Strategies to prevent intraoperative lung injury during cardiopulmonary bypass

Effects and trend of steroid dosage reduction during cardiac surgery: A three-year retrospective analysis at a tertiary medical center

BACKGROUND

Current adult cardiac surgery guidelines recommend against the routine use of prophylactic intravenous corticosteroids during cardiopulmonary bypass (CPB) due to concerns about myocardial injury, despite their potential to reduce postoperative atrial fibrillation. Traditionally, a high dose of 1,000 mg of methylprednisolone was used to attenuate the inflammatory response associated with CPB. Our institution aligned with guideline recommendations and gradually reduced methylprednisolone dosages; thus, we reevaluated the impact on postoperative clinical outcomes.

METHODS

Our study reviewed 1341 cases from a total of 1680 adult cardiac surgeries performed between June 2019 and May 2022 after excluding cases with off-pump procedures, ventricular assist device implantations, heart transplants, and aortic surgeries requiring systemic circulatory arrest. The study timely sorted periods including a baseline data from 2018, and other three periods since 2019 to analyze the effects of three different methylprednisolone dosage: 0 mg, 500 mg, and 1000 mg. We assessed the annual trends in methylprednisolone administration and compared morbidity and mortality rates across the groups.

RESULTS

We observed a significant decline in steroid use, with no-steroid surgeries increasing from 23% to 66.5% by period 3. Despite the decreased use of steroids, our study showed no increase in mortality, new-onset atrial fibrillation, acute kidney injury, cerebrovascular event and prolonged ventilation when compared to baseline data. Notably, less surgical site infection rate was observed in the no-steroid group.

CONCLUSION

The data indicates that a reduction or discontinuation of steroids during CPB can be performed without compromising patient outcomes. This could support a transition towards a more conservative use of steroids in adult cardiac surgery, aligning with current guidelines, and potentially reducing certain postoperative complications.

Con: Mechanical Ventilation During Cardiopulmonary Bypass

The ventilatory strategy to adopt during cardiopulmonary bypass is still being debated. The rationale for using continuous positive airway pressure or mechanical ventilation would be to counteract alveolar collapse and improve ischemia phenomena and passive alveolar diffusion of oxygen. Although there are several studies supporting the hypothesis of a positive effect on oxygenation and systemic inflammatory response, the real clinical impact of ventilation during cardiopulmonary bypass is controversial. Furthermore, the biases present in the literature make the studies' results nonunique in their interpretation.

Predictive role of regional thigh tissue oxygen saturation monitoring during cardiopulmonary bypass in lung injury after cardiac surgery

Acute respiratory distress syndrome (ARDS) is a serious complication following cardiac surgery mainly associated with the use of cardiopulmonary bypass (CPB), which could increase the risk of mortality and morbidity. This study investigated the association of regional oxygen saturation (rSO2) during CPB with postoperative outcomes, including respiratory function. Patients who underwent cardiac surgery with CPB from 2015 to 2019 were included. Near-infrared spectroscopy was used to monitor rSO2 at the forehead, abdomen, and thighs throughout the surgery. Postoperative markers associated with CPB were assessed for correlations with PaO2/FiO2 (P/F) ratios at intensive care unit (ICU) admission. Postoperative lung injury (LI) was defined as moderate or severe ARDS based on the Berlin criteria, and its incidence was 29.9% (20/67). On multiple regression analysis, the following were associated with P/F ratios at ICU admission: vasoactive-inotropic scores at CPB induction (P = 0.03), thigh rSO2 values during CPB (P = 0.04), and body surface area (P < 0.001). A thigh rSO2 of 71% during CPB was significantly predictive of postoperative LI with an area under the curve of 0.71 (P = 0.03), sensitivity of 0.70, and specificity of 0.68. Patients with postoperative LI had longer ventilation time and ICU stays. Thigh rSO2 values during CPB were a potential predictor of postoperative pulmonary outcomes.

Preoperative respiratory muscle training reduces the risk of pulmonary complications and the length of hospital stay after cardiac surgery: a systematic review

QUESTIONS

What is the effect of preoperative respiratory muscle training (RMT) on the incidence of postoperative pulmonary complications (PPCs) after open cardiac surgery? What is the effect of RMT on the duration of mechanical ventilation, postoperative length of stay and respiratory muscle strength?

DESIGN

Systematic review of randomised trials with meta-analysis.

PARTICIPANTS

Adults undergoing elective open cardiac surgery.

INTERVENTION

The experimental groups received preoperative RMT and the comparison groups received no intervention.

OUTCOME MEASURES

The primary outcomes were PPCs, length of hospital stay, respiratory muscle strength, oxygenation and duration of mechanical ventilation. The methodological quality of studies was assessed using the PEDro scale and the overall certainty of the evidence was assessed using the GRADE approach.

RESULTS

Eight trials involving 696 participants were included. Compared with the control group, the respiratory training group had fewer PPCs (RR 0.51, 95% CI 0.38 to 0.70), less pneumonia (RR 0.44, 95% CI 0.25 to 0.78), shorter hospital stay (MD -1.7 days, 95% CI -2.4 to -1.1) and higher maximal inspiratory pressure values at the end of the training protocol (MD 12 cmH2O, 95% CI 8 to 16). The mechanical ventilation time was similar in both groups. The quality of evidence was high for pneumonia, length of hospital stay and maximal inspiratory pressure.

CONCLUSION

Preoperative RMT reduced the risk of PPCs and pneumonia after cardiac surgery. The training also improved the maximal inspiratory pressure and reduced hospital stay. The effects on PPCs were large enough to warrant use of RMT in this population.

REGISTRATION

CRD42021227779.

Flow-controlled versus pressure-controlled ventilation in cardiac surgery with cardiopulmonary bypass - A single-center, prospective, randomized, controlled trial

STUDY OBJECTIVE

Multifactorial comparison of flow-controlled ventilation (FCV) to standard of pressure-controlled ventilation (PCV) in terms of oxygenation in cardiac surgery patients after chest closure.

DESIGN

Prospective, non-blinded, randomized, controlled trial.

SETTING

Operating theatre at an university hospital, Austria.

PATIENTS

Patients scheduled for elective, open, on-pump, cardiac surgery.

INTERVENTIONS

Participants were randomized to either individualized FCV (compliance guided end-expiratory and peak pressure setting) or control of PCV (compliance guided end-expiratory pressure setting and tidal volume of 6-8 ml/kg) for the duration of surgery.

MEASUREMENTS

The primary outcome measure was oxygenation (PaO2/FiO2) 15 min after intraoperative chest closure. Secondary endpoints included CO2-removal assessed as required minute volume to achieve normocapnia and lung tissue aeration assessed by Hounsfield unit distribution in postoperative computed tomography scans.

MAIN RESULTS

Between April 2020 and April 2021 56 patients were enrolled and 50 included in the primary analysis (mean age 70 years, 38 (76%) men). Oxygenation, assessed by PaO2/FiO2, was significantly higher in the FCV group (n = 24) compared to the control group (PCV, n = 26) (356 vs. 309, median difference (MD) 46 (95% CI 3 to 90) mmHg; p = 0.038). Additionally, the minute volume required to obtain normocapnia was significantly lower in the FCV group (4.0 vs. 6.1, MD -2.0 (95% CI -2.5 to -1.5) l/min; p < 0.001) and correlated with a significantly lower exposure to mechanical power (5.1 vs. 9.8, MD -5.1 (95% CI -6.2 to -4.0) J/min; p < 0.001). Evaluation of lung tissue aeration revealed a significantly reduced amount of non-aerated lung tissue in FCV compared to PCV (5 vs. 7, MD -3 (95% CI -4 to -1) %; p < 0.001).

CONCLUSIONS

In patients undergoing on-pump, cardiac surgery individualized FCV significantly improved oxygenation and lung tissue aeration compared to PCV. In addition, carbon dioxide removal was accomplished at a lower minute volume leading to reduced applied mechanical power.

