Acute lung injury after thoracic surgery

Association between cardiopulmonary bypass time and mortality among patients with acute respiratory distress syndrome after cardiac surgery

BACKGROUND

Cardiopulmonary bypass (CPB) can lead to lung injury and even acute respiratory distress syndrome (ARDS) through triggering systemic inflammatory response. The objective of this study was to investigate the impact of CPB time on clinical outcomes in patients with ARDS after cardiac surgery.

METHODS

Totally, patients with ARDS after cardiac surgery in Beijing Anzhen Hospital from January 2005 to December 2015 were retrospectively included and were further divided into three groups according to the median time of CPB. The primary endpoints were the ICU mortality and in-hospital mortality, and ICU and hospital stay. Restricted cubic spline (RCS), logistic regression, cox regression model, and receiver operating characteristic (ROC) curve were adopted to explore the relationship between CPB time and clinical endpoints.

RESULTS

A total of 54,217 patients underwent cardiac surgery during the above period, of whom 210 patients developed ARDS after surgery and were finally included. The ICU mortality and in-hospital mortality were 21.0% and 41.9% in all ARDS patients after cardiac surgery respectively. Patients with long CPB time (CPB time ≥ 173 min) had longer length of ICU stay (P = 0.011), higher ICU (P < 0.001) mortality and in-hospital(P = 0.002) mortality compared with non-CPB patients (CPB = 0). For each ten minutes increment in CPB time, the hazards of a worse outcome increased by 13.3% for ICU mortality and 9.3% for in-hospital mortality after adjusting for potential factors. ROC curves showed CPB time presented more satisfactory power to predict mortality compared with APCHEII score. The optimal cut-off value of CPB time were 160.5 min for ICU mortality and in-hospital mortality.

CONCLUSIONS

Our findings demonstrated the significant prognostic value of CPB time in patients with ARDS after cardiac surgery. Longer time of CPB was associated with poorer clinical outcomes, and could be served as an indicator to predict short-term mortality in patients with ARDS after cardiac surgery.

Temporal and Spatial Patterns of Inflammation and Tissue Injury in Patients with Postoperative Respiratory Failure after Lung Resection Surgery: A Nested Case-Control Study

Thoracic surgeries involving resection of lung tissue pose a risk of severe postoperative pulmonary complications, including acute respiratory distress syndrome (ARDS) and respiratory failure. Lung resections require one-lung ventilation (OLV) and, thus, are at higher risk of ventilator-induced lung injury (VILI) attributable to barotrauma and volutrauma in the one ventilated lung, as well as hypoxemia and reperfusion injury on the operated lung. Further, we also aimed to assess the differences in localized and systemic markers of tissue injury/inflammation in those who developed respiratory failure after lung surgery versus matched controls who did not develop respiratory failure. We aimed to assess the different inflammatory/injury marker patterns induced in the operated and ventilated lung and how this compared to the systemic circulating inflammatory/injury marker pattern. A case-control study nested within a prospective cohort study was performed. Patients with postoperative respiratory failure after lung surgery (n = 5) were matched with control patients (n = 6) who did not develop postoperative respiratory failure. Biospecimens (arterial plasma, bronchoalveolar lavage separately from ventilated and operated lungs) were obtained from patients undergoing lung surgery at two timepoints: (1) just prior to initiation of OLV and (2) after lung resection was completed and OLV stopped. Multiplex electrochemiluminescent immunoassays were performed for these biospecimen. We quantified 50 protein biomarkers of inflammation and tissue injury and identified significant differences between those who did and did not develop postoperative respiratory failure. The three biospecimen types also display unique biomarker patterns.

Peroxiredoxin 6 mediates the protective function of curcumin pretreatment in acute lung injury induced by serum from patients undergoing one-lung ventilation in vitro

Background

Curcumin has attracted much attention due to its wide range of therapeutic effects. In this study, we used serum collected from patients undergoing one-lung ventilation (OLV) to establish an in vitro acute lung injury (ALI) model to explore the potential protective mechanism of curcumin on ALI. Our study provides a new reference for the prevention and treatment of ALI induced by OLV.

Methods

A549 cells were treated with 20% serum from patients undergoing OLV to establish an in vitro ALI model. Curcumin, at a dose of 40 μg/ml, was administered two hours prior to this model. The levels of inflammation and oxidative stress markers were observed by Western blot, qRT–PCR, ELISA and reactive oxygen species assay. Additionally, the expression of peroxiredoxin 6 (Prdx6) and proteins involved in the NF-κB signaling pathway was evaluated.

