The inflammatory response to cardiopulmonary bypass: part 2--anti-inflammatory therapeutic strategies

Prospective Reassessment of the Association Between Pro-Inflammatory Factors and Prognosis After on-Pump Cardiac Surgery

AIM

Elevated levels of pro-inflammatory factors in plasma have been linked to worse prognosis after on-pump cardiac surgery, yet interventions that reduce the levels in patients have failed to improve prognosis. Therefore, we explored whether levels of pro-inflammatory factors are associated with prognosis of patients after valve surgery with cardiopulmonary bypass.

MATERIAL AND METHODS

244 patients were prospectively enrolled into observational study. Levels of tumor necrosis factor (TNF) - α, interleukin-8 and neutrophil elastase were measured once before and several times after cardiopulmonary bypass. The levels were compared between patients who experienced in-hospital adverse events or not, and between patients who experienced major adverse cardiac or cerebrovascular events (MACCEs) during three-year follow-up or not.

RESULTS

Of the 244 patients enrolled, in-hospital adverse events occurred in 38 (15.6 %); of the 237 patients who completed follow-up, MACCEs occurred in 30 (12.7 %). Surgery led to significant increases in levels of all three pro-inflammatory factors, with levels returning to pre-bypass baseline on arrival in the intensive care unit (TNF-α), 4 h after arrival (interleukin-8) or 20 h after arrival (neutrophil elastase). However, pre- and post-bypass levels of all three factors did not differ significantly between patients who experienced adverse events in-hospital or not, or between patients who experienced MACCEs during follow-up or not.

CONCLUSIONS

Levels of TNF-α, interleukin-8 and neutrophil elastase may not be associated with poor prognosis after cardiopulmonary bypass. This may help explain why "cytokine clearance" strategies fail to improve clinical outcomes after on-pump cardiac surgery.

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

Impact of extracorporeal haemoadsorption during prolonged cardiopulmonary bypass on the incidence of acute kidney injury

The usage of cardiopulmonary bypass (CPB) in cardiothoracic surgery contributes to the activation of the inflammatory response. In certain cases, the systemic inflammatory response may be immoderate, leading to organ dysfunction, such as acute renal failure or multiorgan dysfunction. This study aimed to examine the effect of haemoadsorption (HA) therapy on inflammatory markers and renal damage indices during cardiopulmonary bypass and in the early postoperative period. We conducted a retrospective analysis of prospectively collected data in a single tertiary care center on patients operated between January 2021 and May 2022. The levels of inflammatory markers and renal parameters in blood samples (Interleukin (IL) 6, C-reactive protein (CRP), white blood cells, lactate, procalcitonin (PCT), and NT-proBNP, urea, creatinine, glomerular filtration rate (GFR), mechanical ventilation days and intensive care unit (ICU) days) were compared between the three groups. Data from the Jafron HA 330 (n = 20) and CytoSorb300 (n = 20) groups were compared with those from the control group (n = 20). All patients underwent cardiopulmonary bypass for more than 120 min. Baseline patient characteristics were similar in all three groups. Acute kidney injury (AKI) was diagnosed in 17 patients (28.3%); seven patients were in the Jafron HA 330, two in the CytoSorb300, and eight in the control group. We found that IL1α, IL 6, IL8, Lactate dehydrogenase, PCT, NT-proBNP, CRP, Leukocyte, and TNFα had no significant or clinical difference between the CytoSorb 300 and Jafron HA 330 adsorber groups. Our results indicate that haemoadsorption therapy does not significantly reduce the risk of AKI after prolonged CPB, but decreases the need for renal replacement therapy.

Adverse renal effects associated with cardiopulmonary bypass

Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction, one of the most common complications of this surgical cohort. Acute kidney injury (AKI) is associated with increased short-term morbidity and mortality and has been the focus of much research. There is increasing recognition of the role of AKI as the key pathophysiological state leading to the disease entities acute and chronic kidney disease (AKD and CKD). In this narrative review, we will consider the epidemiology of renal dysfunction after cardiac surgery on CPB and the clinical manifestations across the spectrum of disease. We will discuss the transition between different states of injury and dysfunction, and, importantly, the relevance to clinicians. The specific facets of kidney injury on extracorporeal circulation will be described and the current evidence evaluated for the use of perfusion-based techniques to reduce the incidence and mitigate the complications of renal dysfunction after cardiac surgery.

Severe coagulopathy and inflammation occurred after resection of giant right ventricular intimal sarcoma with cardiopulmonary bypass: a case report

BACKGROUND

Primary malignant cardiac tumors are rare in clinic, and surgical resection under cardiopulmonary bypass (CPB) remains the main treatment. The non-physiological perfusion process of CPB leads to contact activation, and the resulting coagulopathy and systemic inflammatory response syndrome (SIRS) are common complications. However, it is difficult to predict the impact of foreign tumor fragments on this pathophysiological process once they enter the bloodstream, making this phenomenon more complex and challenging.

CASE PRESENTATION

We report a case of cardiac intimal sarcoma who developed severe coagulopathy and widespread inflammation after excision of massive right ventricular tumor and replacement of tricuspid valve by median sternotomy under CPB. Although the procedure was expected to cause tumor cell necrosis and precautions were taken, uncontrolled massive postoperative bleeding, persistent fever, abnormally elevated inflammatory markers, and recurrent malignant arrhythmias occurred after surgery. In addition to common factors, the most possible underlying mechanism is contact activation triggered following surgical procedure for intimal sarcoma with CPB.

CONCLUSION

Patients with intracardiac malignant tumors are at a high risk for serious contact activation during CPB. Preventive application of comprehensive anti-inflammatory measures such as drugs and adsorptive CPB technology, as well as point-of-care (POC) monitoring of coagulation status will be helpful for individualized guidance and optimization of CPB management, and improvement of patient prognosis.

Post VV-ECMO Weaning Hyperinflammation-Can Prophylactic Hemoadsorption Treatment Prevent Complications?

Acute respiratory distress syndrome (ARDS) is a severe clinical condition characterized by acute respiratory failure and a high mortality risk despite conventional mechanical ventilatory support. Veno-venous extracorporeal membrane oxygenation (vvECMO) has emerged as an effective life-support technology for patients with ARDS. However, complications may arise following the decannulation of vvECMO, with a relatively frequent development of systemic hyperinflammation (SHI). Among the various treatment strategies for SHI, the use of hemoadsorption with CytoSorb® has shown promising results in removing excessive levels of cytokines and attenuating the hyperinflammatory response. In this case series, we present three critically ill patients with ARDS secondary to pneumonia who underwent vvECMO and subsequently received prophylactic hemoadsorption with CytoSorb® following decannulation as a part of our clinical practice. This case series aims to describe the potential positive effects of hemoadsorption in preventing the development of SHI after vvECMO decannulation in ARDS patients.

