Original review article
Aileen Tan, Judith Anne Nolan. Anesthesia for children with anterior mediastinal masses. Paediatr Anaesth. 2022 Jan;32(1):4-9. PMID: 34714957
This review of the anesthetic management of children with anterior mediastinal masses is yet another reminder of how dangerous and frightening this anesthetic can be. Ron Litman, of blessed memory, discussed the management of these patients in his “Throwback Thursday Feb 18” which I am reprinting/reposting in its entirety. Myron Yaster MD
Good morning and welcome to the Throwback Thursday series, where I’ll discuss an oldie but a goodie – the kind of article that has made such an impression that it forever changed the practice of pediatric anesthesia (suggestions from you always welcome). For our first edition we’ll start with the subject of anesthetic management of the anterior mediastinal mass:
Keon TP. Death on induction of anesthesia for cervical node biopsy. Anesthesiology. 1981 Oct;55(4):471-2. PMID: 7294388
In 1981, Tom Keon, one of the most notable airway management experts in the history of our department (before LMAs were invented!) reported this account of a 9-year-old boy who presented for cervical lymph node biopsy. The boy had been well until 6 weeks prior to admission. In the interim, he developed a flu-like illness, with shortness of breath, decreased exercise tolerance and cough. Four days prior to admission he developed cyanosis and passed out while straining during a bowel movement. A chest x-ray showed an anterior mediastinal mass without apparent airway obstruction. High on the differential was mediastinal lymphoma. Palpable cervical lymph nodes were present with which to obtain a biopsy prior to initiating therapy. Preoperative vital signs were normal.
After premedication with atropine, the child received a halothane induction while in the sitting position with the goal of maintaining spontaneous ventilation. Dr. Keon noticed the onset of cyanosis despite apparent satisfactory ventilation (no pulse oximetry in 1981!). After placing the child supine for tracheal intubation, the heart rhythm progressed from bradycardia to asystole and resuscitative efforts, including open chest cardiac massage, were unsuccessful. On postmortem exam, the tumor encased not only the entire anterior mediastinum, but also the heart, pericardium, pulmonary artery, and left main bronchus.
Keon’s report was the first at that time to underscore the importance of the hazards of cardiac involvement of lymphoma, essentially a superior vena cava syndrome, made worse by the administration of halothane and the supine position. Echocardiography was far into the future.
Patients with an anterior mediastinal mass require a meticulous preoperative assessment to evaluate the location and severity of any intrathoracic airway obstruction or interference with cardiovascular function prior to any procedure requiring general anesthesia or sedation. Depending on the location of the mass and the degree of tracheal compression, administration of anesthetic or sedative agents may impair spontaneous ventilation, which may lead to total tracheal or bronchial occlusion and the inability to provide positive pressure ventilation. In any patient where an increased potential for such obstruction is noted preoperatively, provisions should be made for the availability of a rigid bronchoscope, the ability to easily move the operating room table for changes in position, and the ability to institute cardiopulmonary bypass or extracorporeal membrane oxygenation (ECMO) if necessary.
Computed tomography (CT) of the chest is essential for evaluating the potential for airway compromise and planning the anesthetic induction technique. Compression of greater than 50% of the cross-sectional area of the trachea on CT imaging has been suggested to indicate a risk of airway collapse during induction of general anesthesia. In patients with this degree of tracheal compression, preoperative therapeutic options include radiation therapy, and/or administration of corticosteroids or chemotherapy to shrink the mass. Except in situations in which the size and/or location of the mass is truly life threatening, many oncologists prefer to refrain from the use of such preoperative treatments because of their effect on the histopathology or tumor markers in the specimen. However, in patients in whom the mass causes a high degree of airway compromise, administration of a general anesthetic may be contraindicated. In patients who have additional tissue sites from which a biopsy can be obtained (e.g., cervical, axillary, or inguinal lymph nodes), it may be safer to proceed with the patient in a semi-sitting position using local anesthesia and carefully titrate sedation to preserve spontaneous ventilation (e.g., dexmedetomidine, ketamine, midazolam, etc.). If general anesthesia is essential, patients with a significant degree of upper airway obstruction require an induction technique that preserves spontaneous ventilation. Preoperative echocardiography is essential to rule out compression of the heart or great vessels by the tumor mass.
Here’s a suggested roadmap for these children:
Preoperative
· CT scan and echocardiography to delineate size and effect of mass on surrounding tissues.
· In older children, attempt tissue diagnosis of peripheral blood, lymph nodes, bone marrow, or effusion without the use of sedation or general anesthesia.
· If the mediastinal mass dangerously obstructs the trachea or inflow of blood to the heart, attempt to reduce the size of the mass using chemotherapy (dexamethasone) and/or radiation before proceeding with sedation or general anesthesia. This is rare.
· A rigid bronchoscope and physician with expertise in its use should be immediately available prior to and during induction of general anesthesia.
· Some centers advocate immediate availability of ECMO.
Intraoperative
· Induction of general anesthesia should be performed while maintaining spontaneous ventilation. CPAP may help maintain upper airway patency and preserve FRC.
· Induce general anesthesia in the semi-sitting or lateral position to keep the mass from compressing the trachea.
· Tracheal intubation or supraglottic airway placement (if required) should be accomplished during deep anesthesia and spontaneous ventilation.
· It is preferable to avoid neuromuscular blockade for fear of losing airway muscle tone and exacerbating airway obstruction.
Management of Airway Obstruction
· In the event of airway obstruction during induction of general anesthesia, the standard algorithm for difficult ventilation should be applied.
· If ventilation cannot be accomplished despite tracheal tube placement, perform the following steps:
o Push the endotracheal tube distally past the tracheal obstruction or into the right main bronchus.
o If the endotracheal tube cannot be advanced past the obstruction, rigid bronchoscopy should be performed.
o Alleviate gravity-induced tracheal or great vessel compression by placing the patient in the sitting, lateral, or prone position.
If the above measures are unsuccessful in restoring oxygenation or circulation, institute ECMO immediately.
Ron Litman DO
PS: What to do when a patient is at highest risk of obstruction? As an anesthesiologist my desire is to start chemo or radiation therapy to shrink the tumor. On the other hand, the oncologist believes that this will make tissue diagnosis impossible and thereby doom the patient in the long term. In the current review the authors state “Hack et al. found that a clear diagnosis was found in 95% (17/18) of patients who required steroid pre-treatment, and 100% (18/18) if the treatment course was limited to ≤5 days.(1) In a really tough situation this might be something to show your oncologist, although I don’t think this will change their minds. Myron Yaster MD
1. H A Hack, N B Wright, R F Wynn. The anaesthetic management of children with anterior mediastinal masses. Anaesthesia. 2008 Aug;63(8):837-46. PMID: 18547295
Anesthetic management of children with anterior mediastinal masses
I often thought of this unexpected death and Tom Keon throughout my career, especially if I felt tired or rushed. This was an add-on case at the end of the day. Tom took his time to review the data and be fully prepared under the circumstances in 1981. The risk of C-V collapse was not recognized until this case. Be like Tom Keon !