Isolated High Lactate or Low Central Venous Oxygen Saturation After Cardiac Surgery and Association With Outcome

Impact of postoperative hyperlactatemia in orthotopic heart transplantation

BACKGROUND

Hyperlactatemia (HL) is a common phenomenon after cardiac surgery which is related to tissue hypoperfusion and hypoxia and associated with poor outcomes. It is also often seen in the postoperative period after orthotopic heart transplantation (OHTx), but the association between HL and outcomes after OHTx is not well known. We evaluated the incidence and outcome of HL after OHTx.

METHODS

This was a retrospective study of 209 patients who underwent OHTx between January 2011 and December 2020. Patients were classified into 3 groups according to their peak lactate levels within the first 72 h postoperatively: group 1, normal to mild hyperlactatemia (<5 mmol/L, n = 42); group 2, moderate hyperlactatemia (5-10 mmol/L, n = 110); and group 3, severe hyperlactatemia (>10 mmol/L, n = 57). The primary composite endpoint was all-cause mortality or postoperative initiation of veno-arterial extracorporeal membrane oxygenation (VA ECMO) within 30 days. Secondary endpoints included duration of mechanical ventilation, intensive care unit length of stay, and hospital length of stay.

RESULTS

Patients with higher postoperative peak lactate levels were more commonly transplanted from left ventricular assist device support (33.3 % vs 50.9 % vs 64.9, p < 0.01) and had longer cardiopulmonary bypass time [127 min (109-148) vs 141 min (116-186) vs 153 min (127-182), p = 0.02]. Composite primary endpoint was met in 18 patients (8.6 %) and was significantly more common in patients with higher postoperative peak lactate levels (0.0 % vs 6.4 % vs 19.3 %, p < 0.01).

CONCLUSIONS

Severe hyperlactatemia following orthotopic heart transplant was associated with an increased risk of post-transplant VA ECMO initiation and mortality at 30 days.

Survey on the Updated German S3 Guideline for Intensive Care in Cardiac Surgery Patients

BACKGROUND

The German guideline on intensive care treatment of cardiac surgical patients provides evidence-based recommendations on management and monitoring. It remains unclear if, respectively, to which degree the guidelines are implemented into the daily practice. Therefore, this study aims to characterize the implementation of guideline recommendations in German cardiac surgical intensive care units (ICUs).

METHODS

An internet-based online survey (42 questions, 9 topics) was sent to 158 German head physicians of cardiac surgical ICUs. To compare the effect over time, most questions were based on a previously performed survey (2013) after introduction of the last guideline update in 2008.

RESULTS

A total of n = 65 (41.1%) questionnaires were included. Monitoring changed to increased provision of available transesophageal echocardiography specialists in 86% (2013: 72.6%), SvO2 measurement in 93.8% (2013: 55.1%), and electroencephalography in 58.5% (2013: 2.6%). The use of hydroxyethyl starch declined (9.4% vs. 2013: 38.7%), gelatin 4% presented the most administered colloid with 23.4% (2013: 17.4%). Low cardiac output syndrome was primarily treated with levosimendan (30.8%) and epinephrine (23.1%), while norepinephrine (44.6%) and dobutamine (16.9%) represented the most favored drug combination. The main way of distribution was web-based (50.9%), with increasing impact on therapy regimens (36.9% vs. 2013: 24%).

CONCLUSION

Changes were found in all questioned sectors compared with the preceding survey, with persisting variability between ICUs. Recommendations of the updated guideline have increasingly entered clinical practice, with participants valuing the updated publication as clinically relevant.

Association between intraoperative hyperglycemia/hyperlactatemia and acute kidney injury following on-pump cardiac surgery: a retrospective cohort study

Background

Despite the long-lasting notion about the substantial contribution of intraoperative un-stabilization of homeostasis factors on the incidence on acute kidney injury (AKI), the possible influence of intraoperative glucose or lactate management, as a modifiable factor, on the development of AKI remains inconclusive.

Objectives

To investigated the relationship between intraoperative hyperglycemia, hyperlactatemia, and postoperative AKI in cardiac surgery.