Association of Conventional Ultrafiltration on Postoperative Pulmonary Complications

BACKGROUND

Postoperative pulmonary complications increase mortality after cardiac surgery. Conventional ultrafiltration may reduce pulmonary complications by removing mediators of bypass-induced inflammation and countering hemodilution. We tested the primary hypothesis that conventional ultrafiltration reduces postoperative pulmonary complications, and secondarily, improves early pulmonary function assessed by the ratio of PaO2 to fractional inspired oxygen concentration.

METHODS

This retrospective analysis compared the incidence of postoperative pulmonary complications in adult patients who underwent cardiac surgery, with and without the use of conventional ultrafiltration, by using logistic regression with adjustment for confounding variables. The primary outcome was a composite of reintubation, prolonged ventilation, pneumonia, or pleural effusion. Secondarily, we examined early postoperative lung function using a quantile regression model. We also explored whether red blood cell transfusion differed between groups.

RESULTS

Of 8026 patients, 1043 (13%) received conventional ultrafiltration. After adjustment for confounding variables, the incidence of the composite primary outcome was higher in the conventional ultrafiltration group (12.1% vs 9.9%; P = .03), with an estimated odds ratio of 1.25 (95% CI, 1.02-1.53; P = .03). The median (quantiles) PaO2-to-fractional inspired oxygen concentration ratio was 373 (303-433) vs 368 (303-428), with the estimated adjusted difference in medians of 5 (95% CI, -5.9 to 16; P = .37). The estimated odds ratio of intraoperative transfusion was 1.38 (95% CI, 1.19-1.60; P < .0001) and for postoperative transfusion was 1.30 (95% CI, 1.14-1.49; P = .0001).

CONCLUSIONS

Use of conventional ultrafiltration was not associated with a reduction in the composite of postoperative pulmonary complications or improved early pulmonary function. We found no evidence of benefit from use of conventional ultrafiltration during cardiac surgery.

Correlation Between Cardiac Index, Plasma Troponin I, Myocardial Histopathology, CPB and AoX Duration in Glutamine versus No Glutamine Administered Patients with Low Ejection Fraction Undergoing Elective On-Pump CABG Surgery: Secondary Analysis of an RCT

Purpose

On-pump coronary artery bypass graft (CABG) causes myocardial ischemia, through the cardiopulmonary bypass (CPB) and aortic cross-clamping (AoX). Glutamine supplementation protects cardiac cells during cardiac ischemia. This study analysed the correlation between cardiac index (CI), plasma troponin I, myocardial histopathology, CPB and AoX duration in low ejection fraction patients receiving glutamine and no glutamine undergoing elective on-pump CABG.

Material and Methods

This was a secondary analysis of a double-blind, randomised controlled trial of 60 patients, split into control and intervention (glutamine) groups. Glutamine was administered at a dose of 0.5 g/kg/24 hours. There were 29 patients in each respective groups after a total of two patients dropped out.

Results

A negative correlation (p = 0.037) was observed between CPB duration and CI at 6 hours after CPB in the glutamine group. A positive correlation (p = 0.002) was also observed between AoX duration and plasma troponin I at 6 hours after CPB in the control group. However, no correlation was observed between myocardial histopathology and plasma troponin I level at 5 minutes after CPB.

Conclusion

Significant negative correlation between CPB duration and CI at 6 hours after CPB in the glutamine group, along with significant positive correlation between AoX duration and plasma troponin I level at 6 hours after CPB in the control group demonstrated the myocardial protection qualities of intravenous glutamine administration in patients with low ejection fraction undergoing elective on-pump CABG surgeries.

Preoperative fibrinogen level and postcardiac surgery morbidity and mortality rates

BACKGROUND

High preoperative fibrinogen levels are associated with reduced bleeding rates after cardiac surgery. Fibrinogen is directly involved in inflammatory processes and is a cardiovascular risk factors. Whether high fibrinogen levels before cardiac surgery are a risk factor for mortality or morbidity remains unclear.

AIMS

This study aimed to examine the association between preoperative fibrinogen levels and mortality and morbidity rates after cardiac surgery.

SETTINGS AND DESIGN

This is a single-center retrospective study.

MATERIAL AND METHODS

Patients (n = 1628) were divided into high (HFGr) and normal (NFGr) fibrinogen level groups, based on the cutoff value of 3.3 g/L, derived from the receiver operating characteristic (ROC) curve analysis. The primary outcome was the 30-day mortality rate. The rates of postoperative complications, including postoperative bleeding and transfusion rates, were examined.

STATISTICAL ANALYSIS

Between-group comparisons were performed with the Mann-Whitney U test and Chi-squared test, as suitable. Model discriminative power was examined with the area under the ROC curve.

RESULTS

The HFGr and NFGr included 1103 and 525 patients, respectively. Mortality rate was higher in the HFGr than in the NFGr (2.7% vs. 1.1%, P = 0.04). The 12-h bleeding volume (280 mL [195-400] vs. 305 mL [225-435], P = 0.0003) and 24-h bleeding volume values (400 mL [300-550] vs. 450 mL [340-620], P &lt; 0.0001) were lower in the HFGr than in the NFGr. However, the rate of red blood cell transfusion during hospitalization was higher in the HFGr than in the NFGr (21.7% vs. 5.9%, P = 0.0103). Major complications were more frequent in the HFGr than in the NFGr.

CONCLUSION

High fibrinogen levels were associated with reduced postoperative bleeding volume and increased mortality and morbidity rates.

Anticoagulation Strategies during Extracorporeal Membrane Oxygenation: A Narrative Review

The development of extracorporeal life support technology has added a new dimension to the care of critically ill patients who fail conventional treatment options. Extracorporeal membrane oxygenation (ECMO)—specialized temporary life support for patients with severe cardiac or pulmonary failure—plays a role in bridging the time for organ recovery, transplant, or permanent assistance. The overall patient outcome is dependent on the underlying disease, comorbidities, patient reaction to critical illness, and potential adverse events during ECMO. Moreover, the contact of the blood with the large artificial surface of an extracorporeal system circuit triggers complex inflammatory and coagulation responses. These processes may further lead to endothelial injury and disrupted microcirculation with consequent end-organ dysfunction and the development of adverse events like thromboembolism. Therefore, systemic anticoagulation is considered crucial to alleviate the risk of thrombosis and failure of ECMO circuit components. The gold standard and most used anticoagulant during extracorporeal life support is unfractionated heparin, with all its benefits and disadvantages. However, therapeutic anticoagulation of a critically ill patient carries the risk of clinically relevant bleeding with the potential for permanent injury or death. Similarly, thrombotic events may occur. Therefore, different anticoagulation strategies are employed, while the monitoring and the balance of procoagulant and anticoagulatory factors is of immense importance. This narrative review summarizes the most recent considerations on anticoagulation during ECMO support, with a special focus on anticoagulation monitoring and future directions.

