Thenar Tissue Oxygen Saturation Research Articles

Thenar oxygen saturation during weaning from mechanical ventilation: an observational study

Our aim was to determine whether thenar tissue oxygen saturation (S(tO2)), measured by noninvasive near-infrared spectroscopy, and its changes derived from an ischaemic challenge are associated with weaning outcome. Our study comprised a prospective observational study in a 26-bed medical-surgical intensive care unit. Patients receiving mechanical ventilation for >48 h, and considered ready to wean by their physicians underwent a 30-min weaning trial. S(tO2) was measured continuously on the thenar eminence. A transient vascular occlusion test was performed prior to and at the end of the 30-min weaning trial, in order to obtain S(tO2) deoxygenation and reoxygenation rates, and estimated local oxygen consumption. 37 patients were studied. Patients were classified as weaning success (n=24) or weaning failure (n=13). No significant demographic, respiratory or haemodynamic differences were observed between the groups at inclusion. Patients who failed the overall weaning process showed a significant increase in deoxygenation and in local oxygen consumption from baseline to 30 min of weaning trial, whereas no significant changes were observed in the weaning success group. Failure to wean from mechanical ventilation was associated with higher relative increases in deoxygenation after 30 min of spontaneous ventilation.

Near-infrared spectroscopy in post-cardiac arrest patients undergoing therapeutic hypothermia

AimsTo investigate the relationship between tissue oxygen saturation during a vascular occlusion test with systemic hemodynamics, central and peripheral skin temperature in patients resuscitated from cardiac arrest. MethodsThis prospective, observational study included a convenience sample of 30 patients hospitalized in a multidisciplinary intensive care unit in a university hospital and treated with therapeutic hypothermia. Near infrared spectroscopy (NIRS) was used to measure thenar tissue oxygen saturation, desaturation rate and saturation recovery rate after the vascular occlusion test, conducted within 24h of hospital admission and within 12h of initiating re-warming. Measurements included heart rate (HR), mean arterial blood pressure (MAP), oxygen saturation, use of vasopressors and sedatives, core body (esophageal) and peripheral skin temperature and sequential organ failure assessment (SOFA) score. ResultsPeripheral skin temperature was found to have a significant effect on StO2 deoxygenation and recovery slopes, resulting in lower rates at colder temperatures. This effect was independent of MAP, HR, and core temperature. NIRS-derived variables were not associated with SOFA score or use of vasopressors and did not predict mortality. DiscussionColder peripheral skin temperatures resulting in lower StO2 desaturation rates may be explained by slower aerobic metabolism, thus lower extraction rate of oxygen, in the tissue beds. Lower recovery slopes at colder local temperatures may result from peripheral vasoconstriction during reactive hyperemia. ConclusionWe found that peripheral skin temperature in post-arrest critically ill patients undergoing TH strongly influences tissue oxygen desaturation and reoxygenation rates. In additional, changes in NIRS derived variables were independent of measures of shock, vasopressor use or illness severity.

Masseter tissue oxygen saturation predicts normal central venous oxygen saturation during early goal-directed therapy and predicts mortality in patients with severe sepsis*

This study aimed to investigate, in patients with severe sepsis, the correlation between central venous oxygen saturation and tissue oxygen saturation at different levels. Prospective observational study. General intensive care unit at an academic medical center in France. Thirty-eight patients with underresuscitated severe sepsis and septic shock on intensive care unit admission. None. 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. 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.

Thenar tissue oxygen saturation monitoring

Critical Care Medicine: February 2012 - Volume 40 - Issue 2 - p 712-713 doi: 10.1097/CCM.0b013e31823c8979

Relationship of systemic, hepatosplanchnic, and microcirculatory perfusion parameters with 6-hour lactate clearance in hyperdynamic septic shock patients: an acute, clinical-physiological, pilot study

