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Vascular responsiveness measured by tissue oxygen saturation reperfusion slope is sensitive to different occlusion durations and training status
Author(s) -
McLay Kaitlin M.,
Gilbertson James E.,
Pogliaghi Silvia,
Paterson Donald H.,
Murias Juan M.
Publication year - 2016
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/ep085843
Subject(s) - occlusion , vascular occlusion , cardiology , oxygen , cuff , medicine , oxygen saturation , chemistry , ischemia , anesthesia , surgery , organic chemistry
New FindingsWhat is the central question of this study? Is the near‐infrared spectroscopy‐derived measure of tissue oxygen saturation ( S t O 2) reperfusion slope sensitive to a range of ischaemic conditions, and do differences exist between trained and untrained individuals?What is the main finding and its importance? The S t O 2reperfusion rate is sensitive to different occlusion durations, and changes in the reperfusion slope in response to a variety of ischaemic challenges can be used to detect differences between two groups. These data indicate that near‐infrared spectroscopy‐derived measures of S t O 2, specifically the reperfusion slope following a vascular occlusion, can be used as a sensitive measure of vascular responsiveness.The reperfusion rate of near‐infrared spectroscopy‐derived measures of tissue oxygen saturation ( S t O 2) represents vascular responsiveness. This study examined whether the reperfusion slope of S t O 2is sensitive to different ischaemic conditions (i.e. a dose–response relationship) and whether differences exist between two groups of different fitness levels. Nine healthy trained (T; age 25 ± 3 years; maximal oxygen uptake 63.4 ± 6.7 ml kg −1 min −1 ) and nine healthy untrained men (UT; age 21 ± 1 years; maximal oxygen uptake 46.6 ± 2.5 ml kg −1 min −1 ) performed a series of vascular occlusion tests of different durations (30 s, 1, 2, 3 and 5 min), each separated by 30 min. The S t O 2was measured over the tibialis anterior using near‐infrared spectroscopy, with the S t O 2reperfusion slope calculated as the upslope during 10 s following cuff release. The reperfusion slope was steeper in T compared with UT at all occlusion durations ( P < 0.05). For the T group, the reperfusion slopes for 30 s and 1 min occlusions were less than for all longer durations ( P < 0.05). The reperfusion slope following 2 min occlusion was similar to that for 3 min ( P > 0.05), but both were less steep than for 5 min of occlusion. In UT, the reperfusion slope at 30 s was smaller than for all longer occlusion durations ( P < 0.05), and 1 min occlusion resulted in a reperfusion slope that was less steep than following 2 and 3 min ( P < 0.05), albeit not different from 5 min ( P > 0.05). The present study demonstrated that the reperfusion rate of S t O 2is sensitive to different occlusion durations, and that changes in the reperfusion rate in response to a variety of ischaemic challenges can be used to detect differences in vascular responsiveness between trained and untrained groups.