Results

Twenty percent of serum collected from patients undergoing OLV downregulated the expression of Prdx6, leading to the activation of the NF-κB signaling pathway, which was associated with the subsequent overproduction of inflammatory cytokines and reactive oxygen species. Pretreatment with curcumin restored Prdx6 downregulation and inhibited NF-κB pathway activation by suppressing the nuclear translocation of P65, eventually reducing inflammation and oxidative stress damage in A549 cells.

Conclusions

Prdx6 mediated the protective function of curcumin by inhibiting the activation of the NF-κB pathway in ALI in vitro.

Recommendations from the Italian intersociety consensus on Perioperative Anesthesia Care in Thoracic surgery (PACTS) part 1: preadmission and preoperative care

INTRODUCTION

Anesthetic care in patients undergoing thoracic surgery presents specific challenges that necessitate standardized, multidisciplionary, and continuously updated guidelines for perioperative care.

METHODS

A multidisciplinary expert group, the Perioperative Anesthesia in Thoracic Surgery (PACTS) group, comprising 24 members from 19 Italian centers, was established to develop recommendations for anesthesia practice in patients undergoing thoracic surgery (specifically lung resection for cancer). The project focused on preoperative patient assessment and preparation, intraoperative management (surgical and anesthesiologic care), and postoperative care and discharge. A series of clinical questions was developed, and PubMed and Embase literature searches were performed to inform discussions around these areas, leading to the development of 69 recommendations. The quality of evidence and strength of recommendations were graded using the United States Preventative Services Task Force criteria.

RESULTS

Recommendations for preoperative care focus on risk assessment, patient preparation (prehabilitation), and the choice of procedure (open thoracotomy vs. video-assisted thoracic surgery).

CONCLUSIONS

These recommendations should help pulmonologists to improve preoperative management in thoracic surgery patients. Further refinement of the recommendations can be anticipated as the literature continues to evolve.

Comparison of tracheal intubation with controlled ventilation and laryngeal mask airway with spontaneous ventilation for thoracoscopic bullectomy

General anesthesia with double-lumen endobronchial intubation is considered mandatory for thoracoscopic bullectomy. We assessed the safety and feasibility of thoracoscopic bullectomy for treatment of primary spontaneous pneumothorax (PSP) under intubating laryngeal mask airway (ILMA) with spontaneous breathing sevoflurane anesthesia combined with thoracic paravertebral block (TPB).From January 2018 to December 2018, some 34 consecutive patients with PSP were treated by thoracoscopic bullectomy under ILMA with spontaneous breathing sevoflurane anesthesia combined with TPB (study group). To evaluate the safety and feasibility of this new technique, these patients were compared with the control group consisting of 34 consecutive patients with PSP who underwent thoracoscopic bullectomy using tracheal intubation with controlled ventilation from January 2017 to December 2017. The demographic characteristics, intraoperative surgical and anesthetic results, and postoperative results were assessed.The 2 groups had comparable anesthetic time, operation time, chest drainage time, postoperative hospital stays, and hospitalization cost. Visual analogue score (VAS) scores at 3 hours at rest and at coughing were significantly lower in the study group than in the control group (mean, 0.9 vs 2.0 and 1.8 vs 4.0, P = .024 and P = .006, respectively). No differences were seen in PaO2 values between the 2 groups in the intraoperative stage and postoperative stage (P > .05, respectively). The pH value was significantly lower in the intraoperative stage (mean, 7.28 vs 7.40, P = .01) and higher in the postoperative stage (mean, 7.35 vs 7.33, P = .014) in the study group than in the control group. The PaCO2 value was significantly higher in the intraoperative stage in the study group than in the control group (mean, 57.0 mm Hg vs 42.0 mm Hg, P = .015). In the study group, no cough reflex was found, and the level of collapse of the operative lung was excellent in 31 cases and good in 3 cases.Our study demonstrated that thoracoscopic bullectomy for treatment of PSP can be safely and feasibly performed in highly selected patients under ILMA with spontaneous breathing sevoflurane anesthesia combined with TPB.

