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Estimation of regional tissue oxygenation (rStO2) by near infrared spectroscopy enables non-invasive end-organ oxygen balance monitoring and could be a valuable tool in intensive care. However, the diverse absolute values and dynamics of different devices, and overall poor repeatability of measurements are a problem. The aim of the present study is...
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The aim of this study was to analyse the feasibility of long-term measurements of cerebral (crSO2) and peripheral (prSO2) regional tissue oxygen saturation on the first day of life by determining the amount of artefacts and their influence on rSO2. Near infrared spectroscopy (NIRS) measurements were performed fronto-parietal left (crSO2) and on the...
Cerebral near-infrared spectroscopy (NIRS) oximetry may help clinicians to improve patient treatment. However, the application of NIRS oximeters is increasingly causing confusion to the users due to the inconsistency of tissue oxygen haemoglobin saturation (StO2) readings provided by different oximeters. To establish a comparability of oximeters, i...
Background:
A small oximeter with the probe attached to the examiner's finger has been developed. The aim of this study was to determine the feasibility of measuring regional oxygenation of the brain tissue using this device in healthy term infants immediately after birth.
Methods:
We conducted a prospective observational study. Using a new near...
The aim was to determine the precision of a noninvasive near-infrared spectroscopy (NIRS)-based tissue oximeter (OxyPrem v1.3). Using a linear mixed-effects model, we quantified the variability for cerebral tissue oxygenation (StO2) measurements in 35 preterm neonates to be 2.64%, a value that meets the often-articulated clinicians’ demand for a pr...
Neonates with hypoxic-ischaemic (HI) brain injury were monitored using a broadband near-infrared spectroscopy (NIRS) system in the neonatal intensive care unit. The aim of this work is to use the NIRS cerebral oxygenation data (HbD = oxygenated-haemoglobin – deoxygenated-haemoglobin) combined with arterial saturation (SaO2) from pulse oximetry to c...
Citations
... A fundamental problem of NIRS tissue oximetry is the lack of a reference standard. Therefore, testing and comparing commercially available NIRS equipment at different locations and in different populations is important, as other researchers have also pointed out [37]. ...
... The available literature results do not determine which device is best for assessing rSO 2 . Although the NONIN we used was characterized by the highest variability of measurements, at the same time, the results of comparisons of pulse oximeters suggest that good repeatability comes at the expense of low sensitivity to changes in oxidation [37]. ...
Regional oxygen saturation (rSO2) assessed by near-infrared spectroscopy (NIRS) reflects the perfusion and metabolism of the assessed tissue. The study aimed to determine the reference values of rSO2 for selected body areas, considering gender, age and body composition. We studied 70 healthy volunteers divided into two age groups (18–30 and >60 years). The rSO2 was measured using NIRS in eighteen selected regions of interest (ROIs). Body composition analysis was carried out using dual-energy X-ray absorptiometry (DXA). Significant differences in rSO2 values were found between almost all analyzed ROIs (p < 0.05) with a simultaneous lack of asymmetry between contralateral side of the body. The average rSO2 values from the ROIs analyzed ranged from 40.34 ± 17.65% (Achilles tendon) to 69.94 ± 6.93% (tibialis anterior muscle). Age and the values of adiposity indices and the fat mass content are factors that may significantly reduce the rSO2 value. In most ROIs, higher rSO2 values were recorded for the younger group (p < 0.0001). The rSO2 values at rest are area-specific in young and elderly healthy subjects. The changes in rSO2, both in clinical assessment and research, should be interpreted taking into account the body area being assessed and individual factors such as age and body fat content.
... The other discrepancies between our study and the available literature are probably the result of differences in the dangling protocols used and the diversity in the brands of devices. The values of different types of tissue oximeters cannot be compared, as concluded by Hyttel-Sorensen et al. [24]. ...
Background: Lower extremity free flap dangling protocols are still widely practiced, despite a paucity of evidence for their use. This pilot study investigates the use of tissue oximetry to provide further insight into the physiological effect of postoperative dangling in lower limb free flap transfer.
