Transcript Advanced Life Support Algorithm

Mediastinoscopy
Nadeen mohamed mamdouh Habib
Objectives
• Indications .
• The nature of the procedure.
• Important anesthetic
management principles.
• Anesthetic technique.
• Complications.
Indications
Mediastinoscopy is commonly performed
before thoracotomy to establish the
diagnosis or to determine the resectability of
lung carcinoma.
The nature of the procedure
After a suprasternal notch incision
A tunnel is created by blunt dissection along
the anterior and lateral walls of the trachea into
the mediastinum down to the subcarinal area,
for direct inspection and biopsy of superior
mediastinal lymph nodes.
The mediastinoscope passes anterior to
the trachea but behind the aortic arch
Schematic diagram showing placement of a
mediastinoscope into the superior mediastinum
Lt recurrent
laryngeal nerve
Right common
carotid
Left common
carotid
Right subclavian
Left subclavian
Innominate artery
Aortic arch
Superior vena cava
Anatomic structures that can be
compressed by the mediastinoscope are:
• 1)Thoracic aorta: (rupture, reflex bradycardia)
• 2) Innominate artery: (decreased right carotid
blood flow; can cause cerebrovascular
symptoms, and decreased right subclavian
blood flow; can cause loss of the right radial
pulse).
• 3) Trachea: (stimulus to cough, inability to
ventilate)
• 4) Vena cava: (risk of hemorrhage with superior
vena cava syndrome)
Relative contraindication to mediastinoscopy
include:
Superior vena cava syndrome
Severe tracheal deviation
Cerebrovascular disease
Thoracic aortic aneurysm
Special anesthetic considerations:
• In addition to the routine
preanesthetic evaluation, look for
signs and symptoms of:
• 1) OBSTRUCTION OR DISTORTION OF
THE UPPER AIRWAY
• 2) OBSTRUCTION OF THE SUPERIOR
VENA CAVA
• 3) IMPAIRED CEREBRAL CIRCULATION
Anesthetic technique:
General anesthesia with muscle relaxation
and positive pressure ventilation (facilitates
dissection and management of complications, minimizes
air embolism)
During mediastinoscopy the
anesthesiologist attention is primarily
focused on management of major
complications which are:
• Hemorrhage and hypovolemia
• Compression of the great vessels
• Pneumothorax
• Recurrent laryngeal nerve injury
Significant (occasionally) massive
hemorrhage: the most frequent
major complication it requires
immediate thoracotomy
The anesthesiologist should:
• 1) Rapidly begin volume replacement through one or
more large-bore intravenous cannulas that have been
placed before induction of general anesthesia.
• 2) Send for blood that was reserved for the patient
preoperatively.
• 3) Support the circulation pharmacologically until
volume replacement is achieved
• 4) Ensure adequate oxygenation and ventilation.
• 5) Administer atropine for reflex bradycardia from
aortic compression.
• 6) Reduce or discontinue the dose of all anesthetic
drugs until normovolemia is established.
• 7) If hemorrhage originates from tear in the superior
vena cava, a peripheral line should be rapidly placed in
the lower extremity.
Compression of the great vessels:
A) The vessel most commonly
compressed is the innominate
artery: diminished blood flow to the
right subclavian and right carotid
arteries.
(This phenomenon of special significance
in payients with preexisting
compromised cerebral circulation)
The vessel most commonly
compressed is the innominate
artery: (management)
• 1)Require monitoring of the right upper
extremity blood pressure; via a right radial
arterial line, or alternatively, a pulse oximeter
probe on the right hand that signals
diminution of the blood flow by changes in
the signal strength.
• 2) Any decrease in the right radial artery
pressure requires repositioning of the
mediastinoscope.
• B) Mechanical stimulation of the
aorta can cause arrhythmias, and
compression of the aorta can
cause reflex bradycardia.
Sudden changes in the pulse or the blood
pressure during mediastinoscopy, may
empirically be treated by repositioning
of the mediastinoscope.
Atropine is given for persistent
bradycardia.
Pneumothorax (usually seen
postoperatively)
However patients should be monitored for signs
of intraoperative pneumothorax:
• Increased peak airway pressure
• Tracheal shift
• Distant breath sounds
• Hypotension
• Cyanosis
That requires immediate decompression
• Recurrent laryngeal nerve injury:
• The vocal cords should be visualized
while the patient is spontaneously
breathing (at the time of extubation).
• Postoperative laryngeal obstruction is
a problem if the vocal cords are not
moving or in the midline.
THANK YOU
NADEEN MOHAMED MAMDOUH HABIB