Central Venous Saturation Research Articles

Valor pronóstico de los parámetros gasométricos del dióxido de carbono en pacientes con sepsis. Una revisión bibliográfica

The anaerobic metabolism is the cornerstone in physiopathology of septic shock. Nowadays we have both the central or mixed venous oxigen saturation and lactate levels to monitoring the metabolism in septic patients. Some studies have shown that normalization of systemic hemodynamic and oxygen metabolism variables not prevent progression to multiorgan damage and death.Recently has been proposed the venous-to-arterial carbon dioxide difference (ΔpvaCO2) as an alternative marker of tissue hypoperfusion, like Cardiac Index. High ΔpvaCO2 predicts adverse outcomes. Also has been proposed both, the ratio between the ΔpvaCO2 and arterial-to-venous oxygen content difference (ΔCavO2): ΔpvaCO2/ΔCavO2; and, the ratio between venous-to-arterial carbon dioxide difference (ΔCvaCO2) and ΔCavO2: ΔCvaCO2/ΔCavO2, as markers of anaerobic metabolism. Both of high ratios are related to high levels of lactate and worse prognosis. Therefore in patients with sepsis the combination of markers of resuscitation could be important to improve the outcomes.

High central venous saturation after cardiac surgery is associated with increased organ failure and long-term mortality: an observational cross-sectional study

IntroductionCentral venous saturation (ScvO2) monitoring has been suggested to address the issue of adequate cardiocirculatory function in the context of cardiac surgery. The aim of this study was to determine the impact of low (L) (<60%), normal (N) (60%-80%), and high (H) (>80%) ScvO2 measured on intensive care unit (ICU) admission after cardiac surgery.MethodsWe conducted a retrospective, cross-sectional, observational study at three ICUs of a university hospital department for anaesthesiology and intensive care. Electronic patient records of all adults who underwent cardiac surgery between 2006 and 2013 and available admission measurements of ScvO2 were examined. Patients were allocated to one of three groups according to first ScvO2 measurement after ICU admission: group L (<60%), group N (60%-80%), and group H (>80%). Primary end-points were in-hospital and 3-year follow-up survival.ResultsData from 4,447 patients were included in analysis. Low and high initial measurements of ScvO2 were associated with increased in-hospital mortality (L: 5.6%; N: 3.3%; H: 6.8%), 3-year follow-up mortality (L: 21.6%; N: 19.3%; H: 25.8%), incidence of post-operative haemodialysis (L: 11.5%; N: 7.8%; H: 15.3%), and prolonged hospital length of stay (L: 13 days, 9–22; N: 12 days, 9–19; H: 14 days, 9–21). After adjustment for possible confounding variables, an initial ScvO2 above 80% was associated with adjusted hazard ratios of 2.79 (95% confidence interval (CI) 1.565-4.964, P <0.001) for in-hospital survival and 1.31 (95% CI 1.033-1.672, P = 0.026) for 3-year follow-up survival.ConclusionsPatients with high ScvO2 were particularly affected by unfavourable outcomes. Advanced haemodynamic monitoring may help to identify patients with high ScvO2 who developed extraction dysfunction and to establish treatment algorithms to improve patient outcome in these patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0889-6) contains supplementary material, which is available to authorized users.

Should we restrict erythrocyte transfusion in early goal directed protocols?

BackgroundEarly goal-directed therapy has been endorsed in the guidelines of the Surviving Sepsis Campaign as a key strategy among patients presenting with severe sepsis or septic shock. But more importantly, early goal-directed therapy also became standard care for non-septic critically ill patients and was adopted for high-risk surgical patients.DiscussionImportantly, transfusion of red blood cells is a central part of many protocols of early goal-directed therapy to indicate the need for use of inotropes and red blood cells, as both central venous saturation and hematocrit are used as transfusion triggers. However, burgeoning data has strongly linked transfusion with worse clinical outcomes. If correct, could these early goal-directed therapy ‚bundles’ have better outcome if a restrictive transfusion practice is adopted?SummaryEarly goal-directed therapy has evolved as standard care for most of critically ill patients, and many protocols contain transfusion of red blood cells targeting high hemoglobin level as a key element. As red blood cell transfusions are associated with increased morbidity and mortality, transfusion thresholds need to be more individualized.