Methods: Ten patients undergoing lower extremity free flap reconstruction were included in this study. Free flap tissue oxygen saturation (StO2) was continuously measured using non-invasive near-infrared spectroscopy. Measurements were performed on the free flap and contralateral limb during dangling from postoperative day (POD) 7 until 11, according to the local dangling protocol.
Results: StO2 values measured in the free flap diminished to 70 ± 13.7% during dangling. This minimum StO2 was reached significantly later, and correspondingly the area under the curve (AUC) was significantly larger on POD 11 compared to the start of the dangling protocol on POD 7, reflecting an improving free flap microvascular reactivity. The dangling slope was equal between the free flap and contralateral leg. The reperfusion slope was significantly flatter on POD 7 compared to the other PODs (p < 0.001). Thereafter, no significant differences between PODs were observed. Patients with a history of smoking had significantly lower tissue oximetry values compared to non-smokers.
Conclusions: The application of tissue oximetry during dangling provides further insight into the physiological effect (i.e., changes in microcirculatory function) of the free flap of the reconstructed lower extremity. This information could potentially be useful to either revise or disrupt the use of such dangling protocols.
... Regarding the unquestionable potential of NIRS and its latest promising findings, several problems such as motion artifacts, adipose tissue thickness, its hard and, heavy construction, and variability of probe positioning can contribute to less accurate data [16]. Besides, literature has reported a common issue, which is significant differences between absolute measurements' values both within the same NIRS device as well as between different devices [9,17,18]. The above-mentioned limitations of NIRS sensors and the urgency of new more reliable sensors in the market have motivated the development of a novel NIRS sensor (Train.Red FYER, NL). ...
... What's more, monitors provided by different manufacturers may yield different readings with the same probe positions in the same patients because of differences in designs and algorithms. [33] Our study showed that standard deviation of SmtO 2 at anks and AUCs of the right ank, quadriceps for reductions of 5%, and 10% from the baseline were associated with increasing odds of AKI, which suggested the duration and degree of SmtO 2 change over the threshold [34] may related to AKI. However, in clinical practice, these values are impractical and untimely when an adverse alteration reversed because they need to be calculated and obtained retrospectively. ...
Purpose
Acute kidney injury (AKI) is frequently associated with poor postoperative prognoses. Intra-operative renal ischaemia and hypoxia may contribute to the pathogenesis of postoperative AKI. However, direct monitoring of this condition is difficult. Although near-infrared spectroscopy (NIRS) measurements of muscle tissue oxygen saturation (SmtO2) can predict some postoperative adverse outcomes, their association with AKI in older patients undergoing major abdominal surgery is unclear.
Methods
This prospective observational study recruited a total of 253 patients aged ≥65 years undergoing ≥2-h-long elective abdominal surgeries from September 2021 to August 2022. NIRS monitoring of bilateral flank, quadriceps, and brachioradialis muscles was performed throughout the surgery. The primary outcome was the incidence of AKI , diagnosed using the Kidney Disease: Improving Global Outcomes criteria, within 7 days postoperatively.
Results
AKI occurred in 44/240 patients (18.3%) and was associated with worse secondary outcomes. SmtO2 decline >10% of the baseline values at the right flank (OR, 6.98; 95% CI 1.36 to 35.83; P=0.020), left flank (OR, 6.69; 95% CI 1.55 to 28.9; P=0.011), quadriceps (OR, 2.99; 95% CI 1.36 to 6.55; P=0.006) was associated with AKI. The standard deviation values of SmtO2 at the right flank (OR, 3.32; 95% CI 1.72 to 6.41; P<0.001) and left flank (OR, 1.37; 95% CI 1.01 to 1.86; P=0.048) were also associated with an increased risk of AKI. The area under the curve for SmtO2 measurements 10%, and 5% below the baseline at the right flank and quadriceps were associated with an increased risk of AKI.
Conclusion
SmtO2 is associated with postoperative AKI and may facilitate prevention of AKI.