Perioperative hemostatic management of patients with type A aortic dissection

Coagulopathy is common in patients undergoing thoracic aortic repair for Stanford type A aortic dissection. Non-critical administration of blood products may adversely affect the outcome. It is therefore important to be familiar with the pathologic conditions that lead to coagulopathy in complex cardiac surgery. Adequate care of these patients includes the collection of the medical history regarding the use of antithrombotic and anticoagulant drugs, and a sophisticated diagnosis of the coagulopathy with viscoelastic testing and subsequently adapted coagulation therapy with labile and stable blood products. In addition to the above-mentioned measures, intraoperative blood conservation measures as well as good interdisciplinary coordination and communication contribute to a successful hemostatic management strategy.

Pulmonary reperfusion injury in post-palliative intervention of oligaemic cyanotic CHD: a new catastrophic consequence or just revisiting the same old story?

Pulmonary reperfusion injury is a well-recognised clinical entity in the setting pulmonary artery angioplasty for pulmonary artery stenosis or chronic thromboembolic disease, but not much is known about this complication in post-palliative intervention of oligaemic cyanotic CHD. The pathophysiology of pulmonary reperfusion injury in this population consists of both ischaemic and reperfusion injury, mainly resulting in oxidative stress from reactive oxygen species generation, followed by endothelial dysfunction, and cytokine storm that may induce multiple organ dysfunction. Other mechanisms of pulmonary reperfusion injury are "no-reflow" phenomenon, overcirculation from high pressure in pulmonary artery, and increased left ventricular end-diastolic pressure. Chronic hypoxia in cyanotic CHD eventually depletes endogenous antioxidant and increased the risk of pulmonary reperfusion injury, thus becoming a concern for palliative interventions in the oligaemic subgroup. The incidence of pulmonary reperfusion injury varies depending on multifactors. Despite its inconsistence occurrence, pulmonary reperfusion injury does occur and may lead to morbidity and mortality in this population. The current management of pulmonary reperfusion injury is supportive therapy to prevent deterioration of lung injury. Therefore, a general consensus on pulmonary reperfusion injury is necessary for the diagnosis and management of this complication as well as further studies to establish the use of novel and potential therapies for pulmonary reperfusion injury.

Cardiac surgery in East Africa: a profile of cases and referral to physiotherapy

Background

A significant increase in cardiac surgery has been observed globally, with prolonged length of stay (LOS) still prevalent due to post-operative complications. Physiotherapy pre and post cardiac surgery is known to reduce these complications and LOS, however cases referred for physiotherapy is unknown.

Objective

The study aimed to describe the profile and pre- and post-operative referrals to physiotherapy of patients admitted to the cardiothoracic unit at a selected hospital in Tanzania over a four-year period.

Method

Descriptive, retrospective design. A data extraction sheet was used to capture demographic, cardiac disease, ICU and hospital LOS, post-operative complications and physiotherapy referral data of all patients ≥18 years of age.

Results

105 cardiac surgeries were performed. Patients' mean age was 30.6 years (SD=10.48) and 54.3% (n=57/105) were female. Cardiac surgeries performed declined from 48.6% (n=51/105) in 2010 to 10.5% (n=11/105) in 2013. Cardiac arrest (33%, n=7/21), pneumonia (19%, n=4/21) and lung collapse (4.8%, n=1/21) were the notable documented post-operative complications. ICU mortality was highest (72,7%, n=8/11). Only 1% (n=1/105) of cases were referred pre-operatively versus 77.7% (n=80/103) post-operatively for physiotherapy.

Conclusion

Cardiac surgeries were reduced annually but the post-operative complications need to be reduced. Pre-operative physiotherapy referral may reduce pneumonia and lung collapse following cardiac surgery.

Clinical profile and outcomes of multisystem inflammatory syndrome in children associated with COVID-19 virus after surgery for congenital heart defects

Introduction

To study the clinical presentation, laboratory profile, echocardiographic details, management, and outcomes of children who were diagnosed to have multisystem inflammatory syndrome in children (MIS-C) in the immediate postoperative period after surgery for congenital heart defects (CHDs).

Materials and Methods

This is a prospective case-control study that included children diagnosed to have MIS-C in the postoperative period based on clinical signs, rise in inflammatory markers, and echocardiographic features of ventricular dysfunction or coronary involvement. Management included intravenous immunoglobulin (IVIG), steroids, and antiplatelet medications in addition to routine postoperative care. Out of the 461 children who underwent surgery for CHD between April 1st, 2021, and November 30th, 2021, 18 children were diagnosed with MIS-C. After the initial routine postoperative course, all 18 children had sudden worsening in clinical and laboratory parameters. Other causes such as bacterial infection were ruled out. All of these children had features of MIS-C with ventricular dilatation and dysfunction, coronary artery involvement, and reactive COVID-19 immunoglobulin G antibody. There was a significant improvement in coronary artery dimensions after IVIG administration (P = 0.001). The involvement of the left main coronary artery was associated with significantly increased length of intensive care unit (ICU) and hospital stay (P = 0.019). Mean ICU and hospital stay was prolonged in the MIS-C group. There were two deaths in this group due to severe left ventricular dysfunction.

Conclusions

During the pandemic, a proportion of patients undergoing elective cardiac surgery may develop unexpected worsening in clinical status due to MIS-C. A high index of suspicion and prompt treatment with IVIG and steroids may be helpful in improving outcomes.

Microvascular dysfunction following cardiopulmonary bypass plays a central role in postoperative organ dysfunction

Despite significant advances in surgical technique and strategies for tissue/organ protection, cardiac surgery involving cardiopulmonary bypass is a profound stressor on the human body and is associated with numerous intraoperative and postoperative collateral effects across different tissues and organ systems. Of note, cardiopulmonary bypass has been shown to induce significant alterations in microvascular reactivity. This involves altered myogenic tone, altered microvascular responsiveness to many endogenous vasoactive agonists, and generalized endothelial dysfunction across multiple vascular beds. This review begins with a survey of in vitro studies that examine the cellular mechanisms of microvascular dysfunction following cardiac surgery involving cardiopulmonary bypass, with a focus on endothelial activation, weakened barrier integrity, altered cell surface receptor expression, and changes in the balance between vasoconstrictive and vasodilatory mediators. Microvascular dysfunction in turn influences postoperative organ dysfunction in complex, poorly understood ways. Hence the second part of this review will highlight in vivo studies examining the effects of cardiac surgery on critical organ systems, notably the heart, brain, renal system, and skin/peripheral tissue vasculature. Clinical implications and possible areas for intervention will be discussed throughout the review.

Myocardial Surgical Revascularization in Patients with Reduced Left Ventricular Ejection Fraction

Background

Myocardial surgical revascularization in patients with low left ventricular ejection fraction (LVEF) is accompanied by a high rate of morbidity and mortality.

Objective

The aim of this study was to investigate and eliminate the reasons for the most common perioperative and postoperative complications.

Methods

A total of 64 were analyzed. of patients during 2019 who underwent coronary artery bypass grafting (CABG), average age 61.29±9.12 years.

Results

Out of the total number of operated patients, there were 16 women and 48 men. Patients were divided into two groups. The first group consisted of patients who underwent surgery with the use of cardiopulmonary bypass (cCABG-CPB) and the second group those who underwent surgery without the use of cardiopulmonary bypass (OPCAB). In 41 patients, myocardial infarction was previously recorded. Critical stenosis of the main trunk of the left coronary artery was present in 14 patients. The incidence of postoperative complications was higher in the cCABG-CPB 16/10 group (p0.030).

Conclusion

In our study, we confirmed that myocardial revascularization is justified, especially in the case of multivessel coronary disease. In the long term, it significantly improves the systolic function of the left ventricle, and thus and quality and length of life.

