Muscle Oximetry Research Articles

Best practices for simultaneous measurement of NIRS-based cerebral and muscle oximetry during exercise

Best practices for simultaneous measurement of NIRS-based cerebral and muscle oximetry during exercise

Applications of Muscle Oxygen Saturation Analysis in Cycling Performance Assessment: A Systematic Review

Purposeː Cycling performance is the results of the interplay among a wide range of variables. Different methodological approaches have been described during last 50 years in order to evaluate and understand cycling performance. Our main aim was to systematically review the applications of muscle oximetry in cycling performance assessment. Methods: A structured search was carried out following the PRISMA guidelines in MEDLINE®/PubMed and Scopus databases were searched with additional integration from external sources, between 1 February and 31 March 2020. To meet the inclusion criteria studies published from 2000 to 2020 and that applied muscle oxygen saturation analysis to investigate cyclists’ performance were selected. This review included studies with experimental designs. There were no filters applied to the cyclists’ level, sex, ray or age. Results: Starting from the 955 identified records, 21 items were finally included for the review. Three main investigation topics, related to application of muscle oximetry in cycling science, emerged: cycling performance analysis protocols (n=8); training response and adaptations evaluation (n=8) and impact of different pedaling cadences on cycling performance (n=6). From the studies analyzing performance assessment protocols (38%), emerged how only one threshold, also named breakpoint, seems to be recognizable through NIRS during cycling tests. Studies that focused on training metabolic adaptations (38%) and cadence analysis (25.6%) evidenced how NIRS device may represent a valid tool to analyze cyclists’ metabolic adaptations and optimize pedaling cadence strategy. Conclusionː Despite the wide range of applications and promising data emerging from NIRS studies, further investigations evaluating cycling performance are needed to better delineate possible, laboratory and field, applications, and methodologies.

Značaj praćenja vrednosti saturiranog kiseonika u hemoglobinu u sportskoj dijagnostici

Cardiorespiratory performance is one of the most important determinants of success in sports activities. In order to better prepare for sports challenges, the athletes must be exposed to appropriate training which should be based on individualized physiological parameters during activity. Even though training intensity can be determined in many different ways, the endurance training intensity is often quantified by the lactate thresholds obtained from the blood sampling or the ventilator thresholds obtained from the gas exchange. These data represent delayed indirect indicators of an increased anaerobic ATP resynthesis. The muscle oximetry, based on near-infrared spectroscopy (NIRS), represents non-invasive method that enables the information about the changes in oxygenation in hemoglobin, and potentially represents a very suitable technique to detect a critical exercise threshold directly in the exercising muscle.

Validation of Fabric-Based Thigh-Wearable EMG Sensors and Oximetry for Monitoring Quadriceps Activity during Strength and Endurance Exercises.

Muscle oximetry based on near-infrared spectroscopy (NIRS) and electromyography (EMG) techniques in adherent clothing might be used to monitor the muscular activity of selected muscle groups while exercising. The fusion of these wearable technologies in sporting garments can allow the objective assessment of the quality and the quantity of the muscle activity as well as the continuous monitoring of exercise programs. Several prototypes integrating EMG and NIRS have been developed previously; however, most devices presented the limitations of not measuring regional muscle oxyhemoglobin saturation and did not embed textile sensors for EMG. The purpose of this study was to compare regional muscle oxyhemoglobin saturation and surface EMG data, measured under resting and dynamic conditions (treadmill run and strength exercises) by a recently developed wearable integrated quadriceps muscle oximetry/EMG system adopting smart textiles for EMG, with those obtained by using two “gold standard” commercial instrumentations for EMG and muscle oximetry. The validity and agreement between the wearable integrated muscle oximetry/EMG system and the “gold standard” instrumentations were assessed by using the Bland-Altman agreement plots to determine the bias. The results support the validity of the data provided by the wearable electronic garment developed purposely for the quadriceps muscle group and suggest the potential of using such device to measure strength and endurance exercises in vivo in various populations.

