Use of non-invasive NIRS during a vascular occlusion test to assess dynamic tissue O2 saturation response

• Published in: Intensive care medicine Vol. 34; no. 9; pp. 1600 - 1607
• Main Authors: Gómez, Hernando, Torres, Andrés, Polanco, Patricio, Kim, Hyung Kook, Zenker, Sven, Puyana, Juan Carlos, Pinsky, Michael R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.09.2008; Springer; Springer Nature B.V
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anesthesiology; Biological and medical sciences; Blood coagulation. Blood cells; Critical Care Medicine; Emergency Medicine; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods, hemostasis, fibrinolysis; Intensive; Intensive care medicine; Medical sciences; Medicine; Medicine & Public Health; Molecular and cellular biology; Original; Pain Medicine; Pediatrics; Pneumology/Respiratory System; Microcirculation; Cardiovascular reserve; Human study; Tissue oxygen saturation; Human; Dynamic response; Oxygen; Intensive care; Saturation; Resuscitation
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-008-1145-1

Introduction We assessed tissue O 2 saturation (StO 2 ) and total hemoglobin (HbT) changes during a vascular occlusion test (VOT) as markers of O 2 consumption and cardiovascular reserve. Methods Using the non-invasive InSpectra ® near infrared spectrometer, we studied the effect of VOT to StO 2  < 40% then release on thenar eminence StO 2 and HbT in 15 normal volunteers (controls) and 10 trauma patients. We repeated the VOT four times in controls and twice in patients, with controls exercising during the last VOT, and correlated StO 2 with HbT changes by linear regression analysis. Results StO 2 started to decrease 3–28 s post-occlusion (latency) in controls and then decreased in a linear fashion (−0.18 ± 0.04% O 2 /s, mean ± SD), while post-occlusion StO 2 recovery was rapid (5.20 ± 1.19% O 2 /s). Exercise decreased latency (0–5 s) and increased desaturation rate (−0.18 and −0.69% O 2 /s, P  < 0.005) without altering recovery. Trauma patients showed similar StO 2 desaturation rates, but slower recovery (5.20 ± 1.19 vs. 2.88 ± 1.71%/s, P  < 0.0001). Repeated VOT gave similar recovery results within study groups. The hyperemic response was variable in both groups and, if present, was associated with an increased HbT. HbT pre- and post-VOT were significantly different within each subject. Although HbT slope of recovery correlated significantly with StO 2 recovery in trauma patients (rho 0.76), it was not in controls. Conclusions One VOT defines StO 2 deoxygenation and recovery. That StO 2 and HbT recovery co-vary only in trauma patients suggests that pre-existing vasoconstriction was unmasked by the ischemic challenge consistent with increased sympathetic tone.