The relationship between perioperative central venous oxygen saturation and postoperative complications in highly invasive gastroenterological surgery.

Purpose: Operations for malignant diseases of the bile duct, pancreas, and esophagus are the most invasive gastroenterological surgeries. The frequency of complications after these surgeries is high, which affects the postoperative course and mortality. In patients who undergo these types of surgeries, continuous monitoring of the perioperative central venous oxygen saturation (ScvO2) is possible via a central venous catheter. We aimed to investigate the relationship between continuously monitored perioperative ScvO2 values and postoperative complications. Methods: The medical records of 115 patients who underwent highly invasive gastroenterological surgeries and ScvO2 monitoring from April 2012 to March 2014 were analyzed. Sixty patients met the inclusion criteria, and their ScvO2 levels were continuously monitored perioperatively. The relationship between ScvO2 levels and major postoperative complications, defined as Clavien-Dindo grade ≥ III, was examined using uni- and multivariate analysis. Results: Thirty patients developed major postoperative complications. The adequate cut-off value derived from receiver operating curves of the postoperative average ScvO2 levels for predicting major complications was 75%. Multivariate analysis revealed that low average postoperative ScvO2 levels (p = 0.016) and blood loss ≥ 1000 mL (p = 0.039) were significant predictors of major postoperative complications. Conclusions: Low perioperative ScvO2 values were associated with an increased risk of major postoperative complications. Continuous ScvO2 monitoring will help prevent postoperative complications.

Venoarterial Partial Pressure of Carbon Dioxide Difference: Let's Trend It!

How to cite this article: Ravisankar NR. Venoarterial Partial Pressure of Carbon Dioxide Difference: Let's Trend It! Indian J Crit Care Med 2024;28(4):323-325.

Prediction of postoperative complications after hepatectomy with dynamic monitoring of central venous oxygen saturation.

BACKGROUND: The usefulness of static monitoring using central venous pressure has been reported for anesthetic management in hepatectomy. It is unclear whether intra-hepatectomy dynamic monitoring can predict the postoperative course. We aimed to investigate the association between intraoperative dynamic monitoring and post-hepatectomy complications. Furthermore, we propose a novel anesthetic management strategy to reduce postoperative complication. METHODS: From 2018 to 2021, 93 patients underwent hepatectomy at our hospital. Fifty-three patients who underwent dynamic monitoring during hepatectomy were enrolled. Flo Trac system was used for dynamic monitoring. The baseline central venous oxygen saturation (ScvO2) was defined as the average ScvO2 for 30 min after anesthesia induction. ScvO2 fluctuation (ΔScvO2) was defined as the difference between the baseline and minimum ScvO2. Postoperative complications were evaluated using the comprehensive complication index (CCI). RESULTS: Patients with ΔScvO2 ≥ 10% had significantly higher CCI scores (0 vs. 20.9: p = 0.043). In univariate analysis, patients with higher CCI scores demonstrated significantly higher preoperative C-reactive protein-to-lymphocyte ratio (7.51 vs. 24.49: p = 0.039), intraoperative bleeding (105 vs. 581 ml: p = 0.008), number of patients with major hepatectomy (4/45 vs. 3/8: p = 0.028), and number of patients with ΔScvO2 ≥ 10% (11/45 vs. 6/8; p = 0.010). Multivariate logistic regression analysis revealed that ΔScvO2 ≥ 10% (odds ratio: 9.53, p = 0.016) was the only independent predictor of elevated CCI. CONCLUSIONS: Central venous oxygen saturation fluctuation during hepatectomy is a predictor of postoperative complications. Anesthetic management based on intraoperative dynamic monitoring and minimizing the change in ScvO2 is a potential strategy for decreasing the risk of post-hepatectomy complications.

A possible role for the venous-to-arterial CO2 difference in cardiogenic shock: an exploratory study. / Estudio exploratorio del rol de la diferencia venoarterial de dióxido de carbono en el shock cardiogénico.

