Mediastinoscopy/Mediastinal mass

Question 1

What all is in the mediastinum?

Answer 1

all organs in chest except lungs

Question 2

Anterior, middle, and posterior mediastinum:

Answer 2

Anterior: bordered by sternum front and pericardium posteriorly
Middle: pericardium and all of its contents
Posterior: posterior to pericardial wall, and anterior to thoracic vertebral bodies

Question 3

4 most common medicinal masses. What disease is present in some people with mediastinal masses?

Answer 3

Thymoma: terrible, lymphoma, teratoma, ectopic thyroid. Myasthenia graves is present in 25% of people with mediastinal mass.

Question 4

Speaking of Myasthenia Gravis, what exactly is it? Do symptoms get better or worse with movement? What is the drug of choice to treat this and how does it work?

Answer 4

It’s an autoimmune disease that attacks the post synaptic nicotinic ACh receptors at the NMJ.
Things get worse with movement
pyridostigmine and it is an anti cholinesterase

Question 5

As far as the CNS and PNS, what is always there to start-from the spinal cord? When you go to PNS, what does that synapse on? Somatic system? What about sympathetic (there are four parts to this answer)

Answer 5

-ACh
-ACh synapse on muscarinic terminals (G protein on cardiac and smooth muscle, gland cells, and nerve terminals) (PNS)
Somatic: ACh nicotinic
Sympathetic: Sweat glands: sympathetic, but innervated by cholinergic muscarinic fibers
Cardiac, smooth muscle : alpha and Beta NE
Renal vascular smooth muscle: Dopamin
Adrenal medulla: Epi, NE

Question 6

Always advise MG patients of what? What are the criteria that correlate with the need for mechanical ventilation during the post op period?

Answer 6

The fact that they may require ventilatory support after surgery

• disease longer than 6 years
• COPD unrelated to MG
• daily dose of pyridostigmine higher than 750 mg
• Vital capacity less than 2.9 L (40 mL/kg)
• Upper abdominal surgery
• steroid use!!!

Question 7

What are you looking for on Physical exam of MG patient? Be careful not to give more cholinesterase inhibitor than usual-meaning:

Answer 7

chest infection, degree of muscle weakness, signs of other AI diseases (RA, hypothyroidism)
Meaning-1 mg of neostigmine is equal to 120 mg of PO pyridostigmine-you could trigger a cholinergic crisis

Question 8

Things to keep in mind with MG patients? When would you know whether or not to give aspiration ppx?

Answer 8

Be careful with opines, use multimodal tx. be careful with extubation. Myasthenia crisis?
Bulbar involvement typically requires aspiration prophylaxis due to higher chance of aspiration.

Question 9

Patients with My. Grav are sensitive to which paralytics? resistant to which? IV pyridostigmine is 1/__ of PO pyridostigmine? Acute exacerbations can be treated with:
After surgery they need to go to:

Answer 9

sensitive to NDMB 
Resistant to succinylcholine
1/30
IV Immunoglobulin 
ICU or step down unit-NOT regular post surgical ward

Question 10

What are contraindications to mediastinoscopy?

Answer 10

Thoracic aortic aneurysms, SVC syndrome, Cerebrovascular disease-careful because occlusion the innominate artery can cause cerebral ischemia,
tracheal deviation

Question 11

If you develop increased airway resistance during any surgery, what are you thinking?

Answer 11

Bronchospams 
Foreign body 
tension pneumothorax 
Endobronchial intubation 
poor compliance secondary to lung disease 
Mediastinal mass

Question 12

What is a sign on flow volume loops on intrathoracic compression? What are you looking for on Echo? What if there is severe compression on RVOT?

Answer 12

collapse during expiration
On Echo, we’d be looking for RV outflow obstruction, or right heart dysfunction
If severe compression on RVOT, consider local0talk with surgeon.

Question 13

Can you use a pulse ox instead of right sided arterial waveform?