... In the present study, we aimed to compare the performance of two currently available NIRS devices in three experimental settings, simulating possible clinical situations in patients undergoing treatment for thoracic or thoracoabdominal aortic pathologies. [20,25]. Nevertheless, none of the previous publications compared the performance of these or any other NIRS devices on the back muscles. ...
Purpose
Efficacy of near-infrared spectroscopy monitoring of paraspinal collateral network (cnNIRS) has been shown to provide additional safety in extensive aortic repair. Better understanding of available cnNIRS monitoring systems regarding differences in performance for this specific purpose is required.
Methods
Two systems (FORE-SIGHT®, CAS Medical Systems, USA and INVOS™ 5100C; Medtronic, Ireland) used at 4 paravertebral levels (mid and lower thoracic, upper and lower lumbar) were compared in an acute large animal model during three different experimental sequences mimicking relevant clinical scenarios: segmental artery (SA) occlusion by (1) open-access clip-occlusion (n = 7), (2) endovascular coil-embolization (n = 9) and distal circulatory arrest via (3) aortic cross-clamping (n = 9).
Results
Significant differences in oxygenation measurements between devices were observed only at the lower thoracic level during SA clipping and aortic cross-clamping (p < 0.001). During SA clipping, FORE-SIGHT and INVOS demonstrated reduction to 85% and 72% of baseline values after occlusion of the mid-thoracic region, with mean differences between devices varying from 12.9 to 20.6% (p > 0.05) throughout the experiment. In the aortic cross-clamp sequence, reduction of values was observed in both devices, with FORE-SIGHT having less pronounces decrease during cross-clamping compared to INVOS (mean differences 1.0-14.7%, p > 0.05), and slower response to reperfusion after declamping (72 to 84% within 1 minute in FORE-SIGHT and 57 to 99% in INVOS).
Conclusion
Both devices provide similar cnNIRS monitoring applicability at mid-thoracic, upper and lower lumbar levels. INVOS seems to have a more rapid and pronounced response to open SA sequential occlusion and aortic cross-clamping at the lower thoracic level.
... In addition, the assumed ratio between arterial saturation and venous saturation in the equation to calculate the reference values varies between devices [30]. In a study of Hyttel-Sorensen and colleagues, a comparison of three different oximeters showed different absolute measurement values for all the devices [31]. In the study of Hölzle (O2C (Oxygen 2 see, LEA CO., Gießen, Germany) as well in the study of Akita (TOS-OR (Fujita Medical Instruments Co., Ltd., Tokyo, Japan), a different type of oximeter was used compared to the study of Keller (ViOptix T.Ox Tissue Oximeter (ViOptix Inc., Fremont, CA, USA) [18,19,29]. ...
... Furthermore, as described in a study of Bickler et al., interindividual differences in tissue oxygenation values with the present oximetry technology introduce a major challenge in determining a threshold for regional tissue desaturation [30]. Even though the improvement in monitoring techniques contributes to the ability to detect vascular compromise before clinical evidence for circulatory failure becomes apparent [17,31,32]. These findings illustrate that readings from different devices cannot be directly compared, indicating that device-specific, sensor-specific, and measurement site-specific cut-off values should be considered when determining tissue desaturation thresholds requiring immediate intervention to prevent adverse clinical effects [31,33,34]. ...
... Even though the improvement in monitoring techniques contributes to the ability to detect vascular compromise before clinical evidence for circulatory failure becomes apparent [17,31,32]. These findings illustrate that readings from different devices cannot be directly compared, indicating that device-specific, sensor-specific, and measurement site-specific cut-off values should be considered when determining tissue desaturation thresholds requiring immediate intervention to prevent adverse clinical effects [31,33,34]. ...
Early detection of vascular compromise after autologous breast reconstruction is crucial to enable timely re-exploration for flap salvage. Several studies proposed non-invasive tissue oximetry for early identification of ischemia of deep inferior epigastric perforator (DIEP) flaps. The present study aimed to explore the utility of non-invasive tissue oximetry following DIEP flap surgery using a personalized oxygenation threshold.
