Near-infrared Spectrophotometers Research Articles

A comparison of two different near-infrared spectrophotometers in pediatric and adult cardiac surgeries

A comparison of two different near-infrared spectrophotometers in pediatric and adult cardiac surgeries

Hyperspectral Visible and Near-Infrared Determination of Copper Concentration in Agricultural Polluted Soils

The objective of this research was to develop a hyperspectral imaging system for estimating copper concentration in soils as an alternative to standard chemical analyses and to evaluate the analytical accuracy of the system using the visible–near-infrared and near-infrared regions. Hyperspectral imaging is a complex technology providing elevated information content. This work was carried out on air-dried <2-mm soil fraction contaminated by adding 20 mL of copper sulfate at concentrations ranging from 0 to 1000 mg of copper per kg of soil. The samples were scanned in random order and with orientation using visible–near-infrared and near-infrared spectrophotometers. A range of partial least squares regression models derived from the spectral arrays were tested on their ability to predict copper concentration. Significant correlations between predicted and known chemical concentrations were achieved with a correlation coefficient of 0.93 for the visible–near-infrared and 0.77 for the near infrared.

Effect of a Photopolymerizable Monomer Containing a Hydrogen Bond on Near-Infrared Radiation Transmittance of Nematic Liquid Crystal/Monomers Composites

Polymer dispersed liquid crystal (PDLC) films were prepared by ultraviolet (UV) radiation induced polymerization of photopolymerizable monomers in nematic liquid crystal (LC)/monomers composites. The effect of a photopolymerizable monomer 2-hydroxyethylmethacrylate (HEMA) containing a hydrogen bond on the transmittance of the PDLC films in the wavelength region of 300−2500 nm was investigated by UV−visible (VIS)−near-infrared (NIR) spectrophotometers, scanning electron microscopy, and an infrared spectrometer. It was surprisingly found that the addition of a small amount of HEMA monomer containing a hydrogen bond could dramatically decrease the off-state transmittance in the NIR region partially due to the formation of a compact and thick-border polymer network. Then the conceivable mechanism concerning the effect of HEMA monomers containing a hydrogen bond on the microstructure of the polymer network was investigated experimentally and theoretically. This provided a potential approach for the electrically controlled modulation of NIR radiation.

Monitoring of pre-frontal oxygen status in helicopter pilots using near-infrared spectrophotometers

BackgroundThere are few in-flight studies of cognition-related cerebral oxygen status in helicopter pilots.MethodsFour male helicopter pilots volunteered for nine sorties during visual flight in a BK117 and UH-60J. The pilots' pre-frontal oxy-hemoglobin (O2Hb) and deoxy-hemoglobin (HHb) concentration were continuously monitored from the right/left sections of the forehead using near-infrared spectrophotometers with a consideration of motion artifacts.ResultsThe concentration of O2Hb progressively increased (13.98 μmol•L-1 as a maximum increased concentration) in both the right/left sections of the forehead from the basal level during the heightened cognitive demand of helicopter flight. There was comparatively little change (4.32 μmol•L-1 as a maximum increased concentration) in HHb concentration during measurement of helicopter flight. HHb changes were apparently not affected by a heightened cognitive demand of helicopter pilots.ConclusionThese results demonstrate that near-infrared spectroscopy, especially O2Hb measurements, provides a sensitive method for the monitoring of cognitive demand (maneuvers) in helicopter pilots.

Comparison of different near‐infrared spectroscopic cerebral oxygenation indices with central venous and jugular venous oxygenation saturation in children

We compared two different near-infrared spectrophotometers: cerebral tissue oxygenation index (TOI) measured by NIRO 200 and regional cerebral oxygenation index (rSO(2)) measured by INVOS 5100 with venous oxygen saturation in the jugular bulb (SjO(2)) and central SvO(2) from the superior caval vein (SVC) during elective cardiac catheterization in children. A prospective observational clinical study in 31 children with congenital heart defects in a catheterization laboratory was undertaken. TOI was compared with SjO(2) in the left jugular bulb and with SvO(2). rSO(2) was compared with SjO(2) from the right jugular bulb and SvO(2). Linear regression analysis and Pearson's correlation coefficient were calculated and Bland-Altman analyses were performed. Cerebral TOI and SjO(2) were significantly correlated (r = 0.56, P < 0.0001), as well as TOI and SvO(2) with r = 0.74 (P < 0.0001). Bland-Altman plots showed a mean bias of -4.3% with limits of agreement of 15.7% and -24.3% for TOI and SjO(2) and a mean bias of -4.9% with limits of agreement of 10.3% and -20.1% for TOI and SvO(2). Cerebral rSO(2) and SjO(2) showed a significant correlation (r = 0.83, P < 0.0001) and rSO(2) and SvO(2) showed excellent correlation with r = 0.93 (P < 0.0001). Bland-Altman plots showed a mean bias of -5.2% with limits of agreement of between 8.4% and -18.8% for rSO(2) and SjO(2) and a mean bias of 5.6% with limits of agreement of 13.4% and -2.2% for rSO(2) and SvO(2). Both near-infrared spectroscopy devices demonstrate a significant correlation with SjO(2) and SvO(2) values; nevertheless both devices demonstrate a substantial bias of the measurements to both SjO(2) and SvO(2).