Prospective evaluation of regional oxygen saturation to estimate central venous saturation in sepsis.

Current treatment guidelines for sepsis claim an early goal-directed hemodynamic optimization including fluid resuscitation, use of vasopressors and inotropic agents. We investigated the correlation between the prominent treatment goal central venous saturation (ScvO2) and the frontal and the thenar regional oxygen saturation (rSO2) measured by near infrared spectroscopy. Secondary, we examined the value of ScvO2, lactate levels and rSO2 as surrogate markers of an impaired tissue oxygenation for outcome prediction in sepsis. This prospective, observational study was performed at the surgical intensive care unit of the University Hospital Giessen. A total of 50 patients with sepsis, severe sepsis or septic shock were included. ScvO2, rSO2 and lactate were measured at sepsis diagnosis (baseline), 24 and 48 h, thereafter. We investigated the predictive value of frontal and thenar rSO2 for a decreased SvcO2 under 70%. For survivor and non-survivors ScvO2, rSO2 and lactate were analysed. Patients with ScvO2 >70% showed a trend to higher levels of fontal rSO2 (62.81 ± 8.06 vs. 53.54 ± 15.48; p = 0.058). ROC-analysis revealed a minor prediction of a decreased ScvO2 by frontal rSO2 levels at baseline (AUC = 0.687; 95% CI 0.511-0.863; p = 0.047). Combined measurements of lactate and ScvO2 showed significantly elevated mortality for patients with ScvO2 ≥70% and lactate levels ≥2.5 mmol/l (log rank test p = 0.004). In the group with ScvO2 <70% and lactate levels <2.5 mmol/l no patients died during the observation period. Frontal rSO2 correlates with ScvO2 but both frontal and thenar rSO2 do not exactly discriminate between patients with high or low ScvO2 in sepsis. The combination of elevated lactate >2.5 mmol/l and ScvO2 >70 % is highly associated with poor outcome in ICU patients with sepsis, severe sepsis and septic shock.

Do not drown the patient: appropriate fluid management in critical illness

Administering intravenous fluids to support the circulation in critically ill patients has been a mainstay of emergency medicine and critical care for decades, especially (but not exclusively) in patients with distributive or hypovolemic shock. However, in recent years, this automatic use of large fluid volumes is beginning to be questioned. Analysis from several large trials in severe sepsis and/or acute respiratory distress syndrome have shown independent links between volumes of fluid administered and outcome; conservative fluid strategies have also been associated with lower mortality in trauma patients. In addition, it is becoming ever more clear that central venous pressure, which is often used to guide fluid administration, is a completely unreliable parameter of volume status or fluid responsiveness. Furthermore, 2 recently published large multicenter trials (ARISE and ProCESS) have discredited the “early goal-directed therapy” approach, which used prespecified targets of central venous pressure and venous saturation to guide fluid and vasopressor administration. This article discusses the risks of “iatrogenic submersion” and strategies to avoid this risk while still giving our patients the fluids they need. The key lies in combining good clinical judgement, awareness of the potential harm from excessive fluid use, restraint in reflexive administration of fluids, and use of data from sophisticated monitoring tools such as echocardiography and transpulmonary thermodilution. Use of smaller volumes to perform fluid challenges, monitoring of extravascular lung water, earlier use of norepinephrine, and other strategies can help further reduce morbidity and mortality from severe sepsis.

Cardiac awake extracorporeal life support-bridge to decision?