BackgroundRecent clinical studies have confirmed the strong prognostic value of persistent hyperlactatemia and delayed lactate clearance in septic shock. Several potential hypoxic and nonhypoxic mechanisms have been associated with persistent hyperlactatemia, but the relative contribution of these factors has not been specifically addressed in comprehensive clinical physiological studies. Our goal was to determine potential hemodynamic and perfusion-related parameters associated with 6-hour lactate clearance in a cohort of hyperdynamic, hyperlactatemic, septic shock patients.MethodsWe conducted an acute clinical physiological pilot study that included 15 hyperdynamic, septic shock patients undergoing aggressive early resuscitation. Several hemodynamic and perfusion-related parameters were measured immediately after preload optimization and 6 hours thereafter, with 6-hour lactate clearance as the main outcome criterion. Evaluated parameters included cardiac index, mixed venous oxygen saturation, capillary refill time and central-to-peripheral temperature difference, thenar tissue oxygen saturation (StO2) and its recovery slope after a vascular occlusion test, sublingual microcirculatory assessment, gastric tonometry (pCO2 gap), and plasma disappearance rate of indocyanine green (ICG-PDR). Statistical analysis included Wilcoxon and Mann–Whitney tests.ResultsFive patients presented a 6-hour lactate clearance <10%. Compared with 10 patients with a 6-hour lactate clearance ≥10%, they presented a worse hepatosplanchnic perfusion as represented by significantly more severe derangements of ICG-PDR (9.7 (8–19) vs. 19.6 (9–32)%/min, p < 0.05) and pCO2 gap (33 (9.1-62) vs. 7.7 (3–58) mmHg, p < 0.05) at 6 hours. No other systemic, hemodynamic, metabolic, peripheral, or microcirculatory parameters differentiated these subgroups. We also found a significant correlation between ICG-PDR and pCO2 gap (p = 0.02).ConclusionsImpaired 6-hour lactate clearance could be associated with hepatosplanchnic hypoperfusion in some hyperdynamic septic shock patients. Improvement of systemic, metabolic, and peripheral perfusion parameters does not rule out the persistence of hepatosplanchnic hypoperfusion in this setting. Severe microcirculatory abnormalities can be detected in hyperdynamic septic shock patients, but their role on lactate clearance is unclear. ICG-PDR may be a useful tool to evaluate hepatosplanchnic perfusion in septic shock patients with persistent hyperlactatemia.Trial registrationClinicalTrials.gov Identifier: NCT01271153

The effect of red blood cell transfusion on tissue oxygenation and microcirculation in severe septic patients.

BackgroundMicrocirculation plays a vital role in the development of multiple organ failure in severe sepsis. The effects of red blood cell (RBC) transfusions on these tissue oxygenation and microcirculation variables in early severe sepsis are not well defined.MethodsThis is a prospective, observational study of patients with severe sepsis requiring RBC transfusions of one to two units of non-leukoreduced RBCs for a hemoglobin < 7.0, or for a hemoglobin between 7.0 and 9.0 with lactic acidosis or central venous oxygen saturation < 70%. This study took place in a 54-bed, medical-surgical intensive care unit of a university-affiliated hospital. Thenar tissue oxygen saturation was measured by using a tissue spectrometer on 21 patients, and a vaso-occlusive test was performed before and 1 hour after transfusion. The sublingual microcirculation was assessed with a Sidestream Dark Field device concomitantly on 11 of them.ResultsRBC transfusion resulted in increase in hemoglobin (7.23 (± 0.87) to 8.75 (± 1.06) g/dl; p < 0.001). RBC transfusion did not globally affect near-infrared spectrometry (NIRS)-derived variables. However, percent change in muscle oxygen consumption was negatively correlated with baseline (r = - 0.679, p = 0.001). There was no statistically significant correlation between percent change in vascular reactivity and baseline (p = 0.275). There was a positive correlation between percent change in oxygen consumption and percent change in vascular reactivity (r = 0.442, p = 0.045). In the 11 patients, RBC transfusion did not globally affect NIRS-derived variables or SDF-derived variables. There was no statistically significant correlation between percent change in small vessel perfusion and baseline perfusion (r = -0.474, p = 0.141), between percent change in small vessel flow and baseline flow (r = -0.418, p = 0.201), or between percent change in small vessel perfusion and percent change in small vessel flow (r = 0.435, p = 0.182).ConclusionsIn a small sample population, muscle tissue oxygen consumption, microvascular reactivity and sublingual microcirculation were globally unaltered by RBC transfusion in severe septic patients. However, muscle oxygen consumption improved in patients with low baseline and deteriorated in patients with preserved baseline. Future research with larger samples is needed to further examine the association between RBC transfusion and outcomes of patients resuscitated early in severe sepsis, with an emphasis on elucidating the potential contribution of microvascular factors.