Neurophysiological and paraspinal oximetry monitoring to detect spinal cord ischemia in patients during and after descending aortic repair: An international multicenter explorative study

BackgroundDuring descending aortic repair, critically decreased blood flow to the myelum can result in ischemic spinal cord injury and transient or permanent paraplegia. Assessment of motor evoked potentials (MEPs) has been shown to be a valuable tool which allows to detect spinal cord ischemia (SCI) intraoperatively within a therapeutic window suitable to prevent progression to paraparesis or paraplegia. MEP monitoring is not feasible during postoperative care in the awakening patient. Therefore, ancillary techniques to monitor integrity of spinal cord function are needed to detect delayed spinal cord ischemia. ObjectiveThe purpose of this study is to evaluate whether assessment of long loop reflexes (LLR; F-waves) and paraspinal muscle oximetry using Near-Infrared Spectroscopy (NIRS) are feasible and valid in detecting delayed SCI. MethodsWe aim to include patients from three tertiary referral centers undergoing aortic repair with MEP monitoring in this study.F-wave measurements and paraspinal NIRS oximetry will be operated intra- and postoperatively. Measurement characteristics and feasibility will be assessed in the first 25 patients. Subsequently, a second cohort of 75 patients will be investigated to determine the sensitivity and specificity of F-waves and NIRS in detecting perioperative SCI. In this context for the MEP group SCI is defined intraoperatively as significant MEP changes and postoperatively as newly developed paraplegia. ConclusionsA clinical study design and protocol is proposed to assess if F-waves and/or NIRS-based paraspinal oximetry are feasible and valid in detecting and monitoring for occurrences of delayed SCI.

The inclusion of wildcard players during small-sided games causes alterations on players’ workload

BACKGROUND: Small-sided games are a popular training method that have shown its effectiveness in improving athletic performance in football players. OBJECTIVE: To compare the acute physiological and neuromuscular responses and time-motion characteristics during small-sided games played with and without wildcard players. METHODS: Sixteen amateur male football players completed two small-sided games protocol: 4-a-side and 4-a-side with wildcard players. Time-motion characteristics during games, muscular performance parameters before and after small-sided games protocols, physiological response in terms of heart rate and muscle oximetry and rate of perceived exertion were collected. RESULTS: Both small-sided games formats induced changes in sprint performance (before-after comparison), in the rate of perceived exertion, heart rate-related variables and time-motion parameters (p< 0.05). In a comparison between small-sided games formats, lower values of oxygen saturation, heart rate, rate of perceived exertion and time-motion parameters (p< 0.05) were reported during small-sided games with wildcard players in both working and recovery periods. CONCLUSIONS: The inclusion of wildcard players during small-sided games cause a reduction in perceptual, physiological demands and time-motion parameters when compared to control condition.

Measurement of peripheral muscle oxygen saturation in conscious healthy horses using a near-infrared spectroscopy device

ObjectiveMaintaining adequate muscle tissue oxygenation is of paramount importance during equine general anesthesia. The objectives of this study were to assess the feasibility, reliability and repeatability of near-infrared spectroscopy (NIRS) muscle oximetry using the Inspectra m650 in conscious healthy adult horses. Study designProspective, observational study. AnimalsA group of 30 healthy client-owned adult horses admitted to the equine hospital between July 2017 and July 2018. MethodsThe probe of an Inspectra m650 NIRS tissue oximeter was placed on the hairless surface of five muscle sites (omotransversarius, triceps long head, extensor carpi ulnaris, vastus lateralis and lateral digital extensor) on the left side of the body of each standing, unsedated horse. Each site had muscle oxygenation (StO2) recordings measured in triplicate and statistical modeling used to assess the reading reliability and repeatability within and between muscle sites. ResultsThe readings acquired at the vastus lateralis and extensor carpi ulnaris muscle sites had highly repeatable values [mean (90% confidence interval): StO2, 95% (93.8%, 96.5%) and 93% (91.6%, 93.9%), respectively; intraclass correlation coefficients, 0.92 and 0.80, respectively]. These two sites also had high reliability (represented by the percentage of successful readings; 70% and 86%, respectively). Conclusions and clinical relevanceThe use of NIRS muscle oxygenation technology is a clinically feasible means to assess tissue oxygenation in horses. The vastus lateralis and extensor carpi ulnaris muscle sites provided the most reliable and repeatable readings when using the Inspectra m650 machine in horses.

Near-infrared spectroscopy muscle oximetry of patients with postural orthostatic tachycardia syndrome.

