Intraoperative management of locally advanced mediastinal masses: options and role of extracorporeal cardio-respiratory support through a case-series evaluation

Introduction

Mediastinal masses are histologically and clinically heterogeneous (1). Although some disorders such as lymphomas may benefit from primary chemotherapy and radiotherapy (2), surgery often represents the gold standard treatment in resectable diseases (3). Surgery could be characterized by a high rate of cardiorespiratory complications possibly occurring in any operative phase: patient positioning, induction of anesthesia, surgical manipulation and at extubation (4,5). In some situations, extracorporeal cardio-respiratory (C-R) support may be required to provide hemodynamic or oxygenation external support (6-8). The choice of the most appropriate extracorporeal C-R support for giant or infiltrating mediastinal masses resection is a complex indication. Developing predetermined pathways and a multidisciplinary approach could represent an effective strategy for planning the best management and avoiding emergency situations. Considering the rarity of cases the lack of international guidelines on this specific issue, a series of exemplifying cases are reviewed to propose strategic options and possible approaches. All patients underwent surgery at Policlinico Umberto I hospital in Rome between 2017 and 2024.

We present this article in accordance with the PROCESS reporting checklist (available at https://ccts.amegroups.com/article/view/10.21037/ccts-25-33/rc).

Case presentation

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patients for the publication of this case series and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Case 1—critical airway stenosis

A 27-year-old woman with history of polycystic ovary syndrome and obesity was referred to emergency department for dysphagia and worsening orthopnea. Computed tomography (CT) scan was performed in prone position and revealed a 10 cm × 14 cm × 17 cm giant mass in the anterior mediastinum (Figure 1). The mass compressed the heart, the ascending aorta, the superior vena cava (SVC) while the trachea showed a severe stenosis with a 3-mm lumen at the worst level. The patient underwent tumor biopsy through right anterior mediastinotomy (Chamberlain procedure). This is a common choice in case of anterior mediastinal masses suspected for hematological disease to provide an adequate tissue sampling for diagnosis. During the procedure, in view of possible sudden collapse of the tracheal lumen, a rigid bronchoscopy team was ready for emergency intubation. In this situation, a veno-venous extracorporeal membrane oxygenation (V-V ECMO) team stand-by is necessary after the emergency treatment to allow a possible safe extubation. The procedure was safely performed after local anesthesia injection (subcutaneously and intramuscularly) with the patient awake and conscious in semi-orthopneic position to avoid airway worsening. No emergency bronchoscopy and intubation were required. Histological examination revealed a T-lymphoblastic lymphoma. The patient was thus referred to hematologists for treatment.

Figure 1 Preoperative CT imaging. The giant mediastinal mass compressed the heart, great vessel and the trachea, that presented a compressed lumen of 3.02 mm. The CT scan was performed in prone position due to dyspnea in supine position caused by the mass compression. CT, computed tomography.

Case 2—central cardiopulmonary bypass (CPB)

A 35-year-old woman with history of pituitary dwarfism and Type I neurofibromatosis was admitted to our hospital with chest X-ray showing an enlargement of the mediastinum. CT scan revealed a 70 mm × 75 mm mediastinal mass with firm adhesions to the posterior wall of the ascending aorta, aortic arch, right pulmonary artery and the airway (Figure 2). In addition, SVC and left atrium were compressed and displaced.

Figure 2 Preoperative CT imaging. The mediastinal mass (asterisk) adheres to the main vessels and airways (A). The superior vena cava (arrow) is compressed and laterally displaced (B). CT, computed tomography.

Endobronchial ultrasound disclosed neurofibroma. After multidisciplinary team discussion, the patient was scheduled for surgery. Due to its location and compression of the mediastinal structures, a standing by team was alerted for extracorporeal support. A median sternotomy was planned to achieve the best possible exposure of the mediastinum. During mobilization of the mass and great vessels, the patient showed an increased pulmonary venous pressure (45 mmHg) and high central venous pressure (25 mmHg). Moreover, the patient had persistent systemic hypotension and tachycardia. Thus, a normothermic CPB was performed through ascending aorta and right atrium cannulation after administration of unfractionated heparin 50 UI/kg. The target used for activated clotting time was 180–200 s. With the support of the CPB it was possible to mobilize the aorta, SVC and pulmonary artery without affecting the patient hemodynamic and the mass was safely removed. Intraoperative findings are showed in Figure 3. Total CPB time was thirty-five minutes. The post-operative course was uneventful and the patient was discharged on postoperative day 8.