Risk factors of postoperative acute lung injury following lobectomy for nonsmall cell lung cancer

Acute lung injury following lung resection surgery is not rare and often related to mortality. Although it has been a significant clinical and economic impact associated with increased intensive care unit (ICU) utilization, length of hospital stay, and associated cost, it is unpredictable. Aims of this study were to identify the modifiable risk factors of postoperative acute lung injury (PALI) following lung cancer surgery.We retrospectively analyzed medical records of 354 cases of lung cancer surgery in the tertiary university hospital from January 2012 to December 2015. PALI was defined as bilateral diffuse pulmonary infiltration on chest radiography, oxygenation failure (PaO2/FiO2 < 300), and absence of sign of left ventricular failure within a week from operation. We classified patients into either PALI group or non-PALI group and compared clinical characteristics of two groups. Logistic regression model was fitted to evaluate the risk factor of PALI.Among 354 cases of lung cancer surgeries, 287 lobectomies were analyzed. The overall incidence of PALI was 2.79% (8/287); four patients developed pneumonia with acute respiratory distress syndrome, and four patients developed ALI without clinical infection sign. There was no difference in baseline characteristics between PALI group and non-PALI group, but in operative parameters, a larger amount of fluid infusion was observed in PALI group. Logistic regression model showed underlying ischemic heart disease (OR 7.67, 95% CI 1.21-47.44, P = .03), interstitial lung disease (OR 30.36, 95% CI 2.30-401.52, P = .01), intravascular crystalloid fluid during surgery (OR 1.10, 95% CI 1.00-1.20, P = .04), and intraoperative transfusion (OR 56.4, 95% CI 3.53-901.39, P < .01) were risk factors of PALI. PALI increases ICU admission, use of mechanical ventilator, duration of hospital stay, and mortality.The clinical impact of PALI is marked. Significant independent risk factors have been identified in underlying ischemic heart disease, interstitial lung disease, intravascular crystalloid fluid, and transfusion during surgery.

Effects of Positive End-Expiratory Pressure on the Risk of Postoperative Pulmonary Complications in Patients Undergoing Elective Craniotomy

BACKGROUND

Intraoperative use of positive end-expiratory pressure (PEEP) has a protective effect in patients with acute lung injury and is recommended during anesthesia to minimize postoperative pulmonary complications. However, high levels of pressure might also cause harm to the lung because of overdistension. This retrospective study was designed to compare the effect of low and high levels of PEEP on the risk of postoperative pulmonary complications in patients with normal lung function who were undergoing an elective craniotomy.

METHODS

Two thousand four hundred thirty-seven patients without any pre-existing respiratory disease, who underwent an elective craniotomy, were hospitalized from January 1, 2008, to December 31, 2012. The patients were divided into 2 groups according to the application of an intraoperative PEEP < 5 or ≥ 5 cm H₂O, referred as low and high groups. Primary outcome was the odds of postoperative pneumonia and the requirement for either noninvasive ventilation (NIV) or reintubation and mechanical ventilation (MV).

RESULTS

One thousand twenty-three (42%) of 2437 patients were in the low group, and 1414 patients (58%) were in the high group. Patients in the low group did not show any difference in the incidence of postoperative pneumonia (P = 0.523) or the requirement of postoperative reintubation and MV (P = 0.999) compared with those in the high group. The incidence of reintubation and MV is significantly associated with postoperative pneumonia (P < 0.001).

CONCLUSIONS

Low and high levels of PEEP show similar incidences of postoperative pneumonia and requirement of postoperative NIV or invasive MV in patients with normal function of the lungs undergoing elective craniotomy.

Topography and extent of pulmonary vagus nerve supply with respect to transthoracic oesophagectomy

Pulmonary complications are frequently observed after transthoracic oesophagectomy. These complications may be reduced by sparing the vagus nerve branches to the lung. However, current descriptions of the regional anatomy are insufficient. Therefore, we aimed to provide a highly detailed description of the course of the pulmonary vagus nerve branches. In six fixed adult human cadavers, bilateral microscopic dissection of the vagus nerve branches to the lungs was performed. The level of branching and the number, calibre and distribution of nerve branches were described. Nerve fibres were identified using neurofilament immunohistochemistry, and the nerve calibre was measured using computerized image analysis. Both lungs were supplied by a predominant posterior and a smaller anterior nerve plexus. The right lung was supplied by 13 (10-18) posterior and 3 (2-3) anterior branches containing 77% (62-100%) and 23% (0-38%) of the lung nerve supply, respectively. The left lung was supplied by a median of 12 (8-13) posterior and 3 (2-4) anterior branches containing 74% (60-84%) and 26% (16-40%) of the left lung nerve supply, respectively. During transthoracic oesophagectomy with en bloc lymphadenectomy and transection of the vagus nerves at the level of the azygos vein, 68-100% of the right lung nerve supply and 86-100% of the inferior left lung lobe nerve supply were severed. When vagotomy was performed distally to the last large pulmonary branch, 0-8% and 0-13% of the nerve branches to the right middle/inferior lobes and left inferior lobe, respectively, were lost. In conclusion, this study provides a detailed description of the extensive pulmonary nerve supply provided by the vagus nerves. During oesophagectomy, extensive mediastinal lymphadenectomy denervates the lung to a great extent; however, this can be prevented by performing the vagotomy distal to the caudalmost large pulmonary branch. Further research is required to determine the feasibility of sparing the pulmonary vagus nerve branches without compromising the completeness of lymphadenectomy.