OBJECTIVES: The venous-to-arterial CO2 partial pressure difference (CO2) is a marker of how adequately capillary blood flow is able to remove CO2 from tissues, but evidence regarding its usefulness in patients with cardiogenic shock (CS) is scarce The main objective of this study was to describe the changes in CO2 in patients with cardiogenic shock during the 48 hours after hospital admission. A secondary objective was to analyze the association between CO2 and in-hospital mortality due to cardiovascular disease (CVD) and cardiogenic shock refractory to treatment. MATERIAL AND METHODS: Prospective observational exploratory study in a single hospital. Patients in cardiogenic shock who were admitted to a cardiology critical care unit were included. We measured CO2 on inclusion and 6, 12, 24, and 48 hours after admission to the unit. Variables were explored with logistic regression analysis and areas under the receiver operating characteristic curves were calculated. RESULTS: A total of 50 patients were included. In-hospital mortality due to CVD was 20%. CO2 peaked initially and decreased gradually over the first 48 hours of care. In-hospital mortality tended to be higher in patients with the highest CO2 values, but the difference was not significant. High CO2 values at 24 hours were associated with refractory cardiogenic shock. The negative predictive value of a CO2 value lower than 6 mmHg at 12 hours was 87% for mortality due to CVD. CONCLUSION: This exploratory study suggests that CO2 could be a helpful additional marker to measure when managing cardiogenic shock. CO2 lower than 6 mmHg between 12 and 24 hours after admission may identify patients at low risk of death due to CVD or refractory cardiogenic shock.

OBJETIVO: La diferencia venoarterial de dióxido de carbono (CO2) representa la adecuación del flujo capilar para eliminar CO2 tisular, sin embargo, su evidencia en pacientes con shock cardiogénico (SC) es escasa. El objetivo primario fue caracterizar la cinética de la diferencia venoarterial de CO2 en pacientes con SC durante las primeras 48 horas de ingreso. El objetivo secundario fue analizar la asociación de la CO2 con la mortalidad intrahospitalaria de causa cardiovascular y el SC refractario. METODO: Estudio exploratorio, observacional, prospectivo y unicéntrico. Se incluyeron pacientes en SC ingresados en una unidad de cuidados críticos cardiológicos. Se determinó la CO2 a la inclusión, a las 6, 12, 24 y 48 horas y se realizó un análisis de regresión logística y curvas de la característica operativa del receptor. RESULTADOS: Se incluyeron 50 pacientes. La mortalidad cardiovascular intrahospitalaria fue del 20%. La cinética de la CO2 mostró un pico inicial y un progresivo descenso durante las primeras 48 horas. Los pacientes con valores más altos de CO2 tuvieron una mayor mortalidad cardiovascular intrahospitalaria, pero esta diferencia no fue significativa. A las 24 horas, valores elevados de CO2 se asociaron significativamente con SC refractario. Un valor inferior a 6 mmHg a las 12 horas mostró un valor predictivo negativo del 87% para mortalidad cardiovascular. CONCLUSIONES: Este estudio exploratorio sugiere la potencial utilidad de la CO2 como biomarcador adicional en el manejo del SC. La CO2 permite identificar pacientes con bajo riesgo de mortalidad cardiovascular y SC refractario cuando sus valores son inferiores a 6 mmHg a las 12-24 horas de evolución.

Estudio exploratorio del rol de la diferencia venoarterial de dióxido de carbono en el shock cardiogénico / A possible role for the venous-to-arterial CO2 difference in cardiogenic shock: an exploratory study