Severe acute heart failure requires immediate intensive care unit (ICU) treatment, but prognosis and outcome of further treatment regimens largely depends on the preprocedural status of the patient. Especially, multiorgan failure including mechanical ventilation are unfavorable predictors of clinical outcome. Here, we report a strategy of immediate initiation of extracorporeal life support (ECLS) in awake and spontaneously breathing patients with acute heart failure to achieve early multiorgan recovery and gain sufficient time for further treatment planning. Twenty-three patients with severe cardiac failure refractory to standard medical management underwent ECLS treatment, after first clinical signs of cardiac failure appeared to avoid mechanical ventilation. Hemodynamic parameters and renal and liver functions were monitored. Outcome at 1 and 6 months was determined. Patients 46.1 ± 15.5 years of age were placed on ECLS due to various underlying diagnosis: ischemic heart disease (n = 6), dilatative cardiomyopathy (n = 4), myocarditis (n = 2), graft failure following heart transplantation (n = 6), or other diseases (n = 5). ECLS lasted 11.9 ± 12.9 days. Hemodynamic stabilization was achieved immediately after ECLS initiation. Vasopressors were reduced subsequently and the cardiac situation improved indicated by central venous saturation, which increased from 38.5 ± 11.3% before to 74.26 ± 8.4% (P < 0.0001) 24 h after ECLS initiation. Similarly, serum lactate levels decreased from 4.7 ± 4.6 to 1.7 ± 1.51 mmol/L (P = 0.003). Cumulative 30-day survival was 87.5%, and 6-month survival was 70.8%. In acute cardiac failure, early ECLS treatment is a safe, feasible treatment in awake patients allowing a gain of time for final decision. Moreover, this strategy avoids complications associated with sedation and mechanical ventilation and leads to recovery of secondary organ function, enabling destination therapy.

Reliable assessment of perfusion is the Holy Grail of intensive care.

Reliable assessment of perfusion is the Holy Grail of intensive care.

分光光度法で同時測定された中心静脈血酸素飽和度と混合静脈血酸素飽和度の極座標を用いた追随性の検討

分光光度法で同時測定された中心静脈血酸素飽和度と混合静脈血酸素飽和度の極座標を用いた追随性の検討

Aortic Counterpulsation Therapy in Patients with Advanced Heart Failure: Analysis of the TBRIDGE Registry

BackgroundThe use of aortic counterpulsation therapy in advanced heart failure is controversial.ObjectivesTo evaluate the hemodynamic and metabolic effects of intra-aortic balloon pump (IABP) and its impact on 30-day mortality in patients with heart failure.MethodsHistorical prospective, unicentric study to evaluate all patients treated with IABP betwen August/2008 and July/2013, included in an institutional registry named TBRIDGE (The Brazilian Registry of Intra-aortic balloon pump in Decompensated heart failure - Global Evaluation). We analyzed changes in oxygen central venous saturation (ScvO2), arterial lactate, and use of vasoactive drugs at 48 hours after IABP insertion. The 30-day mortality was estimated by the Kaplan-Meier method and diferences in subgroups were evaluated by the Log-rank test.ResultsA total of 223 patients (mean age 49 ± 14 years) were included. Mean left ventricle ejection fraction was 24 ± 10%, and 30% of patients had Chagas disease. Compared with pre-IABP insertion, we observed an increase in ScvO2 (50.5% vs. 65.5%, p < 0.001) and use of nitroprusside (33.6% vs. 47.5%, p < 0.001), and a decrease in lactate levels (31.4 vs. 16.7 mg/dL, p < 0.001) and use of vasopressors (36.3% vs. 25.6%, p = 0.003) after IABP insertion. Thirty-day survival was 69%, with lower mortality in Chagas disease patients compared without the disease (p = 0.008).ConclusionAfter 48 hours of use, IABP promoted changes in the use of vasoactive drugs, improved tissue perfusion. Chagas etiology was associated with lower 30-day mortality. Aortic counterpulsation therapy is an effective method of circulatory support for patients waiting for heart transplantation.

Clinical research of central venous blood oxygen saturation in elder patients with acute left ventricular failure

Objective To investigate the detection of central venous oxygen saturation （ ScvO2 ） whether can＆amp;nbsp;be alternative mixed venous oxygen saturation （ SvO2 ） in elderly patients with acute left ventricular failure.Methods 42 elderly patients with acute heart failure were detected by central venous oxygen saturation and mixed venous oxy-gen saturation before the treatment and 1h,2h,4h after treatment.Then the parameters index changes were analyzed according to the prognosis.Results Whatever the prognosis of the patients were,the trend of ScvO2 and SvO2 was the same.Before the treatment,the blood oxygen saturation detected by the ScvO2 with patients was no statistical differ-ence with the ScvO2（t=0.867,P〉0.05）,and after treatment of 4h the change trend detected of both has also the consistency,no statistical difference （t=0.681,P〉0.05） The correlation coefficient r=0.998,and the relationship between ScvO2 and SvO2 confirmed the same clinical significance.Conclusion Considering the factors of trauma, complications,costs and so on,ScvO2 can be used to replace SvO2 in elderly patients with acute left heart failure. Key words: Oxygen saturation; Vein; Monitor; Cardiac dysfunction,lefe; Aged

Tissue ischemia microdialysis assessments following severe traumatic haemorrhagic shock: lactate/pyruvate ratio as a new resuscitation end point?

