The Prognostic Effects of Near Infrared Spectroscopy Derived Tissue Oxygenation Saturation and Vascular Occlusion Test on the Outcome of Ards

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details


Multiple system organ failure (MSOF) is the commonest cause of death in critically ill patients. Incomplete reversal and continued occult tissue hypoxia plays an important role in development of MSOF. Reversal and prevention of tissue hypoxia are fundamental goals of resuscitation and survivor in ICU. Reduced microcirculatory flow and increased heterogeneity of microvascular perfusion is a hallmark of sepsis and play an important part in organ dysfunction. Poor peripheral perfusion is considered an early predictor of tissue hypoperfusion and a warning signal of ongoing shock. Therefore, therapeutic strategies should be employed to resuscitate the microcirculation in order to avoid organ dysfunction and to reduce mortality. Unfortunately, global hemodynamic parameters do not correlate with microvascular perfusion. Therefore, assessment of tissue oxygenation at the microvascular level is essential. Near-infrared spectroscopy (NIRS) is a non-invasive technique using the differential absorption properties of oxygenated and deoxygenated hemoglobin to evaluate skeletal muscle and tissue oxygenation in vessels with a diameter < 1 mm (arterioles, capillaries, and venules). Previous studies have applied NIRS-derived tissue oxygen saturation (StO2) to quantify microvascular dysfunction in critically ill patients and have suggested an association between decreased StO2 and tissue hypoperfusion. Combining StO2 with a vascular occlusion test (VOT) can further enhance the discriminatory power and to better evaluate the tissue micro-oxygenation in severe sepsis and septic shock. Reactive hyperemia during VOT can be considered an integral test of microcirculatory reactivity, evaluating the tissue’s ability to adjust oxygen extraction capabilities to oxygen delivery after a hypoxic stimulus induced by a transient interruption in blood flow. Continuous StO2 measurement and VOT derived StO2 deoxygenation slope and StO2 recovery slope have been found to be predictors of mortality and organ dysfunction.. NIRS is also a non-invasive method for transcutaneous monitoring of hepato- splanchnic perfusion and oxygenation and has been suggested to be an alternative method of assessing liver oxygenation in hypoxia. Hepato-splanchnic ischemia and gut hypoxia play an important role in the pathogenesis of shock, sepsis and MSOF. Monitoring splanchnic StO2 can early detect deteriorating regional tissue oxygenation that may herald impending shock and global tissue hypoxia. ARDS is the most severe form of acute lung injury in ICU. The mortality remains high with reported ranges of 41–58%. Bilateral and diffuse consolidation and collapse from marked increased permeability results in severe refractory hypoxemia. Persistent and marked tissue hypoxia and MSOR are the main cause of death. Up to now, nearly all the NIRS studies were performed on sepsis with septic shock, trauma and heart failure patients. However, nearly no NIRS papers are focused on the ARDS. We think that the tissue oxygenation of ARDS should be paid great attention to investigate to decrease the ARDS mortality. Therefore, our study is aimed to explore the relative predictive powers of the baseline and time course changes of muscular and hepatic StO2 and VOT derived deoxygenation and recovery slope on the organ dysfunction and mortality of ARDS patients admitted into ICU and to investigate their correlation with macrohemodynamic and tissue oxygenation assessing variables.

Project IDs

Project ID:PC10308-0906
External Project ID:MOST103-2314-B182-060-MY2
Effective start/end date01/08/1431/07/15


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