Influence of patient variables and sensor location on regional cerebral oxygen saturation measured by INVOS 4100 near-infrared spectrophotometers.

Cerebral oximeter based on near-infrared spectroscopy has been used as a continuous, noninvasive monitoring of regional cerebral oxygen saturation (rSO2). Although the absolute rSO2 values have a wide range of variability, the factors affecting a variability of rSO2 values have not been extensively investigated. The authors investigated the influence of patient variables and sensor location on rSO2 measured by the cerebral oximeter INVOS 4100 in 111 patients anesthetized with sevoflurane, fentanyl, and nitrous oxide in oxygen. The sensors for rSO2 measurements were applied on the right forehead (R), 1 cm lateral to R (R1), on the left forehead (L), 1 cm lateral to L (L1), and on the center of the forehead (C). The relationship between the rSO2 values and patient variables were also analyzed. Values of rSO2 at R1 and L1 were significantly lower than those at R and L, respectively. Values of rSO2 at C were significantly higher compared with those at other sites. There were no significant correlations between the rSO2 values and values of weight, height, and head size. Values of rSO2 were similar between males and females. A significant negative correlation between the rSO2 values and age and a positive correlation between the rSO2 values and hemoglobin concentration were observed. These data indicate that patient age, hemoglobin concentration at the measurement, and sensor location can affect rSO2 values.

Vascular surgical society of great britain and ireland: near-infrared spectroscopic monitoring of patients undergoing carotid endarterectomy under locoregional anaesthesia

BACKGROUND: The level of cerebral desaturation, which is associated with a change in level of consciousness during carotid endarterectomy, was measured by near-infrared spectroscopy. METHODS: Patients were recruited in two centres over 24 months. Surgery was performed under deep and superficial cervical block using 0.5 per cent bupivacaine, with temazepam as a premedication. Cerebral oxygenation was measured by Critikon 2020 near-infrared spectrophotometers (Johnson and Johnson Medical, Newport, UK). RESULTS: Forty-nine procedures were performed on 45 patients (39 men; age range 52-84 (mean 68) years). Recordings were made from the ipsilateral frontal site in 38 patients, from the ipsilateral temporal site in 23 and bifrontally in eight patients. Monitoring failed in three subjects. Percentage changes in regional cerebral oxygen saturation are detailed below. CONCLUSION: Significantly different levels of cerebral desaturation occur in patients with neurological compromise during carotid endarterectomy compared with those who are unaffected.

A Comparison of the Hamamatsu NIRO 500 and the INVOS 3100 Near-Infrared Spectrophotometers

Near-infrared spectroscopy is a technique used for non-invasive measurement of cerebral oxygenation and a number of commercial devices are currently available for use. We compared measurements of cerebral oxygenation made with two near-infrared spectrophotometers--the Somanetics Invos 3100 cerebral oximeter and the Hamamatsu NIRO-500 near-infrared spectrophotometer. Hypoxia was induced in six healthy male volunteers with and without occlusion of scalp blood flow. Oxygen saturation, end-tidal carbon dioxide tension, regional cerebral oxygen saturation, change in regional cerebral oxyhaemoglobin concentration and change in regional cerebral total haemoglobin concentration were measured. The INVOS 3100 displays cerebral oxygen saturation directly. The NIRO-500 displays change in total haemoglobin concentration and oxyhaemoglobin concentration, and the cerebral oxygen saturation was calculated offline. Statistical analysis disproved the assumption that the INVOS 3100 and the NIRO-500 were measuring the same changes in cerebral oxygenation. Neither machine can be confirmed for reliability against a gold standard and operational difficulties mean that neither can be recommended for routine clinical use.

Selection of Samples for Calibration in Near-Infrared Spectroscopy. Part I: General Principles Illustrated by Example

General principles for the selection of samples in the calibration of near-infrared (NIR) spectrophotometers are discussed. The discussion ends with suggestions of alternative strategies, which are illustrated by examples.

DIVISION OF INSTRUMENTATION: LIMITATIONS AND DESIGN PHILOSOPHY IN ULTRAVIOLET, VISIBLE, AND NEAR‐INFRARED SPECTROPHOTOMETERS*

Transactions of the New York Academy of SciencesVolume 24, Issue 2 Series II p. 140-157 DIVISION OF INSTRUMENTATION: LIMITATIONS AND DESIGN PHILOSOPHY IN ULTRAVIOLET, VISIBLE, AND NEAR-INFRARED SPECTROPHOTOMETERS* James D. McCallum, James D. McCallum Beckman Instruments, Inc., Mountainside, N. J.Search for more papers by this author James D. McCallum, James D. McCallum Beckman Instruments, Inc., Mountainside, N. J.Search for more papers by this author First published: December 1961 https://doi.org/10.1111/j.2164-0947.1961.tb00758.xCitations: 2 † This paper, illustrated with slides, was presented at a meeting of the Division on November 14, 1961. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume24, Issue2 Series IIDecember 1961Pages 140-157 RelatedInformation