Postural orthostatic tachycardia syndrome (POTS) is a disabling condition characterized by orthostatic intolerance with tachycardia in the absence of drop-in blood pressure. A custom-built near-infrared spectroscopy device (NIRS) is applied to monitor the muscle oxygenation, noninvasively in patients undergoing incremental head-up tilt table (HUT). Subjects (6 POTS patients and 6 healthy controls) underwent 30 mins of 70°on a HUT. The results showed a significant difference in deoxyhemoglobin (Hb), change-in-oxygenation (ΔOxy) and blood volume (ΔBV) between patients and healthy controls. However, oxyhemoglobin (HbO2) showed a significantly faster rate of change in the healthy controls during the first 10 mins of the tilt and during the recovery. This NIRS muscle oximetry tool provides quantitative measurements of blood oxygenation monitoring in diseases such as POTS.

Changes in Spinal Muscle Oxygenation and Perfusion During the Biering-Sørensen Test: Preliminary Results of a Study Employing NIRS-Based Muscle Oximetry.

We measured muscle perfusion in healthy subjects during the Biering-Sørensen (BS) test (the gold standard for evaluating back muscle endurance) using a commercial near-infrared spectroscopy (NIRS) device. We analysed data sets of five female healthy subjects (age: 34 ± 15years) who reached the maximum of 4 min during the BS test. Muscle oxygenation (SmO2) and perfusion ([tHb]) were measured using the Moxy NIRS device (Fortiori Design LLC, Hutchinson, USA). Probes were set unilaterally on M. longissimus, M. iliocostalis and M. multifidus. Additionally, mean arterial blood pressure (MAP), pulse pressure (PP), heart rate (HR), arterial oxygen saturation (SpO2) and lactate (pre, task, post) were measured. We observed (i) a large inter-subject variability in the SmO2 and [tHb] responses in the three muscles (i.e., SmO2 desaturations in the in M. longissimus across subjects during the task ranging from 1.1% to -56.6%), and (ii) a consistent response of the systemic signals in all subjects (i.e., increase in MAP, PP and HR). Lactate changes (post task minus task period) correlated with changes in PP and SmO2 of the multifidus muscle. Our preliminary results showed that during the BS test the response in the peripheral muscles was more variable than the central systemic response. A goal for future investigations is to explain this variability in the periphery by considering, for example, subject-specific changes in systemic cardiovascular activity, lactate and in the microvascular perfusion of muscle tissue.

Muscle Oximetry in Sports Science: A Systematic Review.

Since the introduction (in 2006) of commercially available portable wireless muscle oximeters, the use of muscle near-infrared spectroscopy (NIRS) technology is gaining in popularity as an application to observe changes in muscle metabolism and muscle oxygenation during and after exercise or training interventions in both laboratory and applied sports settings. The objectives of this systematic review were to highlight the application of muscle oximetry in evaluating oxidative skeletal muscle performance to sport activities and emphasize how this technology has been applied to exercise and training. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in a systematic fashion to search, assess and synthesize existing literature on this topic. The Scopus and MEDLINE/PubMed electronic databases were searched to 1 March 2017. Potential inclusions were screened against eligibility criteria relating to recreationally trained to elite athletes, with or without training programs, who must have assessed physiological variables monitored by commercial oximeters or NIRS instrumentation. Of the 14,609 identified records, only 57 studies met the eligibility criteria. This systematic review highlighted a number of key findings in 16 sporting activities. Overall, NIRS information can be used as a marker of skeletal muscle oxidative capacity and for analyzing muscle performance factors. Although NIRS instrumentation is promising in evaluating oxidative skeletal muscle performance when used in sport settings, there is still the need for further instrumental development and randomized/longitudinal trials to support the detailed advantages of muscle oximetry utilization in sports science.

Quantifying the effect of adipose tissue in muscle oximetry by near infrared spectroscopy.

Change of muscle tissue oxygen saturation (StO2), due to exercise, measured by near infrared spectroscopy (NIRS) is known to be lower for subjects with higher adipose tissue thickness. This is most likely not physiological but caused by the superficial fat and adipose tissue. In this paper we assessed, in vitro, the influence of adipose tissue thickness on muscle StO2, measured by NIRS oximeters. We measured StO2 of a liquid phantom by 3 continuous wave (CW) oximeters (Sensmart Model X-100 Universal Oximetry System, INVOS 5100C, and OxyPrem v1.3), as well as a frequency-domain oximeter, OxiplexTS, through superficial layers with 4 different thicknesses. Later, we employed the results to calibrate OxyPrem v1.3 for adipose tissue thickness in-vivo.