Effect of Ventilation Strategy During Cardiopulmonary Bypass on Arterial Oxygenation and Postoperative Pulmonary Complications After Pediatric Cardiac Surgery: A Randomized Controlled Study

OBJECTIVES

To compare the effects of 3 ventilation strategies during cardiopulmonary bypass (CPB) on arterial oxygenation and postoperative pulmonary complications (PPCs).

DESIGN

A prospective, randomized, controlled study.

SETTING

A single-center tertiary teaching hospital.

PARTICIPANTS

One hundred twenty pediatric patients undergoing elective repair of congenital acyanotic heart diseases with CPB.

INTERVENTIONS

Patients were assigned randomly into 3 groups according to ventilation strategy during CPB as follows: (1) no mechanical ventilation (NOV), (2) continuous positive airway pressure (CPAP) of 5 cmH₂O, (3) low tidal volume (LTV), pressure controlled ventilation (PCV), respiratory rate (RR) 20-to-30/min, and peak inspiratory pressure adjusted to keep tidal volume (Vt) 2 mL/kg.

MEASUREMENTS AND MAIN RESULTS

The PaO₂/fraction of inspired oxygen (F_IO₂) ratio and PaO₂ were higher in the 5 minutes postbypass period in the LTV group but were nonsignificant. The PaO₂/F_IO₂ ratio and PaO₂ were significant after chest closure and 1 hour after arrival to the intensive care unit with a higher PaO₂/F_IO₂ ratio and PaO₂ in the LTV group. Regarding the oxygenation index, the LTV group was superior to the NOV group at the 3 time points, with lower values in the LTV group. There were no significant differences in the predictive indices among the 3 groups, including the extubation time, and postoperative intensive care unit stays days. The incidence of PPCs did not significantly differ among the 3 groups.

CONCLUSIONS

Maintaining ventilation during CPB was associated with better oxygenation and did not reduce the incidence of PPCs in pediatric patients undergoing cardiac surgery.

Lung injury following cardiopulmonary bypass: a clinical update

INTRODUCTION

Cardiopulmonary bypass (CPB) is an integral component of cardiac surgery; however, one of its most critical complications is acute lung injury induced by multiple factors including systemic inflammatory response.

AREAS COVERED

The objective of this review is to investigate the multiple factors that can lead to CPB-induced lung injury. These include contact of blood components with the artificial surface of the CPB circuit, local and systemic inflammatory response syndrome (SIRS), lung ischemia/re-perfusion injury, arrest of ventilation, and circulating endotoxins. We also focus on possible interventions to curtail the negative impact of CPB, such as off-pump surgery, impregnation of the circuit with less biologically active substances, leukocyte depletion filters and ultrafiltration, and pharmacological agents such as steroids and aprotinin.

EXPERT OPINION

Although many aspects of CPB are proposed to contribute to lung injury, its overall role is still not clear. Multiple interventions have been introduced to reduce the risk of pulmonary dysfunction, with many of these interventions having shown promising results, significantly attenuating inflammatory mediators and improving post-operative outcome. However, since lung injury is multifactorial and affected by inextricably linked components, multiple interventions tackling each of them is required.

Impact of body mass index on postoperative oxygenation impairment in patients with acute aortic syndrome

Objective: Oxygenation impairment is a common complication of acute aortic syndrome (AAS) patients after surgical repair. The aim of this study is to identify the relationship between body mass index (BMI) and the risk of postoperative oxygenation impairment in AAS patients.

Methods: A total of 227 consecutive patients who were diagnosed as AAS and underwent surgical repair were recruited. They were divided into two groups based on the postoperative oxygenation impairment (non-oxygenation impairment group and oxygenation impairment group). Logistic regression was conducted to evaluate the association between BMI and the risk of oxygenation impairment after surgery. Dose-response curve and subgroup analysis were used to test the reliability of the results of regression analysis. A meta-analysis was then performed to further confirm these results using Pubmed, Embase, and Web of Science databases.

Results: For the retrospective study, a significant association was observed after adjusting for a series of variables. BMI was significantly correlated with postoperative oxygenation impairment in patients with AAS (OR, 95% CI, P: 1.27, 1.17–1.46, 0.001). Compared with the normal weight group (18.5 kg/m² ≤ BMI <23.0 kg/m²), patients with excessive BMI were at a higher risk of oxygenation impairment for the overweight group (23.0 kg/m² ≤ BMI <25 kg/m²) and obesity group (BMI ≥25 kg/m²) (OR, 95% CI, P: 4.96, 1.62–15.15, 0.005; 9.51, 3.06–29.57, <0.001). The dose-response curve showed that the risk of oxygenation impairment after surgery increased with the increased BMI. Besides, subgroup analysis showed that AAS patients who have an excess weight with a TNF-α ≥ 8.1 pg/ml carried an excess risk of postoperative oxygenation impairment. For the meta-analysis, the pooled result also indicated that AAS patients with high BMI had a significantly increased risk of oxygenation impairment after surgery (OR, 95% CI, P: 1.40, 1.18–1.66, 0.001).

Conclusion: Excessive BMI was an independent risk factor for AAS with postoperative oxygenation impairment.

Near Infrared Spectroscopy for Poor Grade Aneurysmal Subarachnoid Hemorrhage-A Concise Review

Delayed cerebral ischemia (DCI) disproportionately affects poor grade aneurysmal subarachnoid hemorrhage (aSAH) patients. An unreliable neurological exam and the lack of appropriate monitoring leads to unrecognized DCI, which in turn is associated with severe long-term deficits and higher mortality. Near Infrared Spectroscopy (NIRS) offers simple, continuous, real time, non-invasive cerebral monitoring. It provides regional cerebral oxygen saturation (c-rSO2), which reflects the balance between cerebral oxygen consumption and supply. Reports have demonstrated a good correlation with other cerebral oxygen and blood flow monitoring, and credible cerebrovascular reactivity indices were also derived from NIRS signals. Multiple critical c-rSO2 values have been reported in aSAH patients, based on various thresholds, duration, variation from baseline or cerebrovascular reactivity indices. Some were associated with vasospasm, some with DCI and others with clinical outcomes. However, the poor grade aSAH population has not been specifically studied and no randomized clinical trial has been published. The available literature does not support a specific NIRS-based intervention threshold to guide diagnostic or treatment in aSAH patients. We review herein the fundamental basic concepts behind NIRS technology, relationship of c-rSO2 to other brain monitoring values and their potential clinical interpretation. We follow with a critical evaluation of the use of NIRS in the aSAH population, more specifically its ability to diagnose vasospasm, to predict DCI and its association to outcome. In summary, NIRS might offer significant potential for poor grade aSAH in the future. However, current evidence does not support its use in clinical decision-making, and proper technology evaluation is required.

Outcomes in Patients With Severe Chronic Lung Disease Undergoing Index Cardiac Operations

BACKGROUND

This study evaluated the impact of severe chronic lung disease on outcomes of index adult cardiac operations.

METHODS

A single-center, retrospective study of adult patients with severe chronic lung disease (as defined by The Society of Thoracic Surgeons) undergoing index cardiac operations between 2010 and 2018 was performed. Multivariable Cox regression and Kaplan-Meier analyses were used to evaluate survival.

RESULTS

Three hundred fifty-four patients (median age, 69 years; 32.77% women) were identified. Current smokers comprised 42.66% of the population, and 34.65% of patients required home oxygen. Median preoperative forced expiratory volume in 1 second was 48% of predicted (interquartile range, 41%-56%), and median diffusing capacity of the lungs for carbon monoxide was 78% of predicted (interquartile range, 55%-101%). Most patients underwent isolated coronary artery bypass (57.06%) or isolated aortic valve replacement (19.49%). Overall, 33 patients (9.07%) required a tracheostomy (median of 10 days from surgery) for a median of 49 days (interquartile range, 25-114) until decannulation. Preoperative home oxygen use was an independent predictor of 30-day (hazard ratio, 2.91; P = .030) and 1-year (hazard ratio, 2.12; P = .009) mortality. One-year and 5-year postoperative survival were 83.62% and 58.34%, respectively.