Methods

A retrospective cohort study was conducted among 4,435 adult patients who underwent on-pump cardiac surgery from July 2019 to March 2022. Intraoperative hyperglycemia and hyperlactatemia were defined as blood glucose levels >10 mmol/L and lactate levels >2 mmol/L, respectively. The primary outcome was the incidence of AKI. All statistical analyses, including t tests, Wilcoxon rank sum tests, chi-square tests, Fisher's exact test, Kolmogorov-Smirnov test, logistic regression models, subgroup analyses, collinearity analysis, and receiver operating characteristic analysis, were performed using the statistical software program R version 4.1.1.

Results

Among the 4,435 patients in the final analysis, a total of 734 (16.55%) patients developed AKI after on-pump cardiac surgery. All studied intraoperative metabolic disorders was associated with increased AKI risk, with most pronounced odds ratio (OR) noted for both hyperglycemia and hyperlactatemia were present intraoperatively [adjusted OR 3.69, 95% confidence intervals (CI) 2.68-5.13, p < 0.001]. Even when hyperglycemia or hyperlactatemia was present alone, the risk of postoperative AKI remained elevated (adjusted OR 1.97, 95% CI 1.50-2.60, p < 0.001).

Conclusion

The presence of intraoperative hyperglycemia and hyperlactatemia may be associated with postoperative acute kidney injury (AKI) in patients undergoing on-pump cardiac surgery. Proper and timely interventions for these metabolic disorders are crucially important in mitigating the risk of AKI.

Correlation of venous to arterial carbon dioxide partial pressure difference with other cardiac output indices in patients undergoing intracardiac repair for tetralogy of fallot

Background

Clearance of tissue carbon dioxide by circulation is measured by venous to arterial carbon dioxide partial pressure difference (AVCO2) and is correlated with cardiac output (CO) in critically ill adult patients. This study aimed to correlate AVCO2 with other CO indices like arteriovenous oxygen saturation difference (AVO2), central venous oxygen saturation (ScVO2), and serum lactate in pediatric patients undergoing intracardiac repair (ICR) for tetralogy of Fallot (TOF).

Methods

We conducted a prospective observational study in 50 patients, of age 5 months to 5 years, undergoing ICR for TOF and analyzed AVO2, AVCO2, ScVO2, and lactate from arterial and venous blood gas pairs obtained at different time intervals from admission to pediatric intensive care unit (PICU) (T0), at 6 h (T1), 12 h (T2), 24 h (T3), and 48 h (T4) postoperatively. Bivariate correlations were analyzed using Pearson for parametric variables.

Results

Admission AVCO2 was not correlated with AVO2 (R2 = 0.166, P = 0.246), ScVO2 (R2 = -2.2, P = 0.124), and lactate (R2 = -0.07, P = 0.624). At T1, AVCO2 was correlated with AVO2 (R2 = 0.283, P = 0.0464) but not with ScVO2 (R2 = - 0.25, P = 0.079) and lactate (R2 = -0.07, P = 0.623). At T2, T3 and T4, AVCO2 was correlated with AVO2 (R2 = 0.338,0.440 & 0.318, P = 0.0162, 0.0013, and 0.024), ScVO2 (R2 = - 0.344, - 0.488, and -0.366; P = 0.0143, <0.0001, and 0.017), and lactate (R2 = 0.305, 0.467 and 0.607; P = 0.0314, 0.00062 and <0.0001). AVCO2 was negatively correlated with ScVO2. No correlation observed between admission AVCO2 and mechanical ventilation duration. Two nonsurvivors had higher value of admission AVCO2 compared to survivors.

Conclusion

AVCO2 is correlated with other CO surrogates like AVO2, ScVO2, and lactate in pediatric patients undergoing ICR for TOF.

The Association Between Hypophosphatemia and Lactic Acidosis After Cardiac Surgery With Cardiopulmonary Bypass: A Retrospective Cohort Study

OBJECTIVES

The clinical significance of hypophosphatemia in cardiac surgery has not been investigated extensively. The aim of this study was to evaluate the association of postoperative hypophosphatemia and lactic acidosis in cardiac surgery patients at the time of intensive care unit (ICU) admission.

DESIGN

A retrospective cohort study.

SETTING

At a single academic center.