BackgroundIntensive care of severe trauma patients focuses on the treatment of haemorrhagic shock. Tissues should be perfused sufficiently with blood and with sufficient oxygen content to ensure adequate tissue oxygen delivery. Tissue metabolism can be monitored by microdialysis, and the lactate/pyruvate ratio (LPR) may be used as a tissue ischemia marker. The aim of this study was to determine the adequate cardiac output and haemoglobin levels that avoid tissue ischemia.MethodsAdult patients with serious traumatic haemorrhagic shock were enrolled in this prospective observational study. The primary observed parameters included haemoglobin, cardiac output, central venous saturation, arterial lactate and the tissue lactate/pyruvate ratio.ResultsForty-eight patients were analysed. The average age of the patients was 39.8 ± 16.7, and the average ISS was 43.4 ± 12.2. Hb < 70 g/l was associated with pathologic arterial lactate, ScvO2 and LPR. Tissue ischemia (i.e., LPR over 25) developed when CI ≤ 3.2 l/min/m2 and Hb between 70 and 90 g/l were observed. Severe tissue ischemia events were recorded when the Hb dropped below 70 g/l and CI was 3.2-4.8 l/min/m2. CI ≥ 4.8 l/min/m2 was not found to be connected with tissue ischemia, even when Hb ≤ 70 g/l.ConclusionLPR could be a useful marker to manage traumatic haemorrhagic shock therapies. In initial traumatic haemorrhagic shock treatments, it may be better to maintain CI ≥ 3.2 l/min/m2 and Hb ≥ 70 g/l to avoid tissue ischemia. LPR could also be a useful transfusion trigger when it may demonstrate ischemia onset due to low local DO2 and early reveal low/no tissue perfusion.

Monitoring Central Venous Saturation

Monitoring Central Venous Saturation

Impact of nitroglycerin infusion on weaning off hypertensive mechanically ventilated chronic obstructive pulmonary disease patients

IntroductionMechanical ventilation (MV) weaning trial can be compared to a cardiac stress test where spontaneous ventilation is a form of an exercise and therefore hemodynamic compromise can occur during the weaning process in critically ill patients. The combined increase in arterial pressure and heart rate during unsuccessful weaning is quite suggestive of weaning failure of cardiac origin. Assessment and prediction of weaning failure from cardiac origin remain complicated in patients with chronic obstructive pulmonary disease (COPD). Recent data showed that COPD itself is a powerful independent risk factor for cardiovascular morbidity and mortality, suggesting that occult cardiac dysfunction could be frequent in patients with COPD. The immediate transition from positive pressure mechanical ventilation to spontaneous ventilation may generate significant cardiopulmonary alterations that are complex and mainly include the inspiratory fall in intrathoracic pressure, the increase in work of breathing, and the catecholamine discharge that occur during abrupt transfer from mechanical ventilation to spontaneous breathing. Therefore, it could be suggested that a treatment targeting the cardiovascular system decreasing the preload might help the heart to tolerate the critical period of weaning more effectively. MethodsThis study was carried on 60 adult male and female patients admitted to the Critical Care Medicine Departments in the Alexandria Main University Hospital and who fulfilled the diagnosis of acute exacerbation of COPD according to the Global initiative for chronic obstructive lung disease (GOLD) [1], and considered eligible for weaning after at least 24h of invasive mechanical ventilation exhibiting systemic arterial hypertension during the start of spontaneous breathing trial. 30 of them were adult patients and served as the study group (Group I), and the other 30 were age-matched adults who served as the control group (Group II). Each group was subjected to spontaneous breathing trial (SBT) using a T-piece receiving FiO2 the same as during mechanical ventilation. Control group underwent SBT alone while the nitroglycerin group underwent continuous nitroglycerin infusion started at the beginning of the SBT and titrated to maintain normal arterial systolic blood pressure that is; 120–139mmHg). Hemodynamic, oxygenation and respiratory measurements were performed on the start of SBT, and after a 2-h T-piece SBT. ResultsCompared to the start of SBT, systolic arterial blood pressure and mean arterial blood pressure decreased [from (Mean±SD) 150.33±14.26, 112.56±9.37mmHg to 134.33±11.04, 92.78±5.81mmHg, respectively] in the nitroglycerin group, while the opposite occurred in the control group as systolic arterial blood pressure and mean arterial blood pressure increased [from (Mean±SD) 144.67±13.58, 109.78±10.09mmHg to 158.0±19.43, 114.73±10.82mmHg, respectively]. Mixed central venous saturation (ScvO2) decreased significantly in the control group at the end of SBT [from (Mean±SD) 71.90±1.84 to 69.25±2.20%], while in the nitroglycerin group, ScvO2 did not change at the end in comparison to the start of SBT [from (Mean±SD) 71.63±1.75 to 71.12±1.65%]. Nitroglycerin infusion at the start of SBT enabled a successful weaning from mechanical ventilation in 90% of patients in comparison to a successful weaning from mechanical ventilation of only 63.3% in the control group. ConclusionsNitroglycerin infusion might facilitate the weaning off hypertensive COPD patients by alleviating the cardiovascular compromise occurring during liberation from MV.