CONCLUSIONS

Although severe chronic lung disease is a predictor of mortality and morbidity after index cardiac operations, only 9% of patients required a tracheostomy, and most were alive at 5 years after surgery. Home oxygen use may serve as a further stratification tool in this higher risk subset; however the presence of severe chronic lung disease alone should not deter from surgery in otherwise reasonable surgical candidates.

Airway Pressure Release Ventilation Mode Improves Circulatory and Respiratory Function in Patients After Cardiopulmonary Bypass, a Randomized Trial

Importance

Postoperative pulmonary complications and cardiovascular complications are major causes of morbidity, mortality, and resource utilization in cardiac surgery patients.

Objectives

To investigate the effects of airway pressure release ventilation (APRV) on respiration and hemodynamics in post cardiac surgery patients.

Main Outcomes and Measures

A single-center randomized control trial was performed. In total, 138 patients undergoing cardiopulmonary bypass were prospectively screened. Ultimately 39 patients met the inclusion criteria and were randomized into two groups: 19 patients were managed with pressure control ventilation (PCV) and 20 patients were managed with APRV. Respiratory mechanics after 4 h, hemodynamics within the first day, and Chest radiograph score (CRS) and blood gasses within the first three days were recorded and compared.

Results

A higher cardiac index (3.1 ± 0.7 vs. 2.8 ± 0.8 L⋅min^–1⋅m²; p < 0.05), and shock volume index (35.4 ± 9.2 vs. 33.1 ± 9.7 ml m^–2; p < 0.05) were also observed in the APRV group after 4 h as well as within the first day (p < 0.05). Compared to the PCV group, the PaO2/FiO₂ was significantly higher after 4 h in patients of APRV group (340 ± 97 vs. 301 ± 82, p < 0.05) and within the first three days (p < 0.05) in the APRV group. CRS revealed less overall lung injury in the APRV group (p < 0.001). The duration of mechanical ventilation and ICU length of stay were not significantly (p = 0.248 and 0.424, respectively).

Conclusions and Relevance

Compared to PCV, APRV may be associated with increased cardiac output improved oxygenation, and decreased lung injury in postoperative cardiac surgery patients.

Modified central extracorporeal membrane oxygenation for distended left ventricle

A 38-year-old man who was resuscitated from ventricular fibrillation was diagnosed with acute aortic dissection complicated by coronary malperfusion. He underwent total aortic arch replacement and coronary artery bypass grafting to the left anterior descending coronary artery. Due to low cardiac output syndrome from cardiac ischemia, central extracorporeal membrane oxygenator (ECMO) was established with aortic cannulation from the side branch of the implanted prosthetic graft and venous drainage from the femoral vein. Ventricular venting was added from the right upper pulmonary vein for the distended left ventricle. ECMO was weaned off on postoperative Day 4. The patient is back on his normal daily life for more than 1 year after the surgery.

Isoflurane suppresses lung ischemia-reperfusion injury by inactivating NF-κB and inhibiting cell apoptosis

Patients with lung ischemia-reperfusion injury (LIRI), involving cytokines, including interleukin (IL)-6 and IL-8, display poor clinical outcomes. Isoflurane displays protective effects against ischemia-reperfusion injury in numerous organs. In the present study, the effects of isoflurane on LIRI were investigated in vitro using a hypoxia-reoxygenation (HR) cell model. The mRNA expression levels of specific genes were analyzed by reverse transcription-quantitative PCR and protein expression levels were measured by ELISA and western blotting. Cell apoptosis and proliferation were assessed by flow cytometry and the Cell Counting Kit-8 assay, respectively. Isoflurane pretreatment decreased HR-induced IL-6 and IL-8 expression levels in A549 cells. Isoflurane pretreatment also inhibited HR-induced cell apoptosis and Bax expression, and reversed HR-induced downregulation of Bcl-2 expression. Moreover, isoflurane pretreatment decreased HR-induced NF-κB phosphorylated-p65 protein expression and NF-κB activation. Furthermore, HR-induced increases in malondialdehyde concentration and decreases in superoxide dismutase activity were reversed by isoflurane pretreatment. In conclusion, the results indicated that isoflurane suppressed LIRI by inhibiting the activation of NF-κB and the induction of cell apoptosis.

Effects of pulmonary perfusion during cardiopulmonary bypass on lung functions after cardiac operation

BACKGROUND

Pulmonary artery perfusion during cardiopulmonary bypass (CPB) is a known but rarely used technique in adult cardiac surgery. In this study, we aimed to investigate biochemical and histopathological effects of pulmonary artery perfusion during CPB on lung functions.

METHODS

Between May 2014 and August 2014, all patients (n = 24) who gave informed consent for participating this study with inclusion criteria were included. Patients undergoing isolated coronary artery bypass grafting were sequentially randomized to conventional CPB (control group, n = 12) and conventional CPB with selective pulmonary artery perfusion (study group, n = 12). Lung functions were monitored using PF ratio, alveolar-arterial oxygen gradient, and lactate levels. A small sample tissue from the left lung was excised for histopathologic examination. Immunocytochemistry analysis was performed using anti-rabbit polyclonal vascular endothelial growth factor (VEGF), rabbit polyclonal inducible nitric oxide synthase (i-NOS), and BCL-2 antibodies.

RESULTS

Postoperative course of the patients were uneventful without any clinical outcome differences in terms of cardiopulmonary complications, ventilation time and hospital stay. Pulmonary perfusion group had significantly better oxygenation values after extubation and at postoperative 24-hour. Electron microscopy examinations revealed better preservation of the alveolar wall integrity with pulmonary perfusion. The intensity of VEGF, i-NOS, and BCL-2 antibody expressions in bronchial epithelial cells were more prominent in the pulmonary perfusion group.

CONCLUSIONS

Pulmonary artery perfusion during aortic cross-clamping provides better oxygenation and preservation of the wall alveolar integrity after coronary artery bypass grafting surgery. This technique can be used as a protective strategy to minimize CPB-induced lung injury in adult cardiac surgery.

Delineating Pathways to Death by Multisystem Organ Failure in Patients With a Left Ventricular Assist Device

BACKGROUND

This study delineates the sequences of adverse events (AEs) preceding mortality attributed to multisystem organ failure (MSOF) in patients with a left ventricular assist device (LVAD).

METHODS

We analyzed 3765 AEs after 536 LVAD implants recorded in The Society of Thoracic Surgeons Intermacs data registry between 2006 and 2015 that resulted in MSOF death. Hierarchical clustering identified and visualized quantitatively unique clusters of patients with similar AE profiles. Markov modeling was used to illustrate the AE sequences that led to MSOF death within the clusters. Cox proportional hazard models determined the risk-adjusted, preimplant predictors of MSOF.

RESULTS

We identified 2 distinct MSOF clusters based on their proportion of AE types and survival time. The early-death cluster (418 patients, 2304 AEs) had a median survival of 1 month (interquartile range, 3-6 months), whereas the late-death cluster (118 patients, 1,461 AEs) had a median survival of 11 months (interquartile range, 6-22 months). The predominant AE sequences in the early-death and late-death clusters were renal failure, to respiratory failure, to death (62%) and bleeding, to infection, to respiratory failure, to death (45%), respectively. Significant risk-adjusted preimplant predictors of MSOF included line sepsis (hazard ratio [HR] 3.0; 95% confidence interval [CI], 1.1-8.2), extracorporeal membrane oxygenation (HR, 2.2; 95% CI, 1.2-3.9), and dialysis or ultrafiltration (HR, 2.1; 95% CI, 1.5-3.0).