PARTICIPANTS

Patients who underwent nontransplant cardiac surgery with cardiopulmonary bypass between August 2009 and December 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum phosphate and lactate levels were measured upon ICU admission in patients undergoing nontransplant cardiac surgery with cardiopulmonary bypass. There were 681 patients in the low-phosphate (<2.5 mg/dL) group and 2,579 patients in the normal phosphate group (2.5-4.5 mg/dL). A higher proportion of patients in the low phosphate group (26%; 179 of 681; 95% CI: 23-30) had severe lactic acidosis compared to patients in the normal phosphate group (16%; 417 of 2,579; 95% CI: 15-18). In an unadjusted logistic regression model, patients in the low phosphate group had 1.9-times the odds of having severe lactic acidosis (serum lactate ≥4.0 mmol/L) when compared to patients in the normal phosphate group (95% CI: 1.5-2.3), and still 1.4-times the odds (95% CI: 1.1-1.7) after adjusting for several possible confounders.

CONCLUSIONS

Hypophosphatemia is associated with lactic acidosis in the immediate postoperative period in cardiac surgery patients. Future studies will need to investigate it as a potential treatment target for lactic acidosis.

Risk factors of postoperative neurodevelopmental abnormalities in neonates with critical congenital heart disease

OBJECTIVES

To investigate the risk factors of postoperative neuro-developmental abnormalities in neonates with critical congenital heart disease (CCHD).

METHODS

Clinical data of 50 neonates with CCHD admitted in the Cardiac Intensive Care Unit, The Children's Hospital, Zhejiang University School of Medicine from November 2020 to December 2021 were retrospectively analyzed. Neurological assessment was performed with cranial ultrasonography, CT/MRI, video electroencephalogram and clinical symptoms before and after surgical treatment for all patients, and neurodevelopmental abnormalities were documented. Binary logistic stepwise regression was used to analyze risk factors of postoperative new-onset neurodysplasia in children with CCHD, and the predictive value of the risk factors on postoperative neurodevelopmental abnormalities were evaluated using the receiver operating characteristic (ROC) curve.

RESULTS

Neurodevelopmental abnormalities were detected in 22 cases (44.0%) and not detected in 28 cases (56.0%) before surgery. There were no significant differences in gender, birth weight, age at admission, gestational age, preoperative SpO2 level, prematurity, cyanotic congenital heart disease, and ventilator support between the two groups (all P>0.05). After surgery, there were 22 cases (44.0%) with new-onset neurological abnormalities and 28 cases (56.0%) without new-onset abnormalities. Multivariate logistic regression analysis showed that postoperative 24 h peak lactic acid (OR=1.537, 95%CI: 1.170-2.018, P<0.01) and postoperative length of ICU stay (OR=1.172, 95%CI:1.031-1.333, P<0.05) were independent risk factors for postoperative new-onset neurodevelopmental abnormalities. The area under ROC curve (AUC) of the postoperative 24 h peak lactic acid for predicting the new-onset neurological abnormalities after operation was 0.829, with cut-off value of 4.95 mmol/L. The diagnostic sensitivity and specificity were 90.0% and 64.3%, respectively. The AUC of postoperative length of ICU stay for predicting the new-onset neurological abnormalities after operation was 0.712, with cut-off value of 18.0 d. The diagnostic sensitivity and specificity were 50.0% and 96.4%, respectively. The AUC of the combination of the two indicators was 0.917, the diagnostic sensitivity and specificity were 95.5% and 64.3%, respectively.

CONCLUSIONS

The incidence of neurodysplasia in neonatal CCHD is high, and new neurological abnormalities may occur after surgery. The postoperative 24 h peak lactic acid and postoperative length of ICU stay are risk factors for new-onset neurodysplasia after surgery. The combination of the two indicators has good predictive value for neurodevelopmental outcomes after surgery in CCHD infants.

Prolonged Mechanical Ventilation Following Coronary Artery Bypass Graft in Santiago De Cali, Colombia

Purpose

The purpose of this study was to describe factors associated with prolonged ventilatory support in subjects undergoing coronary artery bypass graft.

Patients and Methods

This was an analytical retrospective case-control study. Cases were defined as subjects requiring prolonged mechanical ventilation (>48 hours) following isolated coronary artery bypass graft. Subjects older than 18 years who had undergone surgery were included, while subjects with missing clinical record data, subjects in coma or subjects with prior cardiac surgery were excluded. Variables were measured at the three time points surrounding surgery.

