***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Introduction Near-infrared spectroscopy ( NIRS ) noninvasively measures peripheral tissue oxygen saturation ( StO2 ) . NIRS may be utilized along with a vascular occlusion test , in which limb blood flow is temporarily occluded and released , to quantify a tissue bed 's rate of oxygen exchange during ischemia and recovery . The objective of this study was to test the hypothesis that NIRS-derived StO2 measures ( StO2 initial , StO2 occlusion and StO2 recovery ) identify patients who are in shock and at increased risk of organ dysfunction ( Sequential Organ Failure Assessment ( SOFA ) score ≥ 2 at 24 hours ) and dying in the hospital . Methods This prospect i ve , observational study comprised a convenience sample of three cohorts of adult patients ( age > 17 years ) at three urban university emergency departments : ( 1 ) a septic shock cohort ( systolic blood pressure < 90 after fluid challenge ; the " SHOCK " cohort , n = 58 ) , ( 2 ) a sepsis without shock cohort ( the " SEPSIS " cohort , n = 60 ) and emergency department patients without infection ( n = 50 ) . We measured the StO2 initial , StO2 occlusion and StO2 recovery slopes for all patients . Outcomes were sepsis syndrome severity , organ dysfunction ( SOFA score at 24 hours ) and in-hospital mortality . Results Among the 168 patients enrolled  , mean initial StO2 was lower in the SHOCK cohort than in the SEPSIS cohort ( 76 % vs 81 % ) , with an impaired occlusion slope ( -10.2 and 5.2%/minute vs -13.1 and 4.4%/minute ) and an impaired recovery slope ( 2.4 and 1.6%/second vs 3.9 and 1.7%/second ) ( P < 0.001 for all ) . The recovery slope was well-correlated with SOFA score at 24 hours ( -0.35 ; P < 0.001 ) , with a promising area under the curve ( AUC ) for mortality of 0.81 . The occlusion slope correlation with SOFA score at 24 hours was 0.21 ( P < 0.02 ) , with a fair mortality AUC of 0.70 . The initial StO2 was significantly but less strongly correlated with SOFA score at 24 hours ( -0.18 ; P < 0.04 ) , with a poor mortality AUC of 0.56 . Conclusions NIRS measurements for the StO2 initial , StO2 occlusion and StO2 recovery slope were abnormal in patients with septic shock compared to sepsis patients . The recovery slope was most strongly associated with organ dysfunction and mortality . Further validation is warranted . Trial registration Introduction The aim of this study was to evaluate the effects of red blood cell ( RBC ) transfusions on muscle tissue oxygenation , oxygen metabolism and microvascular reactivity in critically ill patients using near-infrared spectroscopy ( NIRS ) technology . Methods This prospect i ve , observational study included 44 consecutive patients hospitalized in the 31-bed , medical-surgical intensive care unit of a university hospital with anemia requiring red blood cell transfusion .  Thenar tissue oxygen saturation ( StO2 ) and muscle tissue hemoglobin index ( THI ) were measured using a tissue spectrometer ( InSpectra ™ Model 325 ; Hutchinson Technology Inc. , Hutchinson , MN , USA ) . A vaso-occlusive test was performed before and 1 hour after RBC transfusion by rapid inflation of a pneumatic cuff around the upper arm . The following variables were recorded : THI , the StO2 desaturation slope during the occlusion ( % /minute ) and the StO2 upslope of the reperfusion phase following the ischemic period ( % /second ) . Muscle oxygen consumption ( NIR VO2 ; arbitrary units ) was calculated as the product of the inverse StO2 desaturation slope and the mean THI over the first minute of arterial occlusion . Results Blood transfusion result ed in increases in hemoglobin ( from 7.1 ( 6.7 to 7.7 ) to 8.4 ( 7.1 to 9 ) g/dl ; P < 0.01 ) and in oxygen delivery ( from 306 ( 259 to 337 ) to 356 ( 332 to 422 ) ml/minute/m2 ; P < 0.001 ) . However , systemic VO2 was unchanged . RBC transfusion did not globally affect NIRS-derived variables , but there was considerable interindividual variation . Changes in the StO2 upslope of the reperfusion phase after transfusion were negatively correlated with baseline StO2 upslope of the reperfusion phase ( r2 = 0.42 ; P < 0.0001 ) . Changes in NIR VO2 after transfusion were also negatively correlated with baseline NIR VO2 ( r2 = 0.48 ; P = 0.0015 ) . There were no correlations between RBC storage time and changes in StO2 slope or NIR