Anterior Mediastinal Mass: Biopsy

What the Examiner Is Testing

This case tests whether you will resist the reflexive RSI and understand why paralysis in anterior mediastinal mass is potentially fatal. The examiner wants to see you build a plan around preserved spontaneous ventilation — and also articulate a credible rescue plan for the moment the airway collapses.

The Board Trap

The trap is performing a standard RSI because "he needs to be intubated for surgery." Muscle paralysis removes the negative inspiratory pressure that keeps the compressed trachea and SVC patent. When the airway collapses after you give succinylcholine, you may not be able to ventilate or intubate. You've converted a high-risk patient into a cannot-intubate, cannot-oxygenate emergency with no easy escape.

Walk-Through: How This Case Plays Out

Examiner: The CT shows 50% tracheal compression. He's comfortable sitting upright but has orthopnea. How do you proceed?

Me: I would not perform an RSI. The orthopnea and 50% tracheal compression are clear signs that his airway patency depends on his upright position and negative pressure breathing. If I paralyze him, gravity and the loss of inspiratory effort will allow the mass to fully compress the airway. My plan is local anesthesia with minimal sedation for the biopsy. I want the patient cooperative and breathing on his own.

Examiner: The surgeon says a local-only technique won't provide enough operating conditions. They need at least moderate sedation.

Me: I'd use dexmedetomidine — small incremental doses, watching his respiratory pattern the entire time. The goal is anxiolysis and sedation without apnea. I'd keep him in a semi-sitting position throughout. I would not give propofol or midazolam in doses that risk apnea. I want him comfortable enough to tolerate the procedure but breathing spontaneously the entire time.

Examiner: You've agreed to a slow inhalation induction with sevoflurane if absolutely necessary. What are your rescue preparations?

Me: Before induction, I want a thoracic surgeon scrubbed and a rigid bronchoscope immediately available in the room. If the airway collapses, a rigid bronchoscope can be used to stent open the trachea. I'd also pre-consent and pre-prep the groin for femoral-femoral bypass — if the SVC is compressed and we lose cardiac output, femoral-femoral bypass is the only rescue. I would not begin induction without all of that in place.

Examiner: Mid-case, he becomes apneic and you can't ventilate. What's your first move?

Me: I would immediately turn the patient to the lateral or prone position. Gravity shifts the mass away from the trachea in lateral decubitus and can restore airway patency. Simultaneously, I'm calling for the rigid bronchoscope and activating the bypass team. I'm not trying another RSI intubation — I've already established that the airway collapses with positive pressure. I'm getting the bronchoscope in to physically stent the airway open.

Key Phrases That Score Points

• "Orthopnea plus 50% tracheal compression — RSI is contraindicated, I'm preserving spontaneous ventilation."
• "Rigid bronchoscope in the room and thoracic surgeon scrubbed before I start any induction."
• "Femoral-femoral bypass pre-consented and groin prepped — that's my rescue if everything fails."
• "Lateral position immediately if the airway collapses — gravity shifts the mass away."
• "Dexmedetomidine for sedation — anxiolysis without apnea."

Why This Case Appears on the Boards

Anterior mediastinal mass is the prototypical "resist the standard approach" airway case. It tests clinical judgment and preparation — the ability to build a plan around a known failure mode before you start, not after things go wrong.