Results

A total of 204 cases and 408 controls were included. The final logistic model showed an association between prolonged mechanical ventilation and the following presurgical variables: chronic obstructive pulmonary disease (OR 1.85; 95% CI: 1.06-3.23, p = 0.03) and chronic kidney disease (OR 1.90; 95% CI: -3.31; p = 0.02). The associated transurgical variable was the use of intra-aortic balloon pump (OR 3.63; 95% CI: 1.73-7.61, p = 0.00), and associated postsurgical variables were venous oxygen saturation <60% (OR 2.00; 95% CI: 1.18-3.40, p = 0.01), mediastinitis (OR 18.51; 95% CI: 4.06-84.40, p = 0.00), inotrope use (OR 2.82; 95% CI: 1.77-4.48, p = 0.00), pleural effusion requiring drainage (OR 3.57; 95% CI: 2.02-6.32, p = 0.00) and delirium (OR 3.45; 95% CI: 1.91-6.25, p = 0.00).

Conclusion

This study identifies factors associated with prolonged mechanical ventilation in subjects subject to coronary artery bypass graft over the presurgical, transurgical and postsurgical periods, identifying a new factor, delirium, for this type of population.

Does severe hyperlactatemia during cardiopulmonary bypass predict a worse outcome?

INTRODUCTION

The aim of the current study was to evaluate the impact of increased blood lactate levels during cardiopulmonary bypass (CPB) on immediate results in patients who underwent open heart surgery.

MATERIALS AND METHODS

We performed a retrospective single-center study on 1290 patients. Adult cardiac surgical patients who underwent valve surgery, coronary artery bypass graft, combined procedure, adult congenital anomalies and aortic surgery were enrolled. Patients with associated comorbidities such as liver dysfunction, hemodynamic instability before surgery were excluded. Arterial blood lactate concentration was measured immediately after weaning from CPB and evaluated together with clinical data and outcomes including in hospital mortality. Patients were classified into 3 groups according to their peak arterial lactate level: group I [normal lactatemia, lactate ˂ 2 mmol/l (n = 749)], group II [mild hyperlactatemia, lactate 2-5 mmol/l (n = 489)], group III [severe hyperlactatemia, lactate ˃ 5 mmol/l (n = 52)].

RESULTS

When comparing outcomes across the 3 groups, severe hyperlactatemia was correlated with worse outcomes including higher in-hospital mortality, low output cardiac syndrome, postoperative renal insufficiency, myocardial infarction, red blood cell transfusion (RBC) transfusion, prolonged mechanical ventilation and longer intensive care unit (ICU) stay hours.

CONCLUSION

Blood lactate level above 5 mmol/l and more during CPB is associated with higher in-hospital mortality rate and postoperative complications. More attention must be given to correct the common abnormalities conditions inherent of CPB in order to conduct adequate tissue perfusion and reduce the risk of hyperlactatemia.

[S3-Guideline Intensive Care Therapy of Cardiac Surgery Patients - a Practical Approach]

The current S3-Guideline for intensive care therapy in patients after cardiac surgery provides a wealth of information and recommendations ranging from monitoring to treatment options for various perioperative clinical situations. This article focuses on the most relevant information applicable to every-day critical care practice, covering important aspects of general and advanced monitoring, goal directed hemodynamic therapy and treatment principles for perioperative left and right heart failure.

Hyperlactatemia of dialysis-dependent patients after cardiac surgery impacts on in-hospital mortality: a two-center retrospective study

Background

Lactate is a well-known marker to estimate prognosis after cardiac surgery and critically ill patients. The liver and kidney have a major role in lactate metabolism; however, there was less characterized about the change of lactate and threshold to predict in-hospital mortality in dialysis-dependent patients undertaking cardiac surgery. We conducted this retrospective observational study to characterize when and how lactate values after cardiac surgery affected in-hospital mortality.

Methods

This two-center retrospective study included dialysis-dependent patients who underwent cardiac surgery with a cardiopulmonary bypass from January 2014 to December 2018. Lactate values were collected at three points: at ICU admission (T1), the maximum level of lactate within 24 h postoperatively (T2), and 24 h after ICU admission (T3). We determined hyperlactatemia as more than 2 mmol/L following previous studies.