Thenar tissue oxygen saturation monitoring: Noninvasive does not mean simple or accurate!*

Thenar tissue oxygen saturation monitoring: Noninvasive does not mean simple or accurate!*

The relation of near-infrared spectroscopy with changes in peripheral circulation in critically ill patients*

We conducted this observational study to investigate tissue oxygen saturation during a vascular occlusion test in relationship with the condition of peripheral circulation and outcome in critically ill patients. Prospective observational study. Multidisciplinary intensive care unit in a university hospital. Seventy-three critically ill adult patients admitted to the intensive care unit. None. Patients were followed every 24 hrs until day 3 after intensive care admission. Near-infrared spectroscopy was used to measure thenar tissue oxygen saturation, tissue oxygen saturation deoxygenation rate, and tissue oxygen saturation recovery rate after the vascular occlusion test. Measurements included heart rate, mean arterial pressure, forearm-to-fingertip skin-temperature gradient, and physical examination of peripheral perfusion with capillary refill time. Patients were stratified according to the condition of peripheral circulation (abnormal: forearm-to-fingertip skin-temperature gradient ≥4 and capillary refill time >4.5 secs). The outcome was defined based on the daily Sequential Organ Failure Assessment score and blood lactate levels. Upon intensive care unit admission, 35 (47.9%) patients had abnormal peripheral perfusion (forearm-to-fingertip skin-temperature gradient >4 or capillary refill time >4.5 secs). With the exception of the tissue oxygen saturation deoxygenation rate, tissue oxygen saturation baseline and tissue oxygen saturation recovery rate were statistically lower in patients who exhibited abnormal peripheral perfusion than in those with normal peripheral perfusion: 72 ± 9 vs. 81 ± 9; p = .001 and 1.9 ± 0.7 vs. 3.2 ± 0.9; p = .001, respectively. When a mixed-model analysis was performed over time for estimate (s) calculation, adjusted to the condition of disease, we did not find a significant clinical effect between vascular occlusion test-derived tissue oxygen saturation measurements (as response variables) and mean systemic hemodynamic variables (as independent variables): tissue oxygen saturation vs. heart rate: s (95% confidence interval) = 0.007 (-0.08; 0.09); tissue oxygen saturation vs. mean arterial pressure: s (95% confidence interval) = -0.02 (-0.12; 0.08); tissue oxygen saturation deoxygenation rate vs. heart rate: s (95% confidence interval) = 0.002 (-0.0004; 0.006); tissue oxygen saturation deoxygenation rate vs. mean arterial pressure: s (95% confidence interval) - 0.0007 (-0.003; 0.004); tissue oxygen saturation recovery rate vs. heart rate: s (95% confidence interval) = -0.009 (-0.02; -0.0015); tissue oxygen saturation recovery rate vs. mean arterial pressure: s (95% confidence interval) = 0.01 (0.002; 0.018). However, there was a strong association between tissue oxygen saturation baseline and tissue oxygen saturation recovery rate with abnormal peripheral perfusion: tissue oxygen saturation vs. abnormal peripheral perfusion: s (95% confidence interval) = -10.1 (-13.9; -6.2); tissue oxygen saturation recovery rate vs. abnormal peripheral perfusion: s (95% confidence interval) =-10.1 (-13.9; -6.2); tissue oxygen saturation recovery rate vs. abnormal peripheral perfusion: s (95% confidence interval) = -1.1 (-1.4; -0.81). Poor outcome was more closely related to abnormalities in peripheral perfusion than to tissue oxygen saturation-derived parameters. We found that the condition of peripheral circulation in critically ill patients strongly influences tissue oxygen saturation resting values and the tissue oxygen saturation reoxygenation rate but not the tissue oxygen saturation deoxygenation rate. In addition, changes in near-infrared spectroscopy-derived variables were independent of condition of disease and were not accompanied by any major differences in systemic hemodynamic variables.

Near-infrared spectroscopy technique to evaluate the effects of red blood cell transfusion on tissue oxygenation

IntroductionThe 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.MethodsThis prospective, 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.ResultsBlood transfusion resulted 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.ConclusionsMuscle 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.