Inflammation and Oxidative Stress in the Context of Extracorporeal Cardiac and Pulmonary Support

Extracorporeal circulation (ECC) systems, including cardiopulmonary bypass, and extracorporeal membrane oxygenation have been an irreplaceable part of the cardiothoracic surgeries, and treatment of critically ill patients with respiratory and/or cardiac failure for more than half a century. During the recent decades, the concept of extracorporeal circulation has been extended to isolated machine perfusion of the donor organ including thoracic organs (ex-situ organ perfusion, ESOP) as a method for dynamic, semi-physiologic preservation, and potential improvement of the donor organs. The extracorporeal life support systems (ECLS) have been lifesaving and facilitating complex cardiothoracic surgeries, and the ESOP technology has the potential to increase the number of the transplantable donor organs, and to improve the outcomes of transplantation. However, these artificial circulation systems in general have been associated with activation of the inflammatory and oxidative stress responses in patients and/or in the exposed tissues and organs. The activation of these responses can negatively affect patient outcomes in ECLS, and may as well jeopardize the reliability of the organ viability assessment, and the outcomes of thoracic organ preservation and transplantation in ESOP. Both ECLS and ESOP consist of artificial circuit materials and components, which play a key role in the induction of these responses. However, while ECLS can lead to systemic inflammatory and oxidative stress responses negatively affecting various organs/systems of the body, in ESOP, the absence of the organs that play an important role in oxidant scavenging/antioxidative replenishment of the body, such as liver, may make the perfused organ more susceptible to inflammation and oxidative stress during extracorporeal circulation. In the present manuscript, we will review the activation of the inflammatory and oxidative stress responses during ECLP and ESOP, mechanisms involved, clinical implications, and the interventions for attenuating these responses in ECC.

Safety and Efficacy of Human Chorionic Gonadotropin Hormone-Derivative EA-230 in Cardiac Surgery Patients: A Randomized Double-Blind Placebo-Controlled Study

OBJECTIVES

To determine the safety and efficacy of human chorionic gonadotropin hormone-derivative EA-230 in cardiac surgery patients. Cardiac surgery induces systemic inflammation and may impair renal function, affecting patient outcome. EA-230 exerted immunomodulatory and renoprotective effects in preclinical models and was safe and showed efficacy in phase I and II human studies.

DESIGN

Double-blinded, placebo-controlled, randomized study.

SETTING

Collaboration of the Cardiothoracic Surgery, Anesthesiology, and the Intensive Care departments of a tertiary hospital in the Netherlands.

PATIENTS

One hundred eighty patients undergoing an on-pump coronary artery bypass procedure with or without concomitant valve surgery.

INTERVENTIONS

Ninety mg/kg/hr EA-230 or placebo administered during surgery.

MEASUREMENTS AND MAIN RESULTS

During the study, no safety concerns emerged. EA-230 did not modulate interleukin-6 plasma concentrations (area under the curve 2,730 pg/mL × hr [1,968-3,760] vs 2,680 pg/mL × hr [2,090-3,570] for EA-230 and placebo group, respectively; p = 0.80). Glomerular filtration rate increased following surgery (mean ± sem increase in the EA-230 vs placebo groups: glomerular filtration rateiohexol measured using iohexol plasma clearance: 19 ± 2 vs 16 ± 2 mL/min/1.73 m2; p = 0.13 and estimated glomerular filtration rate with the Modification of Diet in Renal Disease equation using creatinine: 6 ± 1 vs 2 ± 1 mL/min/1.73 m2; p = 0.01). The "injury" stage of the Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease criteria for acute kidney injury was 7% in the EA-230 group versus 18% in the placebo group (p = 0.07). In addition, EA-230-treated patients had a less positive fluid balance compared with placebo-treated patients (217 ± 108 vs 605 ± 103 mL; p = 0.01), while the use of vasoactive agents was similar in both groups (p = 0.39). Finally, hospital length of stay was shorter in EA-230 treated patients (8 d [7-11] vs 10 d [8-12]; p = 0.001). Efficacy results were more pronounced in patients that had longer duration of surgery and thus longer duration of study drug infusion.

CONCLUSIONS

EA-230 was safe in patients undergoing on-pump cardiac surgery. It did not modulate interleukin-6 plasma concentrations but appeared to exert beneficial renal and cardiovascular effects and shortened in-hospital length of stay.

Nitric Oxide Attenuates the Inflammatory Effects of Air During Extracorporeal Circulation

Cardiopulmonary bypass causes a systemic inflammatory response reaction that may contribute to postoperative complications. One cause relates to the air/blood interface from the extracorporeal circuit. The modulatory effects of blending nitric oxide (NO) gas into the ventilation/sweep gas of the membrane lung was studied in a porcine model of air-induced inflammation in which NO gas was added and compared with controls with or without an air/blood interface. Healthy swine were supported on partial bypass under four different test conditions. Group 1: no air exposure, group 2: air alone, group 3: air plus 50 ppm NO, and group 4: air plus 500 ppm NO. The NO gas was blended into the ventilation/sweep site of the membrane lung. The platelets and leucocytes were activated by air alone. Addition of NO to the sweep gas attenuated the inflammatory response created by the air/blood interface in this model.

Red blood cell exosome hemoglobin content increases after cardiopulmonary bypass and mediates acute kidney injury in an animal model

OBJECTIVE

Hemolysis, characterized by formation of free hemoglobin (Hb), occurs in patients undergoing cardiopulmonary bypass (CPB). However, there is no study of the dynamic changes in red blood cell (RBC)-derived exosomes (Exos) released during CPB, nor whether these particles mediate acute kidney injury (AKI).

METHODS

This study is a comprehensive time-course analysis, at baseline, 30 minutes, to 24 hours post-crossclamp release (XCR) to determine (1) Exos Hb content; (2) free Hb/heme, haptoglobin, hemopexin; and (3) urinary markers of AKI over the same time period. In addition, we developed a model system in Sprague-Dawley rats to test for AKI after intravenous injection of Exos Hb released during CPB.

