PURPOSE: To examine the utility of near-infrared spectroscopy (NIRS) in assessing lower-leg perfusion, NIRS was performed on the calf muscles of patients who underwent abdominal aortic surgery. METHODS: Thirty patients undergoing elective infrarenal abdominal aortic surgery for abdominal aortic aneurysm (AAA group; n = 16) and aorto-occlusive disease (AOD group; n = 14) were studied. Before induction of anesthesia, NIRS probes were placed over both calf muscles, and muscle oxygen saturation (S(tO2)) was continuously monitored throughout the surgery. RESULTS: The preoperative S(tO2) value was significantly lower in the AOD group (57.0 +/- 11.2%) than in the AAA group (68.7 +/- 7.0%). In both groups, S(tO2) significantly decreased after aortic cross-clamping; the maximal ischemic value of S(tO2) in the AAA group (17.8 +/- 7.2%) was significantly lower than that in the AOD group (46.7 +/- 17.1%). The time taken to reach maximal ischemia was significantly longer in the AAA group (30 +/- 12 min) than in the AOD group (19 +/- 12 min). After release of the aortic clamp, the decreased S(tO2) returned to the preoperative level in the AAA group, whereas it increased above the preoperative value in the AOD group. CONCLUSION: NIRS performed on the calf muscles is a useful method for assessing the changes in lower-leg perfusion during and after abdominal aortic surgery.
PURPOSE: To examine the utility of near-infrared spectroscopy (NIRS) in assessing lower-leg perfusion, NIRS was performed on the calf muscles of patients who underwent abdominal aortic surgery. METHODS: Thirty patients undergoing elective infrarenal abdominal aortic surgery for abdominal aortic aneurysm (AAA group; n = 16) and aorto-occlusive disease (AOD group; n = 14) were studied. Before induction of anesthesia, NIRS probes were placed over both calf muscles, and muscle oxygen saturation (S(tO2)) was continuously monitored throughout the surgery. RESULTS: The preoperative S(tO2) value was significantly lower in the AOD group (57.0 +/- 11.2%) than in the AAA group (68.7 +/- 7.0%). In both groups, S(tO2) significantly decreased after aortic cross-clamping; the maximal ischemic value of S(tO2) in the AAA group (17.8 +/- 7.2%) was significantly lower than that in the AOD group (46.7 +/- 17.1%). The time taken to reach maximal ischemia was significantly longer in the AAA group (30 +/- 12 min) than in the AOD group (19 +/- 12 min). After release of the aortic clamp, the decreased S(tO2) returned to the preoperative level in the AAA group, whereas it increased above the preoperative value in the AOD group. CONCLUSION: NIRS performed on the calf muscles is a useful method for assessing the changes in lower-leg perfusion during and after abdominal aortic surgery.