Answer 13

You can, but its’ not as reliable

Question 14

So, what’s your plan for putting people with a mediastinal mass to sleep? What happens if you lose the airway?

Answer 14

Keep them breathing! don’t paralyze until your’e certain you can ventilate. You can do an inhalational induction with sevo in the sitting position, but you could lose that airway.
If you lose the airway, change patient’s position to lateral or prone. reverse muscle relaxant, use a rigid bronchoscope to push past the obstruction

Question 15

SOB in a patient who has a lung mass and is a smoker:

Answer 15

(1) pulmonary

disease resulting from his tobacco abuse (i.e. COPD and/or pneumonia); (2) mass-
induced ventilation perfusion mismatching; (3) mass-induced post-obstructive

pneumonia; ( 4) superior vena cava syndrome secondary to neoplastic invasion of the
vessel wall (usually in association with intravascular thrombosis), with the resultant
obstruction of venous drainage leading to mucosa! edema and venous engorgement of
the airways and subsequent dyspnea, orthopnea, and coughing; (5) mass compression
of the heart or other great vessels (i.e. direct cardiac compression, pericardia!
effusion, pulmonary artery compression); (6) cardiac disease in this older male
smoker with hypertension and known carotid disease; or (7) a late finding of
Lambert-Eaton Myasthenic syndrome (LES), a known paraneoplastic syndrome that
may also present with signs of autonomic dysfunction, such as constipation and
orthostatic hypotension.

Question 16

Common paraneoplastic syndromes: 
SIADH 
Cushing's 
Lambert Eaton 
Humor hypercalcemia

Answer 16

-Syndrome of Inappropriate secretion of Antidiuretic Hormone (SIADH) -
tumor production of arginine vasopressin can lead to hyponatremia, decreased
serum osmolarity, and inappropriately increased urine osmolarity in the
setting of euvolemia and normal thyroid and adrenal function.
-Cushing’s Syndrome - increased secretion of ACTH or CRH can lead to
hypokalemia, alk:alosis, hypertension, .and psychosis.
-Lambert-Eaton Myasthenic Syndrome - most commonly associated with
small cell lung cancer.
-Humoral Hypercalcemia - Tumor release of parathyroid hormone-related
peptides can lead to muscle weakness, cardiac arrhythmias, nausea, vomiting,
and renal failure.

Question 17

Tell me about Lambert Eaton: What is it? how does it present? How can you treat it?

Answer 17

production of antibodies to prejunctional voltage-gated calcium channels results in
a reduced release of acetylcholine at the motor end-plate.
-proximal weakness of the lower extremities (sometimes progressing to
involve the upper extremities) and signs of autonomic dysfunction, such as dry
mouth, impotence, constipation, and orthostatic hypotension. In contrast to
Myasthenia Gravis where strength improves with rest, patients with LES show
improved strength with muscle activity. While bulbar involvement and respiratory
compromise are less common than with Myasthenia Gravis, they do sometimes occur
(respiratory weakness is a late finding).
In the case of malignancy, treatment begins with (1) cancer therapy. Other
interventions include: (2) plasma exchange, (3) intravenous immune globulin therapy,
(4) the administration of prednisone or azathioprine for immunosuppression, (5)
increasing the release of acetylcholine with 3,4-diaminopyridine (should be continued
up to the time of surgery), or (6) decreasing the degradation of acetylcholine with
pyridostigmine (a cholinesterase inhibitor)

Question 18

Pt serum sodium is 129 and they have a lung mass: what do you think?

Answer 18

could be the
result of SIADH, a paraneoplastic syndrome associated with malignancy, or it could
possibly be the result of diuretic administration if this type of medication were being
used to treat his hypertension (while loop diuretics can lead to hyponatremia, they are
less likely to do so than thiazide diuretics).

Question 19

How do you feel about low sodium levels and surgery?