RESULTS

In 30 patients undergoing CPB, there is a significant increase in plasma Hb-positive Exos but not microvesicles 30 minutes post-XCR versus other time points, with a simultaneous decrease in the haptoglobin/Hb ratio. These changes presage a significant increase in urine neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 at 24 hours. Intravenous injection of plasma Exos (10^9-10 particles obtained 30 minutes post-XCR) into rats causes AKI at 72 hours, manifested by multifocal degeneration of proximal tubular epithelium. At 21 days, there is persistent tubular injury and interstitial fibrosis. Intravenous injection of Exos from 35-day-old stored RBCs into rats results in glomerular-tubular injury, increased kidney ferritin and hemoxygenase-1 expression, and significant elevation of kidney injury molecule-1 and proteinuria at 72 hours.

CONCLUSIONS

These combined studies raise the potential for RBC-derived Exos, released during CPB, to target the kidney and mediate AKI.

Conventional Ultrafiltration During Elective Cardiac Surgery and Postoperative Acute Kidney Injury

OBJECTIVE

Conventional ultrafiltration (CUF) during cardiopulmonary bypass (CPB) serves to hemoconcentrate blood volume to avoid allogeneic blood transfusions. Previous studies have determined CUF volumes as a continuous variable are associated with postoperative acute kidney injury (AKI) after cardiac surgery, but optimal weight-indexed volumes that predict AKI have not been described.

DESIGN

Retrospective cohort.

SETTING

Single-center university hospital.

PARTICIPANTS

A total of 1,641 consecutive patients who underwent elective cardiac surgery between June 2013 and December 2015.

INTERVENTIONS

The CUF volume was removed during CPB in all participants as part of routine practice. The authors investigated the association of dichotomized weight-indexed CUF volume removal with postoperative AKI development to provide pragmatic guidance for clinical practice at the authors' institution.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes of postoperative AKI were defined by the Kidney Disease: Improving Global Outcomes staging criteria and dichotomized, weight-indexed CUF volumes (mL/kg) were defined by (1) extreme quartiles (<Q1 v >Q3) and (2) Youden's criterion that best predicted AKI development. Multivariate logistic regression models were developed to test the association of these dichotomized indices with AKI status. Postoperative AKI occurred in 827 patients (50.4%). Higher CUF volumes were associated with AKI development by quartiles (CUF >Q₃ = 32.6 v CUF < Q₁ = 10.4 mL/kg; odds ratio [OR] = 1.68, 95% CI: 1.19-2.3) and Youden's criterion (CUF ≥ 32.9 v CUF <32.9 mL/kg; OR = 1.60, 95% CI: 1.21-2.13). Despite similar intraoperative nadir hematocrits among groups (p = 0.8), higher CUF volumes were associated with more allogeneic blood transfusions (p = 0.002) and longer lengths of stay (p < 0.001).

CONCLUSIONS

Removal of weight-indexed CUF volumes > 32 mL/kg increased the risk for postoperative AKI development. Importantly, CUF volume removal of any amount did not mitigate allogeneic blood transfusion during elective cardiac surgery. Prospective studies are needed to validate these findings.

Extracorporeal Hemadsorption versus Glucocorticoids during Cardiopulmonary Bypass: A Prospective, Randomized, Controlled Trial

Extracorporeal hemadsorption may reduce inflammatory reaction in cardiopulmonary bypass (CPB) surgery. Glucocorticoids have been used during open-heart surgery for alleviation of systemic inflammation after CPB. We compared intraoperative hemadsorption and methylprednisolone, with usual care, during complex cardiac surgery on CPB, for inflammatory responses, hemodynamics, and perioperative course. Seventy-six patients with prolonged CPB were recruited and randomized, with 60 included in final analysis. Allocation was into three groups: Methylprednisolone (n = 20), Cytosorb (n = 20), and Control group (usual care, n = 20). Proinflammatory (TNF-α, IL-1β, IL-6, and IL-8) and anti-inflammatory (IL-10) cytokines which complement C5a, CD64, and CD163 expression by immune cells were analyzed within the first five postoperative days, in addition to hemodynamic and clinical outcome parameters. Methylprednisolone group, compared to Cytosorb and Control had significantly lower levels of TNF-α (until the end of surgery, p < 0.001), IL-6 (until 48 h after surgery, p < 0.001), and IL-8 (until 24 h after surgery, p < 0.016). CD64 expression on monocytes was the highest in the Cytosorb group and lasted until the 5^th postoperative day (p < 0.016). IL-10 concentration (until the end of surgery) and CD163 expression on monocytes (until 48 h after surgery) were the highest in the Methylprednisolone group (p < 0.016, for all measurements between three groups). No differences between groups in the cardiac index or clinical outcome parameters were found. Methylprednisolone more effectively ameliorates inflammatory responses after CPB surgery compared to hemadsorption and usual care. Hemadsorption compared with usual care causes higher prolonged expression of CD64 on monocytes but short lasting expression of CD163 on granulocytes. Hemadsorption with CytoSorb® was safe and well tolerated. This trial is registered with clinicaltrials.gov (NCT02666703).

Does heart surgery change the capacity of α1-antitrypsin to inhibit the ATP-induced release of monocytic interleukin-1β? A preliminary study

Heart surgery involving cardiopulmonary bypass induces systemic inflammation that is, at least in part, caused by extracellular ATP originating from damaged cells and by proteases secreted by activated neutrophils. The anti-protease α1-antitrypsin (AAT) forms complexes with several proteases including neutrophil elastase, resulting in a mutual loss of activity. We demonstrated recently that AAT inhibits the ATP-induced release of the pro-inflammatory cytokine interleukin-1β by human monocytes by a mechanism involving activation of metabotropic functions at nicotinic acetylcholine receptors. Interleukin-1β importantly contributes to the pathogenesis of sterile inflammatory response syndrome. Thus, AAT might function as an endogenous safeguard against life-threatening systemic inflammation. In this preliminary study, we test the hypothesis that during cardiopulmonary bypass, AAT is inactivated as an anti- protease and as an inhibitor of ATP-induced interleukin-1β release. AAT was affinity-purified from the blood plasma of patients before, during and after surgery. Lipopolysaccharide-primed human monocytic U937 cells were stimulated with ATP in the presence or absence of patient AAT to test for its inhibitory effect on interleukin-1β release. Anti-protease activity was investigated via complex formation with neutrophil elastase. The capacity of patient AAT to inhibit the ATP-induced release of interleukin-1β might be slightly reduced in response to heart surgery and complex formation of patient AAT with neutrophil elastase was unimpaired. We conclude that surgery involving cardiopulmonary bypass does not markedly reduce the anti-inflammatory and the anti-protease activity of AAT. The question if AAT augmentation therapy during heart surgery is suited to attenuate postoperative inflammation warrants further studies in vivo.