CONCLUSIONS

This analysis identified 2 AE clusters and the predominant sequences that result in MSOF-associated mortality. MSOF develops in 1 cluster of patients after chronic bleeding and repeated infections but has prolonged survival, while another group dies early after renal and respiratory complications.

Anti-apoptosis effect of heme oxygenase-1 on lung injury after cardiopulmonary bypass

Background

This study aimed to investigate the anti-apoptosis effects of heme oxygenase-1 (HO-1) on lung injury (LI) after cardiopulmonary bypass (CPB) and its probable mechanisms.

Methods

One hundred and forty-four male Wistar rats were divided into 3 groups randomly: group A (control group), group B (cobalt protoporphyrin, CoPP), and group C [CoPP plus zinc protoporphyrin (ZnPP)]. Lung tissues were harvested at different time: before CPB (T0), 0 min after CPB (T1), 2 h after CPB (T2), 6 h (T3), 12 h (T4), and 24 h (T5).

Results

The HO-1 protein expressions in lung tissue in group B were higher than those in group A and group C in any given time, and the same as HO-1 activity (P<0.05). The expressions of Bcl-2 protein in group B at all time point after bypass were higher than those in group A and group C, and the difference was statistically significant (P<0.05). Apoptosis index (AI) in group B at any time point after bypass were lower than those in group A and group C (P<0.05).

Conclusions

CoPP can significantly increase the expression of HO-1 protein in lung tissue. HO-1 is still highly expressed after CPB, so as to play an important part in anti-apoptosis, and reduce LI.

Fatal Stroke After Reoperation for Lobar Torsion

Lobar torsion is an extremely rare complication after elective lung surgery. Rotation of the bronchovascular pedicle results in airway obstruction and vascular compromise with lobar ischemia and pulmonary infarction. Rapid reoperation with untwisting of the pedicle is usually proposed. We report a case of an upper lobe torsion occurring at postoperative day one after a full thoracoscopic combined middle lobectomy and S⁶ segmentectomy. Lung detorsion resulted in a fatal cerebral infarction.

Is there any connection between method of priming extracorporeal circuit and cerebral oximetry results?

Objectives. To compare the influence of different priming techniques on cerebral oximetry results during CPB in adult patients.

Methods. This study is a single-center retrospective review of data collected from adult patients who underwent isolated CABG with CPB between January and December, 2016. The patients were divided into two standardized groups with the sole difference between them being the method of priming CPB circuit: the first one was the group where we used our modified retrograde method of priming (n = 45) and the second one was the group with standard priming (n = 45). Hematocrit, hemoglobin, cerebral oxygenation were evaluated at the following points: beginning of the operation, start of CPB, cross clamping, 15, 30, 45 minutes and the end of CPB and the end of operation.

Results. In the first group indices of cerebral oximetry were higher comparing to the second group at list of the 45 minutes of CPB (р < 0,001). For the first 15 minutes of CPB hematocrit was also higher in the first group. Priming volume and the need for blood transfusion or ultrafiltration were also smaller in the first group.

Conclusion. Modified priming technique allows to maintain higher indices of cerebral oximetry, decreases volume overload and the need for blood transfusion comparing to standard technique.

Common inflammatory markers after cardiac surgery in infants and their relation to blood stream sepsis

Background

Limited information exists on trends of common inflammatory markers after infant heart surgery and their role in identifying post-operative sepsis.

Methods

275 consecutive infants undergoing cardiac surgery (231 with and 44 without Cardiopulmonary Bypass) were studied prospectively. Daily trends (0-4 day post-operative) of leucocyte counts, platelet counts and C-reactive protein were recorded. Association of these trends with early post-operative bloodstream sepsis, Cardiopulmonary Bypass and surgical outcomes were studied.

Observations

Trends of these inflammatory markers were noted. While off-Cardiopulmonary Bypass Surgery, and sepsis were associated with a statisticaly insignificant rise in total leucocyte count peaking on first post-operative day, Cardiopulmonary Bypass exposure was associated with significant decline (p = 0.002), more pronounced with Cardiopulmonary Bypass-exposure exceeding 150 min. Percentage of neutrophils showed a rise (maximum on first post-operative day) but no significant association with sepsis or Cardiopulmonary Bypass.Platelet counts significantly declined after surgery, with nadir on 2^nd POD (p < 0.001), the drop being more marked in patients operated on Cardiopulmonary Bypass (p < 0.005). Counts were significantly lower in patients exposed to >150 min Cardiopulmonary Bypass compared to those with shorter Cardiopulmonary Bypass. Septic patients had significantly lower platelet counts than uninfected patients, decline >2 SD from mean pre-operative level strongly associated with sepsis (p < 0.001).C-Reactive Protein levels rose markedly after surgery, peaking on 2^nd POD; levels were significantly higher if operated on Cardiopulmonary Bypass. Cardiopulmonary Bypass >150 min was associated with lower mean C-Reactive Protein on first post-operative day, but significantly higher values on third and fourth post-operative days, as compared to Cardiopulmonary Bypass <150 min. Comparison of infected versus non-infected patients showed significantly higher mean C-Reactive Protein in the former group.

Conclusion

While leucocyte count, platelet count and C-Reactive Protein emerged as useful markers of post-operative inflammatory response and reaction to Cardiopulmonary Bypass, they proved unsatisfactory predictors of early post-operative sepsis.

Gas6/Axl signaling attenuates alveolar inflammation in ischemia-reperfusion-induced acute lung injury by up-regulating SOCS3-mediated pathway

Background

Axl is a cell surface receptor tyrosine kinase, and activation of the Axl attenuates inflammation induced by various stimuli. Growth arrest-specific 6 (Gas6) has high affinity for Axl receptor. The role of Gas6/Axl signaling in ischemia-reperfusion-induced acute lung injury (IR-ALI) has not been explored previously. We hypothesized that Gas6/Axl signaling regulates IR-induced alveolar inflammation via a pathway mediated by suppressor of cytokine signaling 3 (SOCS3).

Methods

IR-ALI was induced by producing 30 min of ischemia followed by 90 min of reperfusion in situ in an isolated and perfused rat lung model. The rats were randomly allotted to a control group and IR groups, which were treated with three different doses of Gas6. Mouse alveolar epithelium MLE-12 cells were cultured in control and hypoxia-reoxygenation (HR) conditions with or without Gas6 and Axl inhibitor R428 pretreatment.

Results

We found that Gas6 attenuated IR-induced lung edema, the production of proinflammatory cytokines in perfusates, and the severity of ALI ex vivo. IR down-regulated SOCS3 expression and up-regulated NF-κB, and Gas6 restored this process. In the model of MLE-12 cells with HR, Gas6 suppressed the activation of TRAF6 and NF-κB by up-regulating SOCS3. Axl expression of alveolar epithelium was suppressed in IR-ALI but Gas6 restored phosphorylation of Axl. The anti-inflammatory effect of Gas6 was antagonized by R428, which highlighted that phosphorylation of Axl mediated the protective role of Gas6 in IR-ALI.

Conclusions

Gas6 up-regulates phosphorylation of Axl on alveolar epithelium in IR-ALI. The Gas6/Axl signaling activates the SOCS3-mediated pathway and attenuates IR-related inflammation and injury.

Comparative Study between Different Modes of Ventilation during Cardiopulmonary Bypass and its Effect on Postoperative Pulmonary Dysfunction

Background:

Postoperative pulmonary dysfunction is a prevalent complication after cardiac surgery; it has many contributing considerations due to either the surgery itself, anomalies to gas exchange or maybe as a result of alterations in lung mechanics. The aim of this study was to compare pressure-controlled ventilation versus volume-controlled ventilation in the presence of no ventilation group as a control group during cardiopulmonary bypass and its effect on postoperative pulmonary dysfunction.

