Extracorporeal membrane oxygenation (ECMO) is an advanced form of organ support for critically ill patients in which, through different configurations of cannulation, blood is circulated outside of the body and oxygenated across an artificial membrane. It can be performed with venoarterial cannulation (VA-ECMO) for both cardiac and respiratory support, or with venovenous cannulation (VV-ECMO) for respiratory failure. It is often used to facilitate procedures with high potential of hemodynamic instability or in emergency rescue situations. We present a case in which we electively used VV-ECMO to facilitate safe resection of a nearly obstructing airway tumor through rigid bronchoscopy. Written consent was obtained from the patient for this manuscript and publication.
A 37-year-old male with no significant medical history was referred to our center for the management of an obstructing airway tumor. He was in his usual state of health until about 10 months before, when he began experiencing dyspnea and a foreign body sensation with breathing. His shortness of breath worsened with coughing spells, during which he felt he was unable to move any air, and these spells were increasing in frequency and severity. A chest computed tomography (CT) scan showed a large bilobed mass originating near the carina and partially obstructing both mainstem bronchi (Figure 1). Reliable spirometry was unable to be obtained because of profound coughing with the maneuver. The patient was admitted for rigid bronchoscopy and resection of the tumor. Because of the nearly obstructing tumor, the use of ECMO was initially discussed as a rescue option in case of airway compromise. However, on further consideration, it was decided that the safest course of action would be to initiate elective VV-ECMO preemptively before the induction of general anesthesia rather than instituting VV-ECMO in a situation of airway compromise and inability to ventilate and oxygenate.
The patient was brought to the operating room (OR) and sedated with low-dose dexmedetomidine and propofol infusions, escalated in a stepwise fashion while maintaining spontaneous ventilation. He was anticoagulated with 5000 U IV heparin and underwent bilateral femoral venous cannulation with a 25 Fr multistage inflow cannula in the inferior vena cava (drainage cannula) and a 21 Fr single stage outflow cannula in the right atrium (oxygenated blood return cannula) under fluoroscopic guidance. ECMO was initiated, adequate flow was established, and general anesthesia with muscle relaxation was then induced. While on ECMO, general anesthesia was maintained with propofol, remifentanil, and rocuronium and titrated to bispectral index. Flows were maintained at 2.5–3.8 L/min with 100% Fio2 sweep gas at 2–3 liters per minute throughout the case. Adequacy of gas exchange with ECMO was confirmed by pulse oximetry and point of care arterial blood gas testing. No additional heparin was administered. With oxygenation and ventilation ensured by VV-ECMO, rigid bronchoscopy was performed without the need for high-frequency jet ventilation. The mass was resected using electrocautery snare around the pedunculated base and cryotherapy. Argon plasma coagulation was employed for mild bleeding at the stump after removal of the mass (Figure 2). The patient was then intubated and ventilated with an endotracheal tube, and a brief trial off sweep gas with continuous oxygenation confirmed by pulse oximetry was successfully conducted, and ECMO was discontinued and the venous cannulas were removed; 25 mg protamine was administered for heparin reversal. Total ECMO time was 46 minutes. With the tumor removed, the patient was able to breathe without difficulty and was extubated awake in the operating room. Postoperatively, he recovered in the postanesthesia care unit and was admitted overnight for observation. The patient was discharged to home the next day. Pathology revealed an encapsulated tumor with the diagnosis of endobronchial schwannoma (Figure 3). The patient returned for a 6-month follow-up bronchoscopy that showed normal endobronchial mucosa at the resection site without evidence of tumor recurrence. He reported complete resolution of his symptoms.
Primary tracheal tumors are relatively uncommon, and schwannomas in this location are quite rare. However, Ge et al1 reviewed 51 cases reported between 1950 and 2013. The majority (78%) of these cases occurred in adults, and the tumors were most commonly 1–3 cm in size and usually located in the distal third of the trachea. Our patient’s presentation was typical of this group. Coughing, wheezing, and dyspnea were the predominant symptoms. Many patients were initially misdiagnosed with asthma, and treatment was delayed for an average of 17 months from the onset of symptoms. Most patients were treated with endoscopic or surgical removal of the tumor.1
ECMO is an invasive and advanced intervention that can be lifesaving but also comes with serious risks and possible complications. These include thrombosis within or propagating from the circuit, bleeding at any site from the anticoagulation used to prevent thrombosis as well as coagulopathy acquired from interactions with the circuit, and vascular damage at the cannulation sites. The short duration and choice of peripheral VV-ECMO over cardiopulmonary bypass in this case minimized these risks.
There are a variety of cannulation strategies for VV-ECMO, including femoral, axillary, and internal jugular cannulation sites with the use of 2 single-stage cannulas, as in this case, or a single multistage cannula such as the Avalon catheter. Femoral access was chosen in this case because it was well tolerated with minimal sedation and was away from the area of intervention for the bronchoscopy.
VV-ECMO is different from venovenous bypass in that the blood is oxygenated in the circuit before being returned, whereas venovenous bypass diverts blood around a surgical site. It is distinct from VA-ECMO in that the oxygenated blood is returned to the right atrium, and thus, the heart is not bypassed and still performs the work of circulating the blood through the pulmonary and systemic circulation. This minimizes the hemodynamic, hematologic, and embolic consequences associated with VA-ECMO but requires the presence of relatively normal cardiac performance.
Although VV-ECMO in the management of airway tumors has been reported, it has typically been in a fashion or in circumstances that expose the patient to greater risk, or are more resource intensive for the health care facility. Previously reported cases have typically involved much longer ECMO times. Hong et al2 reported a series of 19 cases of VV-ECMO used in the management of severe airway obstruction between 2009 and 2012. In these cases, ECMO was typically initiated in the intensive care unit (ICU), followed by airway intervention in the OR and subsequent weaning and decannulation in the ICU. Median ECMO time was 20.9 hours.2 Other authors have reported the use of ECMO over a prolonged period of time for multiple airway procedures, using either continuous ECMO throughout the treatment period3 or multiple cannulations and ECMO runs for sequential procedures.4 ECMO in these cases allowed for safe management of airway tumors, but it exposes the patient to increased ECMO time and potential for complications as well as utilizing extensive ICU resources.
ECMO has also been reported in more invasive management of airway tumors, such as a bridge to tracheotomy,5,6 or with central cannulation via sternotomy for surgical airway intervention.7 There has also been a role for the emergency deployment of ECMO as a rescue technique in situations of emergent airway compromise.8,9 Although ECMO is clearly beneficial and a good option in many of the cases, our case illustrates that ECMO can also be useful in the elective, minimally invasive management of critical airway pathology.
There are a number of unique features in the management of this case, in that a relatively short, controlled use of ECMO facilitated tumor removal while minimizing risk of complications or unnecessary resource utilization. Moderate sedation facilitated smooth and safe bilateral femoral cannulation and initiation of VV-ECMO, while maintenance of spontaneous ventilation ensured uninterrupted oxygenation and avoided airway collapse. Initiation of VV-ECMO before other interventions minimized the risks of airway complications associated with the induction of general anesthesia and rigid bronchoscopy. Elective, preemptive VV-ECMO ensured adequate oxygenation and ventilation during airway surgery and avoided the need for emergent rescue techniques with their inherent risks and associated morbidity. Emergent advanced airway interventions or rescue initiation of ECMO in the setting of catastrophic airway compromise significantly increases the procedural risk for iatrogenic trauma and could result in an unpredictable period of hypoxemia and even cardiovascular collapse. After tumor removal, endotracheal intubation secured the airway during removal of venous cannulas and provided a bridge to emergence.
Similar use of ECMO has occasionally been reported, indicating that this technique may have broader applicability, provided there is sufficient institutional experience and resources. Gourdin et al10 reported the use of VV-ECMO with femoral/internal jugular cannulation for the bronchoscopic removal of 2 obstructing endotracheal prostheses in a 27-year-old male patient. Total ECMO time was 120 minutes, and the patient was extubated in the OR.10 Kim et al11 reported the use of VV-ECMO with bifemoral cannulation for the bronchoscopic resection of an airway tumor in an 88-year-old female patient. Total ECMO time was 140 minutes, and the patient was extubated on the first postoperative day.11
Elective use of brief VV-ECMO in the OR for management of airway tumors requires significant institutional experience and resources. The interdisciplinary nature of this approach requires excellent teamwork, communication, and careful planning among surgeons, pulmonologists, anesthesiologists, perfusionists, and nursing staff. VV-ECMO is rarely used in this manner, but it may provide significant benefit in appropriate cases at appropriate centers.
Name: W. Jonathan Dunkman, MD.
Contribution: This author helped write the manuscript.
Name: Alina Nicoara, MD.
Contribution: This author helped plan the case, and edit the manuscript and figures.
Name: Jacob Schroder, MD.
Contribution: This author helped with the case description of surgical care.
Name: Momen M. Wahidi, MD MBA.
Contribution: This author helped with case description of pulmonary care and images.
Name: Aimen El Manafi, MD.
Contribution: This author helped with case description of anesthesia care.
Name: Desiree Bonadonna, MPS.
Contribution: This author helped with case description of perfusion care.
Name: Coral X. Giovacchini, MD.
Contribution: This author helped with case description of presentation, pulmonary care, and follow-up.
Name: Frederick W. Lombard, MB ChB.
Contribution: This author helped edit the manuscript and with case description of anesthesia care.
This manuscript was handled by: Mark C. Phillips, MD.
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