Effect of low-dose dexamethasone on extra vascular lung water in patients following on-pump elective primary coronary artery bypass graft surgery

Background

The primary objective was to compare the effect of a low-dose dexamethasone as against a saline placebo on extravascular lung water index (EVLWI) in patients undergoing elective primary coronary artery bypass surgery. The secondary endpoints were to assess the effect of dexamethasone on other volumetric parameters (pulmonary vascular permeability index, global end diastolic volume index, and intrathoracic blood volume index), Vasoactive Inotrope Scores, hemodynamic parameters and serum osmolality in both groups.

Settings and Design

Prospective observational study performed at a single tertiary cardiac care center.

Materials and Methods

Twenty patients were randomized to receive either dexamethasone (steroid group, n = 10) or placebo (nonsteroid group, n = 10) twice before the institution of cardiopulmonary bypass (CPB). EVLWI and other volumetric parameters were obtained with the help of VolumeView™ Combo Kit connected to EV 1000 clinical platform at predetermined intervals. Hemodynamic parameters, vasoactive-inotropic Scores, hematocrit values were recorded at the predetermined time intervals. Baseline and 1^st postoperative day serum osmolality values were also obtained.

Results

The two groups were evenly matched in terms of demographic and CPB data. Intra- and inter-group comparison of the baseline EVLWI including other volumetric and hemodynamic parameters with those recorded at subsequent intervals revealed no statistical difference and was similar. Generalized estimating equation model was obtained to compare the changes between the groups over the entire study period which showed that on an average the changes between the steroid and nonsteroid group in terms of all volumetric parameters were not statistically significant.

Conclusions

There were no beneficial effects of low-dose dexamethasone on EVLWI or other volumetric parameters in patients subjected to on-pump primary coronary bypass surgery. Hemodynamic parameters were also not affected. Probably, the advanced hemodynamic monitoring aided in optimal fluid management in the nonsteroidal group impacting EVLW accumulation.

Adrenergic Downregulation in Critical Care: Molecular Mechanisms and Therapeutic Evidence

Catecholamines remain the mainstay of therapy for acute cardiovascular dysfunction. However, adrenergic receptors quickly undergo desensitization and downregulation after prolonged stimulation. Moreover, prolonged exposure to high circulating catecholamines levels is associated with several adverse effects on different organ systems. Unfortunately, in critically ill patients, adrenergic downregulation translates into progressive reduction of cardiovascular response to exogenous catecholamine administration, leading to refractory shock. Accordingly, there has been a growing interest in recent years toward use of noncatecholaminergic inotropes and vasopressors. Several studies investigating a wide variety of catecholamine-sparing strategies (eg, levosimendan, vasopressin, β-blockers, steroids, and use of mechanical circulatory support) have been published recently. Use of these agents was associated with improvement in hemodynamics and decreased catecholamine use but without a clear beneficial effect on major clinical outcomes. Accordingly, additional research is needed to define the optimal management of catecholamine-resistant shock.

Akt is a critical node of acute myocardial insulin resistance and cardiac dysfunction after cardiopulmonary bypass

AIMS

Acute myocardial insulin resistance is an independent risk factor for patients who undergo cardiac surgery with cardiopulmonary bypass (CPB). However, the underlying mechanism of insulin resistance during CPB has not been fully investigated.

MATERIALS AND METHODS

To explore the role of myocardial insulin resistance on the cardiac function and its underlying mechanism, CPB operation and pharmacological intervention were applied in mini pigs, and myocardial insulin signaling, glucose uptake, ATP production and cardiac function were examined.

KEY FINDINGS

Our data showed that CPB elicited not only hyperglycemia and hyperinsulinemia, but also inactivated Akt, and impaired the transposition of membrane glucose transporter-4 (GLUT-4), reduced glucose uptake and ATP production in the myocardium as well, which in turn was accompanied with cardiac dysfunction. Meanwhile, linear correlations were established among reduced myocardial glucose uptake, ATP production, and depressed cardiac systolic or diastolic function. Reactivation of Akt by SC79, an Akt agonist, partially alleviated myocardial insulin resistance and restored post CPB cardiac function via augmenting myocardial glucose uptake and ATP production.

SIGNIFICANCE

These findings revealed that acute myocardial insulin resistance due to inactivation of Akt played a key role in cardiac dysfunction post CPB via suppressing glucose metabolism related energy supply.

Review and Update: Hematologic Malignancies and Adult Cardiac Surgery

As treatments for hematologic malignancies continue to advance, many patients with active disease and many more in remission will present for cardiac surgical procedures. Radiation and chemotherapeutic therapies for hematologic malignancies often result in cardiopulmonary injury. Evidence demonstrates that patients with hematologic malignancies undergoing cardiac surgery are at risk for perioperative adverse events, including bleeding, clotting, infection, and immunomodulation. However, short- and long-term mortality has been found to be acceptable. This review will distinguish the important points of characterizing, understanding, and managing hematologic malignancies in the cardiac surgical patient.

High-Dose Vitamin B12 in Vasodilatory Shock: A Narrative Review

Vasodilatory shock, as observed in postoperative states and sepsis, is hallmarked by low systemic vascular resistance and low blood pressure compensated by increased cardiac output. Gasotransmitters, such as nitric oxide and hydrogen sulfide, are implicated in the development and perpetuation of vasodilatory shock. Established therapies do not target these physiologic drivers of vasodilation. Due to their nontoxic and pleotropic effects, micronutrients are being used as rescue therapy in postoperative vasoplegia and septic shock. Here, we outline the pathophysiology of vasodilatory shock, describe the rationale for vitamin B12 (hydroxocobalamin) in vasodilatory shock, and identify literature evaluating its use in vasoplegic states.

Positive end-expiratory pressure (PEEP) level to prevent expiratory flow limitation during cardiac surgery: study protocol for a randomized clinical trial (EFLcore study)

Background

Lung dysfunction commonly occurs after cardiopulmonary bypass (CPB). Randomized evidence suggests that the presence of expiratory flow limitation (EFL) in major abdominal surgery is associated with postoperative pulmonary complications. Appropriate lung recruitment and a correctly set positive end-expiratory pressure (PEEP) level may prevent EFL. According to the available data in the literature, an adequate ventilation strategy during cardiac surgery is not provided. The aim of this study is to assess whether a mechanical ventilation strategy based on optimal lung recruitment with a best PEEP before and after CPB and with a continuous positive airway pressure (CPAP) during CPB would reduce the incidence of respiratory complications after cardiac surgery.

