Abstract
A 39-year-old man experienced total obstruction of a distal tracheal plastic stent by a tumor mass, preventing effective ventilation and resulting in cardiac arrest. Resuscitation by emergency bedside venoarterial extracorporeal membrane oxygenation (ECMO) permitted time to physically remove the obstructing tumor and reestablish successful ventilation and liberation from ventilatory support. We review several other reported cases of emergency ECMO to resuscitate patients with acute airway obstruction.
- extracorporeal membrane oxygenation
- airway obstruction
- cardiac arrest
- ECMO
- mechanical ventilation
- tracheal stent
Introduction
Acute obstruction of the upper airway, including the trachea, is a life-threatening emergency. Common causes include angioedema, foreign body, tumor, blood clots, trauma, and infection. Initial management will depend on the degree of obstruction, the level of obstruction, and the specific cause. Endotracheal intubation or emergency tracheostomy or cricothyroidotomy can be life-saving when obstruction is at the level of the vocal cords or above. In some cases of partial upper-airway obstruction, inhalation of helium-oxygen mixture (heliox) can temporize the situation until definitive removal of the obstructing lesion can be performed. Total occlusion of the upper airway will rapidly lead to death unless obstruction is relieved. Here we report the use of emergency bedside extracorporeal membrane oxygenation (ECMO) as a salvage maneuver in a case of distal tracheal obstruction, and review some reported cases of ECMO use in tracheal obstruction.
Case Report
A 39-year-old male with history of metastatic osteogenic sarcoma was admitted after an episode of fainting and near-respiratory-arrest, which occurred while showering at home. Osteogenic sarcoma of the right leg had become metastatic to the lungs, with complete tumor occlusion of the proximal right main bronchus and involvement of the distal trachea. He was previously treated with laser endobronchial therapy and placement of a plastic stent in the distal trachea, which allowed ventilation of his left lung.
In the emergency department he was initially dyspneic and hypercapnic (PCO2 73 mm Hg, pH 7.22), and was treated with noninvasive mask ventilation. The PCO2 improved to 50 mm Hg, and he was admitted to the intensive care unit. Examination showed blood pressure 98/58 mm Hg, heart rate 126 beats/min, and respiratory rate 22 breaths/min while on noninvasive ventilation. Lung exam revealed absent breath sounds on the right and mild wheezing over the left chest. Chest radiograph demonstrated complete opacification of the right hemithorax, and minor patchy left-lower-lobe infiltrate (Fig. 1). Inhaled bronchodilators, intravenous corticosteroids, and antibiotics were given.
Admission chest radiograph, showing complete opacification of right thorax. The distal tracheal stent is not seen as it is radiolucent.
Moments after arrival in the intensive care unit he developed marked increase in respiratory distress and minimal air movement into the left chest by exam. Pulse oxygen saturation dropped below 80%, and supraventricular tachycardia occurred, with heart rates in the 180–200 beats/min range. Emergency tracheal intubation was accomplished promptly, but ventilation was difficult, with marked resistance to inflation. Fiberoptic bronchoscopy was carried out. The endotracheal tube was in good position, the tip of which was at the proximal end of a plastic tracheal airway stent. The distal end of the stent, at the level of the carina, was completely obstructed by a large piece of tissue. Efforts to remove this were not feasible due to the development of bradycardia and pulselessness requiring chest compressions. Intravenous atropine and epinephrine were given, and the patient briefly regained sinus tachycardia with a pulse, followed quickly by recurrent bradycardia and pulselessness requiring additional cardiopulmonary resuscitation. The right femoral artery and vein were then cannulated with 17 French and 21 French vascular cannulae (Bio-Medicus, Medtronic, Minneapolis, Minnesota), respectively, and the patient was placed on portable venoarterial ECMO, using a hollow-fiber oxygenator (Affinity, Medtronic, Minneapolis, Minnesota) and a centrifugal blood pump (Bio-Pump, Medtronic, Minneapolis, Minnesota). Immediately after extracorporeal circulation was established, blood pressure, heart rate, and oxygenation stabilized at normal levels. Venoarterial flow rates of 3 L/min were maintained, and systemic heparinization was used to achieve activated clotting times of 180–200 s.
After stabilization on ECMO for several hours, repeat fiberoptic bronchoscopy was done, and the tissue mass was now seen to move between the carina at the distal end of the stent and into the left main bronchus. Removal of the tissue mass was accomplished with use of forceps, suctioning, and lavage over a 1-hour period. Histological evaluation of the tissue revealed a spindle cell neoplasm consistent with sarcoma, and extensive necrosis. The following day the patient's extracorporeal flows and oxygenator sweep gas were successfully weaned, and he was able to be ventilated and oxygenated easily with minimal ventilator settings. The ECMO cannulae were surgically removed, and later in the day he was liberated from ventilation and successfully extubated. Repeat bronchoscopy several days later showed a patent stent, tumor filling the takeoff of the right main bronchus, and moderate secretions in the left lung. Echocardiogram showed normal left ventricular function and moderate pulmonary hypertension. He received physical therapy and antibiotics and corticosteroids and was discharged ambulatory several days later.
Discussion
The use of emergency bedside ECMO has become established in some centers as an approach to resuscitate patients failing conventional advanced cardiac life support. The majority of such patients treated have cardiovascular collapse or arrest due to myocardial infarction, postcardiotomy shock, or pulmonary embolism.1 Although controlled clinical studies are nonexistent, analysis of case series reveals improved survival when a treatable underlying condition exists, and when duration of cardiopulmonary resuscitation prior to institution of ECMO does not exceed 30 min.2 Furthermore, for effective use of this procedure, hospitals benefit from preassembled ECMO circuits and a dedicated team of rapid responders capable of establishing arteriovenous cannulation and initiation of extracorporeal circulation expeditiously.3
Acute tracheal obstruction results from a variety of causes, and is a life-threatening emergency requiring swift diagnosis and treatment. In many cases, flexible or rigid bronchoscopy is essential for diagnosis and treatment of upper-airway obstruction, but may not be feasible due to severe hypoxemia, ventilatory failure, or, in extreme cases, shock and cardiac arrest. Establishing airway patency and restoring ventilatory flow are the essential components of treatment. In some cases, attempts at intubation may precipitate crisis or be impossible. Emergency tracheostomy or cricothyroidotomy may be life-saving, depending on the level of obstruction. Pharmacologic interventions such as corticosteroids, epinephrine, or inhaled heliox may provide temporary support in partial obstruction, but will not substantially change mechanical upper-airway obstruction.4 In the case reported here, total obstruction of the distal trachea resulted in asphyxia, leading to bradycardia, severe hypoxemia, and cardiac arrest. ECMO provided sufficient gas exchange and hemodynamic support to maintain life until airway patency could be reestablished.
Through a PubMed literature search, augmented by review of references in relevant articles, we located several published case reports of the emergency use of ECMO for support of patients with acute tracheal obstruction (Table 1).5–16 These cases demonstrate the spectrum of common causes of severe acute airway obstruction, including tumor, foreign body, blood clot, and congenital lesions. Symptoms at presentation ranged from respiratory distress and stridor to full cardiac arrest, as in the present case. Several of these cases represent conditions in which death would have been certain without extracorporeal support. Notably, all survived to hospital discharge. One of the earliest reports of ECMO for tracheal obstruction was that of Hicks in 1986.17 However, in that case ECMO was used preemptively in a patient with a known impossible airway. Also, Weber and Kountzman described an additional 3 cases of ECMO in acute airway obstruction in infants, ages 4–13 months, out of a total of 55 children treated with ECMO for various indications over a 13-year span.18
Prior Reported Cases of Use of ECMO for Acute Upper-Airway Obstruction
In cases of severe acute tracheal obstruction, such as those described above and in the present report, emergency use of bedside ECMO may be considered and may be life-saving. Typically, once airway patency has been established, ECMO can be discontinued fairly promptly. Choice of venoarterial versus venovenous cannulation is dependent on the patient's immediate condition and the rapidity of progression of clinical symptoms. A venoarterial approach is indicated if the patient is in cardiac arrest or shock, whereas venovenous technique may be sufficient where ventilation (CO2 removal) and oxygenation are all that are required. Once extracorporeal flow is established, blood flow and gas flow through the artificial lung are adjusted to achieve hemodynamic and gas exchange goals. Adequacy of tissue perfusion can be monitored by arterial blood pressure, arterial and venous oxygen saturations, and serum lactate levels. Monitoring of oxygen saturation in the venous (outflow) limb of the extracorporeal circuit provides a reasonable surrogate for mixed venous saturation, and thus adequacy of tissue oxygen delivery. Ventilator settings are minimized to protect the lungs. Arterial carbon dioxide levels are usually easily managed by titrating the flow of sweep gas through the membrane oxygenator. Visual inspection of the cannulae, ECMO circuit, and oxygenator for clots is done regularly by the ECMO specialist or perfusionist. Frequent measures of hematocrit and platelet count are necessary, and blood product transfusion is commonly required in extended cases. Monitoring of anticoagulation is done at the bedside, typically using the activated clotting time to guide heparin dosing. Common complications of ECMO include bleeding, thromboembolism, vascular injury from cannulation, and ischemia of the limb distal to an arterial cannula. These complications are managed and lessened in frequency by an experienced ECMO team.
The authors suggest that, in those centers with established capability for rapid bedside ECMO, acute severe tracheal obstruction can be considered a potential indication for this technique.
Footnotes
- Correspondence: David C Willms MD, Department of Critical Care, Sharp Memorial Hospital, 7901 Frost Street, San Diego CA 92123. E-mail: david.willms{at}sharp.com
The authors have disclosed no conflicts of interest.
- Copyright © 2012 by Daedalus Enterprises Inc.