Results

We enrolled 122 dialysis-dependent patients. The mean age was 73 ± 8 years and hyperlactatemia was observed in 100 patients (81.9%). In-hospital mortality was 11.4%. Univariate analysis and area under curve in ROC suggested that T2 lactate was the most significantly associated with in-hospital mortality (AUC = 0.845). Multivariate logistic analysis showed a significant association between in-hospital mortality when patients showed early peak lactate levels of > 4.5 mmol/L after ICU admission (adjusted OR 8.35; 95% CI: 1.44–57.13).

Conclusions

In dialysis-dependent patients after cardiac surgery, the early-onset of a maximum arterial lactate concentration of > 4.5 mmol/L was significantly associated with in-hospital mortality.

Prospective, observational study of carbon dioxide gaps and free energy change and their association with fluid therapy following cardiac surgery

Background Venoarterial carbon dioxide pressure (p_v-a CO₂ ) and content (C_v-a CO₂ ) differences, including the ratio to arteriovenous oxygen content difference (C_a-v O₂ ), and free energy changes (-∆∆G_a-v ) may reflect tissue hypoperfusion. The associations with changes in cardiac output (CO) or oxygen consumption (VO₂ ) following fluid bolus administration were investigated. Methods Single-centre, observational study of 89 adult post-operative cardiac surgical patients admitted to ICU. The p_v-a CO₂ , C_v-a CO₂ and their ratios to C_a-v O₂ as well as the -∆∆G_a-v were determined before and after a 250-500 mL fluid bolus using arterial, central venous and mixed venous blood gas analyses. Responses associated with changes ≥ or <15% in CO or oxygen consumption (VO₂ ) were compared. Results In 234 boluses, the mixed venous to arterial p_v-a CO₂ and its ratio to C_a-v O₂ were independently associated with an increase in CO; odds ratio 1.3 (95% CI 1.1-1.5) and 1.7 (95% CI 1.5-1.9) respectively, P < .001) and VO₂ ; odds ratio 2.1 (95% CI 1.3-3.1), P < .001 for C_a-v O₂ . No measures of p_v-a CO₂ , C_v-a CO₂ or related ratios to the C_a-v O₂ were associated with an increase in CO ≥15% following a single volume bolus. The mixed venous and central venous C_v-a CO₂ to C_a-v O₂ ratios were different for the first bolus episode only; mean differences 0.81 (95% CI 0.13-1.5), P = .02 and 0.44 (95% CI 0.06-0.82), P = .02, respectively, for increased VO₂  ≥ 15%. The -∆∆G_a-v did not change. Conclusion The venoarterial carbon dioxide gradients and related calculations to assess the adequacy of tissue perfusion before a fluid bolus were not associated with subsequent increases in CO of oxygen consumption. Editorial Comment In some shock conditions, regional tissue hypoperfusion can be obvious and arterio-venous differences for CO₂ or O₂ may reflect this. This is not always the case; sometimes there are A-V differences or even a high lactate level without any obvious regional tissue hypoperfusion. Fluid therapy is a cornerstone in shock resuscitation treatment, but determining optimal fluid therapy is challenging, particularly as fluid overload may be detrimental. Fluid challenges are used as an "ex juvantebus" method to dose fluid therapy, but it is not clear if a positive response reflects a state of hypoperfusion or the existence of a cardiac reserve. Still, a better understanding on how to target and guide fluid therapy is welcome, and studies digging into the problem are needed. Here, invasively monitored post-operative cardiac surgery patients are assessed as a model to investigate if carbon dioxide gaps and free energy charge may be useful in detecting possible tissue hypoperfusion.

Central and Mixed Venous O2 Saturation

Mixed and central venous oxygen saturations are commonly used to ascertain the degree of systemic oxygenation in critically ill patients. This review examines the physiological basis for the use of these variables to determine systemic extraction ration, oxygen consumption and tissue oxygenation, and also understand the role they may play in the early treatment of septic individuals.

Thermodilution vs estimated Fick cardiac output measurement in an elderly cohort of patients: A single-centre experience

Aims

Patients referred to the cath-lab are an increasingly elderly population. Thermodilution (TD, gold standard) and the estimated Fick method (eFM) are interchangeably used in the clinical routine to measure cardiac output (CO). However, their correlation in an elderly cohort of cardiac patients has not been tested so far.