Methods/design

This will be a single-center, single-blind, parallel-group, randomized controlled trial. Using a 2-by-2 factorial design, high-risk adult patients undergoing elective cardiac surgery will be randomly assigned to receive either a best PEEP (calculated with a PEEP test) or zero PEEP before and after CPB and CPAP (equal to the best PEEP) or no ventilation (patient disconnected from the circuit) during CPB.

The primary endpoint will be a composite endpoint of the incidence of EFL after the weaning from CPB and postoperative pulmonary complications.

Discussion

This study will help to establish a correct ventilatory strategy before, after, and during CPB. The main purpose is to establish if a ventilation based on a simple and feasible respiratory test may preserve lung function in cardiac surgery.

Trial registration

ClinicalTrials.gov, ID: NCT02633423. Registered on 6 December 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3046-0) contains supplementary material, which is available to authorized users.

Time Course of CD64, a Leukocyte Activation Marker, During Cardiopulmonary Bypass Surgery

Distinction between inflammation secondary to surgery, especially coronary artery bypass graft with cardiopulmonary bypass (CPB), and inflammation due to infection is difficult in surgical intensive care unit (ICU) patients. Development of biomarkers of infection could help clinicians in the early identification and thus treatment of sepsis in these patients. We compared the time course of the neutrophil CD64 index, a high affinity immunoglobulin FC γ receptor I whose expression is increased in bacterial infection, in 39 patients undergoing cardiac surgery with CPB and 11 patients admitted to the ICU with severe sepsis or septic shock. The CD64 index was significantly more elevated in septic patients than in patients who had CPB except at day 5. The CD64 index increased moderately on day 1 after cardiac surgery but the value remained lower than in septic patients. The duration for which the CD64 index was greater than 1.0 was longer in septic than in CPB patients. Receiver operating curves to differentiate CPB from sepsis on day 1 were not significantly different between C-reactive protein (CRP) concentrations and CD 64 index. Nevertheless, combination of low CD64 index with low CRP concentrations on day 1 ruled out sepsis except in three patients. There were no correlations between the CD64 index and cytokine levels (tumor necrosis factor [TNF]-α, interferon [IFN]γ, interleukin [IL]-6, IL-10, IL-8, IL-12) measured in subpopulations. In conclusion, CD64 index only in combination with CRP concentrations could be used to discriminate inflammation due to surgery from that due to infection in this particular population.

Influence of the postoperative inflammatory response on cognitive decline in elderly patients undergoing on-pump cardiac surgery: a controlled, prospective observational study

Background

The role of non-infective inflammatory response (IR) in the aetiology of postoperative cognitive dysfunction (POCD) is still controversial. The aim of this controlled, prospective observational study was to assess the possible relationship between the grade of IR, defined by procalcitonin (PCT) changes, and development of POCD related to cardiac surgery.

Methods

Forty-two patients, who were ≥ 60 years of age and scheduled for elective cardiac surgery, were separated into the low inflammatory (LIR) and high inflammatory (HIR) response groups based on their PCT levels measured on the first postoperative day. A matched normative control group of 32 subjects was recruited from primary care practice. The PCT and C-reactive protein (CRP) levels were monitored daily during the first five postoperative days. The cognitive function and mood state were preoperatively tested with a set of five neurocognitive tests and two mood inventories and at the seventh postoperative day. The Reliable Change Index modified for practice (RCIp) using data from normative controls was applied to determine the significant decline in test performance.

Results

The LIR (n = 20) and HIR (n = 22) groups differed significantly in the PCT (p < 0.001) but not in the CRP time courses. The incidence of POCD at the first postoperative week was 35.7% in the cohort. The LIR and HIR groups did not vary in the RCIp Z scores of neurocognitive tests and frequencies of POCD (7 vs 8 cases, respectively, p > 0.05). Additionally, there was no difference in the mood states, anxiety levels and perioperative parameters known to influence the development of POCD.

Conclusions

In this study, the magnitude of the non-infective inflammatory response generated by on-pump cardiac surgery did not influence the development of POCD in the early postoperative period in elderly patients.

The inflammatory response to extracorporeal membrane oxygenation (ECMO): a review of the pathophysiology

Extracorporeal membrane oxygenation (ECMO) is a technology capable of providing short-term mechanical support to the heart, lungs or both. Over the last decade, the number of centres offering ECMO has grown rapidly. At the same time, the indications for its use have also been broadened. In part, this trend has been supported by advances in circuit design and in cannulation techniques. Despite the widespread adoption of extracorporeal life support techniques, the use of ECMO remains associated with significant morbidity and mortality. A complication witnessed during ECMO is the inflammatory response to extracorporeal circulation. This reaction shares similarities with the systemic inflammatory response syndrome (SIRS) and has been well-documented in relation to cardiopulmonary bypass. The exposure of a patient’s blood to the non-endothelialised surface of the ECMO circuit results in the widespread activation of the innate immune system; if unchecked this may result in inflammation and organ injury. Here, we review the pathophysiology of the inflammatory response to ECMO, highlighting the complex interactions between arms of the innate immune response, the endothelium and coagulation. An understanding of the processes involved may guide the design of therapies and strategies aimed at ameliorating inflammation during ECMO. Likewise, an appreciation of the potentially deleterious inflammatory effects of ECMO may assist those weighing the risks and benefits of therapy.

Perioperative Statin Therapy for Patients Undergoing Coronary Artery Bypass Grafting

Coronary artery bypass grafting is associated with an intense systemic inflammatory response, which is linked to postoperative complications. Beyond lipid lowering, statins exert a constellation of beneficial actions, including an antiinflammatory role, known as pleiotropic effects. There is increasing evidence that perioperative statin therapy improves outcomes in patients undergoing coronary artery bypass grafting. Statins are underused in the coronary artery bypass grafting population, because perioperative discontinuation remains a common practice. This article provides an extensive review of the available literature on the effect of perioperative statin therapy on post–coronary artery bypass grafting outcomes and weighs the evidence for the concerns about increased incidence of statin-related adverse effects in this setting.