Answer 19

Since proceeding with surgery in the presence of a sodium
concentration under 130 mEq/L places the patient at risk of developing significant
cerebral edema, I would prefer to delay the surgery until the cause of the
hyponatremia could be determined, and the sodium level corrected. However, I would
discuss the pros and cons of delaying the case with the surgeon since even a short
delay may be unacceptable if an urgent diagnosis is needed.

Question 20

Carotid artery disease and mediastinoscopy

Answer 20

His carotid artery disease does concern me because of the risk of
inadequate cerebral perfusion secondary to a hypertension-induced rightward shifting
of the cerebral autoregulation curve and/or a surgically-induced decrease in cerebral
blood flow secondary to compression of the innominate artery. A patient with carotid
artery disease may be unable to compensate adequately for these insults resulting in
neurologic damage. In fact, because of the risk of innominate artery compression,
mediastinoscopy is relatively contraindicated in a patient with cerebrovascular
disease.

Question 21

Contraindications to mediastinoscopy, and if you absolutely have to go-then what are you doing:

Answer 21

If I have to go: Therefore, if avoiding mediastinoscopy were not an option, I would monitor the
patient for signs of innominate artery compression (i.e. right radial arterial line or
right upper extremity pulse oximeter tracing), attempt to optimize his blood pressure,
and avoid any additional factors that could compromise cerebral perfusion such as
hypotension, additional obstruction of cerebral venous drainage, hypercapnia, and
acidosis.

Contraindications:
-Previous mediastinoscopy is a strong contraindication to mediastinoscopy.
o Relative contraindications to mediastinoscopy include: (1) severe tracheal
deviation, (2) cerebrovascular disease, (3) severe cervical spine disease with
limited neck extension, ( 4) previous chest radiotherapy, and (5) thoracic aortic
aneurysm.

Question 22

Why does HTN irritate you so much when it comes to cases?

Answer 22

I am concerned about his blood pressure because poorly controlled
hypertensive patients are more prone to intraoperative-end-organ ischemia (i.e.
myocardial infarction and stroke), arrhythmias, congestive heart failure, hypotension,
and hypertension.

Question 23

A reasonable approach to HTN:

Answer 23

A reasonable approach to the management of preoperative hypertension for an
elective procedure is to delay elective surgery for at least 6-8 weeks to optimize
the blood pressure of any patient who: 1) has SBP readings> 180 mmHg or DBP
readings > 110 mmHg, 2) has stage 1 or stage 2 hypertension with concomitant
end-organ damage, and/or 3) is undergoing cardiac surgery, carotid surgery, or
pheochromocytoma resection. However, the decision to delay any case (and the
length of that delay) must weigh the risks of blood pressure optimization against
the risk .of surgical delay.

Question 24

Medical causes of HTN and signs of end organ damage: GO!

Answer 24

Causes of hypertension include: (1) chronic kidney disease, (2) renovascular
disease, (3) chronic steroid therapy (Cushing’s syndrome), (4) sleep apnea, (5)
drugs (i.e. cocaine, amphetamines, certain dietary supplements, oral
contraceptives), (6) alcohol abuse, (7) obesity/metabolic syndrome, (8) thyroid or
parathyroid disease, (9) pheochromocytoma, and (10) coarctation of the aorta.
• Signs of end-organ damage include: (1) left ventricular hypertrophy, (2) angina,
(3) myocardial infarction, ( 4) congestive heart failure, ( 5) coronary artery disease,
(6) stroke, (7) transient ischemic attack, (8) chronic kidney disease, (9)
retinopathy, and (10) peripheral artery disease.

Question 25

You discover the patient is taking an ACE inhibitor. Would you continue this medication throughout the perioperative period?

Answer 25

lJBP Answe:r: Given the fact that his blood pressure is already poorly controlled, I would continue his ACE inhibitor recognizing that this does increase the risk of intraoperative hypotension. Therefore, I would be prepared to quickly identify and treat any hypotension in order to maintain adequate cerebral perfusion pressure in this patient with carotid artery disease.