Central venous saturation in septic shock: co-oximetry vs gasometry

ObjectivesCentral venous oxygen saturation calculated by gasometry (Gaso-Scvo2) is more available than central venous oxygen saturation measured by co-oximetry (Co-oxy-Scvo2) in environments with less resources and underdeveloped countries. Therefore, we aimed to determine the agreement between Co-oxy-Scvo2 and Gaso-Scvo2 and between central venous oxygen tension measured by gasometry (Gaso-Pcvo2) and Co-oxy-Scvo2, respectively. Design and settingsThis is a prospective study in a university hospital’s intensive care unit. PatientsSixteen patients were studied during the first 48 hours after diagnosis of septic shock. All patients were intubated, connected to mechanical ventilation, and resuscitated according to the standards of care. Measurements and resultsOne hundred eleven pairs of central venous blood measurements were analyzed both by conventional gasometry and co-oximetry. Bland and Altman analysis between Co-oxy-Scvo2 and Gaso-Scvo2 showed lack of agreement (1.7 [−10.7, +14.2]). A Gaso-Scvo2 less than 70% had a positive predictive value of 63% in relation to Co-oxy-Scvo2, and its negative predictive value was 90% with 20% false-positives and 5% false-negatives. The area under the receiver operator characteristic curve of Gaso-Pcvo2 to discriminate a Co-oxy-Scvo2 greater than or equal to 70% was 0.87 (confidence interval, 0.80-0.93), and the best cut-off point was a Gaso-Pcvo2 more than 40 mm Hg, (sensitivity, 75%; specificity, 93%). ConclusionsThe reliability of Gaso-Scvo2 determination during the resuscitation phase of septic shock is not acceptable. There is a good agreement between a Gaso-Pcvo2 more than 40 mm Hg and a Co-oxy-Scvo2 greater than or equal to 70%. Our results suggest that given these limitations, Gaso-Scvo2 results should be interpreted with caution, helped by Gaso-Pcvo2 measurements and in context with other perfusion parameters.

Clinical Utility of Central Venous Saturation for the Calculation of Cardiac Index in Cardiac Patients