Shock Management for Cardio-surgical ICU Patients - The Golden Hours

Postoperative shock following cardiac surgery is a serious condition with a high morbidity and mortality. There are four types of shock: cardiogenic, hypovolemic, obstructive and distributive and these can occur alone or in combination. Early identification of the underlying diseases and understanding of the mechanisms at play are key for successful management of shock. Prompt resuscitation measures are necessary to reverse the shock state and avoid permanent organ dysfunction or death. In this review, the authors focus on the management during the first 6 hours of shock (the 'golden hours'). They discuss how to optimise preload, vascular tone, contractility, heart rate and oxygen delivery. The review incorporates the findings of recent trials on early goal-directed therapy and includes practical recommendations in areas in which the evidence is scare or controversial. While the review focuses on cardio-surgical patients, the suggested treatment algorithms might be usefully expanded to other critically ill patients with shock arising from other causes.

Efficacy of Goal-Directed Therapy Using Bioreactance Cardiac Output Monitoring after Valvular Heart Surgery

PURPOSE

We compared the efficacy of postoperative hemodynamic goal-directed therapy (GDT) using a pulmonary artery catheter (PAC) and bioreactance-based noninvasive cardiac output monitoring (NICOM) in patients with atrial fibrillation undergoing valvular heart surgery.

MATERIALS AND METHODS

Fifty eight patients were randomized into two groups of GDT with common goals to maintain a mean arterial pressure of 60-80 mm Hg and cardiac index ≥2 L/min/m²: the PAC group (n=29), based on pulmonary capillary wedge pressure, and the NICOM group (n=29), based on changes in stroke volume index after passive leg raising. The primary efficacy variable was length of hospital stay. Secondary efficacy variables included resource utilization including vasopressor and inotropic requirement, fluid balance, and major morbidity endpoints.

RESULTS

Patient characteristics and operative data were similar between the groups, except that significantly more patients underwent double valve replacement in the NICOM group. The lengths of hospital stay were not different between the two groups (12.2±4.8 days vs. 10.8±4.0 days, p=0.239). Numbers of patients requiring epinephrine (5 vs. 0, p=0.019) and ventilator care >24 h (6 vs. 1, p=0.044) were significantly higher in the PAC group. The PAC group also required significantly larger amounts of colloid (1652±519 mL vs. 11430±463 mL, p=0.004).

CONCLUSION

NICOM-based postoperative hemodynamic GDT showed promising results in patients with atrial fibrillation undergoing valvular heart surgery in terms of resource utilization.

Off-pump CABG surgery reduces systemic inflammation compared with on-pump surgery but does not change systemic endothelial responses: a prospective randomized study

Coronary artery bypass graft (CABG) surgery can result in severe postoperative organ failure. During CABG surgery, cardiopulmonary bypass (CPB) with cardiac arrest is often used (on-pump CABG), which often results in a systemic inflammatory response. To reduce this inflammatory response, off-pump CABG was reintroduced, thereby avoiding CPB. There is increasing evidence that the endothelium plays an important role in the pathophysiology of organ failure after CABG surgery. In this study, 60 patients who were scheduled for elective CABG surgery were randomized to have surgery for on-pump or off-pump CABG. Blood was collected at four time points: start, end, 6 h, and 24 h postoperatively. Levels of inflammatory cytokines, soluble adhesion molecules, and angiogenic factors and their receptors were measured in the plasma. No differences were found in preoperative characteristics between the patient groups. The levels of tumor necrosis factor-α, interleukin 10, and myeloperoxidase, but not interleukin 6, were increased to a greater extent in the on-pump CABG compared with off-pump CABG after sternum closure. The soluble endothelial adhesion molecules E-selectin, vascular cell adhesion molecule 1, and intracellular adhesion molecule 1 were not elevated in the plasma during and after CABG surgery in both on-pump and off-pump CABG. Angiopoietin 2 was only increased 24 h after surgery in both on-pump and off-pump CABG. Higher levels of sFlt-1 were found after sternum closure in off-pump CABG compared with on-pump CABG. Avoiding CPB and aortic cross clamping in CABG surgery reduces the systemic inflammatory response. On-pump CABG does not lead to an increased release of soluble endothelial adhesion molecules in the circulation compared with off-pump CABG.

The effect of modified ultrafiltration on angiopoietins in pediatric cardiothoracic operations

BACKGROUND

Cardiopulmonary bypass subjects patients' blood to hemodilution and nonphysiologic conditions, resulting in a systemic inflammatory response. Modified ultrafiltration (MUF) counteracts hemodilution and has also been postulated to improve outcomes by proinflammatory cytokine removal. The objective of this study was to investigate whether the benefits of MUF include the removal of proinflammatory mediators, such as angiopoietin-2 (angpt-2). We hypothesize that some of the clinical benefits of MUF are related to the preferential removal of angpt-2.

METHODS

We performed a prospective cohort study in children 18 years old or younger undergoing cardiopulmonary bypass. Serum samples were obtained from each patient preoperatively, after cardiopulmonary bypass, and on intensive care unit admission. A fluid sample from the MUF effluent was also analyzed. Angpt-1, angpt-2, interleukin-8, and interleukin-10 levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Thirty-one patients were enrolled. Angpt-1 levels significantly decreased across all time points (p<0.01). Angpt-2 concentrations were significantly elevated at intensive care unit admission when compared with both preoperative and post-cardiopulmonary bypass levels (p<0.01). The angpt-2:1 ratio significantly increased after cardiopulmonary bypass to intensive care unit admission (p<0.01). There was no significant difference between the angpt-2 or angpt-1 percentage of extraction within MUF effluent. Interleukin-8 and interleukin-10 significantly increased from preoperative to intensive care unit admission (both p<0.01).

CONCLUSIONS

The results of this study demonstrate that MUF removes both proinflammatory and antiinflammatory mediators equally. This study suggests that the clinical benefits of MUF cannot be attributed to the removal of larger quantities of proinflammatory mediators such as angpt-2 and interleukin-8.

Acute Effect of Intravenous Administration of Magnesium Sulfate on Serum Levels of Interleukin-6 and Tumor Necrosis Factor-α in Patients Undergoing Elective Coronary Bypass Graft With Cardiopulmonary Bypass

Background:

Cardiovascular problems are among the most common health issues. A considerable number of cardiac patients undergo cardiac surgery, and coronary artery disease patients constitute about two-thirds of all these surgeries. The application of cardiopulmonary bypass (CBP) usually results in some untoward effects.

Objectives:

Studies have suggested magnesium sulfate (MgSO4) as an anti-inflammatory agent in a coronary artery bypass graft (CABG). This study aimed to assess the effect of an IV MgSO₄ infusion during elective CABG (with CBP) on the blood levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α).