Figure 3 Intraoperative imaging. Exeresis of giant mediastinal neurofibroma (asterisk) located cranially to the heart and just behind the aortic arch (A). A central cannulation of ascending aorta and right atrium for CPB was performed (B,C), allowing a safe exeresis of the mass (D). CPB, cardiopulmonary bypass.

Case 3—peripheral CPB

A 20-years-old man with a history of progressive chest pain, weight loss, edema of the neck and upper limbs was referred to our hospital showing a chest X-ray with a large mediastinal mass. A magnetic resonance imaging showed an irregular tumor in the anterior mediastinum of 10 cm × 10 cm diameter, compressing the pulmonary artery bilaterally, the ascending aorta, and the post-azygous SVC. Video assisted thoracic surgery biopsy was performed and the pathologist disclosed seminomatous type germ cell tumor. After multidisciplinary team discussion, the patient was diagnosed as stage II mediastinal seminomatous type germ cell tumor and underwent induction chemotherapy with a bleomycin-etoposide-cisplatin (BEP) regimen. Control CT scan was performed after therapy showing a reduction of the mass (6 cm × 4 cm) (Figure 4). Surgery with radical intent was planned with a median sternotomy approach. The mass was found to infiltrate the SVC and was strictly adherent to the ascending aorta and the left main bronchus. As the finding showed a very challenging dissection and considering the impossibility to reach the central vessels due to the tumor mass, the resection was temporarily stopped and peripheral catheters (cannulation of the right femoral artery and left femoral vein) were placed to have a prompt access. During the dissection, the aortic wall was teared with a massive bleeding requiring hemodynamic support. A peripheral CPB was promptly started thanks to the available femoral catheters. The aorta was partially clamped at the site of the damage and repaired with a non-absorbable running suture. The mass was en bloc resected along with a wedge resection of the right upper lobe and tangential resection of the sub-azygous tract of the SVC. A vascular reconstruction was not required. At the end of operation, the patient was weaned from C-R support. The postoperative course was uneventful and the patient was discharged without complications on postoperative day 7. The latest follow-up showed a disease-free survival of 6 years.

Figure 4 Preoperative CT imaging of seminomatous type germ cell tumor after induction chemotherapy. The tumor appears strictly adherent to the ascending aorta and pulmonary artery, while the subazygous tract of SVC was infiltrated (A,B). CT, computed tomography; SVC, superior vena cava.

Case 4—V-V ECMO

A 37-year-old man was admitted at our emergency department with history of persistent cough, fever and worsening dyspnea since 3 months earlier. Chest CT scan showed an anterior mediastinal mass of 18 cm × 12 cm diameter with heterogeneous enhancement after intravenous contrast. The mass infiltrated and displaced the left pulmonary artery and the left main bronchus, involving the left lung, while left innominate vein and left jugular internal vein were compressed and thrombosed (Figure 5). Blood samples showed high levels of alfa-fetoprotein without evidence of testicular tumors. A transthoracic ultrasound-guided biopsy was performed showing a yolk-sac mediastinal tumor and the patient underwent induction chemotherapy with a BEP regimen with a partial response. A radical surgical treatment was planned after multidisciplinary re-evaluation, involving the mediastinal mass exeresis with possible en bloc pulmonary resection and airway or vascular reconstruction. Considering the possible need of C-R support and the impossibility to intraoperatively achieve SVC and aorta for cannulation, an elective V-V ECMO was started. The choice of a V-V ECMO was due to provide adequate oxygenation during the airway and pulmonary artery clamping and reconstruction (8,9). Considering the thrombosis of the SVC system, the drainage cannula was placed in the right femoral vein with the end placed above the outlet of the supra-hepatic veins in the inferior vena cava (IVC). The return cannula was placed in the right femoral vein with the end in the IVC at a distance greater than 4 cm from the end of the drainage cannula (10). The team was alerted to the possibility of converting the V-V ECMO in into a veno-arterio-venous ECMO (V-AV ECMO, a hybrid configuration), to provide oxygenation of the cardiac preload and hemodynamic support during surgical maneuvers. However, we never exceeded half the patient’s cardiac output and the hybrid configuration was not necessary. Sweep gas flow was gradually increased from 1 to 7 L/min at constant blood flow. Sweep gas flow was changed to maintain a compensated pH and pCO₂.