Introducción y objetivos: La diferencia venoarterial de dióxido de carbono (ΔCO2) representa la adecuación del flujo capilar para eliminar CO2 tisular, sin embargo, su evidencia en pacientes con shock cardiogénico (SC) es escasa”. El objetivo primario fue caracterizar la cinética de la diferencia venoarterial de ΔCO2 en pacientes con SC durante las primeras 48 horas de ingreso. El objetivo secundario fue analizar la asociación de la ΔCO2 con la mortalidad intrahospitalaria de causa cardiovascular y el SC refractario. Método: Estudio exploratorio, observacional, prospectivo y unicéntrico. Se incluyeron pacientes en SC ingresados en una unidad de cuidados críticos cardiológicos. Se determinó la ΔCO2 a la inclusión, a las 6, 12, 24 y 48 horas y se realizó un análisis de regresión logística y curvas de la característica operativa del receptor. Resultados: Se incluyeron 50 pacientes. La mortalidad cardiovascular intrahospitalaria fue del 20%. La cinética de la ΔCO2 mostró un pico inicial y un progresivo descenso durante las primeras 48 horas. Los pacientes con valores más altos de ΔCO2 tuvieron una mayor mortalidad cardiovascular intrahospitalaria, pero esta diferencia no fue significativa. A las 24 horas, valores elevados de ΔCO2 se asociaron significativamente con SC refractario. Un valor inferior a 6 mmHg a las 12 horas mostró un valor predictivo negativo del 87% para mortalidad cardiovascular. Conclusiones: Este estudio exploratorio sugiere la potencial utilidad de la ΔCO2 como biomarcador adicional en el manejo del SC. La ΔCO2 permite identificar pacientes con bajo riesgo de mortalidad cardiovascular y SC refractario cuando sus valores son inferiores a 6 mmHg a las 12-24 horas de evolución. (AU)

Background and objectives: The venous-to-arterial CO2 partial pressure difference ('CO2) is a marker of how adequately capillary blood flow is able to remove CO2 from tissues, but evidence regarding its usefulness in patients with cardiogenic shock (CS) is scarce The main objective of this study was to describe the changes in 'CO2 in patients with cardiogenic shock during the 48 hours after hospital admission. A secondary objective was to analyze the association between 'CO2 and in-hospital mortality due to cardiovascular disease (CVD) and cardiogenic shock refractory to treatment. Methods: Prospective observational exploratory study in a single hospital. Patients in cardiogenic shock who were admitted to a cardiology critical care unit were included. We measured 'CO2 on inclusion and 6, 12, 24, and 48 hours after admission to the unit. Variables were explored with logistic regression analysis and areas under the receiver operating characteristic curves were calculated. Results: A total of 50 patients were included. In-hospital mortality due to CVD was 20%. 'CO2 peaked initially and decreased gradually over the first 48 hours of care. In-hospital mortality tended to be higher in patients with the highest 'CO2 values, but the difference was not significant. High 'CO2 values at 24 hours were associated with refractory cardiogenic shock. The negative predictive value of a 'CO2 value lower than 6 mmHg at 12 hours was 87% for mortality due to CVD. Conclusions: This exploratory study suggests that 'CO2 could be a helpful additional marker to measure when managing cardiogenic shock. 'CO2 lower than 6 mmHg between 12 and 24 hours after admission may identify patients at low risk of death due to CVD or refractory cardiogenic shock. (AU)

Association between regional oxygen saturation and central venous saturation in pediatric patients undergoing cardiac surgery: A prospective observational study.

BACKGROUND: We evaluated the correlation between regional oxygen saturation (rSO2 ) in the frontal and right renal dorsum (cerebral rSO2 and somatic rSO2 ) measured by near-infrared spectroscopy (INVOS™ 5100C, Medtronic) and central venous oxygen saturation (ScvO2 ) measured with a fiber-optic oximetry catheter (PediaSat™, Edwards Lifesciences) during surgery in order to determine whether noninvasive rSO2 could be used as an alternative to ScvO2 in pediatric cardiac surgery patients. We evaluated the correlation between regional tissue oxygen saturation (cerebral rSO2 and somatic rSO2 ) measured by near-infrared spectroscopy and other patient measures with central venous oxygen saturation (ScvO2 ) measured with a fiber-optic oximetry catheter to track global oxygen supply demand as a potential alternative or supplement to ScvO2 . PATIENTS AND METHODS: This single-center prospective observational study enrolled 33 children (weight < 10 kg) who underwent cardiac surgery for congenital heart disease between February 2018 and November 2021. ScvO2 , cerebral rSO2 , and somatic rSO2 were recorded simultaneously after anesthesia induction and central venous catheter placement. Pearson's correlation coefficient and Bland-Altman analysis were used to determine the relationship between ScvO2 and rSO2 . We conducted correlation, Bland Altman, and multiple regression analyses to identify associations between rSO2 , patient measures, and ScvO2 values. RESULTS: The patients' median age was 11.0 (quartile 2.0-16.0) months. Their weight was 7.2 (quartile 4.5-9.2) kg. Cerebral rSO2 was significantly positively correlated with ScvO2 (r2 = 0.29, p = .002 in all patients; r2 = 0.61, p = .013 in the patients without mixing at the atrial level), whereas somatic rSO2 was not. The Bland-Altman analysis demonstrated biases [95% confidence interval; 95% CI] (lower and upper limits of agreement [95% CI]) of 0.27% [-4.26 to 4.80] (-24.79 [-32.61 to -16.96] to 25.33 [17.50 to 33.16]) between cerebral rSO2 and ScvO2 and 0.91% [-5.48 to 7.30] (-34.43 [-45.47 to -23.39] to 36.25 [25.21 to 47.29]) between somatic rSO2 and ScvO2 . Preoperative brain natriuretic peptide (BNP) and SpO2 were independent variables associated with ScvO2 and cerebral and somatic rSO2 . CONCLUSION: Cerebral rSO2 , SpO2 , and BNP were significantly correlated with ScvO2 , although the cerebral rSO2 correlation was greater for lesions without atrial mixing. rSO2 , BNP, and SpO2 might be used to track changes in ScvO2 but cerebral rSO2 is not sufficiently precise to replace it.

