive method for monitoring blood circulation in transplanted tissues, particularly for buried flaps.

[Correlation of brain hypoxia at different degrees with brain function and brain damage investigated using near infrared spectroscopy].

OBJECTIVE: To study correlation of brain hypoxia of different degrees with brain function and damage. METHODS: The brain regional oxygen saturation (rSO2) was determined by using a non-invasive near infrared spectroscopy (NIRS) technique in 15 piglets; the piglets were subjected to inhale 3% - 11% oxygen-nitrogen mixed gas through mechanical ventilation for 30 min. The piglets were divided into groups according to the level of brain rSO2 (i.e. < 30%, 30% - 35%, 35% - 40%, and 40% - 50%), and the data were compared with those of the control group (rSO2 > 60%). Changes of brain function were detected through amplitude and frequency of EEG waves and signal complexity. The piglets were sacrificed via decapitation 72 h after brain damage, and then histopathological and ultrastructural examinations were performed on cerebral cortex and hippocampal CA1 area. RESULTS: In the group with rSO2 > 40%, the mean arterial pressure (MAP) after hypoxia was (56 +/- 0.00) mm Hg (1 mm Hg = 0.133 kPa), the blood lactic acid (LA) was (2.3 +/- 1.2) mmol/L, the EEG findings were within normal range, and there was no change in brain tissue ultrastructure. In the group with brain rSO2 = 30% approximately 40%, the MAP was (73 +/- 8) mm Hg, the LA was (8.2 +/- 3.9) mmol/L, the EEG waves showed decreased amplitude, frequency and complexity, but restored to some extent after hypoxia. The brain tissue ultrastructure showed damages to the cerebral cortex and neuron mitochondria at hippocampal CA1 area. In the group with brain rSO2 < 30%, the MAP was (35 +/- 0) mm Hg, the LA was (12 +/- 2) mmol/L, the EEG showed decreased amplitude, frequency, and complexity of signals compared with those of the normal control group, and was difficult to restore after hypoxia in some of the piglets; the brain tissue ultrastructure appeared to be similar to the changes seen with high-degree swollen cerebral cortex and neuron mitochondria at hippocampal CA1 area. CONCLUSION: Different degrees of hypoxia had different influence on brain function and brain damage. The lower the brain rSO2, the more severe the damages to the brain and its function. The rSO2 of brain tissues detected with noninvasive NIRS can reflect brain injury and its severity during cerebral anoxia.

[Evaluation of early cognitive ability of infants born preterm by near-infrared spectroscopy].

OBJECTIVE: To compare the differences in cerebral oxygenation responses between the infants born preterm and full-term infants and to evaluate the early cognitive ability of infants born preterm. METHODS: Cerebral oxygenation after light stimulation was detected by near infrared spectroscopy (NIRS) in preterm infants at 3 or 6 months corrected gestational age (GA). The results were compared with those of age-matched infants born at term. RESULTS: The start and peak response time of cerebral oxygenation occurring after light stimulation in preterm infants at 3 months corrected GA was 17.2 +/- 5.2 and 38.4 +/- 9.6 seconds respectively, which were significantly longer than in age-matched term infants (13.1 +/- 2.7 and 28.9 +/- 5.0 seconds respectively) (P < 0.05). The maximum response value of hemoglobin, oxyhemoglobin and regional oxygen saturation of the preterm infants at 3 months corrected GA was (1.2 +/- 0.5)%, (1.5 +/- 0.6)%, and (1.3 +/- 0.4)% respectively , which were significantly lower than that of the term infants [(2.3 +/- 0.3)%, (2.8 +/- 0.3)% and (2.4 +/- 0.5)% respectively] (P < 0.05). Cerebral oxygenation responses to light stimulation in preterm infants examined at 6 months corrected GA were not significantly different from age-matched term infants. CONCLUSIONS: Cerebral oxygenation responses to light stimulation in infants born preterm at 3 months corrected GA are not as good as age-matched term infants, but were close to the level of age-matched term infants at 6 months corrected GA. This suggests that the early cognitive ability of preterm infants before 3 months corrected GA might fall behind age-matched term infants.

[Monitoring cerebral oxygenation using near infrared spectroscopy during cardiopulmonary bypass surgery].