BackgroundMixed venous saturation (MVS) obtained from the distal pulmonary artery (PA) during Swan-Ganz catheterization is the criterion standard for calculating cardiac output (CO) and cardiac index (CI) with the use of the Fick method. We think that calculating CI with the use of central venous saturation (CVS) instead of PA-MVS is both feasible and accurate. Earlier studies were small, enrolled heterogeneous patient populations, and resulted in inconsistent findings. MethodsAll patients undergoing right heart catheterization from January 2011 to January 2012 in our catheterization lab with simultaneous measurements of MVS obtained from the distal PA and CVS obtained from the superior vena cava (SVC) or right atrium (RA) were included. Out of the 902 patients enrolled, we excluded patients (n = 50) who had known cardiac shunt or dialysis fistula, had duplicate medical records, or were septic. We calculated the CI with the use of the assumed Fick method using both MVS (criterion standard) and CVS (SVC or RA saturations) in the remaining 852 patients. We measured the correlation and the agreement between the 2 methods with the use of the Pearson correlation coefficient and Bland-Altman analysis. ResultsTotals of 112 patients with simultaneous PA and RA saturation measurements (group I) and 740 patients with simultaneous PA and SVC saturation measurements (group II) were included. We found an excellent linear correlation between SVC and PA saturation (r = 0.928) and between RA and PA saturation (r = 0.95). There was also an excellent correlation between CI calculated with the use of PA saturation and CI calculated with the use of SVC (r = 0.87) or RA (r = 0.93) saturation. The mean bias of CVS-derived CI compared with MVS-derived CI (criterion standard) was −0.1 (95% limits of agreement [LOA] −1 to +0.77) in the SVC group and −0.006 (LOA −0.68 to +0.69) in the RA group. Patients with low CI had stronger correlation and smaller bias between the 2 methods compared with those with normal or high CI. The presence of baseline hypoxemia, valvular heart disease, or acute coronary syndrome had no significant effect on the correlation or the bias between the 2 methods. ConclusionsIn cardiac patients, CVS can be used as a surrogate to true MVS in the calculation of CI. This method is readily available in patients who have central venous access, and may aid in early goal-directed treatment when cardiogenic shock is suspected.

Postresuscitation hemodynamics during therapeutic hypothermia after out-of-hospital cardiac arrest with ventricular fibrillation: A retrospective study

Aims of the studyTo evaluate the incidence of postresuscitation myocardial depression (PRMD) and hemodynamical parameters associated with PRMD in patients treated with therapeutic hypothermia (TH) after out-of-hospital cardiac arrest with ventricular fibrillation (OHCA-VF). MethodsAnalysis of hemodynamical data from computerized clinical databases of two academic ICUs during two year period. We analyzed hemodynamical data from a subgroup of patients with pulmonary artery catheter (PAC). We defined PRMD as a cardiac index (CI) less than 1.5l/(minm2) any time during the first 12h and compared clinical variables and hemodynamical parameters in patients with or without PRMD. ResultsOf 120 included patients PAC monitoring was used in 47 (39%). Of 47, 31 (66%, 95% CI 52% to 80%) developed PRMD. There was no difference in urinary output, lactate, mean arterial or central venous pressures or mixed venous saturation between patients with or without PRMD. Low CI was reversed with dobutamine infusion. Presence or absence PRMD was not associated with 6-month neurological outcome. ConclusionTwo-thirds of the OHCA-VF patients develops transient postresuscitation myocardial depression not easily detected without monitoring of CI during therapeutic hypothermia. Further controlled studies are warranted to evaluate the value of different hemodynamic targets and monitoring after cardiac arrest in terms of outcome.

Diagnostic accuracy of central venous saturation in estimating mixed venous saturation is proportional to cardiac performance among cardiac surgical patients

PurposeAdvanced hemodynamic monitoring in cardiac surgery translates into improvement in outcomes. We evaluated the relationship between central venous (ScvO2) and mixed venous (SvO2) saturations over the early postoperative period. The adequacy of their interchangeability was tested in patients with varying degrees of cardiac performance. MethodsIn this prospective observational study, we evaluated 156 consecutive cardiac surgical patients in an academic center. The ScvO2 and SvO2 data were harvested from 468 paired samples taken preoperatively (T0), after weaning from cardiopulmonary bypass (T1) and on postoperative day 1 (T2). ResultsThe relationship between ScvO2 and SvO2 was inconsistent, with inferior correlations in patients with lower cardiac indices (CI) (Pearson r2 = 0.37 if CI ≤2.0 L/min per square meter vs r2 = 0.73 if CI >2.0 L/min per square meter, both P < .01). Patients with lower CI also had wider 95% limits of agreement between SvO2 and ScvO2. The proportion of patients with a negative SvO2-ScvO2 gradient increased over time (48/156 [31%] at T0 to 73/156 [47%] at T2; P < .01). This subgroup more frequently required inotropes at T2 than patients with a positive SvO2-ScvO2 gradient (odds ratio, 6.46 [95% confidence interval, 0.81-51.87], P = .06) and also had higher serum lactate levels (1.5 ± 0.8 vs 1.0 ± 0.4; P < .01). ConclusionsThe diagnostic accuracy of ScvO2 for estimating SvO2 is proportional to cardiac performance. A negative SvO2-ScvO2 gradient at T2 correlated with inotropic support requirement, higher operative risk score, age, lactate level, and duration of cardiopulmonary bypass.