VO2 . Conclusions Muscle tissue oxygenation , oxygen consumption and microvascular reactivity are globally unaltered by RBC transfusion in critically ill patients . However , muscle oxygen consumption and microvascular reactivity can improve following transfusion in patients with alterations of these variables at baseline Introduction The prognostic value of continuous monitoring of  tissue oxygen saturation ( StO2  ) during early goal -directed therapy of critically ill patients has not been investigated . We conducted this prospect i ve study to test the hypothesis that the persistence of low StO2 levels following intensive care admission is related to adverse outcome . Methods We followed 22 critically ill patients admitted with increased lactate levels ( > 3 mmol/l ) .  Near-infrared spectroscopy ( NIRS ) was used to measure the thenar eminence StO2 and the rate of StO2 increase ( RincStO2 ) after a vascular occlusion test . NIRS dynamic measurements were recorded at intensive care admission and each 2-hour interval during 8 hours of resuscitation . All repeated StO2 measurements were further compared with Sequential Organ Failure Assessment ( SOFA ) , Acute Physiology and Chronic Health Evaluation ( APACHE ) II and hemodynamic physiological variables : heart rate ( HR ) , mean arterial pressure ( MAP ) , central venous oxygen saturation ( ScvO2 ) and parameters of peripheral circulation ( physical examination and peripheral flow index ( PFI ) ) . Results Twelve patients were admitted with low StO2 levels ( StO2 < 70 % ) . The mean scores for SOFA and APACHE II scores were significantly higher in patients who persisted with low StO2 levels ( n = 10 ) than in those who exhibited normal StO2 levels ( n = 12 ) at 8 hours after the resuscitation period ( P < 0.05 ; median ( interquartile range ) : SOFA , 8 ( 7 to 11 ) vs. 5 ( 3 to 8) ; APACHE II , 32(24 to 33 ) vs. 19 ( 15 to 25 ) ) . There was no significant relationship between StO2 and mean global hemodynamic variables ( HR , P = 0.26 ; MAP , P = 0.51 ; ScvO2 , P = 0.11 ) . However , there was a strong association between StO2 with clinical abnormalities of peripheral perfusion ( P = 0.004 ) , PFI ( P = 0.005 ) and RincStO2 ( P = 0.002 ) . The persistence of low StO2 values was associated with a low percentage of lactate decrease ( P < 0.05 ; median ( interquartile range ) : 33 % ( 12 to 43 % ) vs. 43 % ( 30 to 54 % ) ) . Conclusions We found that patients who consistently exhibited low StO2 levels following an initial resuscitation had significantly worse organ failure than did patients with normal StO2 values , and found that StO2 changes had no relationship with global hemodynamic variables Objective : This study aim ed to investigate , in patients with severe sepsis , the correlation between central venous oxygen saturation and tissue oxygen saturation at different levels . Design : Prospect i ve observational study . Setting : General intensive care unit at an academic medical center in France . Patients : Thirty-eight patients with underresuscitated severe sepsis and septic shock on intensive care unit admission . Interventions : None . Measurements and Main Results : During early resuscitation according to the 6-hr bundles of the Surviving Sepsis Campaign guidelines , tissue oxygen saturation  was recorded every other hour at the level of the thenar , masseter , and deltoid muscles along with central hemodynamics , arterial lactate concentrations , and central venous oxygen saturation . Over the 6-hr resuscitation period , thenar tissue oxygen saturation was consistently higher than masseter tissue oxygen saturation ( p = .04 ) and deltoid tissue oxygen saturation ( p = .002 ) , and masseter tissue oxygen saturation was consistently higher than deltoid tissue oxygen saturation ( p = .04 ) . Receiver operating characteristic curves analyses showed that masseter tissue oxygen saturation was better predictor of central venous oxygen saturation > 70 % than thenar tissue oxygen saturation ( area under the curve , 0.80 ; 95 % confidence interval 0.71−0.89 vs. 0.67 ; 95 % confidence interval 0.56–0.77 ; p = .02 ) . The crude 28-day mortality was 36.8 % . Receiver operating characteristic curve analysis showed that masseter tissue oxygen saturation ( area under the curve 0.87 ; 0.75−0.98 ) and deltoid tissue oxygen saturation ( area under the curve 0.88 ; 0.77−0.98 ) but not thenar tissue oxygen saturation ( area under the curve 0.66 ; 0.46–0.86 ) or central venous oxygen saturation ( area under the curve 0.56 ; 0.38–0.80 ) were strong predictors of 28-day mortality . Conclusions : This study suggested that in the early 6-hr resuscitation period , masseter tissue oxygen saturation accurately identified patients with severe sepsis and central venous oxygen saturation > 70 % . Both masseter tissue oxygen saturation and deltoid tissue oxygen saturation but not central venous oxygen saturation or thenar tissue oxygen saturation are strong predictors of 28-day mortality BACKGROUND : Tissue oximetry ( StO2 ) plus a vascular occlusion test is a noninvasive technology that targets indices of oxygen uptake and delivery . We hypothesize that prehospital tissue oximetric values and vascular occlusion test response can predict the need for in-hospital  lifesaving interventions ( LSI ) . METHODS : We conducted a prospect i ve , blinded observational study to evaluate StO2 slopes to predict the need for LSI . We calculated the DeO2 slope using Pearson 's coefficients of regression ( r2 ) for the first 25 % of descent and the ReO2 slope using the entire recovery interval . The primary outcome was LSI defined as the need for emergent operation or transfusion in the first 24 hours of hospitalization . We created multivariable logistic regression models using covariates of age , sex , vital signs , lactate , and mental status . RESULTS : We assessed StO2 in a convenience sample of 150 trauma patients from April to November of 2009 .  In-hospital mortality was 3 % ( 95 % confidence interval [ CI ] , 1.1–7.6 ) ; 31 % ( 95 % CI , 24–39 ) were admitted to the intensive care unit , 6 % ( 95 % CI , 2.8–11.1 ) had an emergent operation , and 10 % ( 95 % CI , 5.7–15.9 ) required transfusion . Decreasing DeO2 was associated with a higher proportion of patients requiring LSI . In the multivariate model , the association between the need for LSI and DeO2 , Glasgow Coma Scale , and age persists . CONCLUSION : Prehospital DeO2 is associated with need for LSI in our trauma population . Further study of DeO2 is warranted to determine whether it can be used as an adjunct triage criterion or an endpoint for resuscitation . LEVEL OF EVIDENCE : III , observational study BACKGROUND In a single-center study published more than a decade ago involving patients presenting to the emergency department with severe sepsis and septic shock , mortality was markedly lower among those who were treated according to a 6-hour protocol of early goal -directed therapy ( EGDT )  , in which intravenous fluids , vasopressors , inotropes , and blood transfusions were adjusted to reach central hemodynamic targets , than among those receiving usual care . We conducted a trial to determine whether these findings were generalizable and whether all aspects of the protocol were necessary . METHODS In 31 emergency departments in the United States , we r and omly assigned patients with septic shock to one of three groups for 6 hours of resuscitation : protocol -based EGDT ; protocol -based st and ard therapy that did not require the placement of a central venous catheter , administration of inotropes , or blood transfusions ; or usual care . The primary end point was 60-day in-hospital mortality . We tested sequentially whether protocol -based care ( EGDT and st and ard- 
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StO2 more rapidly identifies occult shock in human patients compared to traditional methods , which can lead to earlier intervention in these patients .
VETERINARY DATA SYNTHESIS Veterinary studies involving tissue oxygen monitoring are limited , but the technology may have utility for identification of hemorrhagic shock earlier than changes in base excess , blood lactate concentration , or other traditional perfusion parameters .
CONCLUSION Tissue oxygen monitoring is most commonly performed utilizing a noninvasive , portable monitor , which provides real-time , continuous , repeatable StO2 measurements .
A decline in StO2 is an early indicator of shock in both human and veterinary patients .
Low StO2 values in human patients are associated with increased morbidity , mortality , and length of hospitalization , as well as the development of multiple organ system dysfunction and surgical site infections