Detection of changes in muscle oxygen saturation in the human leg: a comparison of two near-infrared spectroscopy devices

Abstract

The purpose of this study was first to evaluate the near infrared spectroscopy (NIRS) device, INVOS 4100 as a method of measuring exercise and arterial occlusion induced muscle ischemia in human leg, by comparison with InSpectra tissue spectrometer Model 325, and secondly to determine the influence of skin and subcutaneous thickness on the NIRS measurements. Twenty healthy subjects (43 ± 8 years) volunteered for the study. Tissue oxygen saturation (StO2) in the anterior tibial muscle was measured simultaneously with InSpectra Model 325 in one leg and INVOS 4100 in the contralateral leg during an exercise test until muscle exhaustion and arterial occlusion with and without exercise. The skin and subcutaneous thickness was identified by ultrasound imaging. Baseline StO2 was 87 ± 8 % detected by InSpectra and 76 ± 6 % by INVOS. Both devices detected an immediate decrease of StO2 (p < 0.001) during exercise, arterial occlusion with and without exercise, and a significant post ischemic hyperaemia (p < 0.001) during recovery. There was a significant inverse correlation between skin and subcutaneous thickness and baseline StO2 (r = -0.78, p < 0.01) as well as change in StO2 during exercise (r = -0.65, p = 0.002) for InSpectra, which was not apparent for INVOS. The results demonstrate that the cerebral/somatic oxygenation monitor (INVOS) is able to detect experimentally induced skeletal muscle ischemia in the human leg as well as the peripheral tissue spectrometer (InSpectra). Muscle oxygen saturation measurement by INVOS is less affected by skin and subcutaneous thickness than measured by InSpectra.

Performance comparison of the MOXY and PortaMon near-infrared spectroscopy muscle oximeters at rest and during exercise

“…Past studies comparing NIRS monitors have highlighted discrepancies in the values obtained at rest and during exercise in human [11][12][13][14] and animal 15 systems. The differences between monitors are likely to be in part associated with the measurement site and spacing of the probes.…”

A comparison of tissue oxygen saturation measurements by 2 different near‐infrared spectroscopy monitors in 21 healthy dogs

“…When we compared the Inspectra to the INVOS over a 2‐minute time period, there was significant difference between the Inspectra and INVOS readings, which stayed consistent over each time point. The difference between baseline StO 2 levels using the Inspectra 650 and INVOS 5100C in this study is greater than the difference between the Inspectra 325 and INVOS 4100 used in a previous study on people . Although the models of these machines were different, the newer models still used the same infrared wavelengths to measure StO 2 as the older models (680, 720, 760, and 800 nm for the Inspectra and 730 and 810 nm for the INVOS).…”

“…Altitude cannot explain the difference in StO 2 noted between the INVOS and ODISsey values, as the ODISsey values were higher than the INVOS despite the INVOS values being obtained at lower altitude. As mentioned in the Sullivan study, probe location (abdomen vs peripheral muscle) may also affect StO 2 values as tissues with greater metabolic demand may result in different baseline StO 2 values . The effect of probe location is probably more dependent on the presence of fat than on the muscle bed evaluated in most cases, as there was no significant difference in values obtained at different muscle locations in dogs of the Hall study (digital extensors, biceps femoris, and sartorius muscles).…”

“…Another study using the Inspectra on people found mean baseline values of 81 ± 10% on the forearm and 87 ± 4% on the thenar eminence . A third human study using the tibial muscle of the leg found statistically significant difference between the Inspectra and INVOS machines, with mean readings of 87 ± 8% and 76 ± 6%, respectively . A study by Fellahi et al, comparing the INVOS and Equanox devices found only a slight difference between these devices, and their INVOS average values were 81 ± 9% while the Equanox average values were 83 ± 5% on the left leg .…”

“…These different machines may yield discrepancies in the values obtained and lead to altered interpretation of those values. Differences between NIRS monitors and location of oxygen probes have been found in human medicine . However, there are limited studies in veterinary medicine.…”