Addressing the Global Burden of Trauma in Major Surgery

Despite a technically perfect procedure, surgical stress can determine the success or failure of an operation. Surgical trauma is often referred to as the "neglected step-child" of global health in terms of patient numbers, mortality, morbidity, and costs. A staggering 234 million major surgeries are performed every year, and depending upon country and institution, up to 4% of patients will die before leaving hospital, up to 15% will have serious post-operative morbidity, and 5-15% will be readmitted within 30 days. These percentages equate to around 1000 deaths and 4000 major complications every hour, and it has been estimated that 50% may be preventable. New frontline drugs are urgently required to make major surgery safer for the patient and more predictable for the surgeon. We review the basic physiology of the stress response from neuroendocrine to genomic systems, and discuss the paucity of clinical data supporting the use of statins, beta-adrenergic blockers and calcium-channel blockers. Since cardiac-related complications are the most common, particularly in the elderly, a key strategy would be to improve ventricular-arterial coupling to safeguard the endothelium and maintain tissue oxygenation. Reduced O2 supply is associated with glycocalyx shedding, decreased endothelial barrier function, fluid leakage, inflammation, and coagulopathy. A healthy endothelium may prevent these "secondary hit" complications, including possibly immunosuppression. Thus, the four pillars of whole body resynchronization during surgical trauma, and targets for new therapies, are: (1) the CNS, (2) the heart, (3) arterial supply and venous return functions, and (4) the endothelium. This is termed the Central-Cardio-Vascular-Endothelium (CCVE) coupling hypothesis. Since similar sterile injury cascades exist in critical illness, accidental trauma, hemorrhage, cardiac arrest, infection and burns, new drugs that improve CCVE coupling may find wide utility in civilian and military medicine.

The effect of perioperative administration of glucocorticoids on pulmonary complications after transthoracic oesophagectomy: a systematic review and meta-analysis

BACKGROUND

Severe pulmonary complications occur frequently following transthoracic oesophagectomy. An exaggerated immunological response is probably a main driving factor, and this might be prevented by perioperative administration of a glucocorticoid.

OBJECTIVE

To determine the clinical benefits and harms of perioperative glucocorticoid during transthoracic oesophagectomy, using pulmonary complications as the primary outcome. Mortality, anastomotic leakage rate and infection were secondary outcomes.

METHODS

A systematic review of interventional trials with a meta-analysis of randomised controlled trials (RCTs).

RESULTS

The search retrieved seven RCTs and four interventional nonrandomised studies. In total, 367 patients received perioperative glucocorticoid and 415 patients did not. A meta-analysis of the RCTs showed no significant effect of glucocorticoid. For pulmonary complications, the pooled risk ratio was 0.69 [95% confidence interval (CI) 0.26 to 1.79], for anastomotic leakage 0.61 (95% CI 0.23 to 1.61) and for infections 1.09 (95% CI 0.41 to 2.93). A subgroup analysis of RCTs that used weight-dependent dosing within 30 min preoperatively showed a pooled risk ratio of 0.28 (95% CI 0.10 to 0.77) for pulmonary complications compared with placebo.

CONCLUSION

In this meta-analysis, perioperative administration of glucocorticoid did not affect the risk of pulmonary complications after transthoracic oesophagectomy, nor did it cause adverse effects. A subgroup analysis showed that a weight-dependent dose of methylprednisolone 10 to 30 mg kg within 30 min preoperatively might be the most promising dosing regimen for further research.

[Postoperative respiratory insufficiency and its treatment]

The development of a postoperative respiratory insufficiency is typically caused by several factors and include patient-related risks, the extent of the procedure and postoperative complications. Morbidity and mortality rates in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are high. It is important to have consistent strategies for prevention and preoperative conditioning is essential primarily for high-risk patients. Treatment of established postoperative lung failure requires early tracheotomy, protective ventilation (tidal volume 6 ml/kg body weight), elevated positive end expiratory pressure (PEEP, 10-20 mmH2O), recurrent bronchoscopy and early patient mobilization. In critical cases an extracorporeal lung assist is considered to be beneficial as a bridge to recovery and for realizing a protective ventilation protocol. Different systems with separate indications are available. The temporary application of a lung assist allows thoracic surgery to be performed safely in patients presenting with insufficient respiratory function.

