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Background Near-infrared spectroscopy (NIRS)-based cerebral oximetry is a noninvasive technology used to estimate regional cerebral oxygen saturation (rSO.sub.2). Extracranial blood flow is known to substantially affect rSO.sub.2 values measured by most clinically available devices. Several studies have also reported that the Trendelenburg position and upright position have a larger effect on rSO.sub.2 measurements than the supine position. Therefore, we investigated the effect of these two positions (the Trendelenburg position versus the upright position) and extracranial contamination on rSO.sub.2 measurements obtained using two commercially available devices and one prototype device. Methods Twelve healthy volunteers were enrolled in the study. They each had three cerebral oximetry devices applied to their forehead (FORE-SIGHT ELITE[TM], CAS Medical Systems Inc., Branford, CT, USA; INVOS 5100c[TM], Medtronic, Minneapolis, MN, USA; and NIRO-TRS, Hamamatsu Photonics, Hamamatsu, Japan). A circumferential pneumatic head cuff was positioned proximal to the NIRS cerebral oximetry sensors. We measured rSO.sub.2, heart rate (HR), and blood pressure (BP) in six conditions (supine, Trendelenburg and upright positions, with and without scalp ischemia induced by head cuff inflation) every 5 min with each oximetry device. Total hemoglobin (tHb), which is associated with cerebral blood volume (CBV) as measured by positron emission tomography, was measured using the NIRO-TRS device to determine extracranial blood volume in each position. Results Measurements of rSO.sub.2 with all the devices were affected by extracranial contamination. The percentage of extracranial contamination was highest with INVOS 5100c[TM] in the upright position (INVOS, 21.3%; FORE-SIGHT, 14.3%; NIRO-TRS, 3.6%). Measurements of rSO.sub.2 obtained in the upright position were significantly lower than those obtained in the supine position, using INVOS-5100c[TM] and FORE-SIGHT ELITE[TM] (71 vs. 74% and 67 vs. 72%, respectively), but not using NIRO-TRS (62 vs. 64%). A significant decrease in tHb was observed after head cuff inflation in the supine and Trendelenburg positions (supine, 0.132-0.123 [mu]mol/l; Trendelenburg, 0.133-0.125 [mu]mol/l). Conclusions Except when using NIRO-TRS, measurements of rSO.sub.2 in the forehead are significantly lower when measured in the upright position than in the supine position. All devices in this study were affected by extracranial contamination., Author(s): Shinya Kato [sup.1] [sup.2] , Kenji Yoshitani [sup.1] [sup.2] , Yosuke Kubota [sup.1] , Yuzuru Inatomi [sup.1] , Yoshihiko Ohnishi [sup.1] Author Affiliations: (1) 0000 0004 0378 8307grid.410796.dDepartment of [...]

Background: Inaccurate measurements of body temperature might be associated with complications during the perioperative period. We conducted a retrospective cohort study to compare the bladder temperature and the tympanic membrane temperature in patients undergoing open repair of abdominal aortic aneurysm., Methods: Fifteen adult patients who had undergone general anesthesia with/without epidural anesthesia were included in the present cohort. The bladder and the tympanic temperatures were simultaneously recorded at 6 points during surgery. One-way repeated measures ANOVA and Bland-Altman analysis were performed to assess statistical significance. The two-tailed P values less than 0.05 were considered statistically significant., Results: No difference was found between the bladder and the tympanic temperatures before abdominal aortic cross-clamping. However, during and after cross-clamping, the bladder temperature values were likely to be lower compared with the tympanic values. The average temperature difference (+/- 2 SD) was 0.4 degrees C (+/- 1.1 degrees C) (95% CI: -1.21-0.78)., Conclusions: The tympanic membrane might be a reliable site for core body temperature measurement in abdominal aortic aneurysm surgery patients.

We describe two cases which developed loss of motor evoked potentials from bilateral lower limbs following thoracoabdominal aortic repair. Paraplegia was suspected in both cases; however, one case of Crawford type 2 aneurysm showed transient left leg monoplegia with a sensory deficit and the other case of aortic pseudoaneurysm showed no neurologic dysfunction postoperatively. We employed epidural cooling and spinal drainage for spinal protection and distal perfusion was provided through aorto-iliac side-arm conduit. Despite the prolonged spinal ischemia during thoracoabdominal aortic repair, spinal drainage and epidural cooling were very helpful for protecting the spinal cord from ischemia. The interpretation of MEPs seems very difficult especially when the potentials remain absent even after reconstruction or reperfusion of segmental arteries, because variety of intraoperative factors may affect them.