Patients and Methods:

Sixty-six patients going through open-heart surgeries were included in the study. They divided into three groups (Group P: Pressure-controlled ventilation, Group V: Volume-controlled ventilation, and Group C: Control group with no ventilation) in accordance with the mode of ventilation. Patients studied for chest X-ray, lung ultrasound, arterial oxygen partial pressure to fractional inspired oxygen ratio, alveolar–arterial oxygen gradient, static lung compliance, and dynamic lung compliance, taken after induction of anesthesia, 1-h post-CPB, and 1 h after arrival to cardiac surgical unit.

Results:

There was no significant difference regarding the chest X-ray and lung ultrasonography results among the three groups of the study. Regarding arterial oxygen partial pressure to fractional inspired oxygen ratio, alveolar–arterial oxygen gradient, static lung compliance, and dynamic lung compliance, the results showed lower values in the postbypass period, and the postoperative period compared to the postinduction period among the three groups of the study with no significant difference.

Conclusions:

The evidence of clear benefits of maintaining ventilation alone during cardiopulmonary bypass is inconsistent. More studies are required to determine the precise role of different lung protective strategies during cardiopulmonary bypass.

Anesthetics to Prevent Lung Injury in Cardiac Surgery (APLICS): a protocol for a randomized controlled trial

Background

Patients undergoing cardiac surgery with cardiopulmonary bypass are at an increased risk of developing postoperative pulmonary complications, potentially leading to excess morbidity and mortality. It is likely that pulmonary ischemia-reperfusion (IR) injury during cardiopulmonary bypass is a major contributor to perioperative lung injury. Therefore, interventions that can minimize IR injury would be valuable in reducing the excess burden of this potentially preventable disease process. Volatile anesthetics including sevoflurane have been shown in both preclinical and human trials to effectively limit pulmonary inflammation in a number of settings including ischemia-reperfusion injury. However, this finding has not yet been demonstrated in the cardiac surgery population. The Anesthetics to Prevent Lung Injury in Cardiac Surgery (APLICS) trial is a randomized controlled trial (RCT) investigating whether sevoflurane anesthetic maintenance can modulate pulmonary inflammation occurring during cardiac surgery with cardiopulmonary bypass and whether this potential effect can translate to a reduction in postoperative pulmonary complications.

Methods

APLICS is a prospective RCT of adult cardiac surgical patients. Participants will be randomized to receive intraoperative anesthetic maintenance with either sevoflurane or propofol. Patients in both groups will be ventilated according to protocols intended to minimize the influences of ventilator-induced lung injury and hyperoxia. Bronchoalveolar lavage (BAL) and blood sampling will take place after anesthetic induction and 2–4 h after pulmonary reperfusion. The primary outcome is a difference between groups in the degree of post-bypass lung inflammation, defined by BAL concentrations of TNFα. Secondary outcomes will include differences in additional relevant BAL and systemic inflammatory markers and the incidence of postoperative pulmonary complications.

Discussion

APLICS investigates whether anesthetic choice can influence lung inflammation and pulmonary outcomes following cardiac surgery with cardiopulmonary bypass. A positive result from this trial would add to the growing body of evidence describing the lung protective properties of the volatile anesthetics and potentially reduce unnecessary morbidity for cardiac surgery patients.

Trial registration

ClinicalTrials.gov, NCT02918877. Registered on 29 September 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3400-x) contains supplementary material, which is available to authorized users.

The Predictive Value of Infant-Specific Preoperative Pulmonary Function Tests in Postoperative Pulmonary Complications in Infants with Congenital Heart Diseases

Background and Objective

To investigate the relationship between infant-specific preoperative pulmonary function tests (PFTs) and postoperative pulmonary complications (PPCs) in infants with congenital heart diseases (CHDs).

Methods

Patients of 1-3 years of age who received surgical treatment for CHDs from January 1^st, 2009, to December 31^st, 2017, were retrieved. Records of preoperative PFTs, methods of operation, anesthesia procedures, intraoperative vital signs, respiratory support modalities, and PPCs was retrieved and analyzed.

Results

122 infants met the preset inclusion criteria, including 72 males and 50 females. There were 76 cases of thoracotomy and 46 cases of cardiac catheterization. The overall incidence of PPCs was 15.6%, including 19.7% after thoracotomy and 8.7% after cardiac catheterization, respectively (p > 0.05). The incidence of PPCs was 35.4% or 2.7% in infants with a rapid or a normal respiratory rate, respectively; 42.1% or 3.6% in infants with an abnormal or a normal time to reach peak tidal expiratory flow versus the total expiratory time (TPTEF/TE), respectively; 39.0% or 3.7% in infants with an abnormal or a normal volume to peak expiratory flow versus the total expiratory volume (VPEF/VE), respectively; and 46.9% or 4.4% in infants with a decreased or a normal lung compliance, respectively (p < 0.01 in all comparisons).

Conclusions

The preoperative abnormal changes in respiratory rate, TPTEF/TE, VPEF/VE, and lung compliance are indicative of the risk of PPCs.

Differences of early immunological responses in on-pump versus off-pump cardiac surgery

INTRODUCTION

Cardiopulmonary bypass surgery is accompanied by an inflammatory response and pulmonary dysfunction that renders patients vulnerable to postoperative complications. The majority of studies investigating the inflammatory response in cardiopulmonary bypass focus on cytokine measurements. This study investigated the early response of peripheral blood cell types and early changes in lung tissue in on-pump versus off-pump cardiopulmonary bypass surgery.

METHODS

Landrace pigs were assigned to the following groups (n = 6 per group): 1. off-pump cardiopulmonary bypass, 2. conventional cardiopulmonary bypass, 3. heparin-coated cardiopulmonary bypass, 4. surface-reduced cardiopulmonary bypass, and 5. surface-reduced cardiopulmonary bypass plus lung perfusion. Surgery was performed under mild hyperthermia (32°C), with 90-minute ischemia and 180-minute reperfusion. Histological and flow cytometric analyses were performed.

RESULTS

Lung water content increased during reperfusion in heparin-coated (84.63 ± 2.99%) compared to conventional cardiopulmonary bypass (76.33 ± 4.56%, p = 0.04). Alveolar septal thickness increased during ischemia at heparin-coated (p < 0.01) and surface-reduced cardiopulmonary bypass plus lung perfusion (p = 0.05). Tumor necrosis factor expression increased significantly (p < 0.01) in peribronchial, perivascular, and peripheral lung areas in all on-pump groups, but not in off-pump cardiopulmonary bypass. The usage of heparin-coated cardiopulmonary bypass led to increased percentages of CD3⁺CD4⁺ (p = 0.03) and CD3⁺CD8⁺ (p = 0.01) T cells compared to an uncoated device. Natural killer and mature B lymphocytes decreased at conventional and surface-reduced cardiopulmonary bypass plus lung perfusion. Activated granulocytes and macrophages increased at conventional cardiopulmonary bypass and heparin-coated cardiopulmonary bypass.

CONCLUSION

Off-pump cardiopulmonary bypass induces less immunological response and lung injury than on-pump surgery. The reduction of cardiopulmonary bypass surface reduces the inflammatory immune response induced by cardiopulmonary bypass. Lung perfusion of surface-reduced cardiopulmonary bypass diminished the extravasation caused by surface reduction of the cardiopulmonary bypass.

Mitochondrial Aldehyde Dehydrogenase in Myocardial Ischemic and Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion (IR) injury during acute myocardial infarction or open-heart surgery would promote oxidative stress, leading to the accumulation of reactive aldehydes that cause cardiac damage. It has been well demonstrated that aldehyde dehydrogenase (ALDH)-2 is an important cardioprotective enzyme for its central role in the detoxification of reactive aldehydes. ALDH2 activation by small molecule activators is a promising approach for cardioprotection for myocardial IR injury.

Effect of preoperative inhaled budesonide on pulmonary injury after cardiopulmonary bypass: A randomized pilot study

BACKGROUND

Cardiopulmonary bypass can result in lung injury. This prospective, double-blinded, randomized trial aimed to evaluate the protective effect of inhaled budesonide on lung injury after cardiopulmonary bypass.