To avoid cerebral hypoxia caused by the imbalance between cerebral oxygen supply and consumption, regional cerebral oxygenation of patients need to be monitored at real time during cardiopulmonary bypass (CPB) surgery, and the physiological parameters can be regulated and emergent treatment can be used according to it. Using the near infrared (NIR) instrument developed by our group, cerebral oxygenation of the patients under cardiac surgery was monitored. The instrument consists of a two-wavelength near infrared light source and two near infrared detectors. Hemoglobin concentration changes of regional cerebral tissue were calculated, and by steady-state spatially resolved spectroscopy (SRS) algorithm, regional cerebral oxygen saturation (rSO2) was also calculated. Physiological parameters of patients, such as mixed venous oxygen saturation (SvO2), were measured by another monitor during CPB. Hemoglobin concentration changes were easily disturbed, but the anti-disturbance ability of rSO2 was good. The value of rSO2 could be detected all over the surgeries, but SvO2 could be detected only during CPB. There were positive correlations between rSO2 and SvO2 in most of the patients, but the correlation coefficients were not very high. This was because SvO2 reflects the saturation of the main venous, but rSO2 reflects regional cerebral oxygenation. So the physiological meaning of rSO2 and SvO2 is different. The results indicate that cerebral oxygenation of patients can be reflected by rSO2 during CPB, while only monitoring SvO2 is not enough.

[Evaluation of relationship between early brain response and neurodevelopment in newborns by using near infrared spectroscopy].

OBJECTIVE: To study the relationship between early brain response to extrinsic stimulation and neurodevelopment in preterm infants, assess the brain function of preterm infants in the early stage, and thereby to provide objective evidence for the degree of neurodevelopment in preterm infants and to evaluate prognosis. METHODS: Using near infrared spectroscopy (NIRS), the brain response to sound stimulation of 90 preterm infants at different gestational age was observed and compared with the result obtained from 20 full term infants. The neonatal behavioral neurological assessment (NBNA) was performed at corrected age of 40 weeks, and the infants were followed up for 2 years. The effect of gestational age and brain damage on preterm infants, the relation between early brain response in preterm infants and their neurodevelopment was evaluated. RESULTS: All the preterm infants responded to different degrees to auditory stimulation after birth. The time to beginning to react and the time to appearance of the peak reaction were attained after auditory stimulation and the time to beginning to resume when the auditory stimulation was stopped was (278 +/- 94) s, (446 +/- 67) s and (199 +/- 52) s, respectively, which were significantly longer than those observed in the full term infants (107 +/- 30) s, (264 +/- 51) s and (131 +/- 46) s, respectively. The maximum reactions of hemoglobin, oxyhemoglobin and regional oxygen saturation in the infants after gestational age 32 weeks was (0.3 +/- 0.3)%, (0.7 +/- 0.5)% and (0.3 +/- 0.3)%, respectively, which were significantly lower than those in the full term infants (1.7 +/- 0.7)%, (1.7 +/- 0.8)% and (1.6 +/- 0.7)%, respectively. When the brain response of preterm infants was compared with that in infants without brain damage, the speed of the reaction was slow, the maximum reaction was low. The brain response in preterm infant was correlated with NBNA at corrected age of 40 weeks. It was found during the following-up that abnormal neurodevelopment was associated with poor brain reaction. CONCLUSIONS: NIRS can be used to evaluate brain response of infants. Preterm infants display brain response to auditory stimulation. Early brain response is correlated with neurodevelopment.

[Regional cerebral oxygen saturation in neonates with meconium aspiration syndrome].

OBJECTIVE: This study examined the changes of regional cerebral oxygen saturation (rSO2) by noninvasive near infrared spectrophotometry in neonates with meconium aspiration syndrome (MAS). METHODS: Seventy-three full neonates with MAS were divided into three groups by respiratory symptoms: asymptomatic group (group 1, n=38), common group (group 2, n=28) and severe group (group 3, n=7). Near infrared spectrophotometry was used to measure the cerebral rSO2 on days 1, 3, 5 and 7 after birth. Thirty healthy full-term newborns served as the Control group. RESULTS: The cerebral rSO2 of group 1 decreased significantly compared with that of the Control group between days 1 and 3 (P < 0.05). The cerebral rSO2 of group 2 or group 3 was significantly lower than that of group 1 and the Control group on days 1, 3 and 5 (P < 0.05). The MAS patients with mild hypoxic-ischemic encephalopathy (HIE) had significantly higher brain rSO2 levels than those with medium or severe HIE on days 2, 3 and 5 (P < 0.05). CONCLUSIONS: The cerebral rSO2 decreased in neonates with MAS. The values for rSO2 correlated with the severity of HIE in MAS patients.