Methods
Patients undergoing immediate/delayed DIEP flap surgery were included in this prospective observational study. DIEP flap tissue oxygenation (StO 2 ) was monitored continuously using near-infrared spectroscopy. A baseline measurement was performed by positioning one sensor at the marked position of the major inferior epigastric perforator on the abdomen. A new sensor was positioned postoperatively on the transplanted tissue. In unilateral procedures, postoperative StO 2 values of the native breast were also obtained. Measurements were continued for 24 h.
Results
Thirty patients (42 flaps) were included. Fourteen patients (46.7%) had an uncomplicated postoperative course. A minor complication was observed in thirteen patients; in five patients, at least one major complication occurred, requiring re-exploration. Median StO 2 readings were significantly lower in patients with major complications compared to uncomplicated cases. In fourteen unilateral DIEP flap procedures, StO 2 values of the native breast were similar to the preoperative baseline measurement (92%; p = 0.452).
Conclusions
Non-invasive tissue oximetry following DIEP flap surgery could aid in early detection of vascular compromise. StO 2 values of the native breast and abdominal wall preoperatively can be used interchangeably and can serve as personalized reference value.
Level of evidence: Level IV, diagnostic / prognostic study.
... For instance, different devices use different wavelengths and sensors, a different ratio between arterial and venous saturation to calculate the rStO 2 %, as well as a different penetration depth [33]. Consequently, Hyttel-Sorensen et al. studied the absolute rStO 2 % values of three different devices and concluded that it is not possible to compare the absolute values for different monitoring systems [34]. We therefore agree with the previous study of our group that it would be better to define device-specific cut-off values than to generalize values [30]. ...
Mastectomy skin flap necrosis (MSFN) and partial DIEP (deep inferior epigastric artery perforator) flap loss represent two frequently reported complications in immediate autologous breast reconstruction. These complications could be prevented when areas of insufficient tissue perfusion are detected intraoperatively. Hyperspectral imaging (HSI) is a relatively novel, non-invasive imaging technique, which could be used to objectively assess tissue perfusion through analysis of tissue oxygenation patterns (StO2%), near-infrared (NIR%), tissue hemoglobin (THI%), and tissue water (TWI%) perfusion indices. This prospective clinical pilot study aimed to evaluate the efficacy of HSI for tissue perfusion assessment and to identify a cut-off value for flap necrosis. Ten patients with a mean age of 55.4 years underwent immediate unilateral autologous breast reconstruction. Prior, during and up to 72 h after surgery, a total of 19 hyperspectral images per patient were acquired. MSFN was observed in 3 out of 10 patients. No DIEP flap necrosis was observed. In all MSFN cases, an increased THI% and decreased StO2%, NIR%, and TWI% were observed when compared to the vital group. StO2% was found to be the most sensitive parameter to detect MSFN with a statistically significant lower mean StO2% (51% in the vital group versus 32% in the necrosis group, p < 0.0001) and a cut-off value of 36.29% for flap necrosis. HSI has the potential to accurately assess mastectomy skin flap perfusion and discriminate between vital and necrotic skin flap during the early postoperative period prior to clinical observation. Although the results should be confirmed in future studies, including DIEP flap necrosis specifically, these findings suggest that HSI can aid clinicians in postoperative mastectomy skin flap and DIEP flap monitoring.
... Although the device detected ischaemia and reperfusion phases, the StO 2 values were comparable with only one device (the INVOS). The differences in absolute StO 2 values between the devices are expected: several previous studies [19][20][21] comparing different (often all commercially available) NIRS devices have noted differences in absolute values due to device heterogeneity (light sources, detector geometries) and variations in experimental setup. ...
... This is especially relevant to the O2C and new device, as they both have a narrow depth of measurement (8 mm and 5 mm), making their measurements more directly affected by differences in tissue composition. Although a previous study comparing NIRS devices found that the variability of repeated measurements was not affected by changes in device position on the forearm, 21 the inability to standardise the content of measured tissue introduces measurement bias. ...