Figure 5 Preoperative CT scan after induction chemotherapy in patient with mediastinal yolk-sac tumor. The mass (asterisk) involved the left lung (A,B), infiltrated and displaced the left pulmonary artery (C) and the left main bronchus (D). CT, computed tomography.

A left pneumonectomy was required to completely remove the mass while airway and vascular reconstruction were not necessary (Figure 6). At the end of surgery, the patient was transferred to intensive care unit. The patient’s ventilation was maintained protective and ECMO blood flow was gradually reduced along with the reduction of sweep gas flow. The extracorporeal blood flow was stepwise reduced to 1 L/min. The blood gases remained stable after a gas flow stop for 60 minutes so we decided to remove ECMO. The postoperative course was characterized by atrial fibrillation due to left mediastinal shift, successfully treated with medical therapy. The patient was discharged on postoperative day 22.

Figure 6 Intraoperative view. The left branch of the PA appeared infiltrated by the tumor (A). Therefore, an en bloc resection of the mediastinal tumor with left pneumonectomy was performed (B). Left PA invasion (arrowhead) and resected main left bronchus (arrow) are visible on the specimen (C). Ao, aorta; PA, pulmonary artery.

Discussion

Surgery for mediastinal masses represents a large spectrum of clinical conditions with possible critical aspects for a safe and effective procedure both for diagnostic purposes and radical approach (1). The clinical scenario can vary largely including upper airway impairment or vascular disorders if not both. The critical phases for a safe and curative approach are various and there is no consensus on the ideal approach as well as no standardized preoperative work up is defined in such difficult cases.

The current knowledge and the state-of-the art is lacking some crucial aspects in the decision-making process for the best patient support during surgery.

We have to consider that surgery may be characterized by a high rate of cardio-pulmonary complications in those patients (4,5). Hemodynamic dysfunction is typically caused by compression of the heart and great vessels; after induction of anesthesia, the drop of systemic blood pressure associated with the increased intrathoracic pressure can compromise both venous return and ventricular ejection. In view of the mediastinal mass features and the surgical approach, the patient position may cause pressure or shifting of the mediastinum, compromising the venous return. Moreover, arrhythmias often occur possibly worsening the hemodynamic status. Intraoperative bleeding is another parameter that could easily affect the hemodynamic status. Respiratory failure typically occurs early after induction due to mass compression on airways, particularly with the use of neuromuscular blocking agents (NMBAs). Moreover, in case of pulmonary artery invasion, the respiratory equilibrium is very unstable during surgical maneuvers.

For these reasons, management of anesthesia in patients with large mediastinal masses includes a series of precautions that should be adopted in order to prevent the aforementioned complications. Based on our experience, the most important tips include:

• To preserve airways patency. Oro-tracheal intubation should be performed without the use of NMBAs to prevent airways collapse. In case of challenging intubation, it should be performed using a video-laryngoscope or flexible bronchoscopy guide. In case of severe compression of the airway, a rigid bronchoscope should be ready for emergency intubation and eventually a tracheal/bronchial stenting. This method was set up in example No. 1.
• A radial artery catheter, for continuous blood pressure monitoring, must be placed before induction. Indeed, patients with giant mediastinal masses often require surgical manipulations on the heart and mediastinal vessels, leading to sudden hemodynamic instability. For this reason, blood pressure control is more than important and cannot be lost during the entire surgery. This method was particularly useful in example No. 2.
• Large bore central venous catheter (CVC) must be available. This is mandatory to quickly administer fluids or blood in case of bleeding or fluids unbalance. In large mediastinal masses with invasion and need for SVC reconstruction, CVC must be placed in a femoral vein. Considering the possibility for an extracorporeal C-R support, femoral vein could be cannulated with a large perfusion cannula. This method was particularly useful in example Nos. 3 and 4.
• Extracorporeal C-R support should always be available in the operating room among with specialized personnel to optimize the use of cardiopulmonary support tools.
• Extracorporeal C-R support represents an effective but not an easy solution giving the high rate of complications associated to the extracorporeal circulation (11,12). However, in selected situations, this could be life-saving and allows a safer removal of the mediastinal mass. Depending on the single situation, two different techniques can be performed:
• ECMO: this device improves gas exchange in patients with respiratory failure. The veno-arterial technique (V-A ECMO) also allows a hemodynamic support.
• CPB: this technique preserves the systemic perfusion in patients at risk of hemodynamic impairment. The central cannulation allows also a limited bleeding around the surgical field when heart, great vessels and lung are involved by the disease to be removed.

In our experience, different types of extracorporeal C-R support have been used for different situations. In case 2, repeated heart pulls and rotations have been required to dissect the tumor from the posterior wall of the heart. These maneuvers caused prolonged hypotension and arrhythmias due to vena cava kinking. Elective CPB with central cannulation of right atrium and ascending aorta provided the adequate systemic perfusion to expose the posterior wall of the heart and safely complete the resection. In this case, a central V-A ECMO could also have provided an adequate intraoperative hemodynamic support. However, the choice of a CPB was done due to a possible aortic rupture and the need for a bloodless surgical field. In case 3, an unexpected complication required an emergency peripheral CPB to repair an aortic tearing. In this case, the preoperative femoral vein cannulation and the presence of a stand-by team for CPB proved to be crucial to promptly activate the extracorporeal support. The choice of a CPB was opted to provide an adequate hemodynamic support during the aortic repair. In patient #4, the need of a pulmonary support to perform a safe mass resection en bloc with left pneumonectomy suggested to engage a V-V ECMO.

The international literature does not provide standard guidelines for intraoperative management of extracorporeal C-R support in giant mediastinal masses. When, why and what technique best fits an effective and safe cardiopulmonary support is still uncertain and based on case report analysis (6,13-16). Through the analysis of selected cases, we propose a schematic flowchart to guide the decision process in the use of intraoperative extracorporeal C-R support in these patients (Figure 7).

Figure 7 Schematic flowchart to guide the intraoperative management of extracorporeal cardio-respiratory support in locally advanced mediastinal masses. CPB, cardiopulmonary bypass; C-R, cardio-respiratory; CVC, central venous catheter; ECMO, extracorporeal membrane oxygenation; NMBA, neuromuscular blocking agent; OT, orotracheal; SVC, superior vena cava; TIVA, total intravenous anesthesia.

Conclusions

In conclusion, our series shows how the choice of extracorporeal C-R support in these patients depends on different factors. Firstly, if a hemodynamic impairment occurs, CPB or V-A ECMO should be preferred over V-V ECMO. CPB is mandatory if a bloodless surgical field is required or if a massive hemodynamic support is needed. However, the mass position and great vessels involvement could affect the choice of a peripheral approach over a central cannulation. V-V ECMO should be preferred in case of selective respiratory impairment. In these cases, a skillful multidisciplinary team and a dedicated commitment between cardio-thoracic surgeons, anesthesiologists and perfusionists is mandatory for an appropriate preoperative and postoperative management, particularly in the planning phase.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the PROCESS reporting checklist. Available at https://ccts.amegroups.com/article/view/10.21037/ccts-25-33/rc

Peer Review File: Available at https://ccts.amegroups.com/article/view/10.21037/ccts-25-33/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://ccts.amegroups.com/article/view/10.21037/ccts-25-33/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patients for the publication of this case series and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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