Near Infrared Brain and Muscle Oximetry: From the Discovery to Current Applications

In the early 1960s, Norris introduced near infrared (NIR) spectroscopy (700–2500 nm) as an analytical technique for agricultural products. In 1977, Jöbsis founded in vivo medical NIR spectroscopy, reporting that the relatively high degree of transparency of brain tissue in the NIR spectral window (700–1000 nm) enables safe real-time non-invasive detection of regional haemoglobin oxygenation using trans-illumination spectroscopy. In order to place current medical NIR spectroscopy in its proper perspective, this review provides a snapshot of the roots of the discovery and the early years of medical NIR spectroscopy research and development. Starting in 1992, the opportunity of measuring quantitatively, by different NIR spectroscopy techniques, regional oxy-haemoglobin saturation by NIR oximetry, it is possible to monitor brain/muscle reserve capacity following tissue oxygen extraction in different pathophysiological conditions. This review reports the status of the current commercial oximeters (including wireless instrumentation) and their main clinical and physiological applications. In the last decade, NIR spectroscopy brain oximetry has obtained significant clinical relevance as suggested by the more than 10,000 instruments sold and the high number of related scientific publications. The most relevant clinical application is represented by the evaluation of cerebral oxy-haemoglobin saturation during adult cardiac surgery and cardiopulmonary bypass. Many commercial oximeters are presently available. However, their relatively poor precision and the lack of standardisation amongst the different instruments suggest that further technological advances are required before NIR spectroscopy oximetry can be adopted more widely under the “guidelines” of regulatory authorities.

QUANTIFICATION OF CALF OXYGENATION IN PARAPLEGIC PATIENTS DURING PASSIVE LEG MOVEMENT

Dear Editor-in-Chief: A recent article (4) demonstrated that passive leg movement can induce both EMG activity and alteration of calf oxygenation in a paralyzed lower limb of spinal cord-injured subjects. Although these results are interesting, the presentation of the muscle oxygenation data is inadequate. For measuring calf oxygenation, Kawashima et al. (4) used a multidistance spatially resolved tissue oximeter (NIRO-300, Hamamatsu Photonics, Japan) without exploiting the offered advantage to quantify muscle oxygenation directly as tissue oxy-hemoglobin (Hb) saturation (%). Tissue oxy-Hb saturation reflects the dynamic balance between O2 supply and O2 consumption and is independent on the path length of the near-infrared photons in the muscle tissue (3). Kawashima et al. (4) report the results only as changes in oxy- and deoxy-Hb values calculated relative to the resting level, and represented in micrometers. These changes should have been eventually presented at least as Δ μM*cm, because no path-length data are available for the calf of spinal cord injury patients. On the other hand, taking into account that these patients present consistent musculoskeletal degeneration (5), it would not be accurate the use of calf path-length data from healthy subjects (2). Subcutaneous adipose tissue thickness has a substantial confounding influence on in vivo muscle near-infrared spectroscopy measurements, therefore it would be essential to incorporate this factor into muscle oximetry studies in order to justify comparisons between different muscle groups (7). Kawashima et al. (4) did not report the thickness of the subcutaneous adipose tissue at the measurement position in each spinal cord-injured subject. Consistent differences in the thickness of subcutaneous adipose tissue are expected among patients, and between patients and controls. The lack of this information could compromise the results of the comparison between spinal cord injury and control subjects. Although Kawashima et al. (4) did not quantify properly muscle oxygenation, the data shown in their Figure 4 clearly suggest that the well-known postexercise hyperemic phase (evidenced as total Hb increase with respect to the pretest level) was evidenced only in the spinal cord injury patients, and it was maintained over 5 min after the end of the protocol. In addition, as previously found in walking mitochondrial disorders and muscular dystrophy patients (1,6), muscle oxygenation is not a limiting factor during passive alternate leg movement in spinal cord-injured subjects. Valentina Quaresima Marco Ferrari Department of Sciences and Biomedical Technologies University of L'Aquila L'Aquila, Italy