Noninvasive Optical Quantification of Cerebral Venous Oxygen Saturation in Humans

Cerebral oxygen extraction, defined as the difference between arterial and venous oxygen saturations (SaO2 and SvO2), is a critical parameter for managing intensive care patients at risk for neurological collapse. Although quantification of SaO2 is easily performed with pulse oximetry or moderately invasive arterial blood draws in peripheral vessels, cerebral SvO2 is frequently not monitored because of the invasiveness and risk associated with obtaining jugular bulb or super vena cava (SVC) blood samples. In this study, near-infrared spectroscopy (NIRS) was used to noninvasively measure cerebral SvO2 in anesthetized and mechanically ventilated pediatric patients (n = 10). To quantify SvO2, the NIRS signal component that fluctuates at the respiration frequency is isolated. This respiratory component is dominated by the venous portion of the interrogated vasculature. The NIRS measurements of SvO2 were validated against the clinical gold standard: invasively measured oxygen saturations from SVC blood samples. This technique was also applied in healthy volunteers (n = 5) without mechanical ventilation to illustrate its potential for use in healthy populations with natural airways. Ten pediatric patients with pulmonary hypertension were studied. In these patients, SvO2 in the SVC exhibited good agreement with NIRS-measured SvO2 (R(2) = 0.80, P = .001, slope = 1.16 ± 0.48). Furthermore, in the healthy adult volunteers, mean (standard deviation) NIRS-measured SvO2 was 79.4 (6.8)%. This value is in good agreement with the expected average central venous saturation reported in literature. Respiration frequency-selected NIRS can noninvasively quantify cerebral SvO2. This bedside technique can be used to help assess brain health in neurologically unstable patients.

Correlation between conventional and advanced hemodynamic parameters versus serum lactate in patients with severe sepsis

The aim of this study was to determine the correlation between levels of serum lactate (SL) and conventional hemodynamic parameters (HPs) (mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), urinary output (UP)) in patients with severe sepsis. In a subgroup, advanced HPs (central venous saturation (SvO2), peripheral temperature (PT), cardiac index (CI), global end-diastolic volume index (GEDI) and extravascular lung water (ELWI)) were compared with levels of SL.

The influence of early goal-directed therapy on procalcitonin expression in severe sepsis and septic shock

Objective To evaluate the influence of early goal-directed therapy (EGDT) on procalcitonin expression in severe sepsis and septic shock,and optimize serum procalcitonin as a prognostic indicator of severe sepsis and septic shock.Methods 100 cases of severe sepsis and septic shock were collected from January 2012 to August 2013.All patients were divided into treatment group and control group according to predesigned project,50 cases in each group; these two groups were then subdivided into three groups based on the severity of global tissue hypoxia at enrolled time point,namely severe global tissue hypoxia group [lactate ≥ 4 mmol/L and central venous oxyhemoglobin saturation (ScvO2) ＜ 70％],moderate global tissue hypoxia group (2 mmol/L ≤ lactate ＜ 4.0 mmol/L and ScvO2 ＜ 70％) and resuscitation group/resolved global tissue hypoxia group (lactate ＜ 2 mmol/L and ScvO2 ≥ 70％).Patients' vital signs,ScvO2,CVP,blood lactate and serum procalcitonin were observed and recorded.Conducted acute physiology and chronic health evaluation (APACHE 1) within 24 h after enrollment,nultiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA) 1,2,3,7,14,21 and 28 d after enrollment.Evaluated the correlation between PCT and scores.Results PCT concentration in EGDT group exemplified patients' conditions and prognosis better,with statistically significant difference (P ＜ 0.05).Aggressive fluid resuscitation significantly reduced serum PCT expression in patients with severe sepsis and septic shock (P ＜ 0.01),and improved patients' condition and prognosis.Conclusion Serum procalcitonin is correlated with progress of severe sepsis and septic shock.Aggressive improvement of hemodynamic and oxygen supply (EGDT) can protect patients with severe sepsis and septic shock,and optimize PCT as a prognosis indicator. Key words: Severe sepsis and septic shock; Early goal-directed therapy; PCT