... Furthermore, they develop sensors with different transmitter-receiver spacing, resulting in different penetration depths, which also affects estimation and calculation of rStO 2 [43]. Hence, it is difficult to define universal cut-off values necessitating prompt intervention [24,44]. In the included studies, most research was performed using the ViOptix device. ...
Rapid identification of possible vascular compromise in free flap reconstruction to minimize time to reoperation improves achieving free flap salvage. Subjective clinical assessment, often complemented with handheld Doppler, is the golden standard for flap monitoring; but this lacks consistency and may be variable. Non-invasive optical methods such as near-infrared spectroscopy (NIRS) and hyperspectral imaging (HSI) could facilitate objective flap monitoring. A systematic review was conducted to compare NIRS with HSI in detecting vascular compromise in reconstructive flap surgery as compared to standard monitoring. A literature search was performed using PubMed and Embase scientific database in August 2021. Studies were selected by two independent reviewers. Sixteen NIRS and five HSI studies were included. In total, 3662 flap procedures were carried out in 1970 patients using NIRS. Simultaneously; 90 flaps were performed in 90 patients using HSI. HSI and NIRS flap survival were 92.5% (95% CI: 83.3–96.8) and 99.2% (95% CI: 97.8–99.7). Statistically significant differences were observed in flap survival (p = 0.02); flaps returned to OR (p = 0.04); salvage rate (p < 0.01) and partial flap loss rate (p < 0.01). However, no statistically significant difference was observed concerning flaps with vascular crisis (p = 0.39). NIRS and HSI have proven to be reliable; accurate and user-friendly monitoring methods. However, based on the currently available literature, no firm conclusions can be drawn concerning non-invasive monitoring technique superiority.
... During arterial occlusion all oxygenation parameters show a decline in a comparable rate. Also, the measured decline in NIRS saturation of 0.21%/sec (12.6%/min) in this study is comparable to previously found values of 10.8, 13.2, 22.8%/min during occlusion of an extremity [25]. However, during a dynamic measurement for measuring mitochondrial oxygen consumption (mitoVO 2 ), with pressure on the measurement probe, a faster decline is seen. ...
Mitochondria are the primary consumers of oxygen and therefore an important location for oxygen availability and consumption measurement. A technique has been developed for mitochondrial oxygen tension (mitoPO2) measurement, incorporated in the COMET. In contrast to most textbooks, relatively high average mitoPO2 values have been reported. The first aim of this study was to verify the validity of the COMET calibration for mitoPO2 measurements in human skin. The second aim was to compare the dynamics of mitoPO2 to several other techniques assessing tissue oxygenation. Firstly, we performed a two-point calibration. Mitochondrial oxygen depletion was achieved with vascular occlusion. A high mitoPO2 was reached by local application of cyanide. MitoPO2 was compared to the arterial oxygen partial pressure (PaO2). Secondly, for deoxygenation kinetics we compared COMET variables with the LEA O2C, SenTec OxiVenT™ and Medtronic INVOS™ parameters during a vascular occlusion test. 20 healthy volunteers were recruited and resulted in 18 datasets (2 times 9 subjects). The lowest measured mitoPO2 value per subject had a median [IQR] of 3.0 [1.0–4.0] mmHg, n = 9. After cyanide application the mitoPO2 was 94.1 mmHg [87.2–110.9] and did not differ significantly (n = 9, p = 0.5) from the PaO2 of 101.0 [98.0–106.0] mmHg. In contrast to O2C, OxiVenT™ and INVOS parameters, mitoPO2 declined within seconds with pressure on the probe. The kinetics from this decline are used to mitochondrial oxygen consumption (mitoVO2). This study validates the calibration of the COMET device in humans. For mitoVO2 measurements not only blood flow cessation but application of local pressure is of great importance to clear the measurement site of oxygen-carrying erythrocytes.
