Near-Infrared Spectra in Buccal Tissue as a Marker for Detection of Hypoxia.
BACKGROUND
Hypoxia caused by high altitude exposure can impair cerebral and mental functions. Blood flow and oxygenation of the buccal tissue can be reliable markers to detect hypoxia. In this study, near infrared spectroscopy was used in combination with a novel optical probe to evaluate the applicability of the novel probe in measuring hypoxia markers in buccal tissue under a hypoxic condition.


METHODS
Six healthy participants were tested at altitudes from 2000 to 16,000 ft inside a hypobaric chamber. The buccal reference measurements of blood flow and oxygen saturation were synchronized with the spectral measurements of the novel near infrared probe and the relationship between the reference measurements and spectral data were evaluated by multivariate partial least square method. In addition, finger oxygen saturation was measured during the experiment and the recordings were compared with buccal oxygen saturation.


RESULTS
The spectral analysis illustrated that the spectral data from the near infrared probe correlated strongly with the absorption features of both buccal flow and oxygenation measured by the reflectance sensors (average R(2) = 0.89). The results showed probably overestimated values for buccal oxygen saturation recorded by the reference pulse oximeter in comparison with finger oxygen saturation, with the mean difference increasing from 1.8% at 2000 ft to 11.4% at 16,000 ft.


CONCLUSIONS
The novel near infrared probe showed promising results for simultaneous measurement of blood flow and oxygen saturation in the buccal tissue. The suggested method can be used as a new technique for early indication of hypoxia in future clinical applications.
Maryam
M
Amini
Jonny
J
Hisdal
Terje
T
Gjøvaag
Nihad
N
Kapetanovic
Trond-Eirik
TE
Strand
Jan Ove
JO
Owe
John Ragnar
JR
Hørthe
Peyman
P
Mirtaheri
D000328:Adult; D000337:Aerospace Medicine; D001273:Atmosphere Exposure Chambers; D015415:Biomarkers / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis*; D008297:Male; D009061:Mouth Mucosa / Q000098:blood supply* / Q000378:metabolism*; D010092:Oximetry; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D012039:Regional Blood Flow; D019265:Spectroscopy, Near-Infrared
D015415:Biomarkers; D010100:Oxygen