Question 26

Mediastinoscopy and monitoring:

Answer 26

I would place a 5-lead ECG and a left radial arterial line to facilitate the rapid identification and treatment of any cardiac ischemia and/or significant hypotension. Moreover, I would monitor the tracing of a pulse oximeter placed on his right upper extremity to quickly identify any compression of the innominate artery, recognizing that this is a known complication of mediastinoscopy. --Some form of monitoring of the right radial pulse is mandatory during mediastinoscopy due to the risk of innominate artery compression with subsequent cerebral ischemia. Methods that may be employed include: (1) placement of a right radial arterial line, (2) monitoring the plethysmographic tracing of a pulse oximeter on the right hand, or (3) continuous palpation of the right carotid or right radial pulse.

Question 27

How do you know if patient is having SVC syndrome?

Answer 27

This patient's worsening cough, shortness of breath, jugular venous distention, and opacification of upper extremity collateral veins on CT are all consistent with superior vena cava syndrome. A defmitive diagnosis could be established by venography. Other signs and symptoms that may be present in a patient with superior vena cava obstruction would include: (1) headache; (2) facial, neck, and upper limb edema; (3) chest pain, ( 4) dysphagia, (7) lightheadedness, (8) orthopnea, (9) hoarseness, (10) nasal stuffiness, (11) nausea, (12) pleural effusions, (13) papilledema, (14) visual disturbances, (15) mental confusion, and (16) facial cyanosis.

Question 28

Pt does have SVC syndrome, does this concern you? And what should you do?

Answer 28

(1) complicated airway management secondary to airway edema, (2) unreliable drug delivery through intravenous lines in the upper extremities (primarily in the setting of surgical damage to the vessel), (3) the potential for massive hemorrhage secondary to damage to any one of several major blood vessels in the surgical field (i.e. azygos vein, innominate artery, aorta, superior vena cava, and pulmonary artery), ( 4) compromised cerebral perfusion in this patient with carotid artery disease (impaired drainage of cerebral veins -7 increased cerebral venous pressure -7 increased ICP and impaired cerebral perfusion), and (5) an increased risk of postoperative respiratory complications, such as acute laryngospasm, bronchospasm, and airway obstruction -(1) prepare for difficult airway management and minimize manipulation of the airway as much as possible to prevent exacerbating any airway edema (especially if there were concomitant tracheal compression, a.k.a . superior mediastinal syndrome); (2) place two large-bore intravenous catheters, with at least one of the lines inserted in his lower extremity (providing reliable delivery of drugs, fluids, and blood products even in the setting of a surgically damaged superior vena cava; (3) type and cross match blood to prepare for possible massive hemorrhage; (4) maintain the patient in the head up position to facilitate venous drainage and avoid increased airway edema and intracranial pressures; (5) employ cautious fluid management, recognizing that too much fluid would lead to venous engorgement and edema, while too little fluid would lead to decreased pre load; ( 6) avoid coughing and bucking during emergence, recognizing that either could lead to exacerbated venous congestion and acute airway obstruction; and (7) maintain endotracheal tube placement and mechanical ventilation during the immediate post-operative period (unless the obstruction of the superior vena cava had been relieved).

Question 29

General or local for mediastinoscopy: Benefits of general:

Answer 29

Given the risk of increased airway edema and acute airway obstruction associated with superior vena cava syndrome, I would prefer to avoid instrumentation of the airway and perform the procedure under local anesthesia (this is possible for anterior mediastinoscopy, but not for cervical mediastinoscopy, (which is the most common approach). Moreover, this technique would avoid exposing this patient with cerebrovascular disease and increased risk for hypotension (secondary to poorly controlled hypertension, possible autonomic neuropathy, SVC syndrome, and ACE inhibitor administration) to the hemodynamic instability associated with laryngoscopy, induction, and general anesthesia; allow more reliable monitoring of neurologic function (i.e. an awake patient); and avoid the increased risk of aspiration associated with general anesthesia in this patient with possible autonomic neuropathy (LES and malignancy are associated with autonomic neuropathy; this patient's symptoms of constipation and orthostatic hypotension are consistent with this condition).