Acute lung injury in thoracic surgery

PURPOSE OF REVIEW

This review will analyze the risk factors of acute lung injury (ALI) in patients undergoing thoracic surgery. Evidence for the occurrence of lung injury following mechanical ventilation and one-lung ventilation (OLV) and the strategies to avoid it will also be discussed.

RECENT FINDINGS

Post-thoracotomy ALI has become one of the leading causes of operative death. The pathogenesis of ALI implicates a multiple-hit sequence of various triggering factors (e.g. preoperative conditions, surgery-induced inflammation, ventilator-induced injury, fluid overload, and transfusion). Conventional ventilation during OLV is performed with high tidal volumes equal to those being used in two-lung ventilation, high FiO(2), and without positive end-expiratory pressure. This practice was originally recommended to improve oxygenation and decrease shunt fraction during OLV. However, a number of recent studies using experimental models or human patients have shown low tidal volumes to be associated with a decrease in inflammatory mediators and a reduction in pulmonary postoperative complications. However, the application of such protective strategies could be harmful if not still properly used.

SUMMARY

The goal of ventilation is to minimize lung trauma by avoiding overdistension and repetitive alveolar collapse, while providing adequate oxygenation. Protective ventilation is not simply synonymous of low tidal volume ventilation, but it also involves positive end-expiratory pressure, lower FiO(2), recruitment maneuvers, and lower ventilatory pressures.

Perioperative fluid management for pulmonary resection surgery and esophagectomy

Perioperative fluid management is of significant importance during pulmonary resection surgery and esophagectomy. Excessive fluid administration has been consistently shown as a risk factor for lung injury after thoracic procedures. Probable causes of this serious complication include fluid overload, lung lymphatics and pulmonary endothelial damage. Along with new insights regarding the Starling equation and the absence of a third space, current evidence supports a restrictive fluid regimen for patients undergoing pulmonary resection surgery and esophagectomy. Multiple minimally invasive hemodyamic monitoring devices, including pulse pressure/stroke volume variation, esophageal Doppler, and extravascular lung water measurement, were evaluated for optimizing perioperative fluid therapy. Further research regarding the prevention, diagnosis, and treatment of acute lung injury after pulmonary resection and esophagectomy is required.

Goal-directed fluid therapy using stroke volume variation does not result in pulmonary fluid overload in thoracic surgery requiring one-lung ventilation

Background. Goal-directed fluid therapy (GDT) guided by functional parameters of preload, such as stroke volume variation (SVV), seems to optimize hemodynamics and possibly improves clinical outcome. However, this strategy is believed to be rather fluid aggressive, and, furthermore, during surgery requiring thoracotomy, the ability of SVV to predict volume responsiveness has raised some controversy. So far it is not known whether GDT is associated with pulmonary fluid overload and a deleterious reduction in pulmonary function in thoracic surgery requiring one-lung-ventilation (OLV). Therefore, we assessed the perioperative course of extravascular lung water index (EVLWI) and p_aO₂/F_iO₂-ratio during and after thoracic surgery requiring lateral thoracotomy and OLV to evaluate the hypothesis that fluid therapy guided by SVV results in pulmonary fluid overload. Methods. A total of 27 patients (group T) were enrolled in this prospective study with 11 patients undergoing lung surgery (group L) and 16 patients undergoing esophagectomy (group E). Goal-directed fluid management was guided by SVV (SVV < 10%). Measurements were performed directly after induction of anesthesia (baseline—BL), 15 minutes after implementation OLV (OLVimpl15), and 15 minutes after termination of OLV (OLVterm15). In addition, postoperative measurements were performed at 6 (6postop), 12 (12postop), and 24 (24postop) hours after surgery. EVLWI was measured at all predefined steps. The p_aO₂/F_iO₂-ratio was determined at each point during mechanical ventilation (group L: BL-OLVterm15; group E: BL-24postop). Results. In all patients (group T), there was no significant change (P > 0.05) in EVLWI during the observation period (BL: 7.8 ± 2.5, 24postop: 8.1 ± 2.4 mL/kg). A subgroup analysis for group L and group E also did not reveal significant changes of EVLWI. The p_aO₂/F_iO₂-ratio decreased significantly during the observation period (group L: BL: 462 ± 140, OLVterm15: 338 ± 112 mmHg; group E: BL: 389 ± 101, 24postop: 303 ± 74 mmHg) but remained >300 mmHg except during OLV. Conclusions. SVV-guided fluid management in thoracic surgery requiring lateral thoracotomy and one-lung ventilation does not result in pulmonary fluid overload. Although oxygenation was reduced, pulmonary function remained within a clinically acceptable range.