Predictive value of extubation failure by decrease in central venous oxygen saturation: A systematic review and meta-analysis.

Background: The predictive power of extubation failure diagnosed by decrease in central venous oxygen saturation (ΔScvO2) varies by studies. Here we summarized the diagnostic value of extubation failure tested by ΔScvO2. Methods: A comprehensive online search was performed to select potentially eligible studies that evaluated the predictive power of extubation failure tested by ΔScvO2. A manual search was also performed to identify additional studies. Data were extracted to calculate the pooled sensitivity, specificity, positive likelihood ratio (LR), negative LR, diagnostic odds ratio (DOR), and area under the receiver operating characteristic curve (AUC) to evaluate the predictive power of extubation failure. Results: Overall, five studies including 353 patients were included in this review, of whom 105 (30%) were extubation failure. The cutoff values of ΔScvO2 varied across studies, ranging from 3.8% to 5.4%. Heterogeneity between studies was assessed with an overall Q = 0.007, I2 = 0%, and P = 0.498. The pooled sensitivity and specificity for the overall population were 0.83 (95% CI: 0.74-0.90) and 0.88 (95% CI: 0.83-0.92), respectively. The pooled positive LR and negative LR were 7.2 (95%CI: 4.6-11.2) and 0.19 (95%CI: 0.12-0.31), respectively. The DOR was 38 (95% CI: 17-86). Overall, the pooled AUROC was 0.92 (95% CI: 0.90-0.94). Conclusions: The ΔScvO2 performed well in predicting extubation failure in adult mechanical ventilation patients. Further studies with a larger data set and well-designed models are required to confirm the diagnostic accuracy and utility of ScvO2 in predicting extubation outcomes in mechanical ventilation patients.

Interactions between intradialytic central venous oxygen saturation, relative blood volume, and all-cause mortality in maintenance hemodialysis patients.

INTRODUCTION: In maintenance hemodialysis (HD) patients, low central venous oxygen saturation (ScvO2 ) and small decline in relative blood volume (RBV) have been associated with adverse outcomes. Here we explore the joint association between ScvO2 and RBV change in relation to all-cause mortality. METHODS: We conducted a retrospective study in maintenance HD patients with central venous catheters as vascular access. During a 6-month baseline period, Crit-Line (Fresenius Medical Care, Waltham, MA) was used to measure continuously intradialytic ScvO2 and hematocrit-based RBV. We defined four groups per median change of RBV and median ScvO2 . Patients with ScvO2 above median and RBV change below median were defined as reference. Follow-up period was 3 years. We constructed Cox proportional hazards model with adjustment for age, diabetes, and dialysis vintage to assess the association between ScvO2 and RBV and all-cause mortality during follow-up. FINDINGS: Baseline comprised 5231 dialysis sessions in 216 patients. The median RBV change was -5.5% and median ScvO2 was 58.8%. During follow-up, 44 patients (20.4%) died. In the adjusted model, all-cause mortality was highest in patients with ScvO2 below median and RBV change above median (HR 6.32; 95% confidence interval [CI] 1.37-29.06), followed by patients with ScvO2 below median and RBV change below median (HR 5.04; 95% CI 1.14-22.35), and ScvO2 above median and RBV change above median (HR 4.52; 95% CI 0.95-21.36). DISCUSSION: Concurrent combined monitoring of intradialytic ScvO2 and RBV change may provide additional insights into a patient's circulatory status. Patients with low ScvO2 and small changes in RBV may represent a specifically vulnerable group of patients at particularly high risk for adverse outcomes, possibly related to poor cardiac reserve and fluid overload.