Materials and Methods:

During a 12 month period, after review board approval and based on inclusion and exclusion criteria, 90 patients were selected and entered randomly into one of the two study groups (MgSO4 or placebo). Anesthesia, surgery and CBP were performed in exactly the same way, except for the use of MgSO4 or a placebo. Both preoperative and postoperative plasma levels of IL-6 and TNF-α were checked and compared between the two groups using an ELISA.

Results:

There was no difference found between the two groups with regard to; gender, basic variables, Ejection Fraction (EF), CBP time and aortic cross-clamp time. The preoperative levels of IL-6 and TNF-α were not different; however, their postoperative levels were significantly higher in the placebo group (P value = 0.01 for IL-6 and 0.005 for TNF-α).

Conclusions:

This study showed that MgSO4 infusion could suppress part of the inflammatory response after CABG with CBP. This was demonstrated by decreased levels of interleukin-6 and TNF-α in postoperative serum levels in elective CABG with CBP.

Acute pulmonary injury with refractory hypoxaemia after implantation of Levitronix CentriMag ventricular assist device: successful treatment with veno-venous extracorporeal membrane oxygenation

Although acute pulmonary injury after cardiopulmonary bypass has been detailed in the literature, it was seldom mentioned in the context of following implantation of a ventricular assist device. We report on a 65-year-old male with end-stage ischemic cardiomyopathy who underwent implantation of Levitronix CentriMag (Levitronix, Waltham, MA) for cardiac support and was listed for heart transplantation. Acute pulmonary injury with profound hypoxaemia was noted 6 h after the implantation. Despite optimal medical treatment and maximal ventilator support, refractory hypoxaemia persisted, and veno-venous extracorporeal membrane oxygenation (oxygenator: Affinity-NT; centrifugal pump: BPX-80 Bio-Pump, Medtronic, Minneapolis, MN, USA) was applied for ventilation support. The patient was weaned from the extracorporeal membrane oxygenation 4 days later and from the ventilator on the next 2 days. He underwent a successful orthotopic heart transplant after a total of 77 days on Levitronix left ventricular device cardiac support.

Hydroxyethyl starch 6%, 130/0.4 vs. a balanced crystalloid solution in cardiopulmonary bypass priming: a randomized, prospective study

Background

Since the advent of cardiopulmonary bypass, many efforts have been made to avoid the complications related with it. Any component of the pump participates in occurrence of these adverse events, one of which is the type of prime solution. In this study, we aimed to compare the effects of 6% hydroxyethyl starch 130/0.4 with a commonly used balanced electrolyte solution on postoperative outcomes following coronary bypass surgery.

Methods

Two hundred patients undergoing elective coronary bypass surgery were prospectively studied. The patients were randomized in to two groups. First group received a balanced electrolyte solution and the second group received 6% hydoxyethyl starch 130/0.4 as prime solution. The postoperative outcomes of the patients were studied.

Results

The mean age of the patients was 61.81 ± 10.12 in the crystalloid group whereas 61.52 ± 9.29 in the HES group. There were 77 male patients in crystalloid group and 74 in HES group. 6% hydroxyethyl starch 130/0.4 did not have any detrimental effects on renal and pulmonary functions. The intensive care unit stay and postoperative hospital length of stay were shorter in hydroxyethyl starch group (p < 0.05 for each). Hydroxyethyl starch did not increase postoperative blood loss, amount of blood and fresh frozen plasma used, but it decreased platelet concentrate requirement. It did not have any effect on occurrence of post-coronary bypass atrial fibrillation (p > 0.05).

Conclusions

6% hydroxyethyl starch 130/0.4 when used as a prime solution did not adversely affect postoperative outcomes including renal functions and postoperative blood transfusion following coronary bypass surgery.

Risk factors for postoperative respiratory mortality and morbidity in patients undergoing coronary artery bypass grafting

ABSTRACT

Nowadays, coronary artery bypass grafting (CABG) is considered to be one of the most common surgical procedures. This procedure has been the main topic in many clinical research studies, which have assessed the effect of the procedure on patients’ outcomes. Like other surgical procedures, this procedure is also accompanied by a number of unwanted complications, including those of the respiratory system. Since the respiratory system plays an integral role in defining the clinical outcome of patients, improvements in studies that can assess and predict clinical outcomes of the respiratory system, assume greater importance. There are a number of predictive models which can assess patients in the preoperative period and introduce a number of risk factors, which could be considered as prognostic factors for patients undergoing CABG. The respiratory system is among the clinical systems that are assessed in many prediction scoring systems. This review assesses the main studies which have evaluated the possible risk factors for postoperative respiratory mortality and morbidity, in patients undergoing CABG.

Perioperative plasma F(2)-Isoprostane levels correlate with markers of impaired ventilation in infants with single-ventricle physiology undergoing stage 2 surgical palliation on the cardiopulmonary bypass

Cardiopulmonary bypass (CPB) produces inflammation and oxidative stress, which contribute to postoperative complications after cardiac surgery. F(2)-Isoprostanes (F(2)-IsoPs) are products of lipid oxidative injury and represent the most accurate markers of oxidative stress. In adults undergoing cardiac surgery, CPB is associated with elevated IsoPs. The relationship between F(2)-IsoPs and perioperative end-organ function in infants with single-ventricle physiology, however, has not been well studied. This study prospectively enrolled 20 infants (ages 3-12 months) with univentricular physiology undergoing elective stage 2 palliation (bidirectional cavopulmonary anastomosis). Blood samples were collected before the surgical incision (T0), 30 min after initiation of CPB (T1), immediately after separation from CPB (T2), and 24 h postoperatively (T3). Plasma F(2)-IsoP levels were measured at each time point and correlated with indices of pulmonary function and other relevant clinical variables. Plasma F(2)-IsoPs increased significantly during surgery, with highest levels seen immediately after separation from CPB (p < 0.001). After separation from CPB, increased F(2)-IsoP was associated with lower arterial pH (ρ = -0.564; p = 0.012), higher partial pressure of carbon dioxide (PaCO(2); ρ = 0.633; p = 0.004), and decreased lung compliance (ρ = -0.783; p ≤ 0.001). After CPB, F(2)-IsoPs did not correlate with duration of CPB, arterial lactate, or immediate postoperative outcomes. In infants with single-ventricle physiology, CPB produces oxidative stress, as quantified by elevated F(2)-IsoP levels. Increased F(2)-IsoP levels correlated with impaired ventilation in the postoperative period. The extent to which F(2)-IsoPs and other bioactive products of lipid oxidative injury might predict or contribute to organ-specific stress warrants further investigation.