Methods

A single, clinically-indicated right heart catheterization was performed on each patient with CO estimated by eFM and TD in 155 consecutive patients (75.1±6.8 years, 57.7% male) between April 2015 and August 2017. Whole Body Oxygen Consumption (VO2) was assumed by applying the formulas of LaFarge (LaF), Dehmer (De) and Bergstra (Be). CO was indexed to body surface area (Cardiac Index, CI).

Results

CI-TD showed an overall moderate correlation to CI-eFM as assessed by LaF, De or Be (r² = 0.53, r² = 0.54, r² = 0.57, all p < .001, respectively) with large limits of agreement (-0.64 to 1.09, -1.07 to 0.77, -1.38 to 0.53 l/m²/min, respectively). The mean difference of CI between methods was 0.22, -0.15 and -0.42 (all p<0.001 for difference to TD), respectively. A rate of error ≥20% occurred with the equations by LaF, De or Be in 40.6%, 26.5% and 36.1% of patients, respectively. A CI <2.2 l/m²min was present in 42.6% of patients according to TD and in 60.0%, 31.0% and in 16.1% of patients according to eFM by the formulas of LaF, De or Be.

Conclusion

Although CI-eFM shows an overall reasonable correlation with CI-TD, the predictive value in a single patient is low. CI-eFM cannot replace CI-TD in elderly patients.

High positive end expiratory pressure levels affect hemodynamics in elderly patients with hypertension admitted to the intensive care unit: a prospective cohort study

Background

To study the effects of different positive end expiratory pressure (PEEP) on blood pressure and heart function in elderly patients with hypertension.

Methods

Forty elderly patients above 65 years of age treated with mechanical ventilation were divided into two groups: a control group of non-hypertensive subjects (n = 18) and a hypertension group (n = 22) patients with essential hypertension. Changes in blood pressure, central venous pressure (CVP), central venous oxygen saturation (ScvO₂), heart rate, and airway pressure were determined in response to different selected PEEP levels of 0, 2, 4, 6, 8, 10 and 12 cm H₂O under SIMV(PC) + PSV mode throughout the study.

Results

In both groups, the increase in PEEP led to an increase in CVP and airway pressure. When PEEP was above 4 cm H₂O in the hypertension group, a decrease in blood pressure and ScvO₂, and an increase of heart rate were observed. These results indicated that cardiac output significantly decreased.

Conclusion

High levels of PEEP can significantly influence changes in blood pressure and heart function in elderly patients with hypertension.

Trial registration

This trial was retrospectively registered, The Chinese trial registration number is ChiCTR-ROC-17012873. The date of registration is 10-2-2017.

[S3 guidelines on intensive medical care of cardiac surgery patients : Hemodynamic monitoring and cardiovascular system-an update]

An update of the S3- guidelines for treatment of cardiac surgery patients in the intensive care unit, hemodynamic monitoring and cardiovascular system was published by the Association of Scientific Medical Societies in Germany (AWMF) in January 2018. This publication updates the guidelines from 2006 and 2011. The guidelines include nine sections that in addition to different methods of hemodynamic monitoring also reviews the topic of volume therapy as well as vasoactive and inotropic drugs. Furthermore, the guidelines also define the goals for cardiovascular treatment. This article describes the most important innovations of these comprehensive guidelines.

Skin perfusion pressure as an indicator of tissue perfusion in valvular heart surgery: Preliminary results from a prospective, observational study

Hemodynamic management aims to provide adequate tissue perfusion, which is often altered during cardiac surgery with cardiopulmonary bypass (CPB). We evaluated whether skin perfusion pressure (SPP) can be used for monitoring of adequacy of tissue perfusion in patients undergoing valvular heart surgery. Seventy-two patients undergoing valve replacement were enrolled. SPP and serum lactate level were assessed after anaesthesia induction (baseline), during CPB, after CPB-off, end of surgery, arrival at intensive care unit, and postoperative 6 h. Lactate was further measured until postoperative 48 h. Association of SPP with lactate and 30-day morbidity comprising myocardial infarction, acute kidney injury, stroke, prolonged intubation, sternal infection, reoperation, and mortality was assessed. Among the lactate levels, postoperative 6 h peak value was most closely linked to composite of 30-day morbidity. The SPP value during CPB and its % change from the baseline value were significantly associated with the postoperative 6 h peak lactate (r = -0.26, P = 0.030 and r = 0.47, P = 0.001, respectively). Optimal cut-off of % decrease in SPP during CPB from baseline value for the postoperative 6 h hyperlactatemia was 48% (area under curve, 0.808; 95% confidence interval (CI), 0.652-0.963; P = 0.001). Decrease in SPP >48% during CPB from baseline value was associated with a 12.8-fold increased risk of composite endpoint of 30-day morbidity (95% CI, 1.48-111.42; P = 0.021) on multivariate logistic regression. Large decrease in SPP during CPB predicts postoperative 6 h hyperlactatemia and 30-day morbidity, which implicates a promising role of SPP monitoring in the achievement of optimal perfusion during CPB.