METHODS

Sixty patients, aged 25 to 65 years, requiring cardiopulmonary bypass were randomized to groups treated with saline or budesonide inhalation preoperatively. The respiratory mechanics were recorded. Bronchoalveolar lavage fluid was collected before cardiopulmonary bypass and after sternal closure. Serum and bronchoalveolar lavage fluid levels of proinflammatory and anti-inflammatory factors were analyzed. The primary end point was the lowest ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen after cardiopulmonary bypass. The durations of ventilation and postoperative recovery time were noted.

RESULTS

Budesonide significantly improved respiratory mechanics after cardiopulmonary bypass. Budesonide improved the partial pressure of arterial oxygen to the fraction of inspired oxygen ratio from 8 to 48 hours after the operation. Budesonide shortened the durations of mechanical ventilation and postoperative recovery time. Budesonide decreased the levels of proinflammatory factors while increasing the levels of anti-inflammatory factors in bronchoalveolar lavage fluid and serum (all P < .05). The macrophage and neutrophil counts, and protein and elastase concentrations were decreased by budesonide treatment.

CONCLUSIONS

Budesonide treatment shortened the durations of mechanical ventilation, inhibited local and systemic inflammation, and improved respiratory function after cardiopulmonary bypass.

Effect of ulinastatin on interleukins and pulmonary function in bypass patients: a meta-analysis of randomized controlled trials

BACKGROUND

Our aim was to evaluate the effect of urinary trypsin inhibitors (UTI) on interleukin, tumor necrosis factor-α (TNF-α), and polymorphonuclear neutrophil elastase (PMNE) levels as well as on pulmonary function in patients undergoing cardiopulmonary bypass.

MATERIALS AND METHODS

We searched the following databases for relevant studies: PubMed, Medline (Ovid SP), Cochrane Library, Wanfang Data, China Biology Medicine Database, Chinese Periodical Database, China Knowledge Resource Integrated Database, and Chinese Clinical Trial Registry. Two investigators independently collected the data and assessed the quality of each study. RevMan 5.3 was used for the meta-analysis.

RESULTS

In total, 15 randomized controlled trials (646 patients) met the inclusion criteria. There was a significant decrease in TNF-α, interleukin-6 (IL-6), IL-8, and PMNE levels at 6 h and 24 h after UTI treatment and an increase in IL-10 levels; additionally, there was a decrease in respiratory index and an improvement in the oxygenation index. Nevertheless, UTI treatment did not affect the length of intensive care unit stay, alveolar-arterial oxygen partial pressure difference, adverse lung events, or hospital mortality. Because of the high heterogeneity of the included trials, the results should be assessed carefully.

CONCLUSION

UTI treatment can suppress proinflammatory cytokine elevation and upregulate the release of anti-inflammatory mediators, thereby reducing pulmonary injury and improving pulmonary function after cardiopulmonary bypass.

Levosimendan prevents bronchoconstriction and adverse respiratory tissue mechanical changes in rabbits

Levosimendan has a calcium-sensitizing effect in the myocardium and opens ATP-sensitive potassium channels (KATP) in vascular smooth muscle. Because airway smooth muscle also expresses KATP, we characterized the protective potential of levosimendan against increased airway and respiratory tissue resistances. Animals were administered levosimendan alone ( group L), levosimendan after pretreatment with a KATP channel blocker (glibenclamide, group LG), glibenclamide only ( group G), or solvent alone (dextrose, group C). Airway resistance (Raw), tissue damping, and elastance were determined by forced oscillations under baseline conditions and following provocation tests with intravenous methacholine (MCh). Cardiac output (CO) was assessed by transpulmonary thermodilution. The same sequence of measurements was then repeated during intravenous infusion of levosimendan in groups L and LG or glucose in groups G and C. Sham treatments in groups C and G had no effect on lung responsiveness. However, levosimendan treatment in group L elevated CO and inhibited the MCh-induced airway responses [Raw changes of 87.8 ± 83% (SD) vs. 24.4 ± 16% at 4 μg·kg−1·min−1 MCh, P < 0.001], and in G (35.2 ± 12.7 vs. 25.2 ± 12.9%, P < 0.05). The preventive affect of levosimendan against lung constriction vanished in the LG group. Levosimendan exerts a KATP-mediated potential to prevent bronchoconstriction and may prohibit adverse lung peripheral changes both in the small bronchi and the pulmonary parenchyma. The identification of a further pleiotropic property of levosimendan that is related to the pulmonary system is of particular importance for patients with decreased cardiorespiratory reserves for which simultaneous circulatory support is complemented with prevention of adverse respiratory events.

Cardiothoracic Critical Care

High-value CCC is rapidly evolving to meet the demands of increased patient acuity and to incorporate advances in technology. The high-performing CCC system and culture should aim to learn quickly and continuously improve. CCC demands a proactive, interactive, precise, an expert team, and continuity.

Different strategies for mechanical VENTilation during CardioPulmonary Bypass (CPBVENT 2014): study protocol for a randomized controlled trial

Background

There is no consensus on which lung-protective strategies should be used in cardiac surgery patients. Sparse and small randomized clinical and animal trials suggest that maintaining mechanical ventilation during cardiopulmonary bypass is protective on the lungs. Unfortunately, such evidence is weak as it comes from surrogate and minor clinical endpoints mainly limited to elective coronary surgery. According to the available data in the academic literature, an unquestionable standardized strategy of lung protection during cardiopulmonary bypass cannot be recommended. The purpose of the CPBVENT study is to investigate the effectiveness of different strategies of mechanical ventilation during cardiopulmonary bypass on postoperative pulmonary function and complications.

Methods/design

The CPBVENT study is a single-blind, multicenter, randomized controlled trial. We are going to enroll 870 patients undergoing elective cardiac surgery with planned use of cardiopulmonary bypass. Patients will be randomized into three groups: (1) no mechanical ventilation during cardiopulmonary bypass, (2) continuous positive airway pressure of 5 cmH₂O during cardiopulmonary bypass, (3) respiratory rate of 5 acts/min with a tidal volume of 2–3 ml/Kg of ideal body weight and positive end-expiratory pressure of 3–5 cmH₂O during cardiopulmonary bypass. The primary endpoint will be the incidence of a PaO₂/FiO₂ ratio <200 until the time of discharge from the intensive care unit. The secondary endpoints will be the incidence of postoperative pulmonary complications and 30-day mortality. Patients will be followed-up for 12 months after the date of randomization.

Discussion

The CPBVENT trial will establish whether, and how, different ventilator strategies during cardiopulmonary bypass will have an impact on postoperative pulmonary complications and outcomes of patients undergoing cardiac surgery.

Trial registration

ClinicalTrials.gov, ID: NCT02090205. Registered on 8 March 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2008-2) contains supplementary material, which is available to authorized users.

Left Main Coronary Artery Thrombosis With Acute Myocardial Infarction: A Management Dilemma

Left main coronary artery (LMCA) thrombosis with acute myocardial infarction is a rare condition with very high mortality. The low incidence of this condition and exclusion of patients with LMCA thrombosis from clinical trials prevent the development of optimal management strategy in these patients. Therefore, there are no clear-cut guidelines describing an evidence-based approach for this condition. We describe a patient with LMCA thrombosis presenting with acute myocardial infarction, who was found to have hypercoagulable state related to homocysteinemia on further work-up. This case highlights the challenges faced during the management of this rare condition due to lack of clear-cut guidelines describing an evidence-based approach.