Variation in central venous oxygen saturation to evaluate fluid responsiveness: a systematic review and meta-analysis.

BACKGROUND: Since oxygen content and oxygen consumption typically remain unchanged within a short period, variation in central venous oxygen saturation (ΔScvO2) during fluid challenge can theoretically track the changes in cardiac output (CO). We conducted this meta-analysis to systematically assess the diagnostic performance of ΔScvO2 during a fluid challenge for fluid responsiveness in mechanically ventilated patients receiving volume expansion. METHODS: Electronic databases were systematically searched to identify relevant studies published before October 24, 2022. As the cutoff value of ΔScvO2 was expected to vary across the included studies, we estimated the area under the hierarchical summary receiver operating characteristic curve (AUHSROC) as the primary measure of diagnostic accuracy. The optimal threshold of ΔScvO2 and the corresponding 95% confidential interval (CI) were also estimated. RESULTS: This meta-analysis included 5 observational studies comprising 240 participants, of whom 133 (55%) were fluid responders. Overall, the ΔScvO2 during the fluid challenge exhibited excellent performance for defining fluid responsiveness in mechanically ventilated patients receiving volume expansion, with an AUHSROC of 0.86 (95% CI 0.83-0.89), a pooled sensitivity of 0.78 (95% CI 0.69-0.85), a pooled specificity of 0.84 (95% CI 0.72-0.91), and a pooled diagnostic odds ratio of 17.7 (95% CI 5.9-53.2). The distribution of the cutoff values was nearly conically symmetrical and concentered between 3 and 5%; the mean and median cutoff values were 4% (95% CI 3-5%) and 4% (95% CI not estimable), respectively. CONCLUSIONS: In mechanically ventilated patients receiving volume expansion, the ΔScvO2 during the fluid challenge is a reliable indicator of fluid responsiveness. Clinical trial registration PROSPERO, https://www.crd.york.ac.uk/prospero/ , registry number: CRD42022370192.

How to integrate hemodynamic variables during resuscitation of septic shock?

Resuscitation of septic shock is a complex issue because the cardiovascular disturbances that characterize septic shock vary from one patient to another and can also change over time in the same patient. Therefore, different therapies (fluids, vasopressors, and inotropes) should be individually and carefully adapted to provide personalized and adequate treatment. Implementation of this scenario requires the collection and collation of all feasible information, including multiple hemodynamic variables. In this review article, we propose a logical stepwise approach to integrate relevant hemodynamic variables and provide the most appropriate treatment for septic shock.

Prolonged Cardiogenic Shock Due to Hydrogen Sulfide Intoxication Requiring Long-Term Venoarterial Extracorporeal Membrane Support.

We describe a case of severe biventricular failure and cardiovascular collapse following exposure to the manure gas hydrogen sulfide. Initial tests indicated uncoupling of cellular bioenergetics in addition to myocardial damage. Cardiopulmonary support with venoarterial extracorporeal membrane oxygenation was initiated, and the patient could be successfully weaned from support after 28 days. (Level of Difficulty: Advanced.).

Comparing near-infrared spectroscopy-measured cerebral oxygen saturation and corresponding venous oxygen saturations in children with congenital heart disease: a systematic review and meta-analysis.

