Hemodynamic changes in rat leg muscles during tourniquet-induced ischemia-reperfusion injury observed by near-infrared spectroscopy.
In this study, we hypothesized that non-invasive continuous wave near-infrared spectroscopy (CWNIRS) can determine the severity or reversibility of muscle damage due to ischemia/reperfusion (I/R), and the results will be highly correlated with those from physical examination and histological analysis. To test this hypothesis, we performed CWNIRS measurements on two groups of male Sprague-Dawley rats ( approximately 400 g) that underwent 2 h (n = 6) or 3 h (n = 7) of pneumatic tourniquet application (TKA). Tissue oxyhemoglobin [HbO(2)] and deoxyhemoglobin [Hb] concentration changes were monitored during the 2 h or 3 h of 250 mmHg TKA and for an additional 2 h post-TKA. Rats were euthanized 24 h post-TKA and examined for injury, edema and viability of muscles. Contralateral muscles served as controls for each animal. In both groups, [HbO(2)] dropped immediately, then gradually decreased further after TKA and then recovered once the tourniquet was released. However, releasing after 2 h of TKA caused [HbO(2)] to overshoot above the baseline during reperfusion while the 3 h group continued to have lower [HbO(2)] than baseline. We found a significant correlation between the elapsed time from tourniquet release to the first recovery peak of [HbO(2)] and the muscle weight ratio between tourniquet and contralateral limb muscles (R = 0.86). Hemodynamic patterns from non-invasive CWNIRS demonstrated significant differences between 2 h and 3 h I/R. The results demonstrate that CWNIRS may be useful as a non-invasive prognostic tool for conditions involving vascular compromise such as extremity compartment syndrome.
Laser Microbeam and Medical Program, Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, USA. jaegk@ici.edu
J G
JG
Kim
J
J
Lee
J
J
Roe
B J
BJ
Tromberg
M
M
Brenner
T J
TJ
Walters
D000818:Animals; D006439:Hemodynamics; D006614:Hindlimb / Q000098:blood supply; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology; D010108:Oxyhemoglobins / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000473:pathology / Q000503:physiopathology*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D014111:Tourniquets
D010108:Oxyhemoglobins