Lactate Elevation During and After Major Cardiac Surgery in Adults: A Review of Etiology, Prognostic Value, and Management

Elevated lactate is a common occurrence after cardiac surgery. This review summarizes the literature on the complex etiology of lactate elevation during and after cardiac surgery, including considerations of oxygen delivery, oxygen utilization, increased metabolism, lactate clearance, medications and fluids, and postoperative complications. Second, the association between lactate and a variety of outcomes are described, and the prognostic role of lactate is critically assessed. Despite the fact that elevated lactate is strongly associated with many important outcomes, including postoperative complications, length of stay, and mortality, little is known about the optimal management of postoperative patients with lactate elevations. This review ends with an assessment of the limited literature on this subject.

Lactate, endothelin, and central venous oxygen saturation as predictors of mortality in patients with Tetralogy of Fallot

Background:

Lactate and central venous oxygen saturation (ScVO₂) are well known biomarkers for adequacy of tissue oxygenation. Endothelin, an inflammatory marker has been associated with patient's nutritional status and degree of cyanosis. The aim of this study was to explore the hypothesis that lactate, ScVO₂ and endothelin before induction may be predictive of mortality in pediatric cardiac surgery.

Methods:

We conducted a prospective observational study of 150 pediatric (6 months to 12 years) patients who were posted for intracardiac repair for tetralogy of fallot and measured lactate, ScVO₂ and endothelin before induction (T₁), 20 minutes after protamine administration (T₂) and 24 hours after admission to ICU (T₃).

Results:

Preinduction lactate and endothelin levels were found to predict mortality in patients of tetralogy of fallot with an odds ratio of 6.020 (95% CI 2.111-17.168) and 1.292(95% CI 1.091-1.531) respectively. In the ROC curve analysis for lactate at T₁, the AUC was 0.713 (95% CI 0.526–0.899 P = 0.019). At the cutoff value of 1.750mmol/lt, the sensitivity and specificity for the prediction of mortality was 63.6% and 65.5%, respectively. For endothelin at T₁, the AUC was 0.699 (95% CI 0.516–0.883, P = 0.028) and the cutoff value was ≤2.50 (sensitivity, 63.6%; specificity, 58.3 %). ScVO₂ (odds ratio 0.85) at all three time intervals, suggested that improving ScVO₂ can lead to 15% reduction in mortality.

Conclusions:

Lactate, ScVO₂ and endothelin all showed association with mortality with lactate having the maximum prediction. Lactate was found to be an independent, reliable and cost-effective measure of prediction of mortality in patients with tetralogy of fallot.

Postoperative Critical Care of the Adult Cardiac Surgical Patient. Part I: Routine Postoperative Care

OBJECTIVES

Cardiac surgery, including coronary artery bypass, cardiac valve, and aortic procedures, is among the most common surgical procedures performed in the United States. Successful outcomes after cardiac surgery depend on optimum postoperative critical care. The cardiac intensivist must have a comprehensive understanding of cardiopulmonary physiology and the sequelae of cardiopulmonary bypass. In this concise review, targeted at intensivists and surgeons, we discuss the routine management of the postoperative cardiac surgical patient.

DATA SOURCE AND SYNTHESIS

Narrative review of relevant English-language peer-reviewed medical literature.

CONCLUSIONS

Critical care of the cardiac surgical patient is a complex and dynamic endeavor. Adequate fluid resuscitation, appropriate inotropic support, attention to rewarming, and ventilator management are key components. Patient safety is enhanced by experienced personnel, a structured handover between the operating room and ICU teams, and appropriate transfusion strategies.

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

INTRODUCTION

Central 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.

METHODS

We 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.

RESULTS

Data 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.

CONCLUSIONS

Patients 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.