Alda-1 Attenuates Lung Ischemia-Reperfusion Injury by Reducing 4-Hydroxy-2-Nonenal in Alveolar Epithelial Cells

OBJECTIVES

Excessive oxidative stress is a main cause of lung ischemia-reperfusion injury, which often results in respiratory insufficiency after open-heart surgery for a cardiopulmonary bypass. Previous studies demonstrate that the activation of aldehyde dehydrogenase-2 could significantly reduce the oxidative stress mediated by toxic aldehydes and attenuate cardiac and cerebral ischemia-reperfusion injury. However, both the involvement of aldehydes and the protective effect of the aldehyde dehydrogenase-2 agonist, Alda-1, in lung ischemia-reperfusion injury remain unknown.

DESIGN

Prospective laboratory and animal investigation were conducted.

SETTING

State Key Laboratory of Cardiovascular Disease.

SUBJECTS

Primary human pulmonary alveolar epithelial cells, human pulmonary microvascular endothelial cells, and Sprague-Dawley rats.

INTERVENTIONS

A hypoxia/reoxygenation cell-culture model of human pulmonary alveolar epithelial cell, human pulmonary microvascular endothelial cell, and an isolated-perfused lung model were applied to mimic lung ischemia-reperfusion injury. We evaluated the effects of Alda-1 on aldehyde dehydrogenase-2 quantity and activity, on aldehyde levels and pulmonary protection.

MEASUREMENTS AND MAIN RESULTS

We have demonstrated that ischemia-reperfusion-induced pulmonary injury concomitantly induced aldehydes accumulation in human pulmonary alveolar epithelial cells and lung tissues, but not in human pulmonary microvascular endothelial cells. Moreover, Alda-1 pretreatment significantly elevated aldehyde dehydrogenase-2 activity, increased surfactant-associated protein C, and attenuated elevation of 4-hydroxy-2-nonenal, apoptosis, intercellular adhesion molecule-1, inflammatory response, and the permeability of pulmonary alveolar capillary barrier, thus alleviated injury.

CONCLUSIONS

Our study indicates that the accumulation of 4-hydroxy-2-nonenal plays an important role in lung ischemia-reperfusion injury. Alda-1 pretreatment can attenuate lung ischemia-reperfusion injury, possibly through the activation of aldehyde dehydrogenase-2, which in turn removes 4-hydroxy-2-nonenal in human pulmonary alveolar epithelial cells. Alda-1 pretreatment has clinical implications to protect lungs during cardiopulmonary bypass.

Ventilation during cardiopulmonary bypass for prevention of respiratory insufficiency: A meta-analysis of randomized controlled trials

BACKGROUND

Cardiopulmonary bypass (CPB) is necessary for most cardiac surgery, which may lead to postoperative lung injury. The objective of this paper is to systematically evaluate whether ventilation during CPB would benefit patients undergoing cardiac surgery.

METHODS

We searched randomized controlled trials (RCTs) through PubMed, Embase, and Cochrane Library from inception to October 2016. Eligible studies compared clinical outcomes of ventilation versus nonventilation during CPB in patients undergoing cardiac surgery. The primary outcome includes oxygenation index (PaO2/FiO2 ratio) or alveolar to arterial oxygen tension difference (AaDO2) immediately after weaning from bypass. The secondary outcomes include postoperative pulmonary complications (PPCs), shunt fraction (Qs/Qt), hospital stay, and AaDO2 4 hours after CPB.

RESULTS

Seventeen trials with 1162 patients were included in this meta-analysis. Ventilation during CPB significantly increased post-CPB PaO2/FiO2 ratio (mean difference [MD] = 21.84; 95% confidence interval [CI] = 1.30 to 42.37; P = 0.04; I = 75%) and reduced post-CPB AaDO2 (MD = -50.17; 95% CI = -71.36 to -28.99; P <0.00001; I = 74%). Qs/Qt immediately after weaning from CPB showed a significant difference between groups (MD = -3.24; 95% CI = -4.48 to -2.01; P <0.00001; I = 0%). Incidence of PPCs (odds ratio [OR] = 0.79; 95% CI = 0.42 to 1.48; P = 0.46; I = 37%) and hospital stay (MD = 0.09; 95% CI = -23 to 0.41; P = 0.58; I = 37%) did not differ significantly between groups.

CONCLUSION

Ventilation during CPB might improve post-CPB oxygenation and gas exchange in patients who underwent cardiac surgery. However, there is no sufficient evidence to show that ventilation during CPB could influence long-term prognosis of these patients. The beneficial effects of ventilation during CPB are requisite to be evaluated in powerful and well-designed RCTs.

Pulmonary Perfusion and Ventilation during Cardiopulmonary Bypass Are Not Associated with Improved Postoperative Outcomes after Cardiac Surgery

OBJECTIVES

Clinical trials of either pulmonary perfusion or ventilation during cardiopulmonary bypass (CBP) are equivocal. We hypothesized that to achieve significant improvement in outcomes both interventions had to be concurrent.

DESIGN

Retrospective case-control study.

SETTINGS

Major academic tertiary referral medical center.

PARTICIPANTS

Two hundred seventy-four consecutive patients who underwent open heart surgery with CBP 2009-2013.

INTERVENTIONS

The outcomes of 86 patients who received pulmonary perfusion and ventilation during CBP were retrospectively compared to the control group of 188 patients.

MEASUREMENTS AND MAIN RESULTS

Respiratory complications rates were similar in both groups (33.7 vs. 33.5%), as were the rates of postoperative pneumonia (4.7 vs. 4.3%), pleural effusions (13.9 vs. 12.2%), and re-intubations (9.3 vs. 9.1%). Rates of adverse postoperative cardiac events including ventricular tachycardia (9.3 vs. 8.5%) and atrial fibrillation (33.7 vs. 28.2%) were equivalent in both groups. Incidence of sepsis (8.1 vs. 5.3%), postoperative stroke (2.3 vs. 2.1%), acute kidney injury (2.3 vs. 3.7%), and renal failure (5.8 vs. 3.7%) was likewise comparable. Despite similar transfusion requirements, coagulopathy (12.8 vs. 5.3%, p = 0.031) and the need for mediastinal re-exploration (17.4 vs. 9.6%, p = 0.0633) were observed more frequently in the pulmonary perfusion and ventilation group, but the difference did not reach the statistical significance. Intensive care unit (ICU) and hospital stays, and the ICU readmission rates (7.0 vs. 8.0%) were similar in both groups.

CONCLUSION

Simultaneous pulmonary perfusion and ventilation during CBP were not associated with improved clinical outcomes.

Independent risk factors for hypoxemia after surgery for acute aortic dissection

Objectives:

To determine risk factors associated with postoperative hypoxemia after surgery for acute type A aortic dissection.

Methods:

We retrospectively analyzed the clinical data of 192 patients with acute type A aortic dissection who underwent surgery in Qingdao Municipal Hospital, Medical College of Qingdao University, Qingdao, China between January 2007 and December 2013. Patients were divided into hypoxemia group (n=55) [arterial partial pressure of oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) ≤200 mm Hg] and non-hypoxemia group (n=137) [PaO₂/FiO₂ >200 mm Hg]. Perioperative clinical data were analyzed and compared between the 2 groups.

Results:

The incidence of postoperative hypoxemia after surgery for acute aortic dissection was 28.6% (55/192). Perioperative death occurred in 13 patients (6.8%). Multivariate regression identified body mass index (BMI) >25 kg/m² (OR=21.929, p=0.000), deep hypothermic circulatory arrest (DHCA) (OR=11.551, p=0.000), preoperative PaO₂/FiO₂ ≤300 mm Hg (OR=7.830, p=0.000) and blood transfusion >6U in 24 hours postoperatively (OR=12.037, p=0.000) as independent predictors of postoperative hypoxemia for patients undergoing Stanford A aortic dissection surgery.

Conclusion:

Our study demonstrated that BMI >25 kg/m², DHCA, preoperative PaO₂/FiO₂ ≤300 mm Hg, and blood transfusion in 24 hours postoperatively >6U were independent risk factors of the hypoxemia after acute type A aortic dissection aneurysm surgery.