[The preliminary study for testing freshness of meat by using near-infrared reflectance spectroscopy].

The value of the volatile basic nitrogen of meat is an important index to determine the freshness of meat. It is difficult to meet the demand of fast and non-destructive measurement by means of classical semimicro-quantitative nitrogent method. A model to predict the value of the volatile basic nitrogen based on near-infrared reflectance spectroscopy was established. Cluster analysis methods were applied to deal with the data of NIRS. If the content of TVB-N is more than 11. 6 mg x (100 g)(-1), the back pork may be rotten. The result shows that using NIRS could indicate the freshness of meat quickly and non-invasively.

[Simultaneous measurement of muscle energy metabolism by MRS and frequency-domain NIR spectroscopy].

The frequency-domain near-infrared spectrometry (NIRS) is capable of measuring the absolute absorption and reduced scattering coefficient of tissue noninvasively. This allows the quantitation of tissue hemoglobin concentration which reflects the balance between oxygen delivery and oxygen utilization of the skeletal muscle. Phosphorus magnetic resonance spectroscopy (31P-MRS) has become a gold standard of noninvasive measurement of human skeletal muscle metabolism. The rate of phosphocreatine (PCr) resynthesis during recovery is an indicator of the rate of oxidative metabolism. The purpose of the present study was the effect of lower intracellular pH (pHi) on PCr and oxygenation recovery. The preliminary results of plantar flexion experiment on a healthy male subject show that both PCr resynthesis and reoxygenation were very much prolonged by severe acidosis (pHi = 6.42).

[Application of near-infrared spectroscopy to postoperative monitoring of flap in plastic surgery].

As a non-invasive technique for the measurement of blood and oxygen in tissue, the near-infrared spectroscopy (NIRS) has an increasing application to the postoperative monitoring of plastic surgery. In authorial research, a set of NIRS oximeter has been used in 6 successful flap-transplantation operations to monitor and contrast the oxygen saturation in the free flap side and in the normal opposite side. It was found in the research that there is a notable difference in the oxygen saturation between those two sides. Another research has been done in an unsuccessful operation. In this experiment, several points in the mandible were measured and the result shows that the oxygen saturation is at an obviously lower level in the anoxic position than in the normal ones. In the above several researches, near infrared spectroscopy showed a high sensitivity to detect the dynamic changes in flaps induced by inhalation of pure oxygen. Therefore, NIRS can be a valuable aid in the post-operative monitoring of free flap after the operation, and must have a great practical future in this field.

In vivo determination of the optical properties of infant brain using frequency-domain near-infrared spectroscopy.

We investigate the optical properties of the brain in 23 neonates in vivo using a frequency domain near-infrared spectroscopy (NIRS). In this study, a calibration procedure is employed to determine the absorption and reduced scattering coefficients with single source-detector separation. The absorption coefficients of the infant foreheads are lower than the values reported in adults. A large intersubject variation in the reduced scattering coefficients is also demonstrated. Furthermore, physiological parameters are derived from the absorption coefficients at two wavelengths (788 and 832 nm). The mean total hemoglobin concentration (THC) is 39.7+/-9.8 microM and the mean cerebral blood oxygen saturation (StO2) is 58.7+/-11.2%. Our preliminary results show that this bedside frequent domain NIRS could provide quantitative optical measurement of the infant brain.

[Spectral colorimetric correction of full view color images in a real scene measurement system].

In the three dimensional multiple modalities scanning real scene measurement system, a color linear CCD was used to obtain the one dimensional linear color information of the scene. Successive one dimensional color images of different angles were patched to constitute the full view color image. If the color image is displayed directly on the color cathode ray tube (CRT) monitor of a computer, colorimetric distortion will occur. Colorimetric correction is then needed. Through thespectral colorimetric correction, the colorimage displayed on the color CRT monitor is matched with the original scene in the colorimetric sense.