Background: Near-infrared spectroscopy (NIRS) is a non-invasive approach that measures cerebral regional oxygen saturation (rScO2). In this study, we evaluated the evidence on the validity of NIRS and the interchangeability between NIRS and common invasive approaches by exploring the correlation and consistency and comparing the mean and standard deviation between the NIRS rScO2 and jugular bulb venous oxygen saturation (SjvO2) as well as central venous oxygen saturation (ScvO2) in the perioperative period of children with congenital heart disease (CHD). Methods: We searched electronic bibliographic databases (PubMed, The Cochrane Library and Embase) and screened the studies that met the inclusion criteria. We included cross-sectional studies of CHD pediatric patients in the perioperative period receiving both tests for NIRS rScO2 and SjvO2 or NIRS rScO2 and ScvO2. Methodological quality assessment and heterogeneity analyses were performed. We qualitatively summarized the results of Bland-Altman's analysis. Meta-regression, subgroup analyses, and sensitivity analyses were carried out to explore the causes of heterogeneity. Results: There was no significant difference in Cohen's d between rScO2 and ScvO2 or between rScO2 and SjvO2 (Cohen's d =0.06, 95% CI: -0.16 to 0.28; Cohen's d =0.03, 95% CI: -0.25 to 0.31, respectively) and notable heterogeneity existed (I2=76.0%, P<0.001; I2=73.6%, P<0.001, respectively). A positive linear correlation was present between rScO2 and ScvO2 or between rScO2 and SjvO2 (r=0.58, 95% CI: 0.54 to 0.63; r=0.60, 95% CI: 0.54 to 0.66, respectively) and the heterogeneity was not significant (I2=36.7%, P=0.065; I2=12.7%, P=0.328, respectively). In most studies, the 95% limits of agreements of Bland-Altman's analysis were large. No evidence of publication bias was observed. Conclusions: The rScO2 measured by NIRS reflected the SjvO2 and ScvO2 monitored by invasive measurements in the perioperative period of children with CHD to some extent. However, wide limits of agreements between rScO2 and SjvO2 as well as ScvO2 indicated that NIRS and SjvO2 as well as ScvO2 are not interchangeable. Whether NIRS plays a prominent role in monitoring cerebral oxygen saturation in children with CHD needs further research.

The Use of Transesophageal Doppler and Central Venous Oxygen Saturation as Predictors of Weaning Success.

OBJECTIVES: Weaning individuals from mechanical ventilation (MV) is a challenge to physicians. Respiratory failure is the main reason for weaning failure (WF), but heart failure plays a pivotal role as well. Transesophageal Doppler (TED) is a minimally invasive method of hemodynamic tracking with fewer problems. The study authors evaluated the role of TED in predicting WF. DESIGN: An observational study. SETTING: A university teaching hospital. PARTICIPANTS: Weaning individuals. INTERVENTIONS: TED was applied before initiating the spontaneous breathing trial (SBT). Hemodynamic parameters, arterial blood gases, and TED (peak velocity [PV], cardiac output [COP]) were reported while cases were on MV before initiating the SBT, and at the successful completion of SBT. Succeeded (group S) and failed individuals (group F, who needed reintubation within 48 hours) were compared. The sensitivity, specificity, and area under the receiver operating curve were calculated. A subgroup of patients with cardiac comorbidities and impaired cardiac contractility was further analyzed. MEASUREMENTS AND MAIN RESULTS: The authors included 39 critically ill patients for weaning from MV. The reintubation rate was 54.8%. In patients with cardiac morbidity, delta change (dC) in PV and COP as predictors of WF showed 100% sensitivity and specificity, with 18% and 14% cut-offs after initiating the SBT (dC between the beginning and end of the successful SBT), respectively. Central venous oxygen saturation revealed a significant difference between patients with cardiac morbidity and noncardiac patients with lower sensitivity and specificity in the prediction of WF. CONCLUSIONS: TED could be a helpful method for the weaning of patients with cardiac morbidity from MV. The dC in PV and COP >18% and >14% were significant predictors of WF in these subjects, respectively.

Prolonged Capillary Refilling as a Predictor of Mortality in Patients With Septic Shock.

INTRODUCTION: Microcirculatory alterations characterize septic shock; increased blood lactate level has been described as markers of microcirculation alteration in patients with septic shock. Although useful, this serological analysis is not always feasible in all settings worldwide. OBJECTIVE: To determine if a prolonged capillary refilling is a predictor of mortality in patients with septic shock. METHODOLOGY: A 10-months prospective cohort study was carried out on 175 patients admitted to the Intensive Care Unit (ICU) with the diagnosis of septic shock. The capillary refilling time (CRT) was evaluated Immediately upon admission and after 6 hours post-resuscitation. Traditional tissue perfusion markers were also used to compare and analyze their predictive value on mortality at 28 days. RESULTS: The area under the ROC curve (AUC) to estimate mortality in patients with septic shock with CRT at admission was 0.666 (0.584-0.748), while at 6 hours was 0.819 (0.753-0.885), with a cut-off point of 4.5 seconds at admission (PPV 52.87% NPV 72.73%) and 3.5 sec at 6 hours (PPV 95.56% NPV 79.23%). In those with CRT > 3.5 seconds at 6 hours, they had a RR of 4.60, while a CRT > 4.5 seconds at admission had a RR of 1.94, with a non-survivor proportion of 95.56% for a CRT > 3.5 sec at 6 hours vs 20.77% for CRT ≤ 3.5 sec (P value < 0.001). The CRT at 6 hours showed significant differences in the survival curves with P-value < 0.001, where for values > 3.5 sec, survival at 28 days was 4.44% vs 79.20% for values ≤ 3.5 sec. CONCLUSION: CRT is a strong predictor of mortality in patients with septic shock. Evaluating changes in CRT during resuscitation from septic shock might be used as an important clinical tool to predict mortality; especially in low-resources settings where using other biomarkers might be sometimes difficult.

Accuracy, Precision, and Trending Ability of Perioperative Central Venous Oxygen Saturation Compared to Mixed Venous Oxygen Saturation in Unselected Cardiac Surgical Patients.

OBJECTIVE: To determine whether central venous oxygen saturation (ScvO2) measurements could be used interchangeably with mixed venous oxygen saturation (SvO2) measurements in adult cardiac surgery patients. DESIGN: A single-center prospective observational study. SETTING: A university hospital. PARTICIPANTS: Eighty-five adult patients undergoing cardiac surgery. INTERVENTIONS: The study authors compared the oxygen saturations in 590 pairs of venous blood samples drawn from the pulmonary artery catheter (PAC) at three different time points during surgery and four different time points in the intensive care unit. They compared samples obtained from the distal pulmonary artery line (SvO2) to those drawn from the proximal central venous line of the PAC (ScvO2) with the Bland-Altman test and the four-quadrant method. MEASUREMENTS AND MAIN RESULTS: The mean bias between SvO2 and ScvO2 was -1.9 (95% confidence interval [CI], -2.3 to -1.5) and the limits of agreement (LOA) were -11.5 to 7.6 (95% CI, -12.5 to -10.7 and 6.8-8.5, respectively). The percentage error (PE) was 13.2%. Based on the four-quadrant plot, only 50% of the measurement pairs were in agreement, indicating deficient trending ability. CONCLUSION: ScvO2 values showed acceptable accuracy as the mean bias was low. The precision was inadequate; although the PE was acceptable, the LOA were wide. Trending ability was inadequate. The authors cannot recommend the use of ScvO2 values interchangeably with SvO2 measurements in the management of adult cardiac surgery patients.

Individualised or liberal red blood cell transfusion after cardiac surgery: a randomised controlled trial.

BACKGROUND: Current practice guidelines for red blood cell (RBC) transfusion in ICUs are based on haemoglobin threshold, without consideration of oxygen delivery or consumption. We aimed to evaluate an individual physiological threshold-guided by central venous oxygen saturation ScvO2. METHODS: In a randomised study in two French academic hospitals, 164 patients who were admitted to ICU after cardiac surgery with postoperative haemoglobin <9 g dl-1 were randomised to receive a transfusion with one unit of RBCs (haemoglobin group) or transfusion only if the ScvO2 was <70% (individualised group). The primary outcome was the number of subjects receiving at least one unit of RBCs. The secondary composite outcome was acute kidney injury, stroke, myocardial infarction, acute heart failure, mesenteric ischaemia, or in-hospital mortality. One- and 6-month mortality were evaluated during follow-up. RESULTS: The primary outcome was observed for 80 of 80 subjects (100%) in the haemoglobin group and in 61 of 77 patients (79%) in the individualised group (absolute risk -21% [-32.0; -14.0]; P<0.001). There was no significant difference in the secondary outcome between the two groups. Follow-up showed a non-significant difference in mortality at 1 and 6 months. CONCLUSIONS: An individualised strategy based on an central venous oxygen saturation threshold of 70% allows for a more restrictive red blood cell transfusion strategy with no incidence on postoperative morbidity or 6-month mortality. CLINICAL TRIAL REGISTRATION: NCT02963883.

Oxygen Extraction and Mortality in Patients Undergoing Chronic Haemodialysis Treatment: A Multicentre Study.

Patients on haemodialysis (HD) suffer a high mortality rate linked to developing subclinical hypoxic parenchymal stress during HD sessions. The oxygen extraction ratio (OER), an estimate of the oxygen claimed by peripheral tissues, might represent a new prognostic factor in HD patients. This study evaluated whether the intradialytic change in OER (ΔOER) identified patients with higher mortality risks. We enrolled chronic HD patients with permanent central venous catheters with available central venous oxygen saturation (ScvO2) measurements; the arterial oxygen saturation was measured with peripheral oximeters (SpO2). We measured OER before and after HD at enrolment; deaths were recorded during two-years of follow-up. In 101 patients (age: 72.9 ± 13.6 years, HD vintage: 9.6 ± 16.6 years), 44 deaths were recorded during 11.6 ± 7.5 months of follow-up. Patients were divided into two groups according to a 40% ΔOER threshold (ΔOER < 40%, n = 56; ΔOER ≥ 40%, n = 45). The ΔOER ≥ 40% group showed a higher incidence of death (60% vs. 30%; p = 0.005). The survival curve (log-rank-test: p = 0.0001) and multivariate analysis (p = 0.0002) confirmed a ΔOER ≥ 40% as a mortality risk factor. This study showed the intradialytic ΔOER ≥ 40% was a mortality risk factor able to highlight critical hypoxic damage. Using a ΔOER ≥ 40% could be clinically applicable to characterise the most fragile patients.

The predictive value of lung ultrasound combined with central venous oxygen saturation variations in the outcome of ventilator weaning in patients after thoracic surgery.

OBJECTIVE: To evaluate the predictive value of lung ultrasound score (LUS) combined with central venous oxygen saturation variations (ΔScvO2) in the outcome of ventilator weaning in patients after thoracic surgery. METHODS: The clinical data of 60 patients who received tracheal intubation ventilator-assisted breathing after thoracic surgery were retrospectively analyzed, and they were divided into successful (n = 35) and failed (n = 25) groups according to the postoperative weaning outcomes. The factors influencing the failure of weaning in patients after thoracic surgery were compared and analyzed, and the values of LUS, ΔScvO2 as well as the combination of both were calculated to predict the failure of weaning in patients after thoracic surgery. RESULTS: The results of logistic regression analysis showed that LUS, ΔScvO2, and partial pressure of carbon dioxide (PaCO2) may be risk factors influencing weaning failure in patients after thoracic surgery (OR = 1.844, 4.006, 1.271, P < 0.001 for all), while diaphragm thickening fraction (DTF) and partial pressure of oxygen (PaO2) may be protective factors (OR = 0.852, 0.674, P = 0.002 for all). Receiver operator characteristic (ROC) curve showed that area under the curves (AUCs) of LUS, ΔScvO2, and the combination of the two was 0.865 (95% CI: 0.766-0.964), 0.874 (95% CI: 0.781-0.967), and 0.925 (95% CI: 0.860-0.990), respectively, in predicting failure of weaning in patients after thoracic surgery. CONCLUSION: LUS and ΔScvO2 were closely related to chest ultrasound index and arterial blood gas index in patients after thoracic surgery, both of which may be risk factors for weaning failure in patients after thoracic surgery, and their combination can effectively predict the occurrence of weaning failure.