Question 30

Benefits of local anesthesia for mediastinoscopy:

Answer 30

However, there are several advantages to performing the procedure under general anesthesia with controlled positive-pressure ventilation, including: (1) increased flexibility for surgical manipulations, (2) decreased risk of surgical trauma resulting from sudden patient movement, (3) reduced risk of air embolism (the tip of the mediastinoscope is intrathoracic, placing the patient at risk for venous air embolism in the presence of venous bleeding and the negative intrathoracic pressure created during spontaneous ventilation), ( 4) improved conditions for the management of a significant complication like massive hemorrhage, and (5) reduced risk of coughing during the procedure (coughing during the procure can lead to venous engorgement with subsequent increased risk of surgical damage to local vessels).

Question 31

You giving depolarizing or non depolarizing agents to patients with LES? so give what?

Answer 31

Not only are patients with LES extremely sensitive to both depolarizers and nondepolarizers, but also the reversal of neuromuscular blockade is less effective-so give Remi I guess

Question 32

The surgeon insists on muscle relaxation. Shortly after induction, he is advancing the mediastinoscope when the right radial arterial line indicates a blood pressure drop from 145/90 mmHg to 90/65 mmHg. What do you think is going on? What are you going to do?

Answer 32

Likely innominate compression, hypotension due to anesthesia, autonomic neuropathy, tension ptx --In managing his hypotension, I would: (1) check the arterial line for accuracy; (2) check the blood pressure in the left arm, recognizing that a difference in pressures between the arms may indicate innominate artery compression; (3) ask the surgeon to rule out massive hemorrhage, innominate artery compression, and compression of other vascular structures; ( 4) ensure adequate ventilation; ( 5) look at my ECG tracing to rule out arrhythmia or cardiac ischemia; ( 6) auscultate the chest for bilateral breath sounds; (7) reduce my volatile agent; (8) quickly review all administered drugs; (9) administer fluids and vasopressors as indicated; and (10) temporarily place the patient in trendelenburg position to improve preload, recognizing that this could exacerbate the venous congestion associated with SVC syndrome.

Question 33

Nitrous and Mediastinoscopy:

Answer 33

I would not use it for this case due to the risk of expanding an unrecognized pneumothorax -Pneumothorax may occur when the pleural space is unintentionally entered during the procedure. It is because of this known complication that a chest x-ray is required prior to discharge for patients who have undergone mediastinoscopy.

Question 34

Surgeon (during mediastinoscopy) says there is bleeding: now wyd? Will you induce hypotension?

Answer 34

In the case of hemorrhage, I would: (1) ask the surgeon discontinue the surgery and pack the wound with surgical sponges, (2) call for help, (3) ensure adequate large-bore access in the lower extremities (if the hemorrhage is resulting from a tear in the superior vena cava, medications and fluids utilized in resuscitation would be lost in the mediastinum), ( 4) initiate resuscitation with fluids and vasopressors, (5) have cross-matched blood brought to the operating room, (6) prepare for massive blood transfusion by notifying the blood bank and ensuring the presence of blood warmers, cell saver, and rapid infusers, (7) place a double-lumen tube or bronchial blocker if the surgeon believes a thoracotomy may be required, (8) place a precordial Doppler, recognizing that there is an increased risk for venous air embolism in the setting of vascular injury, and (9) convert to sternotomy or thoracotomy as necessary. While deliberate hypotension and reverse-trendelenburg positioning are sometimes used to reduce bleeding and improve surgical visualization in this setting, I would not employ these techniques in this case due to the patient's symptomatic cerebrovascular disease, potentially reduced preload (SVC syndrome), poorly controlled hypertension (rightward-shifting of the cerebral autoregulation curve), and possible autonomic neuropathy (may be unable to compensate for a change from supine to a head-up position).

Question 35

With the typical mediastinoscopy: you extubating (provided no issues)?

Answer 35

Patients can usually be extubated following mediastinoscopy and discharged on the same day after a chest x-ray is performed to rule out pneumothorax.

Question 36

Mediastinoscopy pt: Postoperatively, he is extubated in the ICU and immediately becomes dyspneic. What do you think may be going on? What can you do if SVC syndrome worsens during a case?

Answer 36

UBP Answer: His stridor could be caused by: (1) laryngospasm, occurring secondary to superior vena cava syndrome or recent extubation. It could also be a result of: (2) an expanding hematoma, (3) significant airway edema (secondary to superior vena cava syndrome and/or aggressive fluid resuscitation), (4) recurrent laryngeal nerve injury (resulting in obstruction due to unopposed tension of the vocal cords by the cricothyroid muscle), ( 5) incomplete muscle relaxant reversal (patients with LES are more sensitive to nondepolarizers and reversal of neuromuscular blockade is often less effective), ( 6) an impaired ventilatory response to hypoxia and hypercapnia secondary to autonomic neuropathy (these patients are more susceptible to drug- induced respiratory depression), or (7) an allergic reaction. Clinical Note: • If worsening SVC obstruction is suspected during a case, steroids and diuretics may help.

Question 37

You visualize the vocal cords and note that they are not moving and are in the midline position. What will you do?

Answer 37

UBP Answer: This is consistent with bilateral partial recurrent laryngeal nerve injury (injury affecting only the abductor fibers of the nerve), a known complication associated with mediastinoscopy. If the airway obstruction were resulting in inadequate ventilation, I would place an endotracheal tube and provide oxygen, positive pressure ventilation, and sedation as necessary. I would then alert the surgeon and consult an otolaryngologist.

Question 38

Complications associated with mediastinoscopy:

Answer 38

Complications associated with mediastinoscopy include: (1) tracheal compression or laceration, (2) cerebrovascular events (secondary to innominate artery compression), (3) right upper limb ischemia (also secondary to innominate artery compression), (4) compression of the aorta leading to reflex bradycardia, (5) pneumothorax, (6) recurrent laryngeal or phrenic nerve injury, (7) venous air embolism, (8) mediastinal hemorrhage, and (9) esophageal tear.

Question 39

Pt had mediastinal surgery and had a rupture of a vessel intro-You go by the ICU to see the patient later that evening and are just getting ready to leave when his pressure acutely drops from 140/88 mmHg to 75/38 mmHg. What are you going to do?

Answer 39

I would (1) auscultate the chest, (2) check the ventilator settings, (3) ensure adequate oxygenation, ( 4) place the patient in trendelenburg position, and ( 5) administer fluids, vasoconstrictors, and inotropes as indicated. Since the patient suffered a tear of the superior vena cava during the procedure, my differential would include massive hemorrhage or cardiac tamponade. While attempting to identify the cause of his hemodynamic instability, I would (6) ensure adequate intravenous access, (7) order an echocardiogram, (8) call for a surgeon, and (9) consider placing a central

Question 40

On exam you hear muffled heart sounds and notice jugular venous distension. The blood pressure is now 52/31 mmHg. What are you going to do?

Answer 40

While the jugular venous distention was already present due to the obstruction of his superior vena cave, the combination of this finding along with muffled heart sounds is consistent with cardiac tamponade and, if the diagnosis cannot be quickly confirmed by echo, should be treated as such. Since the patient is intubated and sedated, the chest could be reopened in the intensive care unit, waiting to provide additional anesthesia until the pericardia! constriction is relieved and the patient is more stable. If the surgeon is not available, a pericardiocentesis should be performed to at least temporarily relieve the increasing pericardia! pressure, improve diastolic filling, and improve cardiac output. Once the chest is opened, the tamponade is relieved, and the patient is stable, I would administer anesthetic agents that preserve sympathetic tone (e.g. ketamine) while definitive surgical repair occurs.