ABSTRACT
BACKGROUND: The use of wavelengths of the near-infrared region by near-infrared spectroscopy (NIRS) has been studied for several applications in vascular disease. This systematic review aims to explore the clinical relevance of monitoring muscle tissue oxygenation in vascular disease with NIRS. METHODS: A systematic search in PubMed, EMBASE, CINAHL and Cochrane databases was performed to identify clinical NIRS studies, published until April 2015, involving muscle tissue oxygenation in vascular disease. RESULTS: After screening 183 manuscripts, 38 studies (n=2010) were included. Studies concerned peripheral arterial disease (PAD) (twelve studies, n=848), compartment syndrome of lower extremities (seven studies, n=205), deep vein thrombosis (DVT) (six studies, n=429), buttock and lower extremity ischaemia in abdominal aortic aneurysm repair (six studies, n=139), free flap failure (five studies, n=354), and spinal cord ischaemia in thoracoabdominal aortic aneurysm repair (two studies, n=35). Nine studies compared NIRS with gold standards and provided cut-off values. Four studies regarding chronic compartment syndrome and DVT determined higher sensitivity (78%-97%) than specificity (56%-76%). Two studies regarding PAD and buttock claudication determined higher specificity (87%-95%) than sensitivity (33%-88%). Three studies regarding free flap failure determined sensitivity and specificity of 100%. CONCLUSION: We found sufficient evidence to use NIRS in clinical setting for assessment of chronic compartment syndrome of lower extremities, and as surveillance tool for detection of free flap failure. So far, clinical relevance of routine use of NIRS in other vascular applications is less clear. Cut-off values to discriminate are not yet unanimous and better validation has to be awaited for.
Subject(s)
Muscles/blood supply , Muscles/metabolism , Oxygen/metabolism , Spectroscopy, Near-Infrared/methods , Vascular Diseases/metabolism , Compartment Syndromes/metabolism , Free Tissue Flaps/adverse effects , Free Tissue Flaps/blood supply , Humans , Ischemia/metabolism , Peripheral Arterial Disease/metabolism , Venous Thrombosis/metabolismABSTRACT
BACKGROUND: Near-infrared spectroscopy (NIRS) is a noninvasive technique that allows continuous monitoring of regional hemoglobin oxygen saturation (rSo2). We evaluated its application to survey oxygenation of the spinal cord region during open thoracoabdominal aortic aneurysm (TAAA) repair and postoperatively in the intensive care unit (ICU). We also validated its association with motor-evoked potential (MEP) monitoring during the operation. METHODS: The rSo2 curves of 15 patients (8 men; mean age, 64.2 ± 7.7 years) were measured continuously with NIRS at spinal cord levels of the thoracic vertebrae T3 (optode 1, reference spot) and T12 (optode 2) during open TAAA repair. T12/T3 ratios were calculated. NIRS measurements were continued in the intensive care unit and stopped 24 hours after the operation. MEP monitoring was performed in all patients during the procedure. RESULTS: No clinical signs of spinal cord ischemia were documented in any of the patients. Continuous NIRS measurements were successfully performed in all patients during and after the operation. T12/T3 ratios were significantly lower in the MEP ratios that were less than 50% compared with the MEP ratios that were 50% or higher (p = 0.037). CONCLUSIONS: NIRS is an easily applicable noninvasive tool for continuous surveillance of oxygenation of the spinal cord region during TAAA repair and postoperatively in the intensive care unit. The rSo2 curves provide useful information concerning hemodynamic changes in oxygenation of the spinal cord region and might contribute to early detection of spinal cord ischemia